Commit 916e3e5f26 ("KVM: SVM: Do not use user return MSR support for
virtualized TSC_AUX") introduced a local variable used for the rdmsr()
function for the high 32-bits of the MSR value. This variable is not used
after being set and triggers a warning or error, when treating warnings
as errors, when the unused-but-set-variable flag is set. Mark this
variable as __maybe_unused to fix this.
Fixes: 916e3e5f26 ("KVM: SVM: Do not use user return MSR support for virtualized TSC_AUX")
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Message-Id: <0da9874b6e9fcbaaa5edeb345d7e2a7c859fc818.1696271334.git.thomas.lendacky@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
svm_leave_nested() similar to a nested VM exit, get the vCPU out of nested
mode and thus should end the local inhibition of AVIC on this vCPU.
Failure to do so, can lead to hangs on guest reboot.
Raise the KVM_REQ_APICV_UPDATE request to refresh the AVIC state of the
current vCPU in this case.
Fixes: f44509f849 ("KVM: x86: SVM: allow AVIC to co-exist with a nested guest running")
Cc: stable@vger.kernel.org
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20230928173354.217464-4-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
In later revisions of AMD's APM, there is a new 'incomplete IPI' exit code:
"Invalid IPI Vector - The vector for the specified IPI was set to an
illegal value (VEC < 16)"
Note that tests on Zen2 machine show that this VM exit doesn't happen and
instead AVIC just does nothing.
Add support for this exit code by doing nothing, instead of filling
the kernel log with errors.
Also replace an unthrottled 'pr_err()' if another unknown incomplete
IPI exit happens with vcpu_unimpl()
(e.g in case AMD adds yet another 'Invalid IPI' exit reason)
Cc: <stable@vger.kernel.org>
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20230928173354.217464-3-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The following problem exists since x2avic was enabled in the KVM:
svm_set_x2apic_msr_interception is called to enable the interception of
the x2apic msrs.
In particular it is called at the moment the guest resets its apic.
Assuming that the guest's apic was in x2apic mode, the reset will bring
it back to the xapic mode.
The svm_set_x2apic_msr_interception however has an erroneous check for
'!apic_x2apic_mode()' which prevents it from doing anything in this case.
As a result of this, all x2apic msrs are left unintercepted, and that
exposes the bare metal x2apic (if enabled) to the guest.
Oops.
Remove the erroneous '!apic_x2apic_mode()' check to fix that.
This fixes CVE-2023-5090
Fixes: 4d1d7942e3 ("KVM: SVM: Introduce logic to (de)activate x2AVIC mode")
Cc: stable@vger.kernel.org
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Reviewed-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Tested-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20230928173354.217464-2-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Mask off xfeatures that aren't exposed to the guest only when saving guest
state via KVM_GET_XSAVE{2} instead of modifying user_xfeatures directly.
Preserving the maximal set of xfeatures in user_xfeatures restores KVM's
ABI for KVM_SET_XSAVE, which prior to commit ad856280dd ("x86/kvm/fpu:
Limit guest user_xfeatures to supported bits of XCR0") allowed userspace
to load xfeatures that are supported by the host, irrespective of what
xfeatures are exposed to the guest.
There is no known use case where userspace *intentionally* loads xfeatures
that aren't exposed to the guest, but the bug fixed by commit ad856280dd
was specifically that KVM_GET_SAVE{2} would save xfeatures that weren't
exposed to the guest, e.g. would lead to userspace unintentionally loading
guest-unsupported xfeatures when live migrating a VM.
Restricting KVM_SET_XSAVE to guest-supported xfeatures is especially
problematic for QEMU-based setups, as QEMU has a bug where instead of
terminating the VM if KVM_SET_XSAVE fails, QEMU instead simply stops
loading guest state, i.e. resumes the guest after live migration with
incomplete guest state, and ultimately results in guest data corruption.
Note, letting userspace restore all host-supported xfeatures does not fix
setups where a VM is migrated from a host *without* commit ad856280dd,
to a target with a subset of host-supported xfeatures. However there is
no way to safely address that scenario, e.g. KVM could silently drop the
unsupported features, but that would be a clear violation of KVM's ABI and
so would require userspace to opt-in, at which point userspace could
simply be updated to sanitize the to-be-loaded XSAVE state.
Reported-by: Tyler Stachecki <stachecki.tyler@gmail.com>
Closes: https://lore.kernel.org/all/20230914010003.358162-1-tstachecki@bloomberg.net
Fixes: ad856280dd ("x86/kvm/fpu: Limit guest user_xfeatures to supported bits of XCR0")
Cc: stable@vger.kernel.org
Cc: Leonardo Bras <leobras@redhat.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Message-Id: <20230928001956.924301-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Plumb an xfeatures mask into __copy_xstate_to_uabi_buf() so that KVM can
constrain which xfeatures are saved into the userspace buffer without
having to modify the user_xfeatures field in KVM's guest_fpu state.
KVM's ABI for KVM_GET_XSAVE{2} is that features that are not exposed to
guest must not show up in the effective xstate_bv field of the buffer.
Saving only the guest-supported xfeatures allows userspace to load the
saved state on a different host with a fewer xfeatures, so long as the
target host supports the xfeatures that are exposed to the guest.
KVM currently sets user_xfeatures directly to restrict KVM_GET_XSAVE{2} to
the set of guest-supported xfeatures, but doing so broke KVM's historical
ABI for KVM_SET_XSAVE, which allows userspace to load any xfeatures that
are supported by the *host*.
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20230928001956.924301-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Provide common prototypes for arch_register_cpu() and
arch_unregister_cpu(). These are called by acpi_processor.c, with weak
versions, so the prototype for this is already set. It is generally not
necessary for function prototypes to be conditional on preprocessor macros.
Some architectures (e.g. Loongarch) are missing the prototype for this, and
rather than add it to Loongarch's asm/cpu.h, do the job once for everyone.
Since this covers everyone, remove the now unnecessary prototypes in
asm/cpu.h, and therefore remove the 'static' from one of ia64's
arch_register_cpu() definitions.
[ tglx: Bring back the ia64 part and remove the ACPI prototypes ]
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/E1qkoRr-0088Q8-Da@rmk-PC.armlinux.org.uk
Fix erratum #1485 on Zen4 parts where running with STIBP disabled can
cause an #UD exception. The performance impact of the fix is negligible.
Reported-by: René Rebe <rene@exactcode.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Tested-by: René Rebe <rene@exactcode.de>
Cc: <stable@kernel.org>
Link: https://lore.kernel.org/r/D99589F4-BC5D-430B-87B2-72C20370CF57@exactcode.com
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Merge tag 'hyperv-fixes-signed-20231009' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux
Pull hyperv fixes from Wei Liu:
- fixes for Hyper-V VTL code (Saurabh Sengar and Olaf Hering)
- fix hv_kvp_daemon to support keyfile based connection profile
(Shradha Gupta)
* tag 'hyperv-fixes-signed-20231009' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux:
hv/hv_kvp_daemon:Support for keyfile based connection profile
hyperv: reduce size of ms_hyperv_info
x86/hyperv: Add common print prefix "Hyper-V" in hv_init
x86/hyperv: Remove hv_vtl_early_init initcall
x86/hyperv: Restrict get_vtl to only VTL platforms
Check the IO permission bitmap (if present) before emulating IOIO #VC
exceptions for user-space. These permissions are checked by hardware
already before the #VC is raised, but due to the VC-handler decoding
race it needs to be checked again in software.
Fixes: 25189d08e5 ("x86/sev-es: Add support for handling IOIO exceptions")
Reported-by: Tom Dohrmann <erbse.13@gmx.de>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Tested-by: Tom Dohrmann <erbse.13@gmx.de>
Cc: <stable@kernel.org>
A virt scenario can be constructed where MMIO memory can be user memory.
When that happens, a race condition opens between when the hardware
raises the #VC and when the #VC handler gets to emulate the instruction.
If the MOVS is replaced with a MOVS accessing kernel memory in that
small race window, then write to kernel memory happens as the access
checks are not done at emulation time.
Disable MMIO emulation in user mode temporarily until a sensible use
case appears and justifies properly handling the race window.
Fixes: 0118b604c2 ("x86/sev-es: Handle MMIO String Instructions")
Reported-by: Tom Dohrmann <erbse.13@gmx.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Tested-by: Tom Dohrmann <erbse.13@gmx.de>
Cc: <stable@kernel.org>
We found that a panic can occur when a vsyscall is made while LBR sampling
is active. If the vsyscall is interrupted (NMI) for perf sampling, this
call sequence can occur (most recent at top):
__insn_get_emulate_prefix()
insn_get_emulate_prefix()
insn_get_prefixes()
insn_get_opcode()
decode_branch_type()
get_branch_type()
intel_pmu_lbr_filter()
intel_pmu_handle_irq()
perf_event_nmi_handler()
Within __insn_get_emulate_prefix() at frame 0, a macro is called:
peek_nbyte_next(insn_byte_t, insn, i)
Within this macro, this dereference occurs:
(insn)->next_byte
Inspecting registers at this point, the value of the next_byte field is the
address of the vsyscall made, for example the location of the vsyscall
version of gettimeofday() at 0xffffffffff600000. The access to an address
in the vsyscall region will trigger an oops due to an unhandled page fault.
To fix the bug, filtering for vsyscalls can be done when
determining the branch type. This patch will return
a "none" branch if a kernel address if found to lie in the
vsyscall region.
Suggested-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: JP Kobryn <inwardvessel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: stable@vger.kernel.org
The kernel test robot reported kernel-doc warnings here:
monitor.c:34: warning: Cannot understand * @rmid_free_lru A least recently used list of free RMIDs on line 34 - I thought it was a doc line
monitor.c:41: warning: Cannot understand * @rmid_limbo_count count of currently unused but (potentially) on line 41 - I thought it was a doc line
monitor.c:50: warning: Cannot understand * @rmid_entry - The entry in the limbo and free lists. on line 50 - I thought it was a doc line
We don't have a syntax for documenting individual data items via
kernel-doc, so remove the "/**" kernel-doc markers and add a hyphen
for consistency.
Fixes: 6a445edce6 ("x86/intel_rdt/cqm: Add RDT monitoring initialization")
Fixes: 24247aeeab ("x86/intel_rdt/cqm: Improve limbo list processing")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20231006235132.16227-1-rdunlap@infradead.org
In snp_accept_memory(), the npages variables value is calculated from
phys_addr_t variables but is an unsigned int. A very large range passed
into snp_accept_memory() could lead to truncating npages to zero. This
doesn't happen at the moment but let's be prepared.
Fixes: 6c32117963 ("x86/sev: Add SNP-specific unaccepted memory support")
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: <stable@kernel.org>
Link: https://lore.kernel.org/r/6d511c25576494f682063c9fb6c705b526a3757e.1687441505.git.thomas.lendacky@amd.com
SNP retrieves the majority of CPUID information from the SNP CPUID page.
But there are times when that information needs to be supplemented by the
hypervisor, for example, obtaining the initial APIC ID of the vCPU from
leaf 1.
The current implementation uses the MSR protocol to retrieve the data from
the hypervisor, even when a GHCB exists. The problem arises when an NMI
arrives on return from the VMGEXIT. The NMI will be immediately serviced
and may generate a #VC requiring communication with the hypervisor.
Since a GHCB exists in this case, it will be used. As part of using the
GHCB, the #VC handler will write the GHCB physical address into the GHCB
MSR and the #VC will be handled.
When the NMI completes, processing resumes at the site of the VMGEXIT
which is expecting to read the GHCB MSR and find a CPUID MSR protocol
response. Since the NMI handling overwrote the GHCB MSR response, the
guest will see an invalid reply from the hypervisor and self-terminate.
Fix this problem by using the GHCB when it is available. Any NMI
received is properly handled because the GHCB contents are copied into
a backup page and restored on NMI exit, thus preserving the active GHCB
request or result.
[ bp: Touchups. ]
Fixes: ee0bfa08a3 ("x86/compressed/64: Add support for SEV-SNP CPUID table in #VC handlers")
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: <stable@kernel.org>
Link: https://lore.kernel.org/r/a5856fa1ebe3879de91a8f6298b6bbd901c61881.1690578565.git.thomas.lendacky@amd.com
to issues which were introduced after 6.5.
