Commit Graph

1036 Commits

Author SHA1 Message Date
Oliver Upton b74ed7a68e KVM: Actually create debugfs in kvm_create_vm()
Doing debugfs creation after vm creation leaves things in a
quasi-initialized state for a while. This is further complicated by the
fact that we tear down debugfs from kvm_destroy_vm(). Align debugfs and
stats init/destroy with the vm init/destroy pattern to avoid any
headaches.

Note the fix for a benign mistake in error handling for calls to
kvm_arch_create_vm_debugfs() rolled in. Since all implementations of
the function return 0 unconditionally it isn't actually a bug at
the moment.

Lastly, tear down debugfs/stats data in the kvm_create_vm_debugfs()
error path. Previously it was safe to assume that kvm_destroy_vm() would
take out the garbage, that is no longer the case.

Signed-off-by: Oliver Upton <oupton@google.com>
Message-Id: <20220720092259.3491733-6-oliver.upton@linux.dev>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-08-10 15:08:28 -04:00
Oliver Upton 59f82aad59 KVM: Pass the name of the VM fd to kvm_create_vm_debugfs()
At the time the VM fd is used in kvm_create_vm_debugfs(), the fd has
been allocated but not yet installed. It is only really useful as an
identifier in strings for the VM (such as debugfs).

Treat it exactly as such by passing the string name of the fd to
kvm_create_vm_debugfs(), futureproofing against possible misuse of the
VM fd.

Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Oliver Upton <oupton@google.com>
Message-Id: <20220720092259.3491733-5-oliver.upton@linux.dev>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-08-10 15:08:28 -04:00
Oliver Upton 20020f4cf2 KVM: Get an fd before creating the VM
Allocate a VM's fd at the very beginning of kvm_dev_ioctl_create_vm() so
that KVM can use the fd value to generate strigns, e.g. for debugfs,
when creating and initializing the VM.

Signed-off-by: Oliver Upton <oupton@google.com>
Message-Id: <20220720092259.3491733-4-oliver.upton@linux.dev>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-08-10 15:08:27 -04:00
Oliver Upton 58fc116645 KVM: Shove vcpu stats_id init into kvm_vcpu_init()
Initialize stats_id alongside other kvm_vcpu fields to make it more
difficult to unintentionally access stats_id before it's set.

No functional change intended.

Signed-off-by: Oliver Upton <oupton@google.com>
Message-Id: <20220720092259.3491733-3-oliver.upton@linux.dev>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-08-10 15:08:27 -04:00
Oliver Upton f2759c08d8 KVM: Shove vm stats_id init into kvm_create_vm()
Initialize stats_id alongside other struct kvm fields to make it more
difficult to unintentionally access stats_id before it's set.  While at
it, move the format string to the first line of the call and fix the
indentation of the second line.

No functional change intended.

Signed-off-by: Oliver Upton <oupton@google.com>
Message-Id: <20220720092259.3491733-2-oliver.upton@linux.dev>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-08-10 15:08:27 -04:00
Paolo Bonzini 63f4b21041 Merge remote-tracking branch 'kvm/next' into kvm-next-5.20
KVM/s390, KVM/x86 and common infrastructure changes for 5.20

x86:

* Permit guests to ignore single-bit ECC errors

* Fix races in gfn->pfn cache refresh; do not pin pages tracked by the cache

* Intel IPI virtualization

* Allow getting/setting pending triple fault with KVM_GET/SET_VCPU_EVENTS

* PEBS virtualization

* Simplify PMU emulation by just using PERF_TYPE_RAW events

* More accurate event reinjection on SVM (avoid retrying instructions)

* Allow getting/setting the state of the speaker port data bit

* Refuse starting the kvm-intel module if VM-Entry/VM-Exit controls are inconsistent

* "Notify" VM exit (detect microarchitectural hangs) for Intel

* Cleanups for MCE MSR emulation

s390:

* add an interface to provide a hypervisor dump for secure guests

* improve selftests to use TAP interface

* enable interpretive execution of zPCI instructions (for PCI passthrough)

* First part of deferred teardown

* CPU Topology

* PV attestation

* Minor fixes

Generic:

* new selftests API using struct kvm_vcpu instead of a (vm, id) tuple

x86:

* Use try_cmpxchg64 instead of cmpxchg64

* Bugfixes

* Ignore benign host accesses to PMU MSRs when PMU is disabled

* Allow disabling KVM's "MONITOR/MWAIT are NOPs!" behavior

* x86/MMU: Allow NX huge pages to be disabled on a per-vm basis

* Port eager page splitting to shadow MMU as well

* Enable CMCI capability by default and handle injected UCNA errors

* Expose pid of vcpu threads in debugfs

* x2AVIC support for AMD

* cleanup PIO emulation

* Fixes for LLDT/LTR emulation

* Don't require refcounted "struct page" to create huge SPTEs

x86 cleanups:

* Use separate namespaces for guest PTEs and shadow PTEs bitmasks

* PIO emulation

* Reorganize rmap API, mostly around rmap destruction

* Do not workaround very old KVM bugs for L0 that runs with nesting enabled

* new selftests API for CPUID
2022-08-01 03:21:00 -04:00
Anup Patel 4ab0e470c0 KVM: Add gfp_custom flag in struct kvm_mmu_memory_cache
The kvm_mmu_topup_memory_cache() always uses GFP_KERNEL_ACCOUNT for
memory allocation which prevents it's use in atomic context. To address
this limitation of kvm_mmu_topup_memory_cache(), we add gfp_custom flag
in struct kvm_mmu_memory_cache. When the gfp_custom flag is set to some
GFP_xyz flags, the kvm_mmu_topup_memory_cache() will use that instead of
GFP_KERNEL_ACCOUNT.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
Signed-off-by: Anup Patel <anup@brainfault.org>
2022-07-29 17:15:00 +05:30
Vineeth Pillai e36de87d34 KVM: debugfs: expose pid of vcpu threads
Add a new debugfs file to expose the pid of each vcpu threads. This
is very helpful for userland tools to get the vcpu pids without
worrying about thread naming conventions of the VMM.

Signed-off-by: Vineeth Pillai (Google) <vineeth@bitbyteword.org>
Message-Id: <20220523190327.2658-1-vineeth@bitbyteword.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-24 12:44:33 -04:00
David Matlack 837f66c712 KVM: Allow for different capacities in kvm_mmu_memory_cache structs
Allow the capacity of the kvm_mmu_memory_cache struct to be chosen at
declaration time rather than being fixed for all declarations. This will
be used in a follow-up commit to declare an cache in x86 with a capacity
of 512+ objects without having to increase the capacity of all caches in
KVM.

