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Re: [Qemu-devel] [PATCH 2/2] virtio-pci: error out when both legacy and
From: |
Greg Kurz |
Subject: |
Re: [Qemu-devel] [PATCH 2/2] virtio-pci: error out when both legacy and modern modes are disabled |
Date: |
Thu, 8 Sep 2016 11:52:15 +0200 |
On Thu, 08 Sep 2016 09:15:28 +0200
Markus Armbruster <address@hidden> wrote:
> Greg Kurz <address@hidden> writes:
>
> > From: Greg Kurz <address@hidden>
> >
> > Without presuming if we got there because of a user mistake or some
> > more subtle bug in the tooling, it really does not make sense to
> > implement a non-functional device.
> >
> > Signed-off-by: Greg Kurz <address@hidden>
> > Reviewed-by: Marcel Apfelbaum <address@hidden>
> > Reviewed-by: Cornelia Huck <address@hidden>
> > Signed-off-by: Greg Kurz <address@hidden>
> > ---
> > hw/virtio/virtio-pci.c | 8 ++++++++
> > 1 file changed, 8 insertions(+)
> >
> > diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
> > index 268fd8ebb219..4b6a8a356621 100644
> > --- a/hw/virtio/virtio-pci.c
> > +++ b/hw/virtio/virtio-pci.c
> > @@ -1842,6 +1842,14 @@ static void virtio_pci_dc_realize(DeviceState *qdev,
> > Error **errp)
> > VirtIOPCIProxy *proxy = VIRTIO_PCI(qdev);
> > PCIDevice *pci_dev = &proxy->pci_dev;
> >
> > + if (!(virtio_pci_modern(proxy) || virtio_pci_legacy(proxy))) {
> > + error_setg(errp, "device cannot work as neither modern nor legacy
> > mode"
> > + " is enabled");
> > + error_append_hint(errp, "Set either disable-modern or
> > disable-legacy"
> > + " to off\n");
> > + return;
> > + }
> > +
> > if (!(proxy->flags & VIRTIO_PