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We will never need more guest_msrs than there are indices in
vmx_msr_index. Thus, at present, the guest_msrs array will not exceed
168 bytes.
Signed-off-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Commit 37e4c997dadf ("KVM: VMX: validate individual bits of guest
MSR_IA32_FEATURE_CONTROL") broke the KVM_SET_MSRS ABI by instituting
new constraints on the data values that kvm would accept for the guest
MSR, IA32_FEATURE_CONTROL. Perhaps these constraints should have been
opt-in via a new KVM capability, but they were applied
indiscriminately, breaking at least one existing hypervisor.
Relax the constraints to allow either or both of
FEATURE_CONTROL_VMXON_ENABLED_OUTSIDE_SMX and
FEATURE_CONTROL_VMXON_ENABLED_INSIDE_SMX to be set when nVMX is
enabled. This change is sufficient to fix the aforementioned breakage.
Fixes: 37e4c997dadf ("KVM: VMX: validate individual bits of guest MSR_IA32_FEATURE_CONTROL")
Signed-off-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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apic-access-page
According to Intel SDM section 28.3.3.3/28.3.3.4 Guidelines for Use
of the INVVPID/INVEPT Instruction, the hypervisor needs to execute
INVVPID/INVEPT X in case CPU executes VMEntry with VPID/EPTP X and
either: "Virtualize APIC accesses" VM-execution control was changed
from 0 to 1, OR the value of apic_access_page was changed.
In the nested case, the burden falls on L1, unless L0 enables EPT in
vmcs02 but L1 enables neither EPT nor VPID in vmcs12. For this reason
prepare_vmcs02() and load_vmcs12_host_state() have special code to
request a TLB flush in case L1 does not use EPT but it uses
"virtualize APIC accesses".
This special case however is not necessary. On a nested vmentry the
physical TLB will already be flushed except if all the following apply:
* L0 uses VPID
* L1 uses VPID
* L0 can guarantee TLB entries populated while running L1 are tagged
differently than TLB entries populated while running L2.
If the first condition is false, the processor will flush the TLB
on vmentry to L2. If the second or third condition are false,
prepare_vmcs02() will request KVM_REQ_TLB_FLUSH. However, even
if both are true, no extra TLB flush is needed to handle the APIC
access page:
* if L1 doesn't use VPID, the second condition doesn't hold and the
TLB will be flushed anyway.
* if L1 uses VPID, it has to flush the TLB itself with INVVPID and
section 28.3.3.3 doesn't apply to L0.
* even INVEPT is not needed because, if L0 uses EPT, it uses different
EPTP when running L2 than L1 (because guest_mode is part of mmu-role).
In this case SDM section 28.3.3.4 doesn't apply.
Similarly, examining nested_vmx_vmexit()->load_vmcs12_host_state(),
one could note that L0 won't flush TLB only in cases where SDM sections
28.3.3.3 and 28.3.3.4 don't apply. In particular, if L0 uses different
VPIDs for L1 and L2 (i.e. vmx->vpid != vmx->nested.vpid02), section
28.3.3.3 doesn't apply.
Thus, remove this flush from prepare_vmcs02() and nested_vmx_vmexit().
Side-note: This patch can be viewed as removing parts of commit
fb6c81984313 ("kvm: vmx: Flush TLB when the APIC-access address changes”)
that is not relevant anymore since commit
1313cc2bd8f6 ("kvm: mmu: Add guest_mode to kvm_mmu_page_role”).
i.e. The first commit assumes that if L0 use EPT and L1 doesn’t use EPT,
then L0 will use same EPTP for both L0 and L1. Which indeed required
L0 to execute INVEPT before entering L2 guest. This assumption is
not true anymore since when guest_mode was added to mmu-role.
Reviewed-by: Joao Martins <joao.m.martins@oracle.com>
Signed-off-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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vmcs->apic_access_page is simply a token that the hypervisor puts into
the PFN of a 4KB EPTE (or PTE if using shadow-paging) that triggers
APIC-access VMExit or APIC virtualization logic whenever a CPU running
in VMX non-root mode read/write from/to this PFN.
