Commit de7cd3f6 authored by Paolo Bonzini's avatar Paolo Bonzini
Browse files

KVM: x86: check for interrupts before deciding whether to exit the fast path 



The kvm_x86_sync_pir_to_irr callback can sometimes set KVM_REQ_EVENT.
If that happens exactly at the time that an exit is handled as
EXIT_FASTPATH_REENTER_GUEST, vcpu_enter_guest will go incorrectly
through the loop that calls kvm_x86_run, instead of processing
the request promptly.

Fixes: 379a3c8e ("KVM: VMX: Optimize posted-interrupt delivery for timer fastpath")
Cc: stable@vger.kernel.org
Reviewed-by: default avatarSean Christopherson <seanjc@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 9f1ee7b1

arch/x86/kvm/x86.c

+5 −5
Original line number Diff line number Diff line
@@ -9643,13 +9643,13 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) 
		if (likely(exit_fastpath != EXIT_FASTPATH_REENTER_GUEST))

			break;



		if (vcpu->arch.apicv_active)

			static_call(kvm_x86_sync_pir_to_irr)(vcpu);



		if (unlikely(kvm_vcpu_exit_request(vcpu))) {

			exit_fastpath = EXIT_FASTPATH_EXIT_HANDLED;

			break;

		}



		if (vcpu->arch.apicv_active)

			static_call(kvm_x86_sync_pir_to_irr)(vcpu);

	}



	/*