Re: [PATCH v3 1/4] KVM: x86: refactor req_immediate_exit logic

[Paolo Bonzini]

On 9/28/23 12:36, Maxim Levitsky wrote:
> @@ -4176,6 +4176,9 @@ static __no_kcsan fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu)
>   	clgi();
>   	kvm_load_guest_xsave_state(vcpu);
>   
> +	if (vcpu->arch.req_immediate_exit)
> +		smp_send_reschedule(vcpu->cpu);
> +

This code is in a non-standard situation where IF=1 but interrupts are
effectively disabled.  Better something like:

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index beea99c8e8e0..3b945de2d880 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -4148,8 +4148,11 @@ static __no_kcsan fastpath_t svm_vcpu_run(
 		 * is enough to force an immediate vmexit.
 		 */
 		disable_nmi_singlestep(svm);
+		vcpu->arch.req_immediate_exit = true;
+	}
+
+	if (vcpu->arch.req_immediate_exit)
 		smp_send_reschedule(vcpu->cpu);
-	}

 	pre_svm_run(vcpu);


Paolo