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  1. 15 11月, 2019 10 次提交
  3. 22 10月, 2019 17 次提交
  5. 03 10月, 2019 1 次提交
  7. 01 10月, 2019 1 次提交
    • J
      kvm: vmx: Limit guest PMCs to those supported on the host · e1fba49c
      由 Jim Mattson 提交于 
      KVM can only virtualize as many PMCs as the host supports.

Limit the number of generic counters and fixed counters to the number
of corresponding counters supported on the host, rather than to
INTEL_PMC_MAX_GENERIC and INTEL_PMC_MAX_FIXED, respectively.

Note that INTEL_PMC_MAX_GENERIC is currently 32, which exceeds the 18
contiguous MSR indices reserved by Intel for event selectors. Since
the existing code relies on a contiguous range of MSR indices for
event selectors, it can't possibly work for more than 18 general
purpose counters.

Fixes: f5132b01 ("KVM: Expose a version 2 architectural PMU to a guests")
Signed-off-by: NJim Mattson <jmattson@google.com>
Reviewed-by: NMarc Orr <marcorr@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      e1fba49c
  9. 28 9月, 2019 1 次提交
    • W
      KVM: VMX: Set VMENTER_L1D_FLUSH_NOT_REQUIRED if !X86_BUG_L1TF · 19a36d32
      由 Waiman Long 提交于 
      The l1tf_vmx_mitigation is only set to VMENTER_L1D_FLUSH_NOT_REQUIRED
when the ARCH_CAPABILITIES MSR indicates that L1D flush is not required.
However, if the CPU is not affected by L1TF, l1tf_vmx_mitigation will
still be set to VMENTER_L1D_FLUSH_AUTO. This is certainly not the best
option for a !X86_BUG_L1TF CPU.

So force l1tf_vmx_mitigation to VMENTER_L1D_FLUSH_NOT_REQUIRED to make it
more explicit in case users are checking the vmentry_l1d_flush parameter.
Signed-off-by: NWaiman Long <longman@redhat.com>
[Patch rewritten accoring to Borislav Petkov's suggestion. - Paolo]
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      19a36d32
  11. 26 9月, 2019 1 次提交
  13. 25 9月, 2019 3 次提交
  15. 24 9月, 2019 6 次提交
    • M
      kvm: nvmx: limit atomic switch MSRs · f0b5105a
      由 Marc Orr 提交于 
      Allowing an unlimited number of MSRs to be specified via the VMX
load/store MSR lists (e.g., vm-entry MSR load list) is bad for two
reasons. First, a guest can specify an unreasonable number of MSRs,
forcing KVM to process all of them in software. Second, the SDM bounds
the number of MSRs allowed to be packed into the atomic switch MSR lists.
Quoting the "Miscellaneous Data" section in the "VMX Capability
Reporting Facility" appendix:

"Bits 27:25 is used to compute the recommended maximum number of MSRs
that should appear in the VM-exit MSR-store list, the VM-exit MSR-load
list, or the VM-entry MSR-load list. Specifically, if the value bits
27:25 of IA32_VMX_MISC is N, then 512 * (N + 1) is the recommended
maximum number of MSRs to be included in each list. If the limit is
exceeded, undefined processor behavior may result (including a machine
check during the VMX transition)."

Because KVM needs to protect itself and can't model "undefined processor
behavior", arbitrarily force a VM-entry to fail due to MSR loading when
the MSR load list is too large. Similarly, trigger an abort during a VM
exit that encounters an MSR load list or MSR store list that is too large.

The MSR list size is intentionally not pre-checked so as to maintain
compatibility with hardware inasmuch as possible.

Test these new checks with the kvm-unit-test "x86: nvmx: test max atomic
switch MSRs".
Suggested-by: NJim Mattson <jmattson@google.com>
Reviewed-by: NJim Mattson <jmattson@google.com>
Reviewed-by: NPeter Shier <pshier@google.com>
Signed-off-by: NMarc Orr <marcorr@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      f0b5105a
    • T
      KVM: vmx: Introduce handle_unexpected_vmexit and handle WAITPKG vmexit · bf653b78
      由 Tao Xu 提交于 
      As the latest Intel 64 and IA-32 Architectures Software Developer's
Manual, UMWAIT and TPAUSE instructions cause a VM exit if the
RDTSC exiting and enable user wait and pause VM-execution
controls are both 1.

Because KVM never enable RDTSC exiting, the vm-exit for UMWAIT and TPAUSE
should never happen. Considering EXIT_REASON_XSAVES and
EXIT_REASON_XRSTORS is also unexpected VM-exit for KVM. Introduce a common
exit helper handle_unexpected_vmexit() to handle these unexpected VM-exit.
Suggested-by: NSean Christopherson <sean.j.christopherson@intel.com>
Co-developed-by: NJingqi Liu <jingqi.liu@intel.com>
Signed-off-by: NJingqi Liu <jingqi.liu@intel.com>
Signed-off-by: NTao Xu <tao3.xu@intel.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      bf653b78
    • T
      KVM: vmx: Emulate MSR IA32_UMWAIT_CONTROL · 6e3ba4ab
      由 Tao Xu 提交于 
      UMWAIT and TPAUSE instructions use 32bit IA32_UMWAIT_CONTROL at MSR index
E1H to determines the maximum time in TSC-quanta that the processor can
reside in either C0.1 or C0.2.

