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