As every write either triggers an APIC-access VMExit or write is
performed on vmcs->virtual_apic_page, the PFN pointed to by
vmcs->apic_access_page should never actually be touched by CPU.
Therefore, there is no need to mark vmcs02->apic_access_page as dirty
after unpin it on L2->L1 emulated VMExit or when L1 exit VMX operation.
Reviewed-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Reviewed-by: Joao Martins <joao.m.martins@oracle.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Conflicts:
arch/x86/kvm/vmx/vmx.c
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If X86_FEATURE_RTM is disabled, the guest should not be able to access
MSR_IA32_TSX_CTRL. We can therefore use it in KVM to force all
transactions from the guest to abort.
Tested-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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The current guest mitigation of TAA is both too heavy and not really
sufficient. It is too heavy because it will cause some affected CPUs
(those that have MDS_NO but lack TAA_NO) to fall back to VERW and
get the corresponding slowdown. It is not really sufficient because
it will cause the MDS_NO bit to disappear upon microcode update, so
that VMs started before the microcode update will not be runnable
anymore afterwards, even with tsx=on.
Instead, if tsx=on on the host, we can emulate MSR_IA32_TSX_CTRL for
the guest and let it run without the VERW mitigation. Even though
MSR_IA32_TSX_CTRL is quite heavyweight, and we do not want to write
it on every vmentry, we can use the shared MSR functionality because
the host kernel need not protect itself from TSX-based side-channels.
Tested-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Since commit 1313cc2bd8f6 ("kvm: mmu: Add guest_mode to kvm_mmu_page_role"),
guest_mode was added to mmu-role and therefore if L0 use EPT, it will
always run L1 and L2 with different EPTP. i.e. EPTP01!=EPTP02.
Because TLB entries are tagged with EP4TA, KVM can assume
TLB entries populated while running L2 are tagged differently
than TLB entries populated while running L1.
Therefore, update nested_has_guest_tlb_tag() to consider if
L0 use EPT instead of if L1 use EPT.
Reviewed-by: Joao Martins <joao.m.martins@oracle.com>
Reviewed-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Signed-off-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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When L1 guest uses 5-level paging, it fails vm-entry to L2 due to
invalid host-state. It needs to add CR4_LA57 bit to nested CR4_FIXED1
MSR.
Signed-off-by: Chenyi Qiang <chenyi.qiang@intel.com>
Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Reviewed-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Reviewed-by: Mark Kanda <mark.kanda@oracle.com>
Signed-off-by: Liran Alon <liran.alon@oracle.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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The L1 hypervisor may include the IA32_TIME_STAMP_COUNTER MSR in the
vmcs12 MSR VM-exit MSR-store area as a way of determining the highest
TSC value that might have been observed by L2 prior to VM-exit. The
current implementation does not capture a very tight bound on this
value. To tighten the bound, add the IA32_TIME_STAMP_COUNTER MSR to the
vmcs02 VM-exit MSR-store area whenever it appears in the vmcs12 VM-exit
MSR-store area. When L0 processes the vmcs12 VM-exit MSR-store area
during the emulation of an L2->L1 VM-exit, special-case the
IA32_TIME_STAMP_COUNTER MSR, using the value stored in the vmcs02
VM-exit MSR-store area to derive the value to be stored in the vmcs12
VM-exit MSR-store area.
Reviewed-by: Liran Alon <liran.alon@oracle.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Aaron Lewis <aaronlewis@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Rename function find_msr() to vmx_find_msr_index() in preparation for an
upcoming patch where we export it and use it in nested.c.
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Aaron Lewis <aaronlewis@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Rename NR_AUTOLOAD_MSRS to NR_LOADSTORE_MSRS. This needs to be done
due to the addition of the MSR-autostore area that will be added in a
future patch. After that the name AUTOLOAD will no longer make sense.
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Aaron Lewis <aaronlewis@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Add the function read_and_check_msr_entry() which just pulls some code
out of nested_vmx_store_msr(). This will be useful as reusable code in
upcoming patches.
