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@xxxxxxxxxxxxxxx> know about it. >From 0bdbf3b071986ba80731203683cf623d5c0cacb1 Mon Sep 17 00:00:00 2001 From: Shanker Donthineni <shankerd@xxxxxxxxxxxxxx> Date: Thu, 2 Feb 2017 20:30:03 -0600 Subject: KVM: arm/arm64: vgic: Stop injecting the MSI occurrence twice From: Shanker Donthineni <shankerd@xxxxxxxxxxxxxx> 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@xxxxxxxxxx> Reviewed-by: Christoffer Dall <cdall@xxxxxxxxxx> Signed-off-by: Shanker Donthineni <shankerd@xxxxxxxxxxxxxx> Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- 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@xxxxxxxxxxxxxx are queue-4.9/kvm-arm-arm64-vgic-stop-injecting-the-msi-occurrence-twice.patch