Currently, the APIC access page is pinned by KVM for the entire life
of the guest. We want to make it migratable in order to make memory
hot-unplug available for machines that run KVM.
This patch prepares to handle this for the case where there is no nested
virtualization, or where the nested guest does not have an APIC page of
its own. All accesses to kvm->arch.apic_access_page are changed to go
through kvm_vcpu_reload_apic_access_page.
If the APIC access page is invalidated when the host is running, we update
the VMCS in the next guest entry.
If it is invalidated when the guest is running, the MMU notifier will force
an exit, after which we will handle everything as in the previous case.
If it is invalidated when a nested guest is running, the request will update
either the VMCS01 or the VMCS02. Updating the VMCS01 is done at the
next L2->L1 exit, while updating the VMCS02 is done in prepare_vmcs02.
Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Currently, the APIC access page is pinned by KVM for the entire life
of the guest. We want to make it migratable in order to make memory
hot-unplug available for machines that run KVM.
This patch prepares to handle this in generic code, through a new
request bit (that will be set by the MMU notifier) and a new hook
that is called whenever the request bit is processed.
Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This will be used to let the guest run while the APIC access page is
not pinned. Because subsequent patches will fill in the function
for x86, place the (still empty) x86 implementation in the x86.c file
instead of adding an inline function in kvm_host.h.
Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
1. We were calling clear_flush_young_notify in unmap_one, but we are
within an mmu notifier invalidate range scope. The spte exists no more
(due to range_start) and the accessed bit info has already been
propagated (due to kvm_pfn_set_accessed). Simply call
clear_flush_young.
2. We clear_flush_young on a primary MMU PMD, but this may be mapped
as a collection of PTEs by the secondary MMU (e.g. during log-dirty).
This required expanding the interface of the clear_flush_young mmu
notifier, so a lot of code has been trivially touched.
3. In the absence of shadow_accessed_mask (e.g. EPT A bit), we emulate
the access bit by blowing the spte. This requires proper synchronizing
with MMU notifier consumers, like every other removal of spte's does.
Signed-off-by: Andres Lagar-Cavilla <andreslc@google.com>
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Callbacks don't have to do extra computation to learn what the caller
(lvm_handle_hva_range()) knows very well. Useful for
debugging/tracing/printk/future.
Signed-off-by: Andres Lagar-Cavilla <andreslc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Avoid open coded calculations for bank MSRs by using well-defined
macros that hide the index of higher bank MSRs.
No semantic changes.
Signed-off-by: Chen Yucong <slaoub@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Commit 346874c950 ("KVM: x86: Fix CR3 reserved bits") removed non-PAE
reserved bits which were not according to Intel SDM. However, residue was left
in a debug assertion (CR3_NONPAE_RESERVED_BITS). Remove it.
Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Guest which sets the PAT CR to invalid value should get a #GP. Currently, if
vmx supports loading PAT CR during entry, then the value is not checked. This
patch makes the required check in that case.
Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
In 64-bit mode a #GP should be delivered to the guest "if the code segment
descriptor pointed to by the selector in the 64-bit gate doesn't have the L-bit
set and the D-bit clear." - Intel SDM "Interrupt 13—General Protection
Exception (#GP)".
This patch fixes the behavior of CS loading emulation code. Although the
comment says that segment loading is not supported in long mode, this function
is executed in long mode, so the fix is necassary.
Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
A one-line wrapper around kvm_make_request is not particularly
useful. Replace kvm_mmu_flush_tlb() with kvm_make_request().
Signed-off-by: Liang Chen <liangchen.linux@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
- we count KVM_REQ_TLB_FLUSH requests, not actual flushes
(KVM can have multiple requests for one flush)
- flushes from kvm_flush_remote_tlbs aren't counted
- it's easy to make a direct request by mistake
Solve these by postponing the counting to kvm_check_request().
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Liang Chen <liangchen.linux@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Initilization of L2 guest with -cpu host, on L1 guest with -cpu host
triggers:
(qemu) KVM: entry failed, hardware error 0x7
...
nested_vmx_run: VMCS MSR_{LOAD,STORE} unsupported
Nested VMX MSR load/store support is not sufficient to
allow perf for L2 guest.
Until properly fixed, trap CPUID and disable function 0xA.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Commit fc3a9157d3 ("KVM: X86: Don't report L2 emulation failures to
user-space") disabled the reporting of L2 (nested guest) emulation failures to
userspace due to race-condition between a vmexit and the instruction emulator.