This patch emulates MSR IA32_UMWAIT_CONTROL in guest and differentiate
IA32_UMWAIT_CONTROL between host and guest. The variable
mwait_control_cached in arch/x86/kernel/cpu/umwait.c caches the MSR value,
so this patch uses it to avoid frequently rdmsr of IA32_UMWAIT_CONTROL.
Co-developed-by: NJingqi Liu <jingqi.liu@intel.com>
Signed-off-by: NJingqi Liu <jingqi.liu@intel.com>
Signed-off-by: NTao Xu <tao3.xu@intel.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      6e3ba4ab
    • T
      KVM: x86: Add support for user wait instructions · e69e72fa
      由 Tao Xu 提交于 
      UMONITOR, UMWAIT and TPAUSE are a set of user wait instructions.
This patch adds support for user wait instructions in KVM. Availability
of the user wait instructions is indicated by the presence of the CPUID
feature flag WAITPKG CPUID.0x07.0x0:ECX[5]. User wait instructions may
be executed at any privilege level, and use 32bit IA32_UMWAIT_CONTROL MSR
to set the maximum time.

The behavior of user wait instructions in VMX non-root operation is
determined first by the setting of the "enable user wait and pause"
secondary processor-based VM-execution control bit 26.
	If the VM-execution control is 0, UMONITOR/UMWAIT/TPAUSE cause
an invalid-opcode exception (#UD).
	If the VM-execution control is 1, treatment is based on the
setting of the “RDTSC exiting†VM-execution control. Because KVM never
enables RDTSC exiting, if the instruction causes a delay, the amount of
time delayed is called here the physical delay. The physical delay is
first computed by determining the virtual delay. If
IA32_UMWAIT_CONTROL[31:2] is zero, the virtual delay is the value in
EDX:EAX minus the value that RDTSC would return; if
IA32_UMWAIT_CONTROL[31:2] is not zero, the virtual delay is the minimum
of that difference and AND(IA32_UMWAIT_CONTROL,FFFFFFFCH).

Because umwait and tpause can put a (psysical) CPU into a power saving
state, by default we dont't expose it to kvm and enable it only when
guest CPUID has it.

Detailed information about user wait instructions can be found in the
latest Intel 64 and IA-32 Architectures Software Developer's Manual.
Co-developed-by: NJingqi Liu <jingqi.liu@intel.com>
Signed-off-by: NJingqi Liu <jingqi.liu@intel.com>
Signed-off-by: NTao Xu <tao3.xu@intel.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      e69e72fa
    • S
      KVM: VMX: Handle single-step #DB for EMULTYPE_SKIP on EPT misconfig · 1957aa63
      由 Sean Christopherson 提交于 
      VMX's EPT misconfig flow to handle fast-MMIO path falls back to decoding
the instruction to determine the instruction length when running as a
guest (Hyper-V doesn't fill VMCS.VM_EXIT_INSTRUCTION_LEN because it's
technically not defined for EPT misconfigs).  Rather than implement the
slow skip in VMX's generic skip_emulated_instruction(),
handle_ept_misconfig() directly calls kvm_emulate_instruction() with
EMULTYPE_SKIP, which intentionally doesn't do single-step detection, and
so handle_ept_misconfig() misses a single-step #DB.

Rework the EPT misconfig fallback case to route it through
kvm_skip_emulated_instruction() so that single-step #DBs and interrupt
shadow updates are handled automatically.  I.e. make VMX's slow skip
logic match SVM's and have the SVM flow not intentionally avoid the
shadow update.

Alternatively, the handle_ept_misconfig() could manually handle single-
step detection, but that results in EMULTYPE_SKIP having split logic for
the interrupt shadow vs. single-step #DBs, and split emulator logic is
largely what led to this mess in the first place.

Modifying SVM to mirror VMX flow isn't really an option as SVM's case
isn't limited to a specific exit reason, i.e. handling the slow skip in
skip_emulated_instruction() is mandatory for all intents and purposes.

Drop VMX's skip_emulated_instruction() wrapper since it can now fail,
and instead WARN if it fails unexpectedly, e.g. if exit_reason somehow
becomes corrupted.

Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Fixes: d391f120 ("x86/kvm/vmx: do not use vm-exit instruction length for fast MMIO when running nested")
Signed-off-by: NSean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      1957aa63
    • S
      KVM: x86: Remove emulation_result enums, EMULATE_{DONE,FAIL,USER_EXIT} · 60fc3d02
      由 Sean Christopherson 提交于 
      Deferring emulation failure handling (in some cases) to the caller of
x86_emulate_instruction() has proven fragile, e.g. multiple instances of
KVM not setting run->exit_reason on EMULATE_FAIL, largely due to it
being difficult to discern what emulation types can return what result,
and which combination of types and results are handled where.

Now that x86_emulate_instruction() always handles emulation failure,
i.e. EMULATION_FAIL is only referenced in callers, remove the
emulation_result enums entirely.  Per KVM's existing exit handling
conventions, return '0' and '1' for "exit to userspace" and "resume
guest" respectively.  Doing so cleans up many callers, e.g. they can
return kvm_emulate_instruction() directly instead of having to interpret
its result.
Signed-off-by: NSean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      60fc3d02