Commit a80c4ec1 authored by Borislav Petkov's avatar Borislav Petkov Committed by Paolo Bonzini
Browse files

x86/kvm/pmu: Set AMD's virt PMU version to 1

After commit:

  672ff6cf ("KVM: x86: Raise #GP when guest vCPU do not support PMU")

my AMD guests started #GPing like this:

  general protection fault: 0000 [#1] PREEMPT SMP
  CPU: 1 PID: 4355 Comm: bash Not tainted 5.1.0-rc6+ #3

  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
  RIP: 0010:x86_perf_event_update+0x3b/0xa0

with Code: pointing to RDPMC. It is RDPMC because the guest has the
hardware watchdog CONFIG_HARDLOCKUP_DETECTOR_PERF enabled which uses
perf. Instrumenting kvm_pmu_rdpmc() some, showed that it fails due to:

  if (!pmu->version)
  	return 1;

which the above commit added. Since AMD's PMU leaves the version at 0,
that causes the #GP injection into the guest.

Set pmu->version arbitrarily to 1 and move it above the non-applicable
struct kvm_pmu members.
Signed-off-by: default avatarBorislav Petkov <>
Cc: "H. Peter Anvin" <>
Cc: Ingo Molnar <>
Cc: Janakarajan Natarajan <>
Cc: Liran Alon <>
Cc: Mihai Carabas <>
Cc: Paolo Bonzini <>
Cc: Peter Zijlstra <>
Cc: "Radim Krčmář" <>
Cc: Thomas Gleixner <>
Cc: Tom Lendacky <>
Fixes: 672ff6cf

 ("KVM: x86: Raise #GP when guest vCPU do not support PMU")
Signed-off-by: default avatarPaolo Bonzini <>
parent 6f2f8453
......@@ -269,10 +269,10 @@ static void amd_pmu_refresh(struct kvm_vcpu *vcpu)
pmu->counter_bitmask[KVM_PMC_GP] = ((u64)1 << 48) - 1;
pmu->reserved_bits = 0xffffffff00200000ull;
pmu->version = 1;
/* not applicable to AMD; but clean them to prevent any fall out */
pmu->counter_bitmask[KVM_PMC_FIXED] = 0;
pmu->nr_arch_fixed_counters = 0;
pmu->version = 0;
pmu->global_status = 0;
Markdown is supported
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment