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

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

[gregkh]

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 <stable@vger.kernel.org> know about it.


>From 0bdbf3b071986ba80731203683cf623d5c0cacb1 Mon Sep 17 00:00:00 2001
From: Shanker Donthineni <shankerd@codeaurora.org>
Date: Thu, 2 Feb 2017 20:30:03 -0600
Subject: KVM: arm/arm64: vgic: Stop injecting the MSI occurrence twice

From: Shanker Donthineni <shankerd@codeaurora.org>

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.

Reviewed-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Christoffer Dall <cdall@linaro.org>
Signed-off-by: Shanker Donthineni <shankerd@codeaurora.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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

--- a/virt/kvm/arm/vgic/vgic-irqfd.c
+++ b/virt/kvm/arm/vgic/vgic-irqfd.c
@@ -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 shankerd@codeaurora.org are

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