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Merge tag 'mm-hotfixes-stable-2023-10-01-08-34' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull misc fixes from Andrew Morton:
"Fourteen hotfixes, eleven of which are cc:stable. The remainder
pertain to issues which were introduced after 6.5"
* tag 'mm-hotfixes-stable-2023-10-01-08-34' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
Crash: add lock to serialize crash hotplug handling
selftests/mm: fix awk usage in charge_reserved_hugetlb.sh and hugetlb_reparenting_test.sh that may cause error
mm: mempolicy: keep VMA walk if both MPOL_MF_STRICT and MPOL_MF_MOVE are specified
mm/damon/vaddr-test: fix memory leak in damon_do_test_apply_three_regions()
mm, memcg: reconsider kmem.limit_in_bytes deprecation
mm: zswap: fix potential memory corruption on duplicate store
arm64: hugetlb: fix set_huge_pte_at() to work with all swap entries
mm: hugetlb: add huge page size param to set_huge_pte_at()
maple_tree: add MAS_UNDERFLOW and MAS_OVERFLOW states
maple_tree: add mas_is_active() to detect in-tree walks
nilfs2: fix potential use after free in nilfs_gccache_submit_read_data()
mm: abstract moving to the next PFN
mm: report success more often from filemap_map_folio_range()
fs: binfmt_elf_efpic: fix personality for ELF-FDPIC
AMD-derived Hygon processors, and fix a SGX kernel crash in the
page fault handler that can trigger when ksgxd races to reclaim
the SECS special page, by making the SECS page unswappable.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'x86-urgent-2023-10-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Ingo Molnar:
"Misc fixes: a kerneldoc build warning fix, add SRSO mitigation for
AMD-derived Hygon processors, and fix a SGX kernel crash in the page
fault handler that can trigger when ksgxd races to reclaim the SECS
special page, by making the SECS page unswappable"
* tag 'x86-urgent-2023-10-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/sgx: Resolves SECS reclaim vs. page fault for EAUG race
x86/srso: Add SRSO mitigation for Hygon processors
x86/kgdb: Fix a kerneldoc warning when build with W=1
and fix kexec kernel PMI handlers on AMD systems that get loaded
on older kernels that have an unexpected register state.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'perf-urgent-2023-10-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf event fixes from Ingo Molnar:
"Misc fixes: work around an AMD microcode bug on certain models, and
fix kexec kernel PMI handlers on AMD systems that get loaded on older
kernels that have an unexpected register state"
* tag 'perf-urgent-2023-10-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf/x86/amd: Do not WARN() on every IRQ
perf/x86/amd/core: Fix overflow reset on hotplug
In order to fix the L1TF vulnerability, x86 can invert the PTE bits for
PROT_NONE VMAs, which means we cannot move from one PTE to the next by
adding 1 to the PFN field of the PTE. This results in the BUG reported at
[1].
Abstract advancing the PTE to the next PFN through a pte_next_pfn()
function/macro.
Link: https://lkml.kernel.org/r/20230920040958.866520-1-willy@infradead.org
Fixes: bcc6cc8325 ("mm: add default definition of set_ptes()")
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reported-by: syzbot+55cc72f8cc3a549119df@syzkaller.appspotmail.com
Closes: https://lkml.kernel.org/r/000000000000d099fa0604f03351@google.com [1]
Reviewed-by: Yin Fengwei <fengwei.yin@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The SGX EPC reclaimer (ksgxd) may reclaim the SECS EPC page for an
enclave and set secs.epc_page to NULL. The SECS page is used for EAUG
and ELDU in the SGX page fault handler. However, the NULL check for
secs.epc_page is only done for ELDU, not EAUG before being used.
Fix this by doing the same NULL check and reloading of the SECS page as
needed for both EAUG and ELDU.
The SECS page holds global enclave metadata. It can only be reclaimed
when there are no other enclave pages remaining. At that point,
virtually nothing can be done with the enclave until the SECS page is
paged back in.
An enclave can not run nor generate page faults without a resident SECS
page. But it is still possible for a #PF for a non-SECS page to race
with paging out the SECS page: when the last resident non-SECS page A
triggers a #PF in a non-resident page B, and then page A and the SECS
both are paged out before the #PF on B is handled.
Hitting this bug requires that race triggered with a #PF for EAUG.
Following is a trace when it happens.
BUG: kernel NULL pointer dereference, address: 0000000000000000
RIP: 0010:sgx_encl_eaug_page+0xc7/0x210
Call Trace:
? __kmem_cache_alloc_node+0x16a/0x440
? xa_load+0x6e/0xa0
sgx_vma_fault+0x119/0x230
__do_fault+0x36/0x140
do_fault+0x12f/0x400
__handle_mm_fault+0x728/0x1110
handle_mm_fault+0x105/0x310
do_user_addr_fault+0x1ee/0x750
? __this_cpu_preempt_check+0x13/0x20
exc_page_fault+0x76/0x180
asm_exc_page_fault+0x27/0x30
Fixes: 5a90d2c3f5 ("x86/sgx: Support adding of pages to an initialized enclave")
Signed-off-by: Haitao Huang <haitao.huang@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Reviewed-by: Kai Huang <kai.huang@intel.com>
Acked-by: Reinette Chatre <reinette.chatre@intel.com>
Cc:stable@vger.kernel.org
Link: https://lore.kernel.org/all/20230728051024.33063-1-haitao.huang%40linux.intel.com
When the irq_work callback, kvm_pmi_trigger_fn(), is invoked during a
VM-exit that also invokes __kvm_perf_overflow() as a result of
instruction emulation, kvm_pmu_deliver_pmi() will be called twice
before the next VM-entry.
Calling kvm_pmu_deliver_pmi() twice is unlikely to be problematic now that
KVM sets the LVTPC mask bit when delivering a PMI. But using IRQ work to
trigger the PMI is still broken, albeit very theoretically.
E.g. if the self-IPI to trigger IRQ work is be delayed long enough for the
vCPU to be migrated to a different pCPU, then it's possible for
kvm_pmi_trigger_fn() to race with the kvm_pmu_deliver_pmi() from
KVM_REQ_PMI and still generate two PMIs.
KVM could set the mask bit using an atomic operation, but that'd just be
piling on unnecessary code to workaround what is effectively a hack. The
*only* reason KVM uses IRQ work is to ensure the PMI is treated as a wake
event, e.g. if the vCPU just executed HLT.
Remove the irq_work callback for synthesizing a PMI, and all of the
logic for invoking it. Instead, to prevent a vcpu from leaving C0 with
a PMI pending, add a check for KVM_REQ_PMI to kvm_vcpu_has_events().
Fixes: 9cd803d496 ("KVM: x86: Update vPMCs when retiring instructions")
Signed-off-by: Jim Mattson <jmattson@google.com>
Tested-by: Mingwei Zhang <mizhang@google.com>
Tested-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Signed-off-by: Mingwei Zhang <mizhang@google.com>
Link: https://lore.kernel.org/r/20230925173448.3518223-2-mizhang@google.com
[sean: massage changelog]
Signed-off-by: Sean Christopherson <seanjc@google.com>
Per the SDM, "When the local APIC handles a performance-monitoring
counters interrupt, it automatically sets the mask flag in the LVT
performance counter register." Add this behavior to KVM's local APIC
emulation.
Failure to mask the LVTPC entry results in spurious PMIs, e.g. when
running Linux as a guest, PMI handlers that do a "late_ack" spew a large
number of "dazed and confused" spurious NMI warnings.
Fixes: f5132b0138 ("KVM: Expose a version 2 architectural PMU to a guests")
Cc: stable@vger.kernel.org
Signed-off-by: Jim Mattson <jmattson@google.com>
Tested-by: Mingwei Zhang <mizhang@google.com>
Signed-off-by: Mingwei Zhang <mizhang@google.com>
Link: https://lore.kernel.org/r/20230925173448.3518223-3-mizhang@google.com
[sean: massage changelog, correct Fixes]
Signed-off-by: Sean Christopherson <seanjc@google.com>
Performance counters are defined to have width less than 64 bits. The
vPMU code maintains the counters in u64 variables but assumes the value
to fit within the defined width. However, for Intel non-full-width
counters (MSR_IA32_PERFCTRx) the value receieved from the guest is
truncated to 32 bits and then sign-extended to full 64 bits. If a
negative value is set, it's sign-extended to 64 bits, but then in
kvm_pmu_incr_counter() it's incremented, truncated, and compared to the
previous value for overflow detection.
That previous value is not truncated, so it always evaluates bigger than
the truncated new one, and a PMI is injected. If the PMI handler writes
a negative counter value itself, the vCPU never quits the PMI loop.
Turns out that Linux PMI handler actually does write the counter with
the value just read with RDPMC, so when no full-width support is exposed
via MSR_IA32_PERF_CAPABILITIES, and the guest initializes the counter to
a negative value, it locks up.
This has been observed in the field, for example, when the guest configures
atop to use perfevents and runs two instances of it simultaneously.
To address the problem, maintain the invariant that the counter value
always fits in the defined bit width, by truncating the received value
in the respective set_msr methods. For better readability, factor the
out into a helper function, pmc_write_counter(), shared by vmx and svm
parts.
Fixes: 9cd803d496 ("KVM: x86: Update vPMCs when retiring instructions")
Cc: stable@vger.kernel.org
Signed-off-by: Roman Kagan <rkagan@amazon.de>
Link: https://lore.kernel.org/all/20230504120042.785651-1-rkagan@amazon.de
Tested-by: Like Xu <likexu@tencent.com>
[sean: tweak changelog, s/set/write in the helper]
Signed-off-by: Sean Christopherson <seanjc@google.com>
Zen 4 systems running buggy microcode can hit a WARN_ON() in the PMI
handler, as shown below, several times while perf runs. A simple
`perf top` run is enough to render the system unusable:
WARNING: CPU: 18 PID: 20608 at arch/x86/events/amd/core.c:944 amd_pmu_v2_handle_irq+0x1be/0x2b0
This happens because the Performance Counter Global Status Register
(PerfCntGlobalStatus) has one or more bits set which are considered
reserved according to the "AMD64 Architecture Programmer’s Manual,
Volume 2: System Programming, 24593":
https://www.amd.com/system/files/TechDocs/24593.pdf
To make this less intrusive, warn just once if any reserved bit is set
and prompt the user to update the microcode. Also sanitize the value to
what the code is handling, so that the overflow events continue to be
handled for the number of counters that are known to be sane.
Going forward, the following microcode patch levels are recommended
for Zen 4 processors in order to avoid such issues with reserved bits:
Family=0x19 Model=0x11 Stepping=0x01: Patch=0x0a10113e
Family=0x19 Model=0x11 Stepping=0x02: Patch=0x0a10123e
Family=0x19 Model=0xa0 Stepping=0x01: Patch=0x0aa00116
Family=0x19 Model=0xa0 Stepping=0x02: Patch=0x0aa00212
Commit f2eb058afc57 ("linux-firmware: Update AMD cpu microcode") from
the linux-firmware tree has binaries that meet the minimum required
patch levels.
