| Message ID | 20220427173758.517087-4-pbonzini@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | [1/3] KVM: x86: make vendor code check for all nested events | expand |
On Wed, 2022-04-27 at 13:37 -0400, Paolo Bonzini wrote: > kvm_vcpu_check_block is called while not in TASK_RUNNING, and therefore > cannot sleep. Writing to guest memory is therefore forbidden, but it > can happen if kvm_check_nested_events causes a vmexit. > > Fortunately, all events that are caught by kvm_check_nested_events are > also handled by kvm_vcpu_has_events through vendor callbacks such as > kvm_x86_interrupt_allowed or kvm_x86_ops.nested_ops->has_events, so > remove the call. > > Cc: stable@vger.kernel.org > Reported-by: Maxim Levitsky <mlevitsk@redhat.com> > Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> > --- > arch/x86/kvm/x86.c | 3 --- > 1 file changed, 3 deletions(-) > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index d563812ca229..90b4f50b9a84 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -10341,9 +10341,6 @@ static inline int vcpu_block(struct kvm_vcpu *vcpu) > > static inline bool kvm_vcpu_running(struct kvm_vcpu *vcpu) > { > - if (is_guest_mode(vcpu)) > - kvm_check_nested_events(vcpu); > - > return (vcpu->arch.mp_state == KVM_MP_STATE_RUNNABLE && > !vcpu->arch.apf.halted); > } Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> I tested this on AMD, and it seems to work fine, and my nested AVIC test works as good as was before. Note that I forgot to mention, that I had to apply most of the patches manually, they don't apply to kvm/queue. Best regards, Maxim Levitsky
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index d563812ca229..90b4f50b9a84 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -10341,9 +10341,6 @@ static inline int vcpu_block(struct kvm_vcpu *vcpu) static inline bool kvm_vcpu_running(struct kvm_vcpu *vcpu) { - if (is_guest_mode(vcpu)) - kvm_check_nested_events(vcpu); - return (vcpu->arch.mp_state == KVM_MP_STATE_RUNNABLE && !vcpu->arch.apf.halted); }
kvm_vcpu_check_block is called while not in TASK_RUNNING, and therefore cannot sleep. Writing to guest memory is therefore forbidden, but it can happen if kvm_check_nested_events causes a vmexit. Fortunately, all events that are caught by kvm_check_nested_events are also handled by kvm_vcpu_has_events through vendor callbacks such as kvm_x86_interrupt_allowed or kvm_x86_ops.nested_ops->has_events, so remove the call. Cc: stable@vger.kernel.org Reported-by: Maxim Levitsky <mlevitsk@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> --- arch/x86/kvm/x86.c | 3 --- 1 file changed, 3 deletions(-)