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From: Ard Biesheuvel <ardb@kernel.org>
To: Marc Zyngier <maz@kernel.org>
Cc: kvmarm <kvmarm@lists.cs.columbia.edu>,
	 Linux ARM <linux-arm-kernel@lists.infradead.org>,
	 Andre Przywara <andre.przywara@arm.com>,
	Alexandru Elisei <alexandru.elisei@arm.com>,
	 Android Kernel Team <kernel-team@android.com>,
	Pierre Gondois <pierre.gondois@arm.com>,
	 Sami Mujawar <sami.mujawar@arm.com>,
	Will Deacon <will@kernel.org>
Subject: Re: [PATCH][kvmtool] virtio/pci: Signal INTx interrupts as level instead of edge
Date: Mon, 31 Jan 2022 17:04:24 +0100	[thread overview]
Message-ID: <CAMj1kXHyxfe8E028OnN3Ac2PCC4HdyDdonHo785YTDjyXv=1qQ@mail.gmail.com> (raw)
In-Reply-To: <20220131160242.2665191-1-maz@kernel.org>

On Mon, 31 Jan 2022 at 17:03, Marc Zyngier <maz@kernel.org> wrote:
>
> It appears that the way INTx is emulated is "slightly" out of spec
> in kvmtool. We happily inject an edge interrupt, even if the spec
> mandates a level.
>
> This doesn't change much for either the guest or userspace (only
> KVM will have a bit more work tracking the EOI), but at least
> this is correct.
>
> Reported-by: Pierre Gondois <pierre.gondois@arm.com>
> Signed-off-by: Marc Zyngier <maz@kernel.org>
> Cc: Ard Biesheuvel <ardb@kernel.org>
> Cc: Sami Mujawar <sami.mujawar@arm.com>
> Cc: Will Deacon <will@kernel.org>

Acked-by: Ard Biesheuvel <ardb@kernel.org>

> ---
>  pci.c        | 2 +-
>  virtio/pci.c | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/pci.c b/pci.c
> index e5930331..a769ae27 100644
> --- a/pci.c
> +++ b/pci.c
> @@ -61,7 +61,7 @@ int pci__assign_irq(struct pci_device_header *pci_hdr)
>         pci_hdr->irq_line       = irq__alloc_line();
>
>         if (!pci_hdr->irq_type)
> -               pci_hdr->irq_type = IRQ_TYPE_EDGE_RISING;
> +               pci_hdr->irq_type = IRQ_TYPE_LEVEL_HIGH;
>
>         return pci_hdr->irq_line;
>  }
> diff --git a/virtio/pci.c b/virtio/pci.c
> index 41085291..2777d1c8 100644
> --- a/virtio/pci.c
> +++ b/virtio/pci.c
> @@ -413,7 +413,7 @@ int virtio_pci__signal_vq(struct kvm *kvm, struct virtio_device *vdev, u32 vq)
>                         kvm__irq_trigger(kvm, vpci->gsis[vq]);
>         } else {
>                 vpci->isr = VIRTIO_IRQ_HIGH;
> -               kvm__irq_trigger(kvm, vpci->legacy_irq_line);
> +               kvm__irq_line(kvm, vpci->legacy_irq_line, VIRTIO_IRQ_HIGH);
>         }
>         return 0;
>  }
> --
> 2.34.1
>

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  reply	other threads:[~2022-01-31 16:06 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-31 16:02 [PATCH][kvmtool] virtio/pci: Signal INTx interrupts as level instead of edge Marc Zyngier
2022-01-31 16:04 ` Ard Biesheuvel [this message]
2022-02-01  8:21   ` Pierre Gondois
2022-02-01  8:41   ` Pierre Gondois
2022-02-16 16:11 ` Will Deacon

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