Reviewed-by: Liran Alon <liran.alon@oracle.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Aaron Lewis <aaronlewis@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Correct a small inaccuracy in the shattering of vmx.c, which becomes
visible now that pmu_intel.c includes nested.h.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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The "load IA32_PERF_GLOBAL_CTRL" bit for VM-entry and VM-exit should
only be exposed to the guest if IA32_PERF_GLOBAL_CTRL is a valid MSR.
Create a new helper to allow pmu_refresh() to update the VM-Entry and
VM-Exit controls to ensure PMU values are initialized when performing
the is_valid_msr() check.
Suggested-by: Jim Mattson <jmattson@google.com>
Co-developed-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Signed-off-by: Oliver Upton <oupton@google.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Peter Shier <pshier@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Add condition to prepare_vmcs02 which loads IA32_PERF_GLOBAL_CTRL on
VM-entry if the "load IA32_PERF_GLOBAL_CTRL" bit on the VM-entry control
is set. Use SET_MSR_OR_WARN() rather than directly writing to the field
to avoid overwrite by atomic_switch_perf_msrs().
Suggested-by: Jim Mattson <jmattson@google.com>
Co-developed-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Signed-off-by: Oliver Upton <oupton@google.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Peter Shier <pshier@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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The existing implementation for loading the IA32_PERF_GLOBAL_CTRL MSR
on VM-exit was incorrect, as the next call to atomic_switch_perf_msrs()
could cause this value to be overwritten. Instead, call kvm_set_msr()
which will allow atomic_switch_perf_msrs() to correctly set the values.
Define a macro, SET_MSR_OR_WARN(), to set the MSR with kvm_set_msr()
and WARN on failure.
Suggested-by: Jim Mattson <jmattson@google.com>
Co-developed-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Signed-off-by: Oliver Upton <oupton@google.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Peter Shier <pshier@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Add a consistency check on nested vm-entry for host's
IA32_PERF_GLOBAL_CTRL from vmcs12. Per Intel's SDM Vol 3 26.2.2:
If the "load IA32_PERF_GLOBAL_CTRL"
VM-exit control is 1, bits reserved in the IA32_PERF_GLOBAL_CTRL
MSR must be 0 in the field for that register"
Suggested-by: Jim Mattson <jmattson@google.com>
Co-developed-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Signed-off-by: Oliver Upton <oupton@google.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Peter Shier <pshier@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Add condition to nested_vmx_check_guest_state() to check the validity of
GUEST_IA32_PERF_GLOBAL_CTRL. Per Intel's SDM Vol 3 26.3.1.1:
If the "load IA32_PERF_GLOBAL_CTRL" VM-entry control is 1, bits
reserved in the IA32_PERF_GLOBAL_CTRL MSR must be 0 in the field for that
register.
Suggested-by: Jim Mattson <jmattson@google.com>
Co-developed-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Signed-off-by: Oliver Upton <oupton@google.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Peter Shier <pshier@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Create a helper function to check the validity of a proposed value for
IA32_PERF_GLOBAL_CTRL from the existing check in intel_pmu_set_msr().
Per Intel's SDM, the reserved bits in IA32_PERF_GLOBAL_CTRL must be
cleared for the corresponding host/guest state fields.
Suggested-by: Jim Mattson <jmattson@google.com>
Co-developed-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Signed-off-by: Oliver Upton <oupton@google.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Peter Shier <pshier@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Currently, a host perf_event is created for a vPMC functionality emulation.
It’s unpredictable to determine if a disabled perf_event will be reused.
If they are disabled and are not reused for a considerable period of time,
those obsolete perf_events would increase host context switch overhead that
could have been avoided.
If the guest doesn't WRMSR any of the vPMC's MSRs during an entire vcpu
sched time slice, and its independent enable bit of the vPMC isn't set,
we can predict that the guest has finished the use of this vPMC, and then
do request KVM_REQ_PMU in kvm_arch_sched_in and release those perf_events
in the first call of kvm_pmu_handle_event() after the vcpu is scheduled in.