[ sandipan: - add message to prompt users to update microcode
- rework commit message and call out required microcode levels ]
Fixes: 7685665c39 ("perf/x86/amd/core: Add PerfMonV2 overflow handling")
Reported-by: Jirka Hladky <jhladky@redhat.com>
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Sandipan Das <sandipan.das@amd.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/all/3540f985652f41041e54ee82aa53e7dbd55739ae.1694696888.git.sandipan.das@amd.com/
* Fix EL2 Stage-1 MMIO mappings where a random address was used
* Fix SMCCC function number comparison when the SVE hint is set
RISC-V:
* Fix KVM_GET_REG_LIST API for ISA_EXT registers
* Fix reading ISA_EXT register of a missing extension
* Fix ISA_EXT register handling in get-reg-list test
* Fix filtering of AIA registers in get-reg-list test
x86:
* Fixes for TSC_AUX virtualization
* Stop zapping page tables asynchronously, since we don't
zap them as often as before
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull kvm fixes from Paolo Bonzini:
"ARM:
- Fix EL2 Stage-1 MMIO mappings where a random address was used
- Fix SMCCC function number comparison when the SVE hint is set
RISC-V:
- Fix KVM_GET_REG_LIST API for ISA_EXT registers
- Fix reading ISA_EXT register of a missing extension
- Fix ISA_EXT register handling in get-reg-list test
- Fix filtering of AIA registers in get-reg-list test
x86:
- Fixes for TSC_AUX virtualization
- Stop zapping page tables asynchronously, since we don't zap them as
often as before"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
KVM: SVM: Do not use user return MSR support for virtualized TSC_AUX
KVM: SVM: Fix TSC_AUX virtualization setup
KVM: SVM: INTERCEPT_RDTSCP is never intercepted anyway
KVM: x86/mmu: Stop zapping invalidated TDP MMU roots asynchronously
KVM: x86/mmu: Do not filter address spaces in for_each_tdp_mmu_root_yield_safe()
KVM: x86/mmu: Open code leaf invalidation from mmu_notifier
KVM: riscv: selftests: Selectively filter-out AIA registers
KVM: riscv: selftests: Fix ISA_EXT register handling in get-reg-list
RISC-V: KVM: Fix riscv_vcpu_get_isa_ext_single() for missing extensions
RISC-V: KVM: Fix KVM_GET_REG_LIST API for ISA_EXT registers
KVM: selftests: Assert that vasprintf() is successful
KVM: arm64: nvhe: Ignore SVE hint in SMCCC function ID
KVM: arm64: Properly return allocated EL2 VA from hyp_alloc_private_va_range()
When compiled with W=1, the following warning is generated:
arch/x86/kernel/kgdb.c:698: warning: Cannot understand *
on line 698 - I thought it was a doc line
Remove the corresponding empty comment line to fix the warning.
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/aad659537c1d4ebd86912a6f0be458676c8e69af.1695401178.git.christophe.jaillet@wanadoo.fr
- Fix KVM_GET_REG_LIST API for ISA_EXT registers
- Fix reading ISA_EXT register of a missing extension
- Fix ISA_EXT register handling in get-reg-list test
- Fix filtering of AIA registers in get-reg-list test
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Merge tag 'kvm-riscv-fixes-6.6-1' of https://github.com/kvm-riscv/linux into HEAD
KVM/riscv fixes for 6.6, take #1
- Fix KVM_GET_REG_LIST API for ISA_EXT registers
- Fix reading ISA_EXT register of a missing extension
- Fix ISA_EXT register handling in get-reg-list test
- Fix filtering of AIA registers in get-reg-list test
When the TSC_AUX MSR is virtualized, the TSC_AUX value is swap type "B"
within the VMSA. This means that the guest value is loaded on VMRUN and
the host value is restored from the host save area on #VMEXIT.
Since the value is restored on #VMEXIT, the KVM user return MSR support
for TSC_AUX can be replaced by populating the host save area with the
current host value of TSC_AUX. And, since TSC_AUX is not changed by Linux
post-boot, the host save area can be set once in svm_hardware_enable().
This eliminates the two WRMSR instructions associated with the user return
MSR support.
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Message-Id: <d381de38eb0ab6c9c93dda8503b72b72546053d7.1694811272.git.thomas.lendacky@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The checks for virtualizing TSC_AUX occur during the vCPU reset processing
path. However, at the time of initial vCPU reset processing, when the vCPU
is first created, not all of the guest CPUID information has been set. In
this case the RDTSCP and RDPID feature support for the guest is not in
place and so TSC_AUX virtualization is not established.
This continues for each vCPU created for the guest. On the first boot of
an AP, vCPU reset processing is executed as a result of an APIC INIT
event, this time with all of the guest CPUID information set, resulting
in TSC_AUX virtualization being enabled, but only for the APs. The BSP
always sees a TSC_AUX value of 0 which probably went unnoticed because,
at least for Linux, the BSP TSC_AUX value is 0.
Move the TSC_AUX virtualization enablement out of the init_vmcb() path and
into the vcpu_after_set_cpuid() path to allow for proper initialization of
the support after the guest CPUID information has been set.
With the TSC_AUX virtualization support now in the vcpu_set_after_cpuid()
path, the intercepts must be either cleared or set based on the guest
CPUID input.
Fixes: 296d5a17e7 ("KVM: SEV-ES: Use V_TSC_AUX if available instead of RDTSC/MSR_TSC_AUX intercepts")
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Message-Id: <4137fbcb9008951ab5f0befa74a0399d2cce809a.1694811272.git.thomas.lendacky@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
svm_recalc_instruction_intercepts() is always called at least once
before the vCPU is started, so the setting or clearing of the RDTSCP
intercept can be dropped from the TSC_AUX virtualization support.
Extracted from a patch by Tom Lendacky.
Cc: stable@vger.kernel.org
Fixes: 296d5a17e7 ("KVM: SEV-ES: Use V_TSC_AUX if available instead of RDTSC/MSR_TSC_AUX intercepts")
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Stop zapping invalidate TDP MMU roots via work queue now that KVM
preserves TDP MMU roots until they are explicitly invalidated. Zapping
roots asynchronously was effectively a workaround to avoid stalling a vCPU
for an extended during if a vCPU unloaded a root, which at the time
happened whenever the guest toggled CR0.WP (a frequent operation for some
guest kernels).
While a clever hack, zapping roots via an unbound worker had subtle,
unintended consequences on host scheduling, especially when zapping
multiple roots, e.g. as part of a memslot. Because the work of zapping a
root is no longer bound to the task that initiated the zap, things like
the CPU affinity and priority of the original task get lost. Losing the
affinity and priority can be especially problematic if unbound workqueues
aren't affined to a small number of CPUs, as zapping multiple roots can
cause KVM to heavily utilize the majority of CPUs in the system, *beyond*
the CPUs KVM is already using to run vCPUs.
When deleting a memslot via KVM_SET_USER_MEMORY_REGION, the async root
zap can result in KVM occupying all logical CPUs for ~8ms, and result in
high priority tasks not being scheduled in in a timely manner. In v5.15,
which doesn't preserve unloaded roots, the issues were even more noticeable
as KVM would zap roots more frequently and could occupy all CPUs for 50ms+.
Consuming all CPUs for an extended duration can lead to significant jitter
throughout the system, e.g. on ChromeOS with virtio-gpu, deleting memslots
is a semi-frequent operation as memslots are deleted and recreated with
different host virtual addresses to react to host GPU drivers allocating
and freeing GPU blobs. On ChromeOS, the jitter manifests as audio blips
during games due to the audio server's tasks not getting scheduled in
promptly, despite the tasks having a high realtime priority.
Deleting memslots isn't exactly a fast path and should be avoided when
possible, and ChromeOS is working towards utilizing MAP_FIXED to avoid the
memslot shenanigans, but KVM is squarely in the wrong. Not to mention
that removing the async zapping eliminates a non-trivial amount of
complexity.
Note, one of the subtle behaviors hidden behind the async zapping is that
KVM would zap invalidated roots only once (ignoring partial zaps from
things like mmu_notifier events). Preserve this behavior by adding a flag
to identify roots that are scheduled to be zapped versus roots that have
already been zapped but not yet freed.
Add a comment calling out why kvm_tdp_mmu_invalidate_all_roots() can
encounter invalid roots, as it's not at all obvious why zapping
invalidated roots shouldn't simply zap all invalid roots.
Reported-by: Pattara Teerapong <pteerapong@google.com>
Cc: David Stevens <stevensd@google.com>
Cc: Yiwei Zhang<zzyiwei@google.com>
Cc: Paul Hsia <paulhsia@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20230916003916.2545000-4-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
All callers except the MMU notifier want to process all address spaces.
Remove the address space ID argument of for_each_tdp_mmu_root_yield_safe()
and switch the MMU notifier to use __for_each_tdp_mmu_root_yield_safe().
Extracted out of a patch by Sean Christopherson <seanjc@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
- Fix a kexec bug,
- Fix an UML build bug,
- Fix a handful of SRSO related bugs,
- Fix a shadow stacks handling bug & robustify related code.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'x86-urgent-2023-09-22' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull misc x86 fixes from Ingo Molnar:
- Fix a kexec bug
- Fix an UML build bug
- Fix a handful of SRSO related bugs
- Fix a shadow stacks handling bug & robustify related code
* tag 'x86-urgent-2023-09-22' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/shstk: Add warning for shadow stack double unmap
x86/shstk: Remove useless clone error handling
x86/shstk: Handle vfork clone failure correctly
x86/srso: Fix SBPB enablement for spec_rstack_overflow=off
x86/srso: Don't probe microcode in a guest
x86/srso: Set CPUID feature bits independently of bug or mitigation status
x86/srso: Fix srso_show_state() side effect
x86/asm: Fix build of UML with KASAN
x86/mm, kexec, ima: Use memblock_free_late() from ima_free_kexec_buffer()
Add "#define pr_fmt()" in hv_init.c to use "Hyper-V:" as common
print prefix for all pr_*() statements in this file.
Remove the "Hyper-V:" already prefixed in couple of prints.
Signed-off-by: Saurabh Sengar <ssengar@linux.microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Link: https://lore.kernel.org/r/1695123361-8877-1-git-send-email-ssengar@linux.microsoft.com
There has been cases reported where HYPERV_VTL_MODE is enabled by mistake,
on a non Hyper-V platforms. This causes the hv_vtl_early_init function to
be called in an non Hyper-V/VTL platforms which results the memory
corruption.
Remove the early_initcall for hv_vtl_early_init and call it at the end of
hyperv_init to make sure it is never called in a non Hyper-V platform by
mistake.
Reported-by: Mathias Krause <minipli@grsecurity.net>
Closes: https://lore.kernel.org/lkml/40467722-f4ab-19a5-4989-308225b1f9f0@grsecurity.net/
Signed-off-by: Saurabh Sengar <ssengar@linux.microsoft.com>
Acked-by: Mathias Krause <minipli@grsecurity.net>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Link: https://lore.kernel.org/r/1695358720-27681-1-git-send-email-ssengar@linux.microsoft.com
When Linux runs in a non-default VTL (CONFIG_HYPERV_VTL_MODE=y),
get_vtl() must never fail as its return value is used in negotiations
with the host. In the more generic case, (CONFIG_HYPERV_VTL_MODE=n) the
VTL is always zero so there's no need to do the hypercall.
Make get_vtl() BUG() in case of failure and put the implementation under
"if IS_ENABLED(CONFIG_HYPERV_VTL_MODE)" to avoid the call altogether in
the most generic use case.
Signed-off-by: Saurabh Sengar <ssengar@linux.microsoft.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Link: https://lore.kernel.org/r/1695182675-13405-1-git-send-email-ssengar@linux.microsoft.com
Commit
7825451fa4 ("static_call: Add call depth tracking support")
failed to realize the problem fixed there is not specific to call depth
tracking but applies to all return-thunk uses.
Move the fix to the appropriate place and condition.
Fixes: ee88d363d1 ("x86,static_call: Use alternative RET encoding")
Reported-by: David Kaplan <David.Kaplan@amd.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: <stable@kernel.org>
The following commit
095b8303f3 ("x86/alternative: Make custom return thunk unconditional")
made '__x86_return_thunk' a placeholder value. All code setting
X86_FEATURE_RETHUNK also changes the value of 'x86_return_thunk'. So
the optimization at the beginning of apply_returns() is dead code.
Also, before the above-mentioned commit, the optimization actually had a
bug It bypassed __static_call_fixup(), causing some raw returns to
remain unpatched in static call trampolines. Thus the 'Fixes' tag.
Fixes: d2408e043e ("x86/alternative: Optimize returns patching")
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/16d19d2249d4485d8380fb215ffaae81e6b8119e.1693889988.git.jpoimboe@kernel.org
Kernels older than v5.19 do not support PerfMonV2 and the PMI handler
does not clear the overflow bits of the PerfCntrGlobalStatus register.
Because of this, loading a recent kernel using kexec from an older
kernel can result in inconsistent register states on Zen 4 systems.
The PMI handler of the new kernel gets confused and shows a warning when
an overflow occurs because some of the overflow bits are set even if the
corresponding counters are inactive. These are remnants from overflows
that were handled by the older kernel.