The same rational applies also to userspace applications that are permitted by
the guest OS to access MMIO area or perform PIO.
This patch extends the current behavior - of injecting a #UD instead of
reporting it to userspace - also for guest userspace code.
Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
In init_rmode_tss(), there two variables indicating the return
value, r and ret, and it return 0 on error, 1 on success. The function
is only called by vmx_set_tss_addr(), and ret is redundant.
This patch removes the redundant variable, by making init_rmode_tss()
return 0 on success, -errno on failure.
Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The KVM emulator code assumes that the guest virtual address space (in 64-bit)
is 48-bits wide. Fail the KVM_SET_CPUID and KVM_SET_CPUID2 ioctl if
userspace tries to create a guest that does not obey this restriction.
Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
In init_rmode_identity_map(), there two variables indicating the return
value, r and ret, and it return 0 on error, 1 on success. The function
is only called by vmx_create_vcpu(), and ret is redundant.
This patch removes the redundant variable, and makes init_rmode_identity_map()
return 0 on success, -errno on failure.
Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
kvm_arch->ept_identity_pagetable holds the ept identity pagetable page. But
it is never used to refer to the page at all.
In vcpu initialization, it indicates two things:
1. indicates if ept page is allocated
2. indicates if a memory slot for identity page is initialized
Actually, kvm_arch->ept_identity_pagetable_done is enough to tell if the ept
identity pagetable is initialized. So we can remove ept_identity_pagetable.
NOTE: In the original code, ept identity pagetable page is pinned in memroy.
As a result, it cannot be migrated/hot-removed. After this patch, since
kvm_arch->ept_identity_pagetable is removed, ept identity pagetable page
is no longer pinned in memory. And it can be migrated/hot-removed.
Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Reviewed-by: Gleb Natapov <gleb@kernel.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This patch replace the set_bit method by kvm_make_request
to make code more readable and consistent.
Signed-off-by: Guo Hui Liu <liuguohui@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Initially the tracepoint was added only to the APIC_DM_FIXED case,
also because it reported coalesced interrupts that only made sense
for that case. However, the coalesced argument is not used anymore
and tracing other delivery modes is useful, so hoist the call out
of the switch statement.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
We have APIC_DEFAULT_PHYS_BASE defined as 0xfee00000, which is also the address of
apic access page. So use this macro.
Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Reviewed-by: Gleb Natapov <gleb@kernel.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Currently, if a permission error happens during the translation of
the final GPA to HPA, walk_addr_generic returns 0 but does not fill
in walker->fault. To avoid this, add an x86_exception* argument
to the translate_gpa function, and let it fill in walker->fault.
The nested_page_fault field will be true, since the walk_mmu is the
nested_mmu and translate_gpu instead operates on the "outer" (NPT)
instance.
Reported-by: Valentine Sinitsyn <valentine.sinitsyn@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
If a nested page fault happens during emulation, we will inject a vmexit,
not a page fault. However because writeback happens after the injection,
we will write ctxt->eip from L2 into the L1 EIP. We do not write back
if an instruction caused an interception vmexit---do the same for page
faults.
Suggested-by: Gleb Natapov <gleb@kernel.org>
Reviewed-by: Gleb Natapov <gleb@kernel.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This is similar to what the EPT code does with the exit qualification.
This allows the guest to see a valid value for bits 33:32.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Bit 8 would be the "global" bit, which does not quite make sense for non-leaf
page table entries. Intel ignores it; AMD ignores it in PDEs, but reserves it
in PDPEs and PML4Es. The SVM test is relying on this behavior, so enforce it.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The following events can lead to an incorrect KVM_EXIT_MMIO bubbling
up to userspace:
(1) Guest accesses gpa X without a memory slot. The gfn is cached in
struct kvm_vcpu_arch (mmio_gfn). On Intel EPT-enabled hosts, KVM sets
the SPTE write-execute-noread so that future accesses cause
EPT_MISCONFIGs.
(2) Host userspace creates a memory slot via KVM_SET_USER_MEMORY_REGION
covering the page just accessed.
(3) Guest attempts to read or write to gpa X again. On Intel, this
generates an EPT_MISCONFIG. The memory slot generation number that
was incremented in (2) would normally take care of this but we fast
path mmio faults through quickly_check_mmio_pf(), which only checks
the per-vcpu mmio cache. Since we hit the cache, KVM passes a
KVM_EXIT_MMIO up to userspace.
