diff options
| author | Vitaly Kuznetsov | 2022-03-25 14:21:40 +0100 |
|---|---|---|
| committer | Paolo Bonzini | 2022-03-29 13:22:07 -0400 |
| commit | b1e34d325397a33d97d845e312d7cf2a8b646b44 (patch) | |
| tree | 8c8a40aee36f06cdbedcd0a33e9335b4e4dda67c /arch/x86 | |
| parent | 00b5f37189d24ac3ed46cb7f11742094778c46ce (diff) | |
KVM: x86: Forbid VMM to set SYNIC/STIMER MSRs when SynIC wasn't activated
Setting non-zero values to SYNIC/STIMER MSRs activates certain features,
this should not happen when KVM_CAP_HYPERV_SYNIC{,2} was not activated.
Note, it would've been better to forbid writing anything to SYNIC/STIMER
MSRs, including zeroes, however, at least QEMU tries clearing
HV_X64_MSR_STIMER0_CONFIG without SynIC. HV_X64_MSR_EOM MSR is somewhat
'special' as writing zero there triggers an action, this also should not
happen when SynIC wasn't activated.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20220325132140.25650-4-vkuznets@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/kvm/hyperv.c | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c index f715b5a2b0e4..4177c17a26bf 100644 --- a/arch/x86/kvm/hyperv.c +++ b/arch/x86/kvm/hyperv.c @@ -239,7 +239,7 @@ static int synic_set_msr(struct kvm_vcpu_hv_synic *synic, struct kvm_vcpu *vcpu = hv_synic_to_vcpu(synic); int ret; - if (!synic->active && !host) + if (!synic->active && (!host || data)) return 1; trace_kvm_hv_synic_set_msr(vcpu->vcpu_id, msr, data, host); @@ -285,6 +285,9 @@ static int synic_set_msr(struct kvm_vcpu_hv_synic *synic, case HV_X64_MSR_EOM: { int i; + if (!synic->active) + break; + for (i = 0; i < ARRAY_SIZE(synic->sint); i++) kvm_hv_notify_acked_sint(vcpu, i); break; @@ -664,7 +667,7 @@ static int stimer_set_config(struct kvm_vcpu_hv_stimer *stimer, u64 config, struct kvm_vcpu_hv *hv_vcpu = to_hv_vcpu(vcpu); struct kvm_vcpu_hv_synic *synic = to_hv_synic(vcpu); - if (!synic->active && !host) + if (!synic->active && (!host || config)) return 1; if (unlikely(!host && hv_vcpu->enforce_cpuid && new_config.direct_mode && @@ -693,7 +696,7 @@ static int stimer_set_count(struct kvm_vcpu_hv_stimer *stimer, u64 count, struct kvm_vcpu *vcpu = hv_stimer_to_vcpu(stimer); struct kvm_vcpu_hv_synic *synic = to_hv_synic(vcpu); - if (!synic->active && !host) + if (!synic->active && (!host || count)) return 1; trace_kvm_hv_stimer_set_count(hv_stimer_to_vcpu(stimer)->vcpu_id, |