During CPU hotplug, the PerfCntrGlobalCtl and PerfCntrGlobalStatus
registers should always be cleared for PerfMonV2-capable processors.
However, a condition used for NB event constaints applicable only to
older processors currently prevents this from happening. Move the reset
sequence to an appropriate place and also clear the LBR Freeze bit.
Fixes: 21d59e3e2c ("perf/x86/amd/core: Detect PerfMonV2 support")
Signed-off-by: Sandipan Das <sandipan.das@amd.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/882a87511af40792ba69bb0e9026f19a2e71e8a3.1694696888.git.sandipan.das@amd.com
The mmu_notifier path is a bit of a special snowflake, e.g. it zaps only a
single address space (because it's per-slot), and can't always yield.
Because of this, it calls kvm_tdp_mmu_zap_leafs() in ways that no one
else does.
Iterate manually over the leafs in response to an mmu_notifier
invalidation, instead of invoking kvm_tdp_mmu_zap_leafs(). Drop the
@can_yield param from kvm_tdp_mmu_zap_leafs() as its sole remaining
caller unconditionally passes "true".
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20230916003916.2545000-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
There are several ways a thread's shadow stacks can get unmapped. This
can happen on exit or exec, as well as error handling in exec or clone.
The task struct already keeps track of the thread's shadow stack. Use the
size variable to keep track of if the shadow stack has already been freed.
When an attempt to double unmap the thread shadow stack is caught, warn
about it and abort the operation.
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Tested-by: H.J. Lu <hjl.tools@gmail.com>
Link: https://lore.kernel.org/all/20230908203655.543765-4-rick.p.edgecombe%40intel.com
When clone fails after the shadow stack is allocated, any allocated shadow
stack is cleaned up in exit_thread() in copy_process(). So the logic in
copy_thread() is unneeded, and also will not handle failures that happen
outside of copy_thread().
In addition, since there is a second attempt to unmap the same shadow
stack, there is a race where an newly mapped region could get unmapped.
So remove the logic in copy_thread() and rely on exit_thread() to handle
clone failure.
Fixes: b2926a36b9 ("x86/shstk: Handle thread shadow stack")
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Tested-by: H.J. Lu <hjl.tools@gmail.com>
Link: https://lore.kernel.org/all/20230908203655.543765-3-rick.p.edgecombe%40intel.com
Shadow stacks are allocated automatically and freed on exit, depending
on the clone flags. The two cases where new shadow stacks are not
allocated are !CLONE_VM (fork()) and CLONE_VFORK (vfork()). For
!CLONE_VM, although a new stack is not allocated, it can be freed normally
because it will happen in the child's copy of the VM.
However, for CLONE_VFORK the parent and the child are actually using the
same shadow stack. So the kernel doesn't need to allocate *or* free a
shadow stack for a CLONE_VFORK child. CLONE_VFORK children already need
special tracking to avoid returning to userspace until the child exits or
execs. Shadow stack uses this same tracking to avoid freeing CLONE_VFORK
shadow stacks.
However, the tracking is not setup until the clone has succeeded
(internally). Which means, if a CLONE_VFORK fails, the existing logic will
not know it is a CLONE_VFORK and proceed to unmap the parents shadow stack.
This error handling cleanup logic runs via exit_thread() in the
bad_fork_cleanup_thread label in copy_process(). The issue was seen in
the glibc test "posix/tst-spawn3-pidfd" while running with shadow stack
using currently out-of-tree glibc patches.
Fix it by not unmapping the vfork shadow stack in the error case as well.
Since clone is implemented in core code, it is not ideal to pass the clone
flags along the error path in order to have shadow stack code have
symmetric logic in the freeing half of the thread shadow stack handling.
Instead use the existing state for thread shadow stacks to track whether
the thread is managing its own shadow stack. For CLONE_VFORK, simply set
shstk->base and shstk->size to 0, and have it mean the thread is not
managing a shadow stack and so should skip cleanup work. Implement this
by breaking up the CLONE_VFORK and !CLONE_VM cases in
shstk_alloc_thread_stack() to separate conditionals since, the logic is
now different between them. In the case of CLONE_VFORK && !CLONE_VM, the
existing behavior is to not clean up the shadow stack in the child (which
should go away quickly with either be exit or exec), so maintain that
behavior by handling the CLONE_VFORK case first in the allocation path.
This new logioc cleanly handles the case of normal, successful
CLONE_VFORK's skipping cleaning up their shadow stack's on exit as well.
So remove the existing, vfork shadow stack freeing logic. This is in
deactivate_mm() where vfork_done is used to tell if it is a vfork child
that can skip cleaning up the thread shadow stack.
Fixes: b2926a36b9 ("x86/shstk: Handle thread shadow stack")
Reported-by: H.J. Lu <hjl.tools@gmail.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Tested-by: H.J. Lu <hjl.tools@gmail.com>
Link: https://lore.kernel.org/all/20230908203655.543765-2-rick.p.edgecombe%40intel.com
If the user has requested no SRSO mitigation, other mitigations can use
the lighter-weight SBPB instead of IBPB.
Fixes: fb3bd914b3 ("x86/srso: Add a Speculative RAS Overflow mitigation")
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/b20820c3cfd1003171135ec8d762a0b957348497.1693889988.git.jpoimboe@kernel.org
To support live migration, the hypervisor sets the "lowest common
denominator" of features. Probing the microcode isn't allowed because
any detected features might go away after a migration.
As Andy Cooper states:
"Linux must not probe microcode when virtualised. What it may see
instantaneously on boot (owing to MSR_PRED_CMD being fully passed
through) is not accurate for the lifetime of the VM."
Rely on the hypervisor to set the needed IBPB_BRTYPE and SBPB bits.
Fixes: 1b5277c0ea ("x86/srso: Add SRSO_NO support")
Suggested-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/3938a7209606c045a3f50305d201d840e8c834c7.1693889988.git.jpoimboe@kernel.org
Booting with mitigations=off incorrectly prevents the
X86_FEATURE_{IBPB_BRTYPE,SBPB} CPUID bits from getting set.
Also, future CPUs without X86_BUG_SRSO might still have IBPB with branch
type prediction flushing, in which case SBPB should be used instead of
IBPB. The current code doesn't allow for that.
Also, cpu_has_ibpb_brtype_microcode() has some surprising side effects
and the setting of these feature bits really doesn't belong in the
mitigation code anyway. Move it to earlier.
Fixes: fb3bd914b3 ("x86/srso: Add a Speculative RAS Overflow mitigation")
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Nikolay Borisov <nik.borisov@suse.com>
Reviewed-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/869a1709abfe13b673bdd10c2f4332ca253a40bc.1693889988.git.jpoimboe@kernel.org
Reading the 'spec_rstack_overflow' sysfs file can trigger an unnecessary
MSR write, and possibly even a (handled) exception if the microcode
hasn't been updated.
Avoid all that by just checking X86_FEATURE_IBPB_BRTYPE instead, which
gets set by srso_select_mitigation() if the updated microcode exists.
Fixes: fb3bd914b3 ("x86/srso: Add a Speculative RAS Overflow mitigation")
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Nikolay Borisov <nik.borisov@suse.com>
Acked-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/27d128899cb8aee9eb2b57ddc996742b0c1d776b.1693889988.git.jpoimboe@kernel.org
`strncpy` is deprecated for use on NUL-terminated destination strings [1].
`efi_loader_signature` has space for 4 bytes. We are copying "Xen" (3 bytes)
plus a NUL-byte which makes 4 total bytes. With that being said, there is
currently not a bug with the current `strncpy()` implementation in terms of
buffer overreads but we should favor a more robust string interface
either way.
A suitable replacement is `strscpy` [2] due to the fact that it guarantees
NUL-termination on the destination buffer while being functionally the
same in this case.
Link: www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings[1]
Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html [2]
Link: https://github.com/KSPP/linux/issues/90
Cc: linux-hardening@vger.kernel.org
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Justin Stitt <justinstitt@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20230911-strncpy-arch-x86-xen-efi-c-v1-1-96ab2bba2feb@google.com
Signed-off-by: Juergen Gross <jgross@suse.com>
When running as a paravirtualized guest under Xen, Linux is using
"lazy mode" for issuing hypercalls which don't need to take immediate
effect in order to improve performance (examples are e.g. multiple
PTE changes).
There are two different lazy modes defined: MMU and CPU lazy mode.
Today it is not possible to nest multiple lazy mode sections, even if
they are of the same kind. A recent change in memory management added
nesting of MMU lazy mode sections, resulting in a regression when
running as Xen PV guest.
Technically there is no reason why nesting of multiple sections of the
same kind of lazy mode shouldn't be allowed. So add support for that
for fixing the regression.
Fixes: bcc6cc8325 ("mm: add default definition of set_ptes()")
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Link: https://lore.kernel.org/r/20230913113828.18421-4-jgross@suse.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Only Xen is using the paravirt lazy mode code, so it can be moved to
Xen specific sources.
This allows to make some of the functions static or to merge them into
their only call sites.
While at it do a rename from "paravirt" to "xen" for all moved
specifiers.
No functional change.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Link: https://lore.kernel.org/r/20230913113828.18421-3-jgross@suse.com
Signed-off-by: Juergen Gross <jgross@suse.com>
There are several functions involved for performing the functionality
of evtchn_do_upcall():
- __xen_evtchn_do_upcall() doing the real work
- xen_hvm_evtchn_do_upcall() just being a wrapper for
__xen_evtchn_do_upcall(), exposed for external callers
- xen_evtchn_do_upcall() calling __xen_evtchn_do_upcall(), too, but
without any user
Simplify this maze by:
- removing the unused xen_evtchn_do_upcall()
- removing xen_hvm_evtchn_do_upcall() as the only left caller of
__xen_evtchn_do_upcall(), while renaming __xen_evtchn_do_upcall() to
xen_evtchn_do_upcall()
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Juergen Gross <jgross@suse.com>
Building UML with KASAN fails since commit 69d4c0d321 ("entry, kasan,
x86: Disallow overriding mem*() functions") with the following errors:
$ tools/testing/kunit/kunit.py run --kconfig_add CONFIG_KASAN=y
...
ld: mm/kasan/shadow.o: in function `memset':
shadow.c:(.text+0x40): multiple definition of `memset';
arch/x86/lib/memset_64.o:(.noinstr.text+0x0): first defined here
ld: mm/kasan/shadow.o: in function `memmove':
shadow.c:(.text+0x90): multiple definition of `memmove';
arch/x86/lib/memmove_64.o:(.noinstr.text+0x0): first defined here
ld: mm/kasan/shadow.o: in function `memcpy':
shadow.c:(.text+0x110): multiple definition of `memcpy';
arch/x86/lib/memcpy_64.o:(.noinstr.text+0x0): first defined here
UML does not use GENERIC_ENTRY and is still supposed to be allowed to
override the mem*() functions, so use weak aliases in that case.
Fixes: 69d4c0d321 ("entry, kasan, x86: Disallow overriding mem*() functions")
Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20230918-uml-kasan-v3-1-7ad6db477df6@axis.com
The code calling ima_free_kexec_buffer() runs long after the memblock
allocator has already been torn down, potentially resulting in a use
after free in memblock_isolate_range().
With KASAN or KFENCE, this use after free will result in a BUG
from the idle task, and a subsequent kernel panic.
Switch ima_free_kexec_buffer() over to memblock_free_late() to avoid
that bug.
Fixes: fee3ff99bc ("powerpc: Move arch independent ima kexec functions to drivers/of/kexec.c")
Suggested-by: Mike Rappoport <rppt@kernel.org>
Signed-off-by: Rik van Riel <riel@surriel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20230817135558.67274c83@imladris.surriel.com
- Fix an UV boot crash,
- Skip spurious ENDBR generation on _THIS_IP_,
- Fix ENDBR use in putuser() asm methods,
- Fix corner case boot crashes on 5-level paging,
- and fix a false positive WARNING on LTO kernels.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'x86-urgent-2023-09-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Ingo Molnar:
"Misc fixes:
- Fix an UV boot crash
- Skip spurious ENDBR generation on _THIS_IP_
- Fix ENDBR use in putuser() asm methods
- Fix corner case boot crashes on 5-level paging
- and fix a false positive WARNING on LTO kernels"
* tag 'x86-urgent-2023-09-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/purgatory: Remove LTO flags
x86/boot/compressed: Reserve more memory for page tables
x86/ibt: Avoid duplicate ENDBR in __put_user_nocheck*()
x86/ibt: Suppress spurious ENDBR
x86/platform/uv: Use alternate source for socket to node data
balancing bug, and a topology setup bug on (Intel) hybrid processors.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'sched-urgent-2023-09-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fixes from Ingo Molnar:
"Fix a performance regression on large SMT systems, an Intel SMT4
balancing bug, and a topology setup bug on (Intel) hybrid processors"
* tag 'sched-urgent-2023-09-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/sched: Restore the SD_ASYM_PACKING flag in the DIE domain
sched/fair: Fix SMT4 group_smt_balance handling
sched/fair: Optimize should_we_balance() for large SMT systems
-flto* implies -ffunction-sections. With LTO enabled, ld.lld generates
multiple .text sections for purgatory.ro:
$ readelf -S purgatory.ro | grep " .text"
[ 1] .text PROGBITS 0000000000000000 00000040
[ 7] .text.purgatory PROGBITS 0000000000000000 000020e0
[ 9] .text.warn PROGBITS 0000000000000000 000021c0
[13] .text.sha256_upda PROGBITS 0000000000000000 000022f0
[15] .text.sha224_upda PROGBITS 0000000000000000 00002be0
[17] .text.sha256_fina PROGBITS 0000000000000000 00002bf0
[19] .text.sha224_fina PROGBITS 0000000000000000 00002cc0
This causes WARNING from kexec_purgatory_setup_sechdrs():
WARNING: CPU: 26 PID: 110894 at kernel/kexec_file.c:919
kexec_load_purgatory+0x37f/0x390
Fix this by disabling LTO for purgatory.
[ AFAICT, x86 is the only arch that supports LTO and purgatory. ]
We could also fix this with an explicit linker script to rejoin .text.*
sections back into .text. However, given the benefit of LTOing purgatory
is small, simply disable the production of more .text.* sections for now.
Fixes: b33fff07e3 ("x86, build: allow LTO to be selected")
Signed-off-by: Song Liu <song@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Link: https://lore.kernel.org/r/20230914170138.995606-1-song@kernel.org
The decompressor has a hard limit on the number of page tables it can
allocate. This limit is defined at compile-time and will cause boot
failure if it is reached.
The kernel is very strict and calculates the limit precisely for the
worst-case scenario based on the current configuration. However, it is
easy to forget to adjust the limit when a new use-case arises. The
worst-case scenario is rarely encountered during sanity checks.
In the case of enabling 5-level paging, a use-case was overlooked. The
limit needs to be increased by one to accommodate the additional level.
This oversight went unnoticed until Aaron attempted to run the kernel
via kexec with 5-level paging and unaccepted memory enabled.
Update wost-case calculations to include 5-level paging.
To address this issue, let's allocate some extra space for page tables.
128K should be sufficient for any use-case. The logic can be simplified
by using a single value for all kernel configurations.
[ Also add a warning, should this memory run low - by Dave Hansen. ]
Fixes: 34bbb0009f ("x86/boot/compressed: Enable 5-level paging during decompression stage")
Reported-by: Aaron Lu <aaron.lu@intel.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20230915070221.10266-1-kirill.shutemov@linux.intel.com
Commit 8f2d6c41e5 ("x86/sched: Rewrite topology setup") dropped the
SD_ASYM_PACKING flag in the DIE domain added in commit 044f0e27de
("x86/sched: Add the SD_ASYM_PACKING flag to the die domain of hybrid
processors"). Restore it on hybrid processors.
The die-level domain does not depend on any build configuration and now
x86_sched_itmt_flags() is always needed. Remove the build dependency on
CONFIG_SCHED_[SMT|CLUSTER|MC].
Fixes: 8f2d6c41e5 ("x86/sched: Rewrite topology setup")
Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Chen Yu <yu.c.chen@intel.com>
Tested-by: Caleb Callaway <caleb.callaway@intel.com>
Link: https://lkml.kernel.org/r/20230815035747.11529-1-ricardo.neri-calderon@linux.intel.com
Commit cb855971d7 ("x86/putuser: Provide room for padding") changed
__put_user_nocheck_*() into proper functions but failed to note that
SYM_FUNC_START() already provides ENDBR, rendering the explicit ENDBR
superfluous.
Fixes: cb855971d7 ("x86/putuser: Provide room for padding")
Reported-by: David Kaplan <David.Kaplan@amd.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20230802110323.086971726@infradead.org
It was reported that under certain circumstances GCC emits ENDBR
instructions for _THIS_IP_ usage. Specifically, when it appears at the
start of a basic block -- but not elsewhere.
Since _THIS_IP_ is never used for control flow, these ENDBR
instructions are completely superfluous. Override the _THIS_IP_
definition for x86_64 to avoid this.
Less ENDBR instructions is better.
Fixes: 156ff4a544 ("x86/ibt: Base IBT bits")
Reported-by: David Kaplan <David.Kaplan@amd.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20230802110323.016197440@infradead.org
The UV code attempts to build a set of tables to allow it to do
bidirectional socket<=>node lookups.
But when nr_cpus is set to a smaller number than actually present, the
cpu_to_node() mapping information for unused CPUs is not available to
build_socket_tables(). This results in skipping some nodes or sockets
when creating the tables and leaving some -1's for later code to trip.
over, causing oopses.
The problem is that the socket<=>node lookups are created by doing a
loop over all CPUs, then looking up the CPU's APICID and socket. But
if a CPU is not present, there is no way to start this lookup.
Instead of looping over all CPUs, take CPUs out of the equation
entirely. Loop over all APICIDs which are mapped to a valid NUMA node.
Then just extract the socket-id from the APICID.
This avoid tripping over disabled CPUs.
Fixes: 8a50c58519 ("x86/platform/uv: UV support for sub-NUMA clustering")
Signed-off-by: Steve Wahl <steve.wahl@hpe.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/all/20230807141730.1117278-1-steve.wahl%40hpe.com
CONFIG_EFI_RUNTIME_MAP needs to be enabled in order for kexec to be able
to provide the required information about the EFI runtime mappings to
the incoming kernel, regardless of whether kexec_load() or
kexec_file_load() is being used. Without this information, kexec boot in
EFI mode is not possible.
The CONFIG_EFI_RUNTIME_MAP option is currently directly configurable if
CONFIG_EXPERT is enabled, so that it can be turned on for debugging
purposes even if KEXEC is not enabled. However, the upshot of this is
that it can also be disabled even when it shouldn't.
So tweak the Kconfig declarations to avoid this situation.
Reported-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Only the arch_efi_call_virt() macro that some architectures override
needs to be a macro, given that it is variadic and encapsulates calls
via function pointers that have different prototypes.
The associated setup and teardown code are not special in this regard,
and don't need to be instantiated at each call site. So turn them into
ordinary C functions and move them out of line.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
fix a ld.lld linker (in)compatibility quirk and make the x86 SMP init code a bit
more conservative to fix kexec() lockups.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'x86-urgent-2023-09-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Ingo Molnar:
"Fix preemption delays in the SGX code, remove unnecessarily
UAPI-exported code, fix a ld.lld linker (in)compatibility quirk and
make the x86 SMP init code a bit more conservative to fix kexec()
lockups"
* tag 'x86-urgent-2023-09-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/sgx: Break up long non-preemptible delays in sgx_vepc_release()
x86: Remove the arch_calc_vm_prot_bits() macro from the UAPI
x86/build: Fix linker fill bytes quirk/incompatibility for ld.lld
x86/smp: Don't send INIT to non-present and non-booted CPUs
affecting certain Intel systems.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'perf-urgent-2023-09-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 perf event fix from Ingo Molnar:
"Work around a firmware bug in the uncore PMU driver, affecting certain
Intel systems"
* tag 'perf-urgent-2023-09-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf/x86/uncore: Correct the number of CHAs on EMR
* Clean up vCPU targets, always returning generic v8 as the preferred target
* Trap forwarding infrastructure for nested virtualization (used for traps
that are taken from an L2 guest and are needed by the L1 hypervisor)
* FEAT_TLBIRANGE support to only invalidate specific ranges of addresses
when collapsing a table PTE to a block PTE. This avoids that the guest
refills the TLBs again for addresses that aren't covered by the table PTE.
* Fix vPMU issues related to handling of PMUver.
* Don't unnecessary align non-stack allocations in the EL2 VA space
* Drop HCR_VIRT_EXCP_MASK, which was never used...
* Don't use smp_processor_id() in kvm_arch_vcpu_load(),
but the cpu parameter instead
* Drop redundant call to kvm_set_pfn_accessed() in user_mem_abort()
* Remove prototypes without implementations
RISC-V:
* Zba, Zbs, Zicntr, Zicsr, Zifencei, and Zihpm support for guest
* Added ONE_REG interface for SATP mode
* Added ONE_REG interface to enable/disable multiple ISA extensions
* Improved error codes returned by ONE_REG interfaces
* Added KVM_GET_REG_LIST ioctl() implementation for KVM RISC-V
* Added get-reg-list selftest for KVM RISC-V
s390:
* PV crypto passthrough enablement (Tony, Steffen, Viktor, Janosch)
Allows a PV guest to use crypto cards. Card access is governed by
the firmware and once a crypto queue is "bound" to a PV VM every
other entity (PV or not) looses access until it is not bound
anymore. Enablement is done via flags when creating the PV VM.
* Guest debug fixes (Ilya)
x86:
* Clean up KVM's handling of Intel architectural events
* Intel bugfixes
* Add support for SEV-ES DebugSwap, allowing SEV-ES guests to use debug
registers and generate/handle #DBs
* Clean up LBR virtualization code
* Fix a bug where KVM fails to set the target pCPU during an IRTE update
* Fix fatal bugs in SEV-ES intrahost migration
* Fix a bug where the recent (architecturally correct) change to reinject
#BP and skip INT3 broke SEV guests (can't decode INT3 to skip it)
* Retry APIC map recalculation if a vCPU is added/enabled
* Overhaul emergency reboot code to bring SVM up to par with VMX, tie the
"emergency disabling" behavior to KVM actually being loaded, and move all of
the logic within KVM
* Fix user triggerable WARNs in SVM where KVM incorrectly assumes the TSC
ratio MSR cannot diverge from the default when TSC scaling is disabled
up related code
* Add a framework to allow "caching" feature flags so that KVM can check if
the guest can use a feature without needing to search guest CPUID
* Rip out the ancient MMU_DEBUG crud and replace the useful bits with
CONFIG_KVM_PROVE_MMU
* Fix KVM's handling of !visible guest roots to avoid premature triple fault
injection
* Overhaul KVM's page-track APIs, and KVMGT's usage, to reduce the API surface
that is needed by external users (currently only KVMGT), and fix a variety
of issues in the process
This last item had a silly one-character bug in the topic branch that
was sent to me. Because it caused pretty bad selftest failures in
some configurations, I decided to squash in the fix. So, while the
exact commit ids haven't been in linux-next, the code has (from the
kvm-x86 tree).
Generic:
* Wrap kvm_{gfn,hva}_range.pte in a union to allow mmu_notifier events to pass
action specific data without needing to constantly update the main handlers.
* Drop unused function declarations
Selftests:
* Add testcases to x86's sync_regs_test for detecting KVM TOCTOU bugs
* Add support for printf() in guest code and covert all guest asserts to use
printf-based reporting
* Clean up the PMU event filter test and add new testcases
* Include x86 selftests in the KVM x86 MAINTAINERS entry
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull kvm updates from Paolo Bonzini:
"ARM:
- Clean up vCPU targets, always returning generic v8 as the preferred
target
- Trap forwarding infrastructure for nested virtualization (used for
traps that are taken from an L2 guest and are needed by the L1
hypervisor)
- FEAT_TLBIRANGE support to only invalidate specific ranges of
addresses when collapsing a table PTE to a block PTE. This avoids
that the guest refills the TLBs again for addresses that aren't
covered by the table PTE.
- Fix vPMU issues related to handling of PMUver.
