Patch "KVM: arm/arm64: vgic: Stop injecting the MSI occurrence twice" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

KVM: arm/arm64: vgic: Stop injecting the MSI occurrence twice

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
kvm-arm-arm64-vgic-stop-injecting-the-msi-occurrence-twice.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Shanker Donthineni <[email protected]>
Date: Thu, 2 Feb 2017 20:30:03 -0600
Subject: KVM: arm/arm64: vgic: Stop injecting the MSI occurrence twice

From: Shanker Donthineni <[email protected]>

commit 0bdbf3b071986ba80731203683cf623d5c0cacb1 upstream.

The IRQFD framework calls the architecture dependent function twice if the corresponding GSI type is edge triggered. For ARM, the function kvm_set_msi() is getting called twice whenever the IRQFD receives the event signal. The rest of the code path is trying to inject the MSI without any validation checks. No need to call the function vgic_its_inject_msi() second time to avoid an unnecessary overhead in IRQ queue logic. It also avoids the possibility of VM seeing the MSI twice.

Simple fix, return -1 if the argument 'level' value is zero.

---
 virt/kvm/arm/vgic/vgic-irqfd.c |    3 +++
 1 file changed, 3 insertions(+)

@@ -99,6 +99,9 @@ int kvm_set_msi(struct kvm_kernel_irq_ro
 	if (!vgic_has_its(kvm))
 		return -ENODEV;
 
+	if (!level)
+		return -1;
+
 	return vgic_its_inject_msi(kvm, &msi);
 }
 

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/kvm-arm-arm64-vgic-stop-injecting-the-msi-occurrence-twice.patch