diff options
| author | Mingwei Zhang <mizhang@google.com> | 2024-01-23 23:12:20 +0100 |
|---|---|---|
| committer | Sean Christopherson <seanjc@google.com> | 2024-02-02 23:07:27 +0100 |
| commit | 05519c86d6997cfb9bb6c82ce1595d1015b718dc (patch) | |
| tree | 0f72bb68d3bf88055d35843a8276e35a8d419c1b /arch/x86 | |
| parent | KVM: x86: make KVM_REQ_NMI request iff NMI pending for vcpu (diff) | |
| download | linux-05519c86d6997cfb9bb6c82ce1595d1015b718dc.tar.xz linux-05519c86d6997cfb9bb6c82ce1595d1015b718dc.zip | |
KVM: x86/pmu: Fix type length error when reading pmu->fixed_ctr_ctrl
Use a u64 instead of a u8 when taking a snapshot of pmu->fixed_ctr_ctrl
when reprogramming fixed counters, as truncating the value results in KVM
thinking fixed counter 2 is already disabled (the bug also affects fixed
counters 3+, but KVM doesn't yet support those). As a result, if the
guest disables fixed counter 2, KVM will get a false negative and fail to
reprogram/disable emulation of the counter, which can leads to incorrect
counts and spurious PMIs in the guest.
Fixes: 76d287b2342e ("KVM: x86/pmu: Drop "u8 ctrl, int idx" for reprogram_fixed_counter()")
Cc: stable@vger.kernel.org
Signed-off-by: Mingwei Zhang <mizhang@google.com>
Link: https://lore.kernel.org/r/20240123221220.3911317-1-mizhang@google.com
[sean: rewrite changelog to call out the effects of the bug]
Signed-off-by: Sean Christopherson <seanjc@google.com>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/kvm/vmx/pmu_intel.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c index a6216c874729..315c7c2ba89b 100644 --- a/arch/x86/kvm/vmx/pmu_intel.c +++ b/arch/x86/kvm/vmx/pmu_intel.c @@ -71,7 +71,7 @@ static int fixed_pmc_events[] = { static void reprogram_fixed_counters(struct kvm_pmu *pmu, u64 data) { struct kvm_pmc *pmc; - u8 old_fixed_ctr_ctrl = pmu->fixed_ctr_ctrl; + u64 old_fixed_ctr_ctrl = pmu->fixed_ctr_ctrl; int i; pmu->fixed_ctr_ctrl = data; |