- Don't unnecessary align non-stack allocations in the EL2 VA space
- Drop HCR_VIRT_EXCP_MASK, which was never used...
- Don't use smp_processor_id() in kvm_arch_vcpu_load(), but the cpu
parameter instead
- Drop redundant call to kvm_set_pfn_accessed() in user_mem_abort()
- Remove prototypes without implementations
RISC-V:
- Zba, Zbs, Zicntr, Zicsr, Zifencei, and Zihpm support for guest
- Added ONE_REG interface for SATP mode
- Added ONE_REG interface to enable/disable multiple ISA extensions
- Improved error codes returned by ONE_REG interfaces
- Added KVM_GET_REG_LIST ioctl() implementation for KVM RISC-V
- Added get-reg-list selftest for KVM RISC-V
s390:
- PV crypto passthrough enablement (Tony, Steffen, Viktor, Janosch)
Allows a PV guest to use crypto cards. Card access is governed by
the firmware and once a crypto queue is "bound" to a PV VM every
other entity (PV or not) looses access until it is not bound
anymore. Enablement is done via flags when creating the PV VM.
- Guest debug fixes (Ilya)
x86:
- Clean up KVM's handling of Intel architectural events
- Intel bugfixes
- Add support for SEV-ES DebugSwap, allowing SEV-ES guests to use
debug registers and generate/handle #DBs
- Clean up LBR virtualization code
- Fix a bug where KVM fails to set the target pCPU during an IRTE
update
- Fix fatal bugs in SEV-ES intrahost migration
- Fix a bug where the recent (architecturally correct) change to
reinject #BP and skip INT3 broke SEV guests (can't decode INT3 to
skip it)
- Retry APIC map recalculation if a vCPU is added/enabled
- Overhaul emergency reboot code to bring SVM up to par with VMX, tie
the "emergency disabling" behavior to KVM actually being loaded,
and move all of the logic within KVM
- Fix user triggerable WARNs in SVM where KVM incorrectly assumes the
TSC ratio MSR cannot diverge from the default when TSC scaling is
disabled up related code
- Add a framework to allow "caching" feature flags so that KVM can
check if the guest can use a feature without needing to search
guest CPUID
- Rip out the ancient MMU_DEBUG crud and replace the useful bits with
CONFIG_KVM_PROVE_MMU
- Fix KVM's handling of !visible guest roots to avoid premature
triple fault injection
- Overhaul KVM's page-track APIs, and KVMGT's usage, to reduce the
API surface that is needed by external users (currently only
KVMGT), and fix a variety of issues in the process
Generic:
- Wrap kvm_{gfn,hva}_range.pte in a union to allow mmu_notifier
events to pass action specific data without needing to constantly
update the main handlers.
- Drop unused function declarations
Selftests:
- Add testcases to x86's sync_regs_test for detecting KVM TOCTOU bugs
- Add support for printf() in guest code and covert all guest asserts
to use printf-based reporting
- Clean up the PMU event filter test and add new testcases
- Include x86 selftests in the KVM x86 MAINTAINERS entry"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (279 commits)
KVM: x86/mmu: Include mmu.h in spte.h
KVM: x86/mmu: Use dummy root, backed by zero page, for !visible guest roots
KVM: x86/mmu: Disallow guest from using !visible slots for page tables
KVM: x86/mmu: Harden TDP MMU iteration against root w/o shadow page
KVM: x86/mmu: Harden new PGD against roots without shadow pages
KVM: x86/mmu: Add helper to convert root hpa to shadow page
drm/i915/gvt: Drop final dependencies on KVM internal details
KVM: x86/mmu: Handle KVM bookkeeping in page-track APIs, not callers
KVM: x86/mmu: Drop @slot param from exported/external page-track APIs
KVM: x86/mmu: Bug the VM if write-tracking is used but not enabled
KVM: x86/mmu: Assert that correct locks are held for page write-tracking
KVM: x86/mmu: Rename page-track APIs to reflect the new reality
KVM: x86/mmu: Drop infrastructure for multiple page-track modes
KVM: x86/mmu: Use page-track notifiers iff there are external users
KVM: x86/mmu: Move KVM-only page-track declarations to internal header
KVM: x86: Remove the unused page-track hook track_flush_slot()
drm/i915/gvt: switch from ->track_flush_slot() to ->track_remove_region()
KVM: x86: Add a new page-track hook to handle memslot deletion
drm/i915/gvt: Don't bother removing write-protection on to-be-deleted slot
KVM: x86: Reject memslot MOVE operations if KVMGT is attached
...
On large enclaves we hit the softlockup warning with following call trace:
xa_erase()
sgx_vepc_release()
__fput()
task_work_run()
do_exit()
The latency issue is similar to the one fixed in:
8795359e35 ("x86/sgx: Silence softlockup detection when releasing large enclaves")
The test system has 64GB of enclave memory, and all is assigned to a single VM.
Release of 'vepc' takes a longer time and causes long latencies, which triggers
the softlockup warning.
Add cond_resched() to give other tasks a chance to run and reduce
latencies, which also avoids the softlockup detector.
[ mingo: Rewrote the changelog. ]
Fixes: 540745ddbc ("x86/sgx: Introduce virtual EPC for use by KVM guests")
Reported-by: Yu Zhang <yu.zhang@ionos.com>
Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Yu Zhang <yu.zhang@ionos.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Reviewed-by: Kai Huang <kai.huang@intel.com>
Acked-by: Haitao Huang <haitao.huang@linux.intel.com>
Cc: stable@vger.kernel.org
The arch_calc_vm_prot_bits() macro uses VM_PKEY_BIT0 etc. which are
not part of the UAPI, so the macro is completely useless for userspace.
It is also hidden behind the CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS
config switch which we shouldn't expose to userspace. Thus let's move
this macro into a new internal header instead.
Fixes: 8f62c88322 ("x86/mm/pkeys: Add arch-specific VMA protection bits")
Signed-off-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
Acked-by: Dave Hansen <dave.hansen@intel.com>
Link: https://lore.kernel.org/r/20230906162658.142511-1-thuth@redhat.com
With ":text =0xcccc", ld.lld fills unused text area with 0xcccc0000.
Example objdump -D output:
ffffffff82b04203: 00 00 add %al,(%rax)
ffffffff82b04205: cc int3
ffffffff82b04206: cc int3
ffffffff82b04207: 00 00 add %al,(%rax)
ffffffff82b04209: cc int3
ffffffff82b0420a: cc int3
Replace it with ":text =0xcccccccc", so we get the following instead:
ffffffff82b04203: cc int3
ffffffff82b04204: cc int3
ffffffff82b04205: cc int3
ffffffff82b04206: cc int3
ffffffff82b04207: cc int3
ffffffff82b04208: cc int3
gcc/ld doesn't seem to have the same issue. The generated code stays the
same for gcc/ld.
Signed-off-by: Song Liu <song@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Fixes: 7705dc8557 ("x86/vmlinux: Use INT3 instead of NOP for linker fill bytes")
Link: https://lore.kernel.org/r/20230906175215.2236033-1-song@kernel.org
Starting from SPR, the basic uncore PMON information is retrieved from
the discovery table (resides in an MMIO space populated by BIOS). It is
called the discovery method. The existing value of the type->num_boxes
is from the discovery table.
On some SPR variants, there is a firmware bug that makes the value from the
discovery table incorrect. We use the value from the
SPR_MSR_UNC_CBO_CONFIG MSR to replace the one from the discovery table:
38776cc45e ("perf/x86/uncore: Correct the number of CHAs on SPR")
Unfortunately, the SPR_MSR_UNC_CBO_CONFIG isn't available for the EMR
XCC (Always returns 0), but the above firmware bug doesn't impact the
EMR XCC.
Don't let the value from the MSR replace the existing value from the
discovery table.
Fixes: 38776cc45e ("perf/x86/uncore: Correct the number of CHAs on SPR")
Reported-by: Stephane Eranian <eranian@google.com>
Reported-by: Yunying Sun <yunying.sun@intel.com>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Yunying Sun <yunying.sun@intel.com>
Link: https://lore.kernel.org/r/20230905134248.496114-1-kan.liang@linux.intel.com
- Enable -Wenum-conversion warning option
- Refactor the rpm-pkg target
- Fix scripts/setlocalversion to consider annotated tags for rt-kernel
- Add a jump key feature for the search menu of 'make nconfig'
- Support Qt6 for 'make xconfig'
- Enable -Wformat-overflow, -Wformat-truncation, -Wstringop-overflow, and
-Wrestrict warnings for W=1 builds
- Replace <asm/export.h> with <linux/export.h> for alpha, ia64, and sparc
- Support DEB_BUILD_OPTIONS=parallel=N for the debian source package
- Refactor scripts/Makefile.modinst and fix some modules_sign issues
- Add a new Kconfig env variable to warn symbols that are not defined anywhere
- Show help messages of config fragments in 'make help'
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Merge tag 'kbuild-v6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild updates from Masahiro Yamada:
- Enable -Wenum-conversion warning option
- Refactor the rpm-pkg target
- Fix scripts/setlocalversion to consider annotated tags for rt-kernel
- Add a jump key feature for the search menu of 'make nconfig'
- Support Qt6 for 'make xconfig'
- Enable -Wformat-overflow, -Wformat-truncation, -Wstringop-overflow,
and -Wrestrict warnings for W=1 builds
- Replace <asm/export.h> with <linux/export.h> for alpha, ia64, and
sparc
- Support DEB_BUILD_OPTIONS=parallel=N for the debian source package
- Refactor scripts/Makefile.modinst and fix some modules_sign issues
- Add a new Kconfig env variable to warn symbols that are not defined
anywhere
- Show help messages of config fragments in 'make help'
* tag 'kbuild-v6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (62 commits)
kconfig: fix possible buffer overflow
kbuild: Show marked Kconfig fragments in "help"
kconfig: add warn-unknown-symbols sanity check
kbuild: dummy-tools: make MPROFILE_KERNEL checks work on BE
Documentation/llvm: refresh docs
modpost: Skip .llvm.call-graph-profile section check
kbuild: support modules_sign for external modules as well
kbuild: support 'make modules_sign' with CONFIG_MODULE_SIG_ALL=n
kbuild: move more module installation code to scripts/Makefile.modinst
kbuild: reduce the number of mkdir calls during modules_install
kbuild: remove $(MODLIB)/source symlink
kbuild: move depmod rule to scripts/Makefile.modinst
kbuild: add modules_sign to no-{compiler,sync-config}-targets
kbuild: do not run depmod for 'make modules_sign'
kbuild: deb-pkg: support DEB_BUILD_OPTIONS=parallel=N in debian/rules
alpha: remove <asm/export.h>
alpha: replace #include <asm/export.h> with #include <linux/export.h>
ia64: remove <asm/export.h>
ia64: replace #include <asm/export.h> with #include <linux/export.h>
sparc: remove <asm/export.h>
...
- Drop 32-bit checksum implementation and re-use it from arch/x86
- String function cleanup
- Fixes for -Wmissing-variable-declarations and -Wmissing-prototypes builds
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Merge tag 'uml-for-linus-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux
Pull UML updates from Richard Weinberger:
- Drop 32-bit checksum implementation and re-use it from arch/x86
- String function cleanup
- Fixes for -Wmissing-variable-declarations and -Wmissing-prototypes
builds
* tag 'uml-for-linus-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux:
um: virt-pci: fix missing declaration warning
um: Refactor deprecated strncpy to memcpy
um: fix 3 instances of -Wmissing-prototypes
um: port_kern: fix -Wmissing-variable-declarations
uml: audio: fix -Wmissing-variable-declarations
um: vector: refactor deprecated strncpy
um: use obj-y to descend into arch/um/*/
um: Hard-code the result of 'uname -s'
um: Use the x86 checksum implementation on 32-bit
asm-generic: current: Don't include thread-info.h if building asm
um: Remove unsued extern declaration ldt_host_info()
um: Fix hostaudio build errors
um: Remove strlcpy usage
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Merge tag 'hyperv-next-signed-20230902' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux
Pull hyperv updates from Wei Liu:
- Support for SEV-SNP guests on Hyper-V (Tianyu Lan)
- Support for TDX guests on Hyper-V (Dexuan Cui)
- Use SBRM API in Hyper-V balloon driver (Mitchell Levy)
- Avoid dereferencing ACPI root object handle in VMBus driver (Maciej
Szmigiero)
- A few misecllaneous fixes (Jiapeng Chong, Nathan Chancellor, Saurabh
Sengar)
* tag 'hyperv-next-signed-20230902' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux: (24 commits)
x86/hyperv: Remove duplicate include
x86/hyperv: Move the code in ivm.c around to avoid unnecessary ifdef's
x86/hyperv: Remove hv_isolation_type_en_snp
x86/hyperv: Use TDX GHCI to access some MSRs in a TDX VM with the paravisor
Drivers: hv: vmbus: Bring the post_msg_page back for TDX VMs with the paravisor
x86/hyperv: Introduce a global variable hyperv_paravisor_present
Drivers: hv: vmbus: Support >64 VPs for a fully enlightened TDX/SNP VM
x86/hyperv: Fix serial console interrupts for fully enlightened TDX guests
Drivers: hv: vmbus: Support fully enlightened TDX guests
x86/hyperv: Support hypercalls for fully enlightened TDX guests
x86/hyperv: Add hv_isolation_type_tdx() to detect TDX guests
x86/hyperv: Fix undefined reference to isolation_type_en_snp without CONFIG_HYPERV
x86/hyperv: Add missing 'inline' to hv_snp_boot_ap() stub
hv: hyperv.h: Replace one-element array with flexible-array member
Drivers: hv: vmbus: Don't dereference ACPI root object handle
x86/hyperv: Add hyperv-specific handling for VMMCALL under SEV-ES
x86/hyperv: Add smp support for SEV-SNP guest
clocksource: hyper-v: Mark hyperv tsc page unencrypted in sev-snp enlightened guest
x86/hyperv: Use vmmcall to implement Hyper-V hypercall in sev-snp enlightened guest
drivers: hv: Mark percpu hvcall input arg page unencrypted in SEV-SNP enlightened guest
...
Vasant reported that kexec() can hang or reset the machine when it tries to
park CPUs via INIT. This happens when the kernel is using extended APIC,
but the present mask has APIC IDs >= 0x100 enumerated.
As extended APIC can only handle 8 bit of APIC ID sending INIT to APIC ID
0x100 sends INIT to APIC ID 0x0. That's the boot CPU which is special on
x86 and INIT causes the system to hang or resets the machine.
Prevent this by sending INIT only to those CPUs which have been booted
once.
Fixes: 45e34c8af5 ("x86/smp: Put CPUs into INIT on shutdown if possible")
Reported-by: Dheeraj Kumar Srivastava <dheerajkumar.srivastava@amd.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Vasant Hegde <vasant.hegde@amd.com>
Link: https://lore.kernel.org/r/87cyzwjbff.ffs@tglx
Currently the Kconfig fragments in kernel/configs and arch/*/configs
that aren't used internally aren't discoverable through "make help",
which consists of hard-coded lists of config fragments. Instead, list
all the fragment targets that have a "# Help: " comment prefix so the
targets can be generated dynamically.
Add logic to the Makefile to search for and display the fragment and
comment. Add comments to fragments that are intended to be direct targets.
Signed-off-by: Kees Cook <keescook@chromium.org>
Co-developed-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
* Fix PKRU covert channel
* Fix -Wmissing-variable-declarations warning for ia32_xyz_class
* Fix kernel-doc annotation warning
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Merge tag 'x86-urgent-2023-09-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Dave Hansen:
"The most important fix here adds a missing CPU model to the recent
Gather Data Sampling (GDS) mitigation list to ensure that mitigations
are available on that CPU.
There are also a pair of warning fixes, and closure of a covert
channel that pops up when protection keys are disabled.
Summary:
- Mark all Skylake CPUs as vulnerable to GDS
- Fix PKRU covert channel
- Fix -Wmissing-variable-declarations warning for ia32_xyz_class
- Fix kernel-doc annotation warning"
* tag 'x86-urgent-2023-09-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/fpu/xstate: Fix PKRU covert channel
x86/irq/i8259: Fix kernel-doc annotation warning
x86/speculation: Mark all Skylake CPUs as vulnerable to GDS
x86/audit: Fix -Wmissing-variable-declarations warning for ia32_xyz_class
Here is the big set of char/misc and other small driver subsystem
changes for 6.6-rc1.
Stuff all over the place here, lots of driver updates and changes and
new additions. Short summary is:
- new IIO drivers and updates
- Interconnect driver updates
- fpga driver updates and additions
- fsi driver updates
- mei driver updates
- coresight driver updates
- nvmem driver updates
- counter driver updates
- lots of smaller misc and char driver updates and additions
All of these have been in linux-next for a long time with no reported
problems.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'char-misc-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc
Pull char/misc driver updates from Greg KH:
"Here is the big set of char/misc and other small driver subsystem
changes for 6.6-rc1.
Stuff all over the place here, lots of driver updates and changes and
new additions. Short summary is:
- new IIO drivers and updates
- Interconnect driver updates
- fpga driver updates and additions
- fsi driver updates
- mei driver updates
- coresight driver updates
- nvmem driver updates
- counter driver updates
- lots of smaller misc and char driver updates and additions
All of these have been in linux-next for a long time with no reported
problems"
* tag 'char-misc-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (267 commits)
nvmem: core: Notify when a new layout is registered
nvmem: core: Do not open-code existing functions
nvmem: core: Return NULL when no nvmem layout is found
nvmem: core: Create all cells before adding the nvmem device
nvmem: u-boot-env:: Replace zero-length array with DECLARE_FLEX_ARRAY() helper
nvmem: sec-qfprom: Add Qualcomm secure QFPROM support
dt-bindings: nvmem: sec-qfprom: Add bindings for secure qfprom
dt-bindings: nvmem: Add compatible for QCM2290
nvmem: Kconfig: Fix typo "drive" -> "driver"
nvmem: Explicitly include correct DT includes
nvmem: add new NXP QorIQ eFuse driver
dt-bindings: nvmem: Add t1023-sfp efuse support
dt-bindings: nvmem: qfprom: Add compatible for MSM8226
nvmem: uniphier: Use devm_platform_get_and_ioremap_resource()
nvmem: qfprom: do some cleanup
nvmem: stm32-romem: Use devm_platform_get_and_ioremap_resource()
nvmem: rockchip-efuse: Use devm_platform_get_and_ioremap_resource()
nvmem: meson-mx-efuse: Convert to devm_platform_ioremap_resource()
nvmem: lpc18xx_otp: Convert to devm_platform_ioremap_resource()
nvmem: brcm_nvram: Use devm_platform_get_and_ioremap_resource()
...
Here is a small set of driver core updates and additions for 6.6-rc1.
Included in here are:
- stable kernel documentation updates
- class structure const work from Ivan on various subsystems
- kernfs tweaks
- driver core tests!
- kobject sanity cleanups
- kobject structure reordering to save space
- driver core error code handling fixups
- other minor driver core cleanups
All of these have been in linux-next for a while with no reported
problems.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'driver-core-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
Pull driver core updates from Greg KH:
"Here is a small set of driver core updates and additions for 6.6-rc1.
Included in here are:
- stable kernel documentation updates
- class structure const work from Ivan on various subsystems
- kernfs tweaks
- driver core tests!
- kobject sanity cleanups
- kobject structure reordering to save space
- driver core error code handling fixups
- other minor driver core cleanups
All of these have been in linux-next for a while with no reported
problems"
* tag 'driver-core-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (32 commits)
driver core: Call in reversed order in device_platform_notify_remove()
driver core: Return proper error code when dev_set_name() fails
kobject: Remove redundant checks for whether ktype is NULL
kobject: Add sanity check for kset->kobj.ktype in kset_register()
drivers: base: test: Add missing MODULE_* macros to root device tests
drivers: base: test: Add missing MODULE_* macros for platform devices tests
drivers: base: Free devm resources when unregistering a device
drivers: base: Add basic devm tests for platform devices
drivers: base: Add basic devm tests for root devices
kernfs: fix missing kernfs_iattr_rwsem locking
docs: stable-kernel-rules: mention that regressions must be prevented
docs: stable-kernel-rules: fine-tune various details
docs: stable-kernel-rules: make the examples for option 1 a proper list
docs: stable-kernel-rules: move text around to improve flow
docs: stable-kernel-rules: improve structure by changing headlines
base/node: Remove duplicated include
kernfs: attach uuid for every kernfs and report it in fsid
kernfs: add stub helper for kernfs_generic_poll()
x86/resctrl: make pseudo_lock_class a static const structure
x86/MSR: make msr_class a static const structure
...
When XCR0[9] is set, PKRU can be read and written from userspace with
XSAVE and XRSTOR, even when CR4.PKE is clear.
Clear XCR0[9] when protection keys are disabled.
Reported-by: Tavis Ormandy <taviso@google.com>
Signed-off-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/r/20230831043228.1194256-1-jmattson@google.com
Convert IBT selftest to asm to fix objtool warning
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Merge tag 'x86_shstk_for_6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 shadow stack support from Dave Hansen:
"This is the long awaited x86 shadow stack support, part of Intel's
Control-flow Enforcement Technology (CET).
CET consists of two related security features: shadow stacks and
indirect branch tracking. This series implements just the shadow stack
part of this feature, and just for userspace.
The main use case for shadow stack is providing protection against
return oriented programming attacks. It works by maintaining a
secondary (shadow) stack using a special memory type that has
protections against modification. When executing a CALL instruction,
the processor pushes the return address to both the normal stack and
to the special permission shadow stack. Upon RET, the processor pops
the shadow stack copy and compares it to the normal stack copy.
For more information, refer to the links below for the earlier
versions of this patch set"
Link: https://lore.kernel.org/lkml/20220130211838.8382-1-rick.p.edgecombe@intel.com/
Link: https://lore.kernel.org/lkml/20230613001108.3040476-1-rick.p.edgecombe@intel.com/
* tag 'x86_shstk_for_6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (47 commits)
x86/shstk: Change order of __user in type
x86/ibt: Convert IBT selftest to asm
x86/shstk: Don't retry vm_munmap() on -EINTR
x86/kbuild: Fix Documentation/ reference
x86/shstk: Move arch detail comment out of core mm
x86/shstk: Add ARCH_SHSTK_STATUS
x86/shstk: Add ARCH_SHSTK_UNLOCK
x86: Add PTRACE interface for shadow stack
selftests/x86: Add shadow stack test
x86/cpufeatures: Enable CET CR4 bit for shadow stack
x86/shstk: Wire in shadow stack interface
x86: Expose thread features in /proc/$PID/status
x86/shstk: Support WRSS for userspace
x86/shstk: Introduce map_shadow_stack syscall
x86/shstk: Check that signal frame is shadow stack mem
x86/shstk: Check that SSP is aligned on sigreturn
x86/shstk: Handle signals for shadow stack
x86/shstk: Introduce routines modifying shstk
x86/shstk: Handle thread shadow stack
x86/shstk: Add user-mode shadow stack support
...
Fix this warning:
arch/x86/kernel/i8259.c:235: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
* ELCR registers (0x4d0, 0x4d1) control edge/level of IRQ
CC arch/x86/kernel/irqinit.o
Signed-off-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20230830131211.88226-1-vincenzopalazzodev@gmail.com
The Gather Data Sampling (GDS) vulnerability is common to all Skylake
processors. However, the "client" Skylakes* are now in this list:
https://www.intel.com/content/www/us/en/support/articles/000022396/processors.html
which means they are no longer included for new vulnerabilities here:
https://www.intel.com/content/www/us/en/developer/topic-technology/software-security-guidance/processors-affected-consolidated-product-cpu-model.html
or in other GDS documentation. Thus, they were not included in the
original GDS mitigation patches.
Mark SKYLAKE and SKYLAKE_L as vulnerable to GDS to match all the
other Skylake CPUs (which include Kaby Lake). Also group the CPUs
so that the ones that share the exact same vulnerabilities are next
to each other.
Last, move SRBDS to the end of each line. This makes it clear at a
glance that SKYLAKE_X is unique. Of the five Skylakes, it is the
only "server" CPU and has a different implementation from the
clients of the "special register" hardware, making it immune to SRBDS.