This lazy mechanism delays the event release time to the beginning of the
next scheduled time slice if vPMC's MSRs aren't changed during this time
slice. If guest comes back to use this vPMC in next time slice, a new perf
event would be re-created via perf_event_create_kernel_counter() as usual.
Suggested-by: Wei Wang <wei.w.wang@intel.com>
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Like Xu <like.xu@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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The perf_event_create_kernel_counter() in the pmc_reprogram_counter() is
a heavyweight and high-frequency operation, especially when host disables
the watchdog (maximum 21000000 ns) which leads to an unacceptable latency
of the guest NMI handler. It limits the use of vPMUs in the guest.
When a vPMC is fully enabled, the legacy reprogram_*_counter() would stop
and release its existing perf_event (if any) every time EVEN in most cases
almost the same requested perf_event will be created and configured again.
For each vPMC, if the reuqested config ('u64 eventsel' for gp and 'u8 ctrl'
for fixed) is the same as its current config AND a new sample period based
on pmc->counter is accepted by host perf interface, the current event could
be reused safely as a new created one does. Otherwise, do release the
undesirable perf_event and reprogram a new one as usual.
It's light-weight to call pmc_pause_counter (disable, read and reset event)
and pmc_resume_counter (recalibrate period and re-enable event) as guest
expects instead of release-and-create again on any condition. Compared to
use the filterable event->attr or hw.config, a new 'u64 current_config'
field is added to save the last original programed config for each vPMC.
Based on this implementation, the number of calls to pmc_reprogram_counter
is reduced by ~82.5% for a gp sampling event and ~99.9% for a fixed event.
In the usage of multiplexing perf sampling mode, the average latency of the
guest NMI handler is reduced from 104923 ns to 48393 ns (~2.16x speed up).
If host disables watchdog, the minimum latecy of guest NMI handler could be
speed up at ~3413x (from 20407603 to 5979 ns) and at ~786x in the average.
Suggested-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Like Xu <like.xu@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Introduce a new callback msr_idx_to_pmc that returns a struct kvm_pmc*,
and change kvm_pmu_is_valid_msr to return ".msr_idx_to_pmc(vcpu, msr) ||
.is_valid_msr(vcpu, msr)" and AMD just returns false from .is_valid_msr.
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Like Xu <like.xu@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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The leagcy pmu_ops->msr_idx_to_pmc is only called in kvm_pmu_rdpmc, so
this function actually receives the contents of ECX before RDPMC, and
translates it to a kvm_pmc. Let's clarify its semantic by renaming the
existing msr_idx_to_pmc to rdpmc_ecx_to_pmc, and is_valid_msr_idx to
is_valid_rdpmc_ecx; likewise for the wrapper kvm_pmu_is_valid_msr_idx.
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Like Xu <like.xu@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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When L1 don't use TPR-Shadow to run L2, L0 configures vmcs02 without
TPR-Shadow and install intercepts on CR8 access (load and store).
If L1 do not intercept L2 CR8 access, L0 intercepts on those accesses
will emulate load/store on L1's LAPIC TPR. If in this case L2 lowers
TPR such that there is now an injectable interrupt to L1,
apic_update_ppr() will request a KVM_REQ_EVENT which will trigger a call
to update_cr8_intercept() to update TPR-Threshold to highest pending IRR
priority.
However, this update to TPR-Threshold is done while active vmcs is
vmcs02 instead of vmcs01. Thus, when later at some point L0 will
emulate an exit from L2 to L1, L1 will still run with high
TPR-Threshold. This will result in every VMEntry to L1 to immediately
exit on TPR_BELOW_THRESHOLD and continue to do so infinitely until
some condition will cause KVM_REQ_EVENT to be set.
(Note that TPR_BELOW_THRESHOLD exit handler do not set KVM_REQ_EVENT
until apic_update_ppr() will notice a new injectable interrupt for PPR)
To fix this issue, change update_cr8_intercept() such that if L2 lowers
L1's TPR in a way that requires to lower L1's TPR-Threshold, save update
to TPR-Threshold and apply it to vmcs01 when L0 emulates an exit from
L2 to L1.
