FAILED: patch "[PATCH] KVM: x86: check for interrupts before deciding whether to" failed to apply to 5.10-stable tree

The patch below does not apply to the 5.10-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From de7cd3f6761f49bef044ec49493d88737a70f1a6 Mon Sep 17 00:00:00 2001
From: Paolo Bonzini <[email protected]>
Date: Wed, 20 Oct 2021 06:27:36 -0400
Subject: [PATCH] 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.

index 0c8b5129effd..381384a54790 100644
@@ -9643,14 +9643,14 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
 		if (likely(exit_fastpath != EXIT_FASTPATH_REENTER_GUEST))
 			break;
 
-                if (unlikely(kvm_vcpu_exit_request(vcpu))) {
+		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);
-        }
+	}
 
 	/*
 	 * Do this here before restoring debug registers on the host.  And