This change requires each cache now specify its capacity at runtime,
since the cache struct itself no longer has a fixed capacity known at
compile time. To protect against someone accidentally defining a
kvm_mmu_memory_cache struct directly (without the extra storage), this
commit includes a WARN_ON() in kvm_mmu_topup_memory_cache().

In order to support different capacities, this commit changes the
objects pointer array to be dynamically allocated the first time the
cache is topped-up.

While here, opportunistically clean up the stack-allocated
kvm_mmu_memory_cache structs in riscv and arm64 to use designated
initializers.

No functional change intended.

Reviewed-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: David Matlack <dmatlack@google.com>
Message-Id: <20220516232138.1783324-22-dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-24 04:52:00 -04:00
Sean Christopherson 943dfea8f1 KVM: Do not zero initialize 'pfn' in hva_to_pfn()
Drop the unnecessary initialization of the local 'pfn' variable in
hva_to_pfn().  First and foremost, '0' is not an invalid pfn, it's a
perfectly valid pfn on most architectures.  I.e. if hva_to_pfn() were to
return an "uninitializd" pfn, it would actually be interpeted as a legal
pfn by most callers.

Second, hva_to_pfn() can't return an uninitialized pfn as hva_to_pfn()
explicitly sets pfn to an error value (or returns an error value directly)
if a helper returns failure, and all helpers set the pfn on success.

The zeroing of 'pfn' was introduced by commit 2fc843117d ("KVM:
reorganize hva_to_pfn"), probably to avoid "uninitialized variable"
warnings on statements that return pfn.  However, no compiler seems
to produce them, making the initialization unnecessary.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220429010416.2788472-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-20 06:21:36 -04:00
Sean Christopherson b14b2690c5 KVM: Rename/refactor kvm_is_reserved_pfn() to kvm_pfn_to_refcounted_page()
Rename and refactor kvm_is_reserved_pfn() to kvm_pfn_to_refcounted_page()
to better reflect what KVM is actually checking, and to eliminate extra
pfn_to_page() lookups.  The kvm_release_pfn_*() an kvm_try_get_pfn()
helpers in particular benefit from "refouncted" nomenclature, as it's not
all that obvious why KVM needs to get/put refcounts for some PG_reserved
pages (ZERO_PAGE and ZONE_DEVICE).

Add a comment to call out that the list of exceptions to PG_reserved is
all but guaranteed to be incomplete.  The list has mostly been compiled
by people throwing noodles at KVM and finding out they stick a little too
well, e.g. the ZERO_PAGE's refcount overflowed and ZONE_DEVICE pages
didn't get freed.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220429010416.2788472-10-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-20 06:21:35 -04:00
Sean Christopherson 284dc49307 KVM: Take a 'struct page', not a pfn in kvm_is_zone_device_page()
Operate on a 'struct page' instead of a pfn when checking if a page is a
ZONE_DEVICE page, and rename the helper accordingly.  Generally speaking,
KVM doesn't actually care about ZONE_DEVICE memory, i.e. shouldn't do
anything special for ZONE_DEVICE memory.  Rather, KVM wants to treat
ZONE_DEVICE memory like regular memory, and the need to identify
ZONE_DEVICE memory only arises as an exception to PG_reserved pages. In
other words, KVM should only ever check for ZONE_DEVICE memory after KVM
has already verified that there is a struct page associated with the pfn.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220429010416.2788472-9-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-20 06:21:34 -04:00
Sean Christopherson b1624f99aa KVM: Remove kvm_vcpu_gfn_to_page() and kvm_vcpu_gpa_to_page()
Drop helpers to convert a gfn/gpa to a 'struct page' in the context of a
vCPU.  KVM doesn't require that guests be backed by 'struct page' memory,
thus any use of helpers that assume 'struct page' is bound to be flawed,
as was the case for the recently removed last user in x86's nested VMX.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220429010416.2788472-8-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-20 06:21:34 -04:00
Sean Christopherson 6573a6910c KVM: Don't WARN if kvm_pfn_to_page() encounters a "reserved" pfn
Drop a WARN_ON() if kvm_pfn_to_page() encounters a "reserved" pfn, which
in this context means a struct page that has PG_reserved but is not a/the
ZERO_PAGE and is not a ZONE_DEVICE page.  The usage, via gfn_to_page(),
in x86 is safe as gfn_to_page() is used only to retrieve a page from
KVM-controlled memslot, but the usage in PPC and s390 operates on
arbitrary gfns and thus memslots that can be backed by incompatible
memory.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220429010416.2788472-7-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-20 06:21:33 -04:00
Sean Christopherson 8e1c69149f KVM: Avoid pfn_to_page() and vice versa when releasing pages
Invert the order of KVM's page/pfn release helpers so that the "inner"
helper operates on a page instead of a pfn.  As pointed out by Linus[*],
converting between struct page and a pfn isn't necessarily cheap, and
that's not even counting the overhead of is_error_noslot_pfn() and
kvm_is_reserved_pfn().  Even if the checks were dirt cheap, there's no
reason to convert from a page to a pfn and back to a page, just to mark
the page dirty/accessed or to put a reference to the page.

Opportunistically drop a stale declaration of kvm_set_page_accessed()
from kvm_host.h (there was no implementation).

No functional change intended.

[*] https://lore.kernel.org/all/CAHk-=wifQimj2d6npq-wCi5onYPjzQg4vyO4tFcPJJZr268cRw@mail.gmail.com

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220429010416.2788472-5-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-20 06:21:32 -04:00
Sean Christopherson a1040b0d42 KVM: Don't set Accessed/Dirty bits for ZERO_PAGE
Don't set Accessed/Dirty bits for a struct page with PG_reserved set,
i.e. don't set A/D bits for the ZERO_PAGE.  The ZERO_PAGE (or pages
depending on the architecture) should obviously never be written, and
similarly there's no point in marking it accessed as the page will never
be swapped out or reclaimed.  The comment in page-flags.h is quite clear
that PG_reserved pages should be managed only by their owner, and
strictly following that mandate also simplifies KVM's logic.

Fixes: 7df003c852 ("KVM: fix overflow of zero page refcount with ksm running")
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220429010416.2788472-4-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-20 06:21:31 -04:00
Sean Christopherson 28b85ae06f KVM: Drop bogus "pfn != 0" guard from kvm_release_pfn()
Remove a check from kvm_release_pfn() to bail if the provided @pfn is
zero.  Zero is a perfectly valid pfn on most architectures, and should
not be used to indicate an error or an invalid pfn.  The bogus check was
added by commit 917248144d ("x86/kvm: Cache gfn to pfn translation"),
which also did the bad thing of zeroing the pfn and gfn to mark a cache
invalid.  Thankfully, that bad behavior was axed by commit 357a18ad23
("KVM: Kill kvm_map_gfn() / kvm_unmap_gfn() and gfn_to_pfn_cache").