Reviewed-by: Joao Martins <joao.m.martins@oracle.com>
Signed-off-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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No functional changes.
Reviewed-by: Joao Martins <joao.m.martins@oracle.com>
Signed-off-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Intel SDM section 25.2 OTHER CAUSES OF VM EXITS specifies the following
on INIT signals: "Such exits do not modify register state or clear pending
events as they would outside of VMX operation."
When commit 4b9852f4f389 ("KVM: x86: Fix INIT signal handling in various CPU states")
was applied, I interepted above Intel SDM statement such that
INIT_SIGNAL exit don’t consume the LAPIC INIT pending event.
However, when Nadav Amit run matching kvm-unit-test on a bare-metal
machine, it turned out my interpetation was wrong. i.e. INIT_SIGNAL
exit does consume the LAPIC INIT pending event.
(See: https://www.spinics.net/lists/kvm/msg196757.html)
Therefore, fix KVM code to behave as observed on bare-metal.
Fixes: 4b9852f4f389 ("KVM: x86: Fix INIT signal handling in various CPU states")
Reported-by: Nadav Amit <nadav.amit@gmail.com>
Reviewed-by: Mihai Carabas <mihai.carabas@oracle.com>
Reviewed-by: Joao Martins <joao.m.martins@oracle.com>
Signed-off-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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It's enough to check the exit value and issue a direct call to avoid
the retpoline for all the common vmexit reasons.
Of course CONFIG_RETPOLINE already forbids gcc to use indirect jumps
while compiling all switch() statements, however switch() would still
allow the compiler to bisect the case value. It's more efficient to
prioritize the most frequent vmexits instead.
The halt may be slow paths from the point of the guest, but not
necessarily so from the point of the host if the host runs at full CPU
capacity and no host CPU is ever left idle.
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Eliminate wasteful call/ret non RETPOLINE case and unnecessary fentry
dynamic tracing hooking points.
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Streamline the PID.PIR check and change its call sites to use
the newly added helper.
Suggested-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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When vCPU enters block phase, pi_pre_block() inserts vCPU to a per pCPU
linked list of all vCPUs that are blocked on this pCPU. Afterwards, it
changes PID.NV to POSTED_INTR_WAKEUP_VECTOR which its handler
(wakeup_handler()) is responsible to kick (unblock) any vCPU on that
linked list that now has pending posted interrupts.
While vCPU is blocked (in kvm_vcpu_block()), it may be preempted which
will cause vmx_vcpu_pi_put() to set PID.SN. If later the vCPU will be
scheduled to run on a different pCPU, vmx_vcpu_pi_load() will clear
PID.SN but will also *overwrite PID.NDST to this different pCPU*.
Instead of keeping it with original pCPU which vCPU had entered block
phase on.
This results in an issue because when a posted interrupt is delivered, as
the wakeup_handler() will be executed and fail to find blocked vCPU on
its per pCPU linked list of all vCPUs that are blocked on this pCPU.
Which is due to the vCPU being placed on a *different* per pCPU
linked list i.e. the original pCPU in which it entered block phase.
The regression is introduced by commit c112b5f50232 ("KVM: x86:
Recompute PID.ON when clearing PID.SN"). Therefore, partially revert
it and reintroduce the condition in vmx_vcpu_pi_load() responsible for
avoiding changing PID.NDST when loading a blocked vCPU.
Fixes: c112b5f50232 ("KVM: x86: Recompute PID.ON when clearing PID.SN")
Tested-by: Nathan Ni <nathan.ni@oracle.com>
Co-developed-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Commit 17e433b54393 ("KVM: Fix leak vCPU's VMCS value into other pCPU")
introduced vmx_dy_apicv_has_pending_interrupt() in order to determine
if a vCPU have a pending posted interrupt. This routine is used by
kvm_vcpu_on_spin() when searching for a a new runnable vCPU to schedule
on pCPU instead of a vCPU doing busy loop.
vmx_dy_apicv_has_pending_interrupt() determines if a
vCPU has a pending posted interrupt solely based on PID.ON. However,
when a vCPU is preempted, vmx_vcpu_pi_put() sets PID.SN which cause
raised posted interrupts to only set bit in PID.PIR without setting
PID.ON (and without sending notification vector), as depicted in VT-d
manual section 5.2.3 "Interrupt-Posting Hardware Operation".