This makes the diff much harder to read, but the resulting table is
worth it.
I very much appreciate the report from Michael Zhivich about this
issue. Despite what level of support a hardware vendor is providing,
the kernel very much needs an accurate and up-to-date list of
vulnerable CPUs. More reports like this are very welcome.
* Client Skylakes are CPUID 406E3/506E3 which is family 6, models
0x4E and 0x5E, aka INTEL_FAM6_SKYLAKE and INTEL_FAM6_SKYLAKE_L.
Reported-by: Michael Zhivich <mzhivich@akamai.com>
Fixes: 8974eb5882 ("x86/speculation: Add Gather Data Sampling mitigation")
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Explicitly include mmu.h in spte.h instead of relying on the "parent" to
include mmu.h. spte.h references a variety of macros and variables that
are defined/declared in mmu.h, and so including spte.h before (or instead
of) mmu.h will result in build errors, e.g.
arch/x86/kvm/mmu/spte.h: In function ‘is_mmio_spte’:
arch/x86/kvm/mmu/spte.h:242:23: error: ‘enable_mmio_caching’ undeclared
242 | likely(enable_mmio_caching);
| ^~~~~~~~~~~~~~~~~~~
arch/x86/kvm/mmu/spte.h: In function ‘is_large_pte’:
arch/x86/kvm/mmu/spte.h:302:22: error: ‘PT_PAGE_SIZE_MASK’ undeclared
302 | return pte & PT_PAGE_SIZE_MASK;
| ^~~~~~~~~~~~~~~~~
arch/x86/kvm/mmu/spte.h: In function ‘is_dirty_spte’:
arch/x86/kvm/mmu/spte.h:332:56: error: ‘PT_WRITABLE_MASK’ undeclared
332 | return dirty_mask ? spte & dirty_mask : spte & PT_WRITABLE_MASK;
| ^~~~~~~~~~~~~~~~
Fixes: 5a9624affe ("KVM: mmu: extract spte.h and spte.c")
Link: https://lore.kernel.org/r/20230808224059.2492476-1-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
When attempting to allocate a shadow root for a !visible guest root gfn,
e.g. that resides in MMIO space, load a dummy root that is backed by the
zero page instead of immediately synthesizing a triple fault shutdown
(using the zero page ensures any attempt to translate memory will generate
a !PRESENT fault and thus VM-Exit).
Unless the vCPU is racing with memslot activity, KVM will inject a page
fault due to not finding a visible slot in FNAME(walk_addr_generic), i.e.
the end result is mostly same, but critically KVM will inject a fault only
*after* KVM runs the vCPU with the bogus root.
Waiting to inject a fault until after running the vCPU fixes a bug where
KVM would bail from nested VM-Enter if L1 tried to run L2 with TDP enabled
and a !visible root. Even though a bad root will *probably* lead to
shutdown, (a) it's not guaranteed and (b) the CPU won't read the
underlying memory until after VM-Enter succeeds. E.g. if L1 runs L2 with
a VMX preemption timer value of '0', then architecturally the preemption
timer VM-Exit is guaranteed to occur before the CPU executes any
instruction, i.e. before the CPU needs to translate a GPA to a HPA (so
long as there are no injected events with higher priority than the
preemption timer).
If KVM manages to get to FNAME(fetch) with a dummy root, e.g. because
userspace created a memslot between installing the dummy root and handling
the page fault, simply unload the MMU to allocate a new root and retry the
instruction. Use KVM_REQ_MMU_FREE_OBSOLETE_ROOTS to drop the root, as
invoking kvm_mmu_free_roots() while holding mmu_lock would deadlock, and
conceptually the dummy root has indeeed become obsolete. The only
difference versus existing usage of KVM_REQ_MMU_FREE_OBSOLETE_ROOTS is
that the root has become obsolete due to memslot *creation*, not memslot
deletion or movement.
Reported-by: Reima Ishii <ishiir@g.ecc.u-tokyo.ac.jp>
Cc: Yu Zhang <yu.c.zhang@linux.intel.com>
Link: https://lore.kernel.org/r/20230729005200.1057358-6-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Explicitly inject a page fault if guest attempts to use a !visible gfn
as a page table. kvm_vcpu_gfn_to_hva_prot() will naturally handle the
case where there is no memslot, but doesn't catch the scenario where the
gfn points at a KVM-internal memslot.
Letting the guest backdoor its way into accessing KVM-internal memslots
isn't dangerous on its own, e.g. at worst the guest can crash itself, but
disallowing the behavior will simplify fixing how KVM handles !visible
guest root gfns (immediately synthesizing a triple fault when loading the
root is architecturally wrong).
Link: https://lore.kernel.org/r/20230729005200.1057358-5-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Explicitly check that tdp_iter_start() is handed a valid shadow page
to harden KVM against bugs, e.g. if KVM calls into the TDP MMU with an
invalid or shadow MMU root (which would be a fatal KVM bug), the shadow
page pointer will be NULL.
Opportunistically stop the TDP MMU iteration instead of continuing on
with garbage if the incoming root is bogus. Attempting to walk a garbage
root is more likely to caused major problems than doing nothing.
Cc: Yu Zhang <yu.c.zhang@linux.intel.com>
Link: https://lore.kernel.org/r/20230729005200.1057358-4-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Harden kvm_mmu_new_pgd() against NULL pointer dereference bugs by sanity
checking that the target root has an associated shadow page prior to
dereferencing said shadow page. The code in question is guaranteed to
only see roots with shadow pages as fast_pgd_switch() explicitly frees the
current root if it doesn't have a shadow page, i.e. is a PAE root, and
that in turn prevents valid roots from being cached, but that's all very
subtle.
Link: https://lore.kernel.org/r/20230729005200.1057358-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Add a dedicated helper for converting a root hpa to a shadow page in
anticipation of using a "dummy" root to handle the scenario where KVM
needs to load a valid shadow root (from hardware's perspective), but
the guest doesn't have a visible root to shadow. Similar to PAE roots,
the dummy root won't have an associated kvm_mmu_page and will need special
handling when finding a shadow page given a root.
Opportunistically retrieve the root shadow page in kvm_mmu_sync_roots()
*after* verifying the root is unsync (the dummy root can never be unsync).
Link: https://lore.kernel.org/r/20230729005200.1057358-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Get/put references to KVM when a page-track notifier is (un)registered
instead of relying on the caller to do so. Forcing the caller to do the
bookkeeping is unnecessary and adds one more thing for users to get
wrong, e.g. see commit 9ed1fdee9e ("drm/i915/gvt: Get reference to KVM
iff attachment to VM is successful").
Reviewed-by: Yan Zhao <yan.y.zhao@intel.com>
Tested-by: Yongwei Ma <yongwei.ma@intel.com>
Link: https://lore.kernel.org/r/20230729013535.1070024-29-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Refactor KVM's exported/external page-track, a.k.a. write-track, APIs
to take only the gfn and do the required memslot lookup in KVM proper.
Forcing users of the APIs to get the memslot unnecessarily bleeds
KVM internals into KVMGT and complicates usage of the APIs.
No functional change intended.
Reviewed-by: Yan Zhao <yan.y.zhao@intel.com>
Tested-by: Yongwei Ma <yongwei.ma@intel.com>
Link: https://lore.kernel.org/r/20230729013535.1070024-28-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Bug the VM if something attempts to write-track a gfn, but write-tracking
isn't enabled. The VM is doomed (and KVM has an egregious bug) if KVM or
KVMGT wants to shadow guest page tables but can't because write-tracking
isn't enabled.
Tested-by: Yongwei Ma <yongwei.ma@intel.com>
Link: https://lore.kernel.org/r/20230729013535.1070024-27-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
When adding/removing gfns to/from write-tracking, assert that mmu_lock
is held for write, and that either slots_lock or kvm->srcu is held.
mmu_lock must be held for write to protect gfn_write_track's refcount,
and SRCU or slots_lock must be held to protect the memslot itself.
Tested-by: Yan Zhao <yan.y.zhao@intel.com>
Tested-by: Yongwei Ma <yongwei.ma@intel.com>
Link: https://lore.kernel.org/r/20230729013535.1070024-26-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Rename the page-track APIs to capture that they're all about tracking
writes, now that the facade of supporting multiple modes is gone.
Opportunstically replace "slot" with "gfn" in anticipation of removing
the @slot param from the external APIs.
No functional change intended.
Tested-by: Yongwei Ma <yongwei.ma@intel.com>
Link: https://lore.kernel.org/r/20230729013535.1070024-25-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Drop "support" for multiple page-track modes, as there is no evidence
that array-based and refcounted metadata is the optimal solution for
other modes, nor is there any evidence that other use cases, e.g. for
access-tracking, will be a good fit for the page-track machinery in
general.
E.g. one potential use case of access-tracking would be to prevent guest
access to poisoned memory (from the guest's perspective). In that case,
the number of poisoned pages is likely to be a very small percentage of
the guest memory, and there is no need to reference count the number of
access-tracking users, i.e. expanding gfn_track[] for a new mode would be
grossly inefficient. And for poisoned memory, host userspace would also
likely want to trap accesses, e.g. to inject #MC into the guest, and that
isn't currently supported by the page-track framework.
A better alternative for that poisoned page use case is likely a
variation of the proposed per-gfn attributes overlay (linked), which
would allow efficiently tracking the sparse set of poisoned pages, and by
default would exit to userspace on access.
Link: https://lore.kernel.org/all/Y2WB48kD0J4VGynX@google.com
Cc: Ben Gardon <bgardon@google.com>
Tested-by: Yongwei Ma <yongwei.ma@intel.com>
Link: https://lore.kernel.org/r/20230729013535.1070024-24-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Disable the page-track notifier code at compile time if there are no
external users, i.e. if CONFIG_KVM_EXTERNAL_WRITE_TRACKING=n. KVM itself
now hooks emulated writes directly instead of relying on the page-track
mechanism.
Provide a stub for "struct kvm_page_track_notifier_node" so that including
headers directly from the command line, e.g. for testing include guards,
doesn't fail due to a struct having an incomplete type.
Reviewed-by: Yan Zhao <yan.y.zhao@intel.com>
Tested-by: Yongwei Ma <yongwei.ma@intel.com>
Link: https://lore.kernel.org/r/20230729013535.1070024-23-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Bury the declaration of the page-track helpers that are intended only for
internal KVM use in a "private" header. In addition to guarding against
unwanted usage of the internal-only helpers, dropping their definitions
avoids exposing other structures that should be KVM-internal, e.g. for
memslots. This is a baby step toward making kvm_host.h a KVM-internal
header in the very distant future.
Tested-by: Yongwei Ma <yongwei.ma@intel.com>
Link: https://lore.kernel.org/r/20230729013535.1070024-22-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Remove ->track_remove_slot(), there are no longer any users and it's
unlikely a "flush" hook will ever be the correct API to provide to an
external page-track user.
Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Yan Zhao <yan.y.zhao@intel.com>
Tested-by: Yongwei Ma <yongwei.ma@intel.com>
Link: https://lore.kernel.org/r/20230729013535.1070024-21-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Add a new page-track hook, track_remove_region(), that is called when a
memslot DELETE operation is about to be committed. The "remove" hook
will be used by KVMGT and will effectively replace the existing
track_flush_slot() altogether now that KVM itself doesn't rely on the
"flush" hook either.
The "flush" hook is flawed as it's invoked before the memslot operation
is guaranteed to succeed, i.e. KVM might ultimately keep the existing
memslot without notifying external page track users, a.k.a. KVMGT. In
practice, this can't currently happen on x86, but there are no guarantees
that won't change in the future, not to mention that "flush" does a very
poor job of describing what is happening.
Pass in the gfn+nr_pages instead of the slot itself so external users,
i.e. KVMGT, don't need to exposed to KVM internals (memslots). This will
help set the stage for additional cleanups to the page-track APIs.
Opportunistically align the existing srcu_read_lock_held() usage so that
the new case doesn't stand out like a sore thumb (and not aligning the
new code makes bots unhappy).
Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
Tested-by: Yongwei Ma <yongwei.ma@intel.com>
Signed-off-by: Yan Zhao <yan.y.zhao@intel.com>
Co-developed-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20230729013535.1070024-19-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Tom Lendacky