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220429010416.2788472-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-20 06:21:31 -04:00
Lai Jiangshan f24b44e48d KVM: Rename ack_flush() to ack_kick()
Make it use the same verb as in kvm_kick_many_cpus().

Signed-off-by: Lai Jiangshan <jiangshan.ljs@antgroup.com>
Message-Id: <20220605063417.308311-5-jiangshanlai@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-15 08:07:53 -04:00
Paolo Bonzini e15f5e6fa6 Merge branch 'kvm-5.20-early'
s390:

* add an interface to provide a hypervisor dump for secure guests

* improve selftests to show tests

x86:

* Intel IPI virtualization

* Allow getting/setting pending triple fault with KVM_GET/SET_VCPU_EVENTS

* PEBS virtualization

* Simplify PMU emulation by just using PERF_TYPE_RAW events

* More accurate event reinjection on SVM (avoid retrying instructions)

* Allow getting/setting the state of the speaker port data bit

* Rewrite gfn-pfn cache refresh

* Refuse starting the module if VM-Entry/VM-Exit controls are inconsistent

* "Notify" VM exit
2022-06-09 11:38:12 -04:00
Maxim Levitsky 18869f26df KVM: x86: disable preemption around the call to kvm_arch_vcpu_{un|}blocking
On SVM, if preemption happens right after the call to finish_rcuwait
but before call to kvm_arch_vcpu_unblocking on SVM/AVIC, it itself
will re-enable AVIC, and then we will try to re-enable it again
in kvm_arch_vcpu_unblocking which will lead to a warning
in __avic_vcpu_load.

The same problem can happen if the vCPU is preempted right after the call
to kvm_arch_vcpu_blocking but before the call to prepare_to_rcuwait
and in this case, we will end up with AVIC enabled during sleep -
Ooops.

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20220606180829.102503-7-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-09 10:52:20 -04:00
Paolo Bonzini 66da65005a KVM/riscv fixes for 5.19, take #1
- Typo fix in arch/riscv/kvm/vmid.c
 
 - Remove broken reference pattern from MAINTAINERS entry
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Merge tag 'kvm-riscv-fixes-5.19-1' of https://github.com/kvm-riscv/linux into HEAD

KVM/riscv fixes for 5.19, take #1

- Typo fix in arch/riscv/kvm/vmid.c

- Remove broken reference pattern from MAINTAINERS entry
2022-06-09 09:45:00 -04:00
Zeng Guang 1d5e740d51 KVM: Move kvm_arch_vcpu_precreate() under kvm->lock
kvm_arch_vcpu_precreate() targets to handle arch specific VM resource
to be prepared prior to the actual creation of vCPU. For example, x86
platform may need do per-VM allocation based on max_vcpu_ids at the
first vCPU creation. It probably leads to concurrency control on this
allocation as multiple vCPU creation could happen simultaneously. From
the architectual point of view, it's necessary to execute
kvm_arch_vcpu_precreate() under protect of kvm->lock.

Currently only arm64, x86 and s390 have non-nop implementations at the
stage of vCPU pre-creation. Remove the lock acquiring in s390's design
and make sure all architecture can run kvm_arch_vcpu_precreate() safely
under kvm->lock without recrusive lock issue.

Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Zeng Guang <guang.zeng@intel.com>
Message-Id: <20220419154409.11842-1-guang.zeng@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-08 04:47:28 -04:00
Paolo Bonzini b31455e96f Merge branch 'kvm-5.20-early-patches' into HEAD 2022-06-07 12:06:39 -04:00
Paolo Bonzini a280e35846 Merge branch 'kvm-5.19-early-fixes' into HEAD 2022-06-07 12:06:02 -04:00
Alexey Kardashevskiy e8bc242701 KVM: Don't null dereference ops->destroy
A KVM device cleanup happens in either of two callbacks:
1) destroy() which is called when the VM is being destroyed;
2) release() which is called when a device fd is closed.

Most KVM devices use 1) but Book3s's interrupt controller KVM devices
(XICS, XIVE, XIVE-native) use 2) as they need to close and reopen during
the machine execution. The error handling in kvm_ioctl_create_device()
assumes destroy() is always defined which leads to NULL dereference as
discovered by Syzkaller.

This adds a checks for destroy!=NULL and adds a missing release().

This is not changing kvm_destroy_devices() as devices with defined
release() should have been removed from the KVM devices list by then.

Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-07 11:18:59 -04:00
Linus Torvalds bf9095424d S390:
* ultravisor communication device driver
 
 * fix TEID on terminating storage key ops
 
 RISC-V:
 
 * Added Sv57x4 support for G-stage page table
 
 * Added range based local HFENCE functions
 
 * Added remote HFENCE functions based on VCPU requests
 
 * Added ISA extension registers in ONE_REG interface
 
 * Updated KVM RISC-V maintainers entry to cover selftests support
 
 ARM:
 
 * Add support for the ARMv8.6 WFxT extension
 
 * Guard pages for the EL2 stacks
 
 * Trap and emulate AArch32 ID registers to hide unsupported features
 
 * Ability to select and save/restore the set of hypercalls exposed
   to the guest
 
 * Support for PSCI-initiated suspend in collaboration with userspace
 
 * GICv3 register-based LPI invalidation support
 
 * Move host PMU event merging into the vcpu data structure
 
 * GICv3 ITS save/restore fixes
 
 * The usual set of small-scale cleanups and fixes
 
 x86:
 
 * New ioctls to get/set TSC frequency for a whole VM
 
 * Allow userspace to opt out of hypercall patching
 
 * Only do MSR filtering for MSRs accessed by rdmsr/wrmsr
 
 AMD SEV improvements:
 
 * Add KVM_EXIT_SHUTDOWN metadata for SEV-ES
 
 * V_TSC_AUX support
 
 Nested virtualization improvements for AMD:
 
 * Support for "nested nested" optimizations (nested vVMLOAD/VMSAVE,
   nested vGIF)
 
 * Allow AVIC to co-exist with a nested guest running
 
 * Fixes for LBR virtualizations when a nested guest is running,
   and nested LBR virtualization support
 
 * PAUSE filtering for nested hypervisors
 
 Guest support:
 
 * Decoupling of vcpu_is_preempted from PV spinlocks
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull kvm updates from Paolo Bonzini:
 "S390:

   - ultravisor communication device driver

   - fix TEID on terminating storage key ops

  RISC-V:

   - Added Sv57x4 support for G-stage page table

   - Added range based local HFENCE functions

   - Added remote HFENCE functions based on VCPU requests

   - Added ISA extension registers in ONE_REG interface

   - Updated KVM RISC-V maintainers entry to cover selftests support

  ARM:

   - Add support for the ARMv8.6 WFxT extension

   - Guard pages for the EL2 stacks

   - Trap and emulate AArch32 ID registers to hide unsupported features

   - Ability to select and save/restore the set of hypercalls exposed to
     the guest

   - Support for PSCI-initiated suspend in collaboration with userspace

   - GICv3 register-based LPI invalidation support

   - Move host PMU event merging into the vcpu data structure

   - GICv3 ITS save/restore fixes

   - The usual set of small-scale cleanups and fixes

  x86:

   - New ioctls to get/set TSC frequency for a whole VM

   - Allow userspace to opt out of hypercall patching

   - Only do MSR filtering for MSRs accessed by rdmsr/wrmsr

  AMD SEV improvements:

   - Add KVM_EXIT_SHUTDOWN metadata for SEV-ES

   - V_TSC_AUX support

  Nested virtualization improvements for AMD:

   - Support for "nested nested" optimizations (nested vVMLOAD/VMSAVE,
     nested vGIF)

   - Allow AVIC to co-exist with a nested guest running

   - Fixes for LBR virtualizations when a nested guest is running, and
     nested LBR virtualization support

   - PAUSE filtering for nested hypervisors

  Guest support:

   - Decoupling of vcpu_is_preempted from PV spinlocks"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (199 commits)
  KVM: x86: Fix the intel_pt PMI handling wrongly considered from guest
  KVM: selftests: x86: Sync the new name of the test case to .gitignore
  Documentation: kvm: reorder ARM-specific section about KVM_SYSTEM_EVENT_SUSPEND
  x86, kvm: use correct GFP flags for preemption disabled
  KVM: LAPIC: Drop pending LAPIC timer injection when canceling the timer
  x86/kvm: Alloc dummy async #PF token outside of raw spinlock
  KVM: x86: avoid calling x86 emulator without a decoded instruction
  KVM: SVM: Use kzalloc for sev ioctl interfaces to prevent kernel data leak
  x86/fpu: KVM: Set the base guest FPU uABI size to sizeof(struct kvm_xsave)
  s390/uv_uapi: depend on CONFIG_S390
  KVM: selftests: x86: Fix test failure on arch lbr capable platforms
  KVM: LAPIC: Trace LAPIC timer expiration on every vmentry
  KVM: s390: selftest: Test suppression indication on key prot exception
  KVM: s390: Don't indicate suppression on dirtying, failing memop
  selftests: drivers/s390x: Add uvdevice tests
  drivers/s390/char: Add Ultravisor io device
  MAINTAINERS: Update KVM RISC-V entry to cover selftests support
  RISC-V: KVM: Introduce ISA extension register
  RISC-V: KVM: Cleanup stale TLB entries when host CPU changes
  RISC-V: KVM: Add remote HFENCE functions based on VCPU requests
  ...
2022-05-26 14:20:14 -07:00
Sean Christopherson 58cd407ca4 KVM: Fix multiple races in gfn=>pfn cache refresh
Rework the gfn=>pfn cache (gpc) refresh logic to address multiple races
between the cache itself, and between the cache and mmu_notifier events.

The existing refresh code attempts to guard against races with the
mmu_notifier by speculatively marking the cache valid, and then marking
it invalid if a mmu_notifier invalidation occurs.  That handles the case
where an invalidation occurs between dropping and re-acquiring gpc->lock,
but it doesn't handle the scenario where the cache is refreshed after the
cache was invalidated by the notifier, but before the notifier elevates
mmu_notifier_count.  The gpc refresh can't use the "retry" helper as its
invalidation occurs _before_ mmu_notifier_count is elevated and before
mmu_notifier_range_start is set/updated.

  CPU0                                    CPU1
  ----                                    ----

  gfn_to_pfn_cache_invalidate_start()
  |
  -> gpc->valid = false;
                                          kvm_gfn_to_pfn_cache_refresh()
                                          |
                                          |-> gpc->valid = true;

                                          hva_to_pfn_retry()
                                          |
                                          -> acquire kvm->mmu_lock
                                             kvm->mmu_notifier_count == 0
                                             mmu_seq == kvm->mmu_notifier_seq
                                             drop kvm->mmu_lock
                                             return pfn 'X'
  acquire kvm->mmu_lock
  kvm_inc_notifier_count()
  drop kvm->mmu_lock()
  kernel frees pfn 'X'
                                          kvm_gfn_to_pfn_cache_check()
                                          |
                                          |-> gpc->valid == true

                                          caller accesses freed pfn 'X'

Key off of mn_active_invalidate_count to detect that a pfncache refresh
needs to wait for an in-progress mmu_notifier invalidation.  While
mn_active_invalidate_count is not guaranteed to be stable, it is
guaranteed to be elevated prior to an invalidation acquiring gpc->lock,
so either the refresh will see an active invalidation and wait, or the
invalidation will run after the refresh completes.

Speculatively marking the cache valid is itself flawed, as a concurrent
kvm_gfn_to_pfn_cache_check() would see a valid cache with stale pfn/khva
values.  The KVM Xen use case explicitly allows/wants multiple users;
even though the caches are allocated per vCPU, __kvm_xen_has_interrupt()
can read a different vCPU (or vCPUs).  Address this race by invalidating
the cache prior to dropping gpc->lock (this is made possible by fixing
the above mmu_notifier race).

Complicating all of this is the fact that both the hva=>pfn resolution
and mapping of the kernel address can sleep, i.e. must be done outside
of gpc->lock.

Fix the above races in one fell swoop, trying to fix each individual race
is largely pointless and essentially impossible to test, e.g. closing one
hole just shifts the focus to the other hole.