Therefore, checking PID.ON is insufficient to determine if a vCPU has
pending posted interrupts and instead we should also check if there is
some bit set on PID.PIR if PID.SN=1.
Fixes: 17e433b54393 ("KVM: Fix leak vCPU's VMCS value into other pCPU")
Reviewed-by: Jagannathan Raman <jag.raman@oracle.com>
Co-developed-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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The Outstanding Notification (ON) bit is part of the Posted Interrupt
Descriptor (PID) as opposed to the Posted Interrupts Register (PIR).
The latter is a bitmap for pending vectors.
Reviewed-by: Joao Martins <joao.m.martins@oracle.com>
Signed-off-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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VMX already does so if the host has SMEP, in order to support the combination of
CR0.WP=1 and CR4.SMEP=1. However, it is perfectly safe to always do so, and in
fact VMX already ends up running with EFER.NXE=1 on old processors that lack the
"load EFER" controls, because it may help avoiding a slow MSR write. Removing
all the conditionals simplifies the code.
SVM does not have similar code, but it should since recent AMD processors do
support SMEP. So this patch also makes the code for the two vendors more similar
while fixing NPT=0, CR0.WP=1 and CR4.SMEP=1 on AMD processors.
Cc: stable@vger.kernel.org
Cc: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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If the "virtualize APIC accesses" VM-execution control is set in the
VMCS, the APIC virtualization hardware is triggered when a page walk
in VMX non-root mode terminates at a PTE wherein the address of the 4k
page frame matches the APIC-access address specified in the VMCS. On
hardware, the APIC-access address may be any valid 4k-aligned physical
address.
KVM's nVMX implementation enforces the additional constraint that the
APIC-access address specified in the vmcs12 must be backed by
a "struct page" in L1. If not, L0 will simply clear the "virtualize
APIC accesses" VM-execution control in the vmcs02.
The problem with this approach is that the L1 guest has arranged the
vmcs12 EPT tables--or shadow page tables, if the "enable EPT"
VM-execution control is clear in the vmcs12--so that the L2 guest
physical address(es)--or L2 guest linear address(es)--that reference
the L2 APIC map to the APIC-access address specified in the
vmcs12. Without the "virtualize APIC accesses" VM-execution control in
the vmcs02, the APIC accesses in the L2 guest will directly access the
APIC-access page in L1.
When there is no mapping whatsoever for the APIC-access address in L1,
the L2 VM just loses the intended APIC virtualization. However, when
the APIC-access address is mapped to an MMIO region in L1, the L2
guest gets direct access to the L1 MMIO device. For example, if the
APIC-access address specified in the vmcs12 is 0xfee00000, then L2
gets direct access to L1's APIC.
Since this vmcs12 configuration is something that KVM cannot
faithfully emulate, the appropriate response is to exit to userspace
with KVM_INTERNAL_ERROR_EMULATION.
Fixes: fe3ef05c7572 ("KVM: nVMX: Prepare vmcs02 from vmcs01 and vmcs12")
Reported-by: Dan Cross <dcross@google.com>
Signed-off-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Peter Shier <pshier@google.com>
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Hoist support for RDMSR/WRMSR of IA32_XSS from vmx into common code so
that it can be used for svm as well.
Right now, kvm only allows the guest IA32_XSS to be zero,
so the guest's usage of XSAVES will be exactly the same as XSAVEC.
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Aaron Lewis <aaronlewis@google.com>
Change-Id: Ie4b0f777d71e428fbee6e82071ac2d7618e9bb40
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Hoist the vendor-specific code related to loading the hardware IA32_XSS
MSR with guest/host values on VM-entry/VM-exit to common x86 code.
