From: Vitaly Kuznetsov vkuznets@redhat.com
stable inclusion from stable-v5.10.110 commit 09c771c45c1243e295470225aaee726693fdc242 bugzilla: https://gitee.com/openeuler/kernel/issues/I574AL
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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commit b1e34d325397a33d97d845e312d7cf2a8b646b44 upstream.
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Yu Liao liaoyu15@huawei.com Reviewed-by: Wei Li liwei391@huawei.com Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com --- arch/x86/kvm/hyperv.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c index 328f37e4fd3a..d806139377bc 100644 --- a/arch/x86/kvm/hyperv.c +++ b/arch/x86/kvm/hyperv.c @@ -207,7 +207,7 @@ static int synic_set_msr(struct kvm_vcpu_hv_synic *synic, struct kvm_vcpu *vcpu = 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); @@ -253,6 +253,9 @@ 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; @@ -636,7 +639,7 @@ static int stimer_set_config(struct kvm_vcpu_hv_stimer *stimer, u64 config, struct kvm_vcpu *vcpu = stimer_to_vcpu(stimer); struct kvm_vcpu_hv_synic *synic = vcpu_to_synic(vcpu);
- if (!synic->active && !host) + if (!synic->active && (!host || config)) return 1;
trace_kvm_hv_stimer_set_config(stimer_to_vcpu(stimer)->vcpu_id, @@ -660,7 +663,7 @@ static int stimer_set_count(struct kvm_vcpu_hv_stimer *stimer, u64 count, struct kvm_vcpu *vcpu = stimer_to_vcpu(stimer); struct kvm_vcpu_hv_synic *synic = vcpu_to_synic(vcpu);
- if (!synic->active && !host) + if (!synic->active && (!host || count)) return 1;
trace_kvm_hv_stimer_set_count(stimer_to_vcpu(stimer)->vcpu_id,