Fixes: 982ed0de47 ("KVM: Reinstate gfn_to_pfn_cache with invalidation support")
Cc: stable@vger.kernel.org
Cc: David Woodhouse <dwmw@amazon.co.uk>
Cc: Mingwei Zhang <mizhang@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220429210025.3293691-8-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-05-25 05:23:44 -04:00
Paolo Bonzini 47e8eec832 KVM/arm64 updates for 5.19
- Add support for the ARMv8.6 WFxT extension
 
 - Guard pages for the EL2 stacks
 
 - Trap and emulate AArch32 ID registers to hide unsupported features
 
 - Ability to select and save/restore the set of hypercalls exposed
   to the guest
 
 - Support for PSCI-initiated suspend in collaboration with userspace
 
 - GICv3 register-based LPI invalidation support
 
 - Move host PMU event merging into the vcpu data structure
 
 - GICv3 ITS save/restore fixes
 
 - The usual set of small-scale cleanups and fixes
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Merge tag 'kvmarm-5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

KVM/arm64 updates for 5.19

- Add support for the ARMv8.6 WFxT extension

- Guard pages for the EL2 stacks

- Trap and emulate AArch32 ID registers to hide unsupported features

- Ability to select and save/restore the set of hypercalls exposed
  to the guest

- Support for PSCI-initiated suspend in collaboration with userspace

- GICv3 register-based LPI invalidation support

- Move host PMU event merging into the vcpu data structure

- GICv3 ITS save/restore fixes

- The usual set of small-scale cleanups and fixes

[Due to the conflict, KVM_SYSTEM_EVENT_SEV_TERM is relocated
 from 4 to 6. - Paolo]
2022-05-25 05:09:23 -04:00
Sean Christopherson c87661f855 KVM: Free new dirty bitmap if creating a new memslot fails
Fix a goof in kvm_prepare_memory_region() where KVM fails to free the
new memslot's dirty bitmap during a CREATE action if
kvm_arch_prepare_memory_region() fails.  The logic is supposed to detect
if the bitmap was allocated and thus needs to be freed, versus if the
bitmap was inherited from the old memslot and thus needs to be kept.  If
there is no old memslot, then obviously the bitmap can't have been
inherited

The bug was exposed by commit 86931ff720 ("KVM: x86/mmu: Do not create
SPTEs for GFNs that exceed host.MAXPHYADDR"), which made it trivally easy
for syzkaller to trigger failure during kvm_arch_prepare_memory_region(),
but the bug can be hit other ways too, e.g. due to -ENOMEM when
allocating x86's memslot metadata.

The backtrace from kmemleak:

  __vmalloc_node_range+0xb40/0xbd0 mm/vmalloc.c:3195
  __vmalloc_node mm/vmalloc.c:3232 [inline]
  __vmalloc+0x49/0x50 mm/vmalloc.c:3246
  __vmalloc_array mm/util.c:671 [inline]
  __vcalloc+0x49/0x70 mm/util.c:694
  kvm_alloc_dirty_bitmap virt/kvm/kvm_main.c:1319
  kvm_prepare_memory_region virt/kvm/kvm_main.c:1551
  kvm_set_memslot+0x1bd/0x690 virt/kvm/kvm_main.c:1782
  __kvm_set_memory_region+0x689/0x750 virt/kvm/kvm_main.c:1949
  kvm_set_memory_region virt/kvm/kvm_main.c:1962
  kvm_vm_ioctl_set_memory_region virt/kvm/kvm_main.c:1974
  kvm_vm_ioctl+0x377/0x13a0 virt/kvm/kvm_main.c:4528
  vfs_ioctl fs/ioctl.c:51
  __do_sys_ioctl fs/ioctl.c:870
  __se_sys_ioctl fs/ioctl.c:856
  __x64_sys_ioctl+0xfc/0x140 fs/ioctl.c:856
  do_syscall_x64 arch/x86/entry/common.c:50
  do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
  entry_SYSCALL_64_after_hwframe+0x44/0xae

And the relevant sequence of KVM events:

  ioctl(3, KVM_CREATE_VM, 0)              = 4
  ioctl(4, KVM_SET_USER_MEMORY_REGION, {slot=0,
                                        flags=KVM_MEM_LOG_DIRTY_PAGES,
                                        guest_phys_addr=0x10000000000000,
                                        memory_size=4096,
                                        userspace_addr=0x20fe8000}
       ) = -1 EINVAL (Invalid argument)

Fixes: 244893fa28 ("KVM: Dynamically allocate "new" memslots from the get-go")
Cc: stable@vger.kernel.org
Reported-by: syzbot+8606b8a9cc97a63f1c87@syzkaller.appspotmail.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220518003842.1341782-1-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-05-20 13:02:05 -04:00
Sean Christopherson f502cc568d KVM: Add max_vcpus field in common 'struct kvm'
For TDX guests, the maximum number of vcpus needs to be specified when the
TDX guest VM is initialized (creating the TDX data corresponding to TDX
guest) before creating vcpu.  It needs to record the maximum number of
vcpus on VM creation (KVM_CREATE_VM) and return error if the number of
vcpus exceeds it

Because there is already max_vcpu member in arm64 struct kvm_arch, move it
to common struct kvm and initialize it to KVM_MAX_VCPUS before
kvm_arch_init_vm() instead of adding it to x86 struct kvm_arch.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
Message-Id: <e53234cdee6a92357d06c80c03d77c19cdefb804.1646422845.git.isaku.yamahata@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-05-02 11:42:42 -04:00
Paolo Bonzini 73331c5d84 Merge branch 'kvm-fixes-for-5.18-rc5' into HEAD
Fixes for (relatively) old bugs, to be merged in both the -rc and next
development trees:

* Fix potential races when walking host page table

* Fix bad user ABI for KVM_EXIT_SYSTEM_EVENT

* Fix shadow page table leak when KVM runs nested
2022-04-29 12:39:34 -04:00
Paolo Bonzini d495f942f4 KVM: fix bad user ABI for KVM_EXIT_SYSTEM_EVENT
When KVM_EXIT_SYSTEM_EVENT was introduced, it included a flags
member that at the time was unused.  Unfortunately this extensibility
mechanism has several issues:

- x86 is not writing the member, so it would not be possible to use it
  on x86 except for new events

- the member is not aligned to 64 bits, so the definition of the
  uAPI struct is incorrect for 32- on 64-bit userspace.  This is a
  problem for RISC-V, which supports CONFIG_KVM_COMPAT, but fortunately
  usage of flags was only introduced in 5.18.

Since padding has to be introduced, place a new field in there
that tells if the flags field is valid.  To allow further extensibility,
in fact, change flags to an array of 16 values, and store how many
of the values are valid.  The availability of the new ndata field
is tied to a system capability; all architectures are changed to
fill in the field.

To avoid breaking compilation of userspace that was using the flags
field, provide a userspace-only union to overlap flags with data[0].
The new field is placed at the same offset for both 32- and 64-bit
userspace.

Cc: Will Deacon <will@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Peter Gonda <pgonda@google.com>
Cc: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reported-by: kernel test robot <lkp@intel.com>
Message-Id: <20220422103013.34832-1-pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-04-29 12:38:22 -04:00
Mingwei Zhang 683412ccf6 KVM: SEV: add cache flush to solve SEV cache incoherency issues
Flush the CPU caches when memory is reclaimed from an SEV guest (where
reclaim also includes it being unmapped from KVM's memslots).  Due to lack
of coherency for SEV encrypted memory, failure to flush results in silent
data corruption if userspace is malicious/broken and doesn't ensure SEV
guest memory is properly pinned and unpinned.

