* Re: [PATCH] KVM: arm/arm64: vgic: Stop injecting the MSI occurrence twice
[not found] <1486089003-413-1-git-send-email-shankerd@codeaurora.org>
@ 2017-02-03 13:53 ` Christoffer Dall
0 siblings, 0 replies; only message in thread
From: Christoffer Dall @ 2017-02-03 13:53 UTC (permalink / raw)
To: Shanker Donthineni
Cc: Marc Zyngier, linux-kernel, linux-arm-kernel, Paolo Bonzini,
kvmarm
Hi Shanker,
[please cc the kvmarm list for kvm/arm patches, thanks]
On Thu, Feb 02, 2017 at 08:30:03PM -0600, Shanker Donthineni wrote:
> 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.
>
> Signed-off-by: Shanker Donthineni <shankerd@codeaurora.org>
> ---
> virt/kvm/arm/vgic/vgic-irqfd.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/virt/kvm/arm/vgic/vgic-irqfd.c b/virt/kvm/arm/vgic/vgic-irqfd.c
> index d918dcf..f138ed2 100644
> --- 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_routing_entry *e,
> if (!vgic_has_its(kvm))
> return -ENODEV;
>
> + if (!level)
> + return -1;
> +
> return vgic_its_inject_msi(kvm, &msi);
> }
>
> --
Reviewed-by: Christoffer Dall <cdall@linaro.org>
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