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Aaron Lewis <aaronlewis@google.com>
Change-Id: Ic6e3430833955b98eb9b79ae6715cf2a3fdd6d82
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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When the guest can execute the XSAVES/XRSTORS instructions, use wrmsr to
set the hardware IA32_XSS MSR to guest/host values on VM-entry/VM-exit,
rather than the MSR-load areas. By using the same approach as AMD, we
will be able to use a common implementation for both (in the next
patch).
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Aaron Lewis <aaronlewis@google.com>
Change-Id: I9447d104b2615c04e39e4af0c911e1e7309bf464
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Volume 4 of the SDM says that IA32_XSS is supported
if CPUID(EAX=0DH,ECX=1):EAX.XSS[bit 3] is set, so only the
X86_FEATURE_XSAVES check is necessary (X86_FEATURE_XSAVES is the Linux
name for CPUID(EAX=0DH,ECX=1):EAX.XSS[bit 3]).
Fixes: 4d763b168e9c5 ("KVM: VMX: check CPUID before allowing read/write of IA32_XSS")
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Aaron Lewis <aaronlewis@google.com>
Change-Id: I9059b9f2e3595e4b09a4cdcf14b933b22ebad419
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Cache whether XSAVES is enabled in the guest by adding xsaves_enabled to
vcpu->arch.
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Aaron Lewis <aaronlewis@google.com>
Change-Id: If4638e0901c28a4494dad2e103e2c075e8ab5d68
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Rename {vmx,nested_vmx}_vcpu_setup() to match what they really do.
Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Move the initialization of vmx->guest_msrs[] from vmx_vcpu_setup() to
vmx_create_vcpu(), and put it right after its allocation.
This also is the preperation for next patch.
Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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... It can be removed here because the same code is called later in
vmx_vcpu_reset() as the flow:
kvm_arch_vcpu_setup()
-> kvm_vcpu_reset()
-> vmx_vcpu_reset()
Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Move the code that writes vmx->vpid to vmcs from vmx_vcpu_reset() to
vmx_vcpu_setup(), because vmx->vpid is allocated when creating vcpu and
never changed. So we don't need to update the vmcs.vpid when resetting
vcpu.
Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Generally, APICv for all vcpus in the VM are enable/disable in the same
manner. So, get_enable_apicv() should represent APICv status of the VM
instead of each VCPU.
Modify kvm_x86_ops.get_enable_apicv() to take struct kvm as parameter
instead of struct kvm_vcpu.
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Handle caching CR3 (from VMX's VMCS) into struct kvm_vcpu via the common
cache_reg() callback and drop the dedicated decache_cr3(). The name
decache_cr3() is somewhat confusing as the caching behavior of CR3
follows that of GPRs, RFLAGS and PDPTRs, (handled via cache_reg()), and
has nothing in common with the caching behavior of CR0/CR4 (whose
decache_cr{0,4}_guest_bits() likely provided the 'decache' verbiage).
This would effectivel adds a BUG() if KVM attempts to cache CR3 on SVM.
Change it to a WARN_ON_ONCE() -- if the cache never requires filling,
the value is already in the right place -- and opportunistically add one
in VMX to provide an equivalent check.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Add helpers to prettify code that tests and/or marks whether or not a
register is available and/or dirty.
Suggested-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Rework vmx_set_rflags() to avoid the extra code need to handle emulation
of real mode and invalid state when unrestricted guest is disabled. The
primary reason for doing so is to avoid the call to vmx_get_rflags(),
which will incur a VMREAD when RFLAGS is not already available. When
running nested VMs, the majority of calls to vmx_set_rflags() will occur
without an associated vmx_get_rflags(), i.e. when stuffing GUEST_RFLAGS
during transitions between vmcs01 and vmcs02.
Note, vmx_get_rflags() guarantees RFLAGS is marked available.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
[Replace "else" with early "return" in the unrestricted guest branch. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Capture struct vcpu_vmx in a local variable to improve the readability
of vmx_{g,s}et_rflags().
No functional change intended.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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