Cache coherency is not enforced across the VM boundary in SEV (AMD APM
vol.2 Section 15.34.7). Confidential cachelines, generated by confidential
VM guests have to be explicitly flushed on the host side. If a memory page
containing dirty confidential cachelines was released by VM and reallocated
to another user, the cachelines may corrupt the new user at a later time.

KVM takes a shortcut by assuming all confidential memory remain pinned
until the end of VM lifetime. Therefore, KVM does not flush cache at
mmu_notifier invalidation events. Because of this incorrect assumption and
the lack of cache flushing, malicous userspace can crash the host kernel:
creating a malicious VM and continuously allocates/releases unpinned
confidential memory pages when the VM is running.

Add cache flush operations to mmu_notifier operations to ensure that any
physical memory leaving the guest VM get flushed. In particular, hook
mmu_notifier_invalidate_range_start and mmu_notifier_release events and
flush cache accordingly. The hook after releasing the mmu lock to avoid
contention with other vCPUs.

Cc: stable@vger.kernel.org
Suggested-by: Sean Christpherson <seanjc@google.com>
Reported-by: Mingwei Zhang <mizhang@google.com>
Signed-off-by: Mingwei Zhang <mizhang@google.com>
Message-Id: <20220421031407.2516575-4-mizhang@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-04-21 15:41:00 -04:00
Tom Rix a413a625b4 KVM: SPDX style and spelling fixes
SPDX comments use use /* */ style comments in headers anad
// style comments in .c files.  Also fix two spelling mistakes.

Signed-off-by: Tom Rix <trix@redhat.com>
Message-Id: <20220410153840.55506-1-trix@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-04-21 13:16:13 -04:00
Sean Christopherson 5c697c367a KVM: Initialize debugfs_dentry when a VM is created to avoid NULL deref
Initialize debugfs_entry to its semi-magical -ENOENT value when the VM
is created.  KVM's teardown when VM creation fails is kludgy and calls
kvm_uevent_notify_change() and kvm_destroy_vm_debugfs() even if KVM never
attempted kvm_create_vm_debugfs().  Because debugfs_entry is zero
initialized, the IS_ERR() checks pass and KVM derefs a NULL pointer.

  BUG: kernel NULL pointer dereference, address: 0000000000000018
  #PF: supervisor read access in kernel mode
  #PF: error_code(0x0000) - not-present page
  PGD 1068b1067 P4D 1068b1067 PUD 1068b0067 PMD 0
  Oops: 0000 [#1] SMP
  CPU: 0 PID: 871 Comm: repro Not tainted 5.18.0-rc1+ #825
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
  RIP: 0010:__dentry_path+0x7b/0x130
  Call Trace:
   <TASK>
   dentry_path_raw+0x42/0x70
   kvm_uevent_notify_change.part.0+0x10c/0x200 [kvm]
   kvm_put_kvm+0x63/0x2b0 [kvm]
   kvm_dev_ioctl+0x43a/0x920 [kvm]
   __x64_sys_ioctl+0x83/0xb0
   do_syscall_64+0x31/0x50
   entry_SYSCALL_64_after_hwframe+0x44/0xae
   </TASK>
  Modules linked in: kvm_intel kvm irqbypass

Fixes: a44a4cc1c9 ("KVM: Don't create VM debugfs files outside of the VM directory")
Cc: stable@vger.kernel.org
Cc: Marc Zyngier <maz@kernel.org>
Cc: Oliver Upton <oupton@google.com>
Reported-by: syzbot+df6fbbd2ee39f21289ef@syzkaller.appspotmail.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Oliver Upton <oupton@google.com>
Message-Id: <20220415004622.2207751-1-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-04-21 13:16:11 -04:00
Paolo Bonzini a44e2c207c KVM/arm64 fixes for 5.18, take #1
- Some PSCI fixes after introducing PSCIv1.1 and SYSTEM_RESET2
 
 - Fix the MMU write-lock not being taken on THP split
 
 - Fix mixed-width VM handling
 
 - Fix potential UAF when debugfs registration fails
 
 - Various selftest updates for all of the above
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Merge tag 'kvmarm-fixes-5.18-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

KVM/arm64 fixes for 5.18, take #1

- Some PSCI fixes after introducing PSCIv1.1 and SYSTEM_RESET2

- Fix the MMU write-lock not being taken on THP split

- Fix mixed-width VM handling

- Fix potential UAF when debugfs registration fails

- Various selftest updates for all of the above
2022-04-08 12:30:04 -04:00
Oliver Upton a44a4cc1c9 KVM: Don't create VM debugfs files outside of the VM directory
Unfortunately, there is no guarantee that KVM was able to instantiate a
debugfs directory for a particular VM. To that end, KVM shouldn't even
attempt to create new debugfs files in this case. If the specified
parent dentry is NULL, debugfs_create_file() will instantiate files at
the root of debugfs.

For arm64, it is possible to create the vgic-state file outside of a
VM directory, the file is not cleaned up when a VM is destroyed.
Nonetheless, the corresponding struct kvm is freed when the VM is
destroyed.

Nip the problem in the bud for all possible errant debugfs file
creations by initializing kvm->debugfs_dentry to -ENOENT. In so doing,
debugfs_create_file() will fail instead of creating the file in the root
directory.

Cc: stable@kernel.org
Fixes: 929f45e324 ("kvm: no need to check return value of debugfs_create functions")
Signed-off-by: Oliver Upton <oupton@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220406235615.1447180-2-oupton@google.com
2022-04-07 08:46:13 +01:00
Paolo Bonzini 5593473a1e KVM: avoid NULL pointer dereference in kvm_dirty_ring_push
kvm_vcpu_release() will call kvm_dirty_ring_free(), freeing
ring->dirty_gfns and setting it to NULL.  Afterwards, it calls
kvm_arch_vcpu_destroy().

However, if closing the file descriptor races with KVM_RUN in such away
that vcpu->arch.st.preempted == 0, the following call stack leads to a
NULL pointer dereference in kvm_dirty_run_push():

 mark_page_dirty_in_slot+0x192/0x270 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3171
 kvm_steal_time_set_preempted arch/x86/kvm/x86.c:4600 [inline]
 kvm_arch_vcpu_put+0x34e/0x5b0 arch/x86/kvm/x86.c:4618
 vcpu_put+0x1b/0x70 arch/x86/kvm/../../../virt/kvm/kvm_main.c:211
 vmx_free_vcpu+0xcb/0x130 arch/x86/kvm/vmx/vmx.c:6985
 kvm_arch_vcpu_destroy+0x76/0x290 arch/x86/kvm/x86.c:11219
 kvm_vcpu_destroy arch/x86/kvm/../../../virt/kvm/kvm_main.c:441 [inline]

The fix is to release the dirty page ring after kvm_arch_vcpu_destroy
has run.