This patch fixes the issue by using the memslot generation number
to validate the mmio cache.
Cc: stable@vger.kernel.org
Signed-off-by: David Matlack <dmatlack@google.com>
[xiaoguangrong: adjust the code to make it simpler for stable-tree fix.]
Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Reviewed-by: David Matlack <dmatlack@google.com>
Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Tested-by: David Matlack <dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
vcpu exits and memslot mutations can run concurrently as long as the
vcpu does not aquire the slots mutex. Thus it is theoretically possible
for memslots to change underneath a vcpu that is handling an exit.
If we increment the memslot generation number again after
synchronize_srcu_expedited(), vcpus can safely cache memslot generation
without maintaining a single rcu_dereference through an entire vm exit.
And much of the x86/kvm code does not maintain a single rcu_dereference
of the current memslots during each exit.
We can prevent the following case:
vcpu (CPU 0) | thread (CPU 1)
--------------------------------------------+--------------------------
1 vm exit |
2 srcu_read_unlock(&kvm->srcu) |
3 decide to cache something based on |
old memslots |
4 | change memslots
| (increments generation)
5 | synchronize_srcu(&kvm->srcu);
6 retrieve generation # from new memslots |
7 tag cache with new memslot generation |
8 srcu_read_unlock(&kvm->srcu) |
... |
<action based on cache occurs even |
though the caching decision was based |
on the old memslots> |
... |
<action *continues* to occur until next |
memslot generation change, which may |
be never> |
|
By incrementing the generation after synchronizing with kvm->srcu readers,
we ensure that the generation retrieved in (6) will become invalid soon
after (8).
Keeping the existing increment is not strictly necessary, but we
do keep it and just move it for consistency from update_memslots to
install_new_memslots. It invalidates old cached MMIOs immediately,
instead of having to wait for the end of synchronize_srcu_expedited,
which makes the code more clearly correct in case CPU 1 is preempted
right after synchronize_srcu() returns.
To avoid halving the generation space in SPTEs, always presume that the
low bit of the generation is zero when reconstructing a generation number
out of an SPTE. This effectively disables MMIO caching in SPTEs during
the call to synchronize_srcu_expedited. Using the low bit this way is
somewhat like a seqcount---where the protected thing is a cache, and
instead of retrying we can simply punt if we observe the low bit to be 1.
Cc: stable@vger.kernel.org
Signed-off-by: David Matlack <dmatlack@google.com>
Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Reviewed-by: David Matlack <dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The next patch will give a meaning (a la seqcount) to the low bit of the
generation number. Ensure that it matches between kvm->memslots->generation
and kvm_current_mmio_generation().
Cc: stable@vger.kernel.org
Reviewed-by: David Matlack <dmatlack@google.com>
Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The check introduced in commit d7a2a246a1 (KVM: x86: #GP when attempts to write reserved bits of Variable Range MTRRs, 2014-08-19)
will break if the guest maxphyaddr is higher than the host's (which
sometimes happens depending on your hardware and how QEMU is
configured).
To fix this, use cpuid_maxphyaddr similar to how the APIC_BASE MSR
does already.
Reported-by: Jan Kiszka <jan.kiszka@siemens.com>
Tested-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
In the beggining was on_each_cpu(), which required an unused argument to
kvm_arch_ops.hardware_{en,dis}able, but this was soon forgotten.
Remove unnecessary arguments that stem from this.
Signed-off-by: Radim KrÄmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Unlike VMCALL, the instructions VMXOFF, VMLAUNCH and VMRESUME should cause a UD
exception in real-mode or vm86. However, the emulator considers all these
instructions the same for the matter of mode checks, and emulation upon exit
due to #UD exception.
As a result, the hypervisor behaves incorrectly on vm86 mode. VMXOFF, VMLAUNCH
or VMRESUME cause on vm86 exit due to #UD. The hypervisor then emulates these
instruction and inject #GP to the guest instead of #UD.
This patch creates a new group for these instructions and mark only VMCALL as
an instruction which can be emulated.
Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sparse reports the following easily fixed warnings:
arch/x86/kvm/vmx.c:8795:48: sparse: Using plain integer as NULL pointer
arch/x86/kvm/vmx.c:2138:5: sparse: symbol vmx_read_l1_tsc was not declared. Should it be static?
arch/x86/kvm/vmx.c:6151:48: sparse: Using plain integer as NULL pointer
arch/x86/kvm/vmx.c:8851:6: sparse: symbol vmx_sched_in was not declared. Should it be static?
arch/x86/kvm/svm.c:2162:5: sparse: symbol svm_read_l1_tsc was not declared. Should it be static?
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This patch fix bug https://bugzilla.kernel.org/show_bug.cgi?id=61411
TPR shadow/threshold feature is important to speed up the Windows guest.
Besides, it is a must feature for certain VMM.
We map virtual APIC page address and TPR threshold from L1 VMCS. If
TPR_BELOW_THRESHOLD VM exit is triggered by L2 guest and L1 interested
in, we inject it into L1 VMM for handling.
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com>
[Add PAGE_ALIGNED check, do not write useless virtual APIC page address
if TPR shadowing is disabled. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Introduce function nested_get_vmcs12_pages() to check the valid
of nested apic access page and virtual apic page earlier.
Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Fix commit 7b46268d29, which mistakenly
included the new tracepoint under #ifdef CONFIG_X86_64.
Reported-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Tracepoint for dynamic PLE window, fired on every potential change.
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Window is increased on every PLE exit and decreased on every sched_in.
The idea is that we don't want to PLE exit if there is no preemption
going on.
We do this with sched_in() because it does not hold rq lock.
There are two new kernel parameters for changing the window:
ple_window_grow and ple_window_shrink
ple_window_grow affects the window on PLE exit and ple_window_shrink
does it on sched_in; depending on their value, the window is modifier
like this: (ple_window is kvm_intel's global)
ple_window_shrink/ |
ple_window_grow | PLE exit | sched_in
-------------------+--------------------+---------------------
< 1 | = ple_window | = ple_window
< ple_window | *= ple_window_grow | /= ple_window_shrink
otherwise | += ple_window_grow | -= ple_window_shrink
A third new parameter, ple_window_max, controls the maximal ple_window;
it is internally rounded down to a closest multiple of ple_window_grow.
VCPU's PLE window is never allowed below ple_window.
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Change PLE window into per-VCPU variable, seeded from module parameter,
to allow greater flexibility.
Brings in a small overhead on every vmentry.
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
sched_in preempt notifier is available for x86, allow its use in
specific virtualization technlogies as well.
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Introduce preempt notifiers for architecture specific code.
Advantage over creating a new notifier in every arch is slightly simpler
code and guaranteed call order with respect to kvm_sched_in.
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Replace reference to X86_FEATURE_NX using bit shift with the defined
X86_FEATURE_NX.
Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
These were reported when running Jailhouse on AMD processors.
Initialize ctxt->exception.vector with an invalid exception number,
and warn if it remained invalid even though the emulator got
an X86EMUL_PROPAGATE_FAULT return code.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Always get it through emulate_exception or emulate_ts. This
ensures that the ctxt->exception fields have been populated.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
kvm_pmu_cpuid_update makes a lot of bit manuiplation operations, when in fact
there are already unions that can be used instead. Changing the bit
manipulation to the union for clarity. This patch does not change the
functionality.
Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
EPT misconfig handler in kvm will check which reason lead to EPT
misconfiguration after vmexit. One of the reasons is that an EPT
paging-structure entry is configured with settings reserved for
future functionality. However, the handler can't identify if
paging-structure entry of reserved bits for 1-GByte page are
configured, since PDPTE which point to 1-GByte page will reserve
bits 29:12 instead of bits 7:3 which are reserved for PDPTE that
references an EPT Page Directory. This patch fix it by reserve
bits 29:12 for 1-GByte page.
Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Currently, recalculate_apic_map ignores vcpus whose lapic is software disabled
through the spurious interrupt vector. However, once it is re-enabled, the map
is not recalculated. Therefore, if the guest OS configured DFR while lapic is
software-disabled, the map may be incorrect. This patch recalculates apic map
after software enabling the lapic.
Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Intel SDM 10.5.4.1 says "When the timer generates an interrupt, it disarms
itself and clears the IA32_TSC_DEADLINE MSR".
This patch clears the MSR upon timer interrupt delivery which delivered on
deadline mode. Since the MSR may be reconfigured while an interrupt is
pending, causing the new value to be overriden, pending timer interrupts are
checked before setting a new deadline.
Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Tang Chen