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@xxxxxxxxxxxxxxx
> Reported-by: Maxim Levitsky <mlevitsk@xxxxxxxxxx>
> Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> ---
> 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@xxxxxxxxxx>
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
