FAILED: patch "[PATCH] KVM: arm64: Wake-up from WFI when iqrchip is in userspace" failed to apply to 6.12-stable tree

The patch below does not apply to the 6.12-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]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y
git checkout FETCH_HEAD
git cherry-pick -x 4ce98bf0865c349e7026ad9c14f48da264920953
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026051236-wistful-naming-15fe@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

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

From 4ce98bf0865c349e7026ad9c14f48da264920953 Mon Sep 17 00:00:00 2001
From: Marc Zyngier <[email protected]>
Date: Thu, 23 Apr 2026 17:36:07 +0100
Subject: [PATCH] KVM: arm64: Wake-up from WFI when iqrchip is in userspace

It appears that there is nothing in the wake-up path that evaluates whether the in-kernel interrupts are pending unless we have a vgic.

This means that the userspace irqchip support has been broken for about four years, and nobody noticed. It was also broken before as we wouldn't wake-up on a PMU interrupt, but hey, who cares...

It is probably time to remove the feature altogether, because it was a terrible idea 10 years ago, and it still is.

index 176cbe8baad3..8bb2c7422cc8 100644
@@ -824,6 +824,10 @@ int kvm_arch_vcpu_runnable(struct kvm_vcpu *v)
 {
 	bool irq_lines = *vcpu_hcr(v) & (HCR_VI | HCR_VF | HCR_VSE);
 
+	irq_lines |= (!irqchip_in_kernel(v->kvm) &&
+		      (kvm_timer_should_notify_user(v) ||
+		       kvm_pmu_should_notify_user(v)));
+
 	return ((irq_lines || kvm_vgic_vcpu_pending_irq(v))
 		&& !kvm_arm_vcpu_stopped(v) && !v->arch.pause);
 }

commit 4ce98bf0865c349e7026ad9c14f48da264920953 upstream

It appears that there is nothing in the wake-up path that evaluates whether the in-kernel interrupts are pending unless we have a vgic.

This means that the userspace irqchip support has been broken for about four years, and nobody noticed. It was also broken before as we wouldn't wake-up on a PMU interrupt, but hey, who cares...

It is probably time to remove the feature altogether, because it was a terrible idea 10 years ago, and it still is.

---
 arch/arm64/kvm/arm.c | 5 +++++
 1 file changed, 5 insertions(+)

index 7d301da8ff289..376a865e88426 100644
@@ -729,6 +729,11 @@ int kvm_arch_vcpu_ioctl_set_mpstate(struct kvm_vcpu *vcpu,
 int kvm_arch_vcpu_runnable(struct kvm_vcpu *v)
 {
 	bool irq_lines = *vcpu_hcr(v) & (HCR_VI | HCR_VF);
+
+	irq_lines |= (!irqchip_in_kernel(v->kvm) &&
+		      (kvm_timer_should_notify_user(v) ||
+		       kvm_pmu_should_notify_user(v)));
+
 	return ((irq_lines || kvm_vgic_vcpu_pending_irq(v))
 		&& !kvm_arm_vcpu_stopped(v) && !v->arch.pause);
 }

2.47.3