Reported-by: Qiuhao Li <qiuhao@sysec.org>
Reported-by: Gaoning Pan <pgn@zju.edu.cn>
Reported-by: Yongkang Jia <kangel@zju.edu.cn>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-04-06 13:26:30 -04:00
Sean Christopherson df06dae3f2 KVM: Don't actually set a request when evicting vCPUs for GFN cache invd
Don't actually set a request bit in vcpu->requests when making a request
purely to force a vCPU to exit the guest.  Logging a request but not
actually consuming it would cause the vCPU to get stuck in an infinite
loop during KVM_RUN because KVM would see the pending request and bail
from VM-Enter to service the request.

Note, it's currently impossible for KVM to set KVM_REQ_GPC_INVALIDATE as
nothing in KVM is wired up to set guest_uses_pa=true.  But, it'd be all
too easy for arch code to introduce use of kvm_gfn_to_pfn_cache_init()
without implementing handling of the request, especially since getting
test coverage of MMU notifier interaction with specific KVM features
usually requires a directed test.

Opportunistically rename gfn_to_pfn_cache_invalidate_start()'s wake_vcpus
to evict_vcpus.  The purpose of the request is to get vCPUs out of guest
mode, it's supposed to _avoid_ waking vCPUs that are blocking.

Opportunistically rename KVM_REQ_GPC_INVALIDATE to be more specific as to
what it wants to accomplish, and to genericize the name so that it can
used for similar but unrelated scenarios, should they arise in the future.
Add a comment and documentation to explain why the "no action" request
exists.

Add compile-time assertions to help detect improper usage.  Use the inner
assertless helper in the one s390 path that makes requests without a
hardcoded request.

Cc: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220223165302.3205276-1-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-04-02 05:34:39 -04:00
David Matlack 70375c2d8f Revert "KVM: set owner of cpu and vm file operations"
This reverts commit 3d3aab1b97.

Now that the KVM module's lifetime is tied to kvm.users_count, there is
no need to also tie it's lifetime to the lifetime of the VM and vCPU
file descriptors.

Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: David Matlack <dmatlack@google.com>
Message-Id: <20220303183328.1499189-3-dmatlack@google.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-03-29 13:02:25 -04:00
David Matlack 5f6de5cbeb KVM: Prevent module exit until all VMs are freed
Tie the lifetime the KVM module to the lifetime of each VM via
kvm.users_count. This way anything that grabs a reference to the VM via
kvm_get_kvm() cannot accidentally outlive the KVM module.

Prior to this commit, the lifetime of the KVM module was tied to the
lifetime of /dev/kvm file descriptors, VM file descriptors, and vCPU
file descriptors by their respective file_operations "owner" field.
This approach is insufficient because references grabbed via
kvm_get_kvm() do not prevent closing any of the aforementioned file
descriptors.

This fixes a long standing theoretical bug in KVM that at least affects
async page faults. kvm_setup_async_pf() grabs a reference via
kvm_get_kvm(), and drops it in an asynchronous work callback. Nothing
prevents the VM file descriptor from being closed and the KVM module
from being unloaded before this callback runs.

Fixes: af585b921e ("KVM: Halt vcpu if page it tries to access is swapped out")
Fixes: 3d3aab1b97 ("KVM: set owner of cpu and vm file operations")
Cc: stable@vger.kernel.org
Suggested-by: Ben Gardon <bgardon@google.com>
[ Based on a patch from Ben implemented for Google's kernel. ]
Signed-off-by: David Matlack <dmatlack@google.com>
Message-Id: <20220303183328.1499189-2-dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-03-29 13:02:25 -04:00
Paolo Bonzini 37b2a6510a KVM: use __vcalloc for very large allocations
Allocations whose size is related to the memslot size can be arbitrarily
large.  Do not use kvzalloc/kvcalloc, as those are limited to "not crazy"
sizes that fit in 32 bits.

Cc: stable@vger.kernel.org
Fixes: 7661809d49 ("mm: don't allow oversized kvmalloc() calls")
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-03-08 09:30:57 -05:00
Paolo Bonzini 0564eeb71b Merge branch 'kvm-bugfixes' into HEAD
Merge bugfixes from 5.17 before merging more tricky work.
2022-03-04 18:39:29 -05:00
Sean Christopherson 2f6f66ccd2 KVM: Drop kvm_reload_remote_mmus(), open code request in x86 users
Remove the generic kvm_reload_remote_mmus() and open code its
functionality into the two x86 callers.  x86 is (obviously) the only
architecture that uses the hook, and is also the only architecture that
uses KVM_REQ_MMU_RELOAD in a way that's consistent with the name.  That
will change in a future patch, as x86's usage when zapping a single
shadow page x86 doesn't actually _need_ to reload all vCPUs' MMUs, only
MMUs whose root is being zapped actually need to be reloaded.

s390 also uses KVM_REQ_MMU_RELOAD, but for a slightly different purpose.

Drop the generic code in anticipation of implementing s390 and x86 arch
specific requests, which will allow dropping KVM_REQ_MMU_RELOAD entirely.

Opportunistically reword the x86 TDP MMU comment to avoid making
references to functions (and requests!) when possible, and to remove the
rather ambiguous "this".

No functional change intended.

Cc: Ben Gardon <bgardon@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Ben Gardon <bgardon@google.com>
Message-Id: <20220225182248.3812651-4-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-03-01 08:58:25 -05:00
Vipin Sharma e45cce30ea KVM: Move VM's worker kthreads back to the original cgroup before exiting.
VM worker kthreads can linger in the VM process's cgroup for sometime
after KVM terminates the VM process.

KVM terminates the worker kthreads by calling kthread_stop() which waits
on the 'exited' completion, triggered by exit_mm(), via mm_release(), in
do_exit() during the kthread's exit.  However, these kthreads are
removed from the cgroup using the cgroup_exit() which happens after the
exit_mm(). Therefore, A VM process can terminate in between the
exit_mm() and cgroup_exit() calls, leaving only worker kthreads in the
cgroup.

Moving worker kthreads back to the original cgroup (kthreadd_task's
cgroup) makes sure that the cgroup is empty as soon as the main VM
process is terminated.

Signed-off-by: Vipin Sharma <vipinsh@google.com>
Suggested-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220222054848.563321-1-vipinsh@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-02-25 08:20:14 -05:00
Wanpeng Li 4cb9a998b1 KVM: Fix lockdep false negative during host resume
I saw the below splatting after the host suspended and resumed.

   WARNING: CPU: 0 PID: 2943 at kvm/arch/x86/kvm/../../../virt/kvm/kvm_main.c:5531 kvm_resume+0x2c/0x30 [kvm]
   CPU: 0 PID: 2943 Comm: step_after_susp Tainted: G        W IOE     5.17.0-rc3+ #4
   RIP: 0010:kvm_resume+0x2c/0x30 [kvm]
   Call Trace:
    <TASK>
    syscore_resume+0x90/0x340
    suspend_devices_and_enter+0xaee/0xe90
    pm_suspend.cold+0x36b/0x3c2
    state_store+0x82/0xf0
    kernfs_fop_write_iter+0x1b6/0x260
    new_sync_write+0x258/0x370
    vfs_write+0x33f/0x510
    ksys_write+0xc9/0x160
    do_syscall_64+0x3b/0xc0
    entry_SYSCALL_64_after_hwframe+0x44/0xae

lockdep_is_held() can return -1 when lockdep is disabled which triggers
this warning. Let's use lockdep_assert_not_held() which can detect
incorrect calls while holding a lock and it also avoids false negatives
when lockdep is disabled.

Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Message-Id: <1644920142-81249-1-git-send-email-wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-02-17 09:52:50 -05:00
Jinrong Liang b56bd8e03c KVM: Remove unused "kvm" of kvm_make_vcpu_request()
The "struct kvm *kvm" parameter of kvm_make_vcpu_request() is not used,
so remove it. No functional change intended.

Signed-off-by: Jinrong Liang <cloudliang@tencent.com>
Message-Id: <20220125095909.38122-19-cloudliang@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-02-10 13:47:15 -05:00
Linus Torvalds 3cd7cd8a62 Two larger x86 series:
* Redo incorrect fix for SEV/SMAP erratum
 
 * Windows 11 Hyper-V workaround
 
 Other x86 changes:
 
 * Various x86 cleanups
 
 * Re-enable access_tracking_perf_test
 
 * Fix for #GP handling on SVM
 
 * Fix for CPUID leaf 0Dh in KVM_GET_SUPPORTED_CPUID
 
 * Fix for ICEBP in interrupt shadow
 
 * Avoid false-positive RCU splat
 
 * Enable Enlightened MSR-Bitmap support for real
 
 ARM:
 
 * Correctly update the shadow register on exception injection when
 running in nVHE mode
 
 * Correctly use the mm_ops indirection when performing cache invalidation
 from the page-table walker
 
 * Restrict the vgic-v3 workaround for SEIS to the two known broken
 implementations
 
 Generic code changes:
 
 * Dead code cleanup
 
 There will be another pull request for ARM fixes next week, but
 those patches need a bit more soak time.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull kvm fixes from Paolo Bonzini:
 "Two larger x86 series:

   - Redo incorrect fix for SEV/SMAP erratum

   - Windows 11 Hyper-V workaround

  Other x86 changes:

   - Various x86 cleanups

   - Re-enable access_tracking_perf_test

   - Fix for #GP handling on SVM

   - Fix for CPUID leaf 0Dh in KVM_GET_SUPPORTED_CPUID

   - Fix for ICEBP in interrupt shadow

   - Avoid false-positive RCU splat

   - Enable Enlightened MSR-Bitmap support for real

  ARM:

   - Correctly update the shadow register on exception injection when
     running in nVHE mode

   - Correctly use the mm_ops indirection when performing cache
     invalidation from the page-table walker

   - Restrict the vgic-v3 workaround for SEIS to the two known broken
     implementations

  Generic code changes:

   - Dead code cleanup"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (43 commits)
  KVM: eventfd: Fix false positive RCU usage warning
  KVM: nVMX: Allow VMREAD when Enlightened VMCS is in use
  KVM: nVMX: Implement evmcs_field_offset() suitable for handle_vmread()
  KVM: nVMX: Rename vmcs_to_field_offset{,_table}
  KVM: nVMX: eVMCS: Filter out VM_EXIT_SAVE_VMX_PREEMPTION_TIMER
  KVM: nVMX: Also filter MSR_IA32_VMX_TRUE_PINBASED_CTLS when eVMCS
  selftests: kvm: check dynamic bits against KVM_X86_XCOMP_GUEST_SUPP
  KVM: x86: add system attribute to retrieve full set of supported xsave states
  KVM: x86: Add a helper to retrieve userspace address from kvm_device_attr
  selftests: kvm: move vm_xsave_req_perm call to amx_test
  KVM: x86: Sync the states size with the XCR0/IA32_XSS at, any time
  KVM: x86: Update vCPU's runtime CPUID on write to MSR_IA32_XSS
  KVM: x86: Keep MSR_IA32_XSS unchanged for INIT
  KVM: x86: Free kvm_cpuid_entry2 array on post-KVM_RUN KVM_SET_CPUID{,2}
  KVM: nVMX: WARN on any attempt to allocate shadow VMCS for vmcs02
  KVM: selftests: Don't skip L2's VMCALL in SMM test for SVM guest
  KVM: x86: Check .flags in kvm_cpuid_check_equal() too
  KVM: x86: Forcibly leave nested virt when SMM state is toggled
  KVM: SVM: drop unnecessary code in svm_hv_vmcb_dirty_nested_enlightenments()
  KVM: SVM: hyper-v: Enable Enlightened MSR-Bitmap support for real
  ...
2022-01-28 19:00:26 +02:00
Sean Christopherson 31c2558569 Revert "KVM: SVM: avoid infinite loop on NPF from bad address"
Revert a completely broken check on an "invalid" RIP in SVM's workaround
for the DecodeAssists SMAP errata.  kvm_vcpu_gfn_to_memslot() obviously
expects a gfn, i.e. operates in the guest physical address space, whereas
RIP is a virtual (not even linear) address.  The "fix" worked for the
problematic KVM selftest because the test identity mapped RIP.

Fully revert the hack instead of trying to translate RIP to a GPA, as the
non-SEV case is now handled earlier, and KVM cannot access guest page
tables to translate RIP.

This reverts commit e72436bc3a.

Fixes: e72436bc3a ("KVM: SVM: avoid infinite loop on NPF from bad address")
Reported-by: Liam Merwick <liam.merwick@oracle.com>
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Liam Merwick <liam.merwick@oracle.com>
Message-Id: <20220120010719.711476-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-01-26 12:14:59 -05:00
Xianting Tian 1625566ec8 KVM: remove async parameter of hva_to_pfn_remapped()
The async parameter of hva_to_pfn_remapped() is not used, so remove it.

Signed-off-by: Xianting Tian <xianting.tian@linux.alibaba.com>
Message-Id: <20220124020456.156386-1-xianting.tian@linux.alibaba.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-01-24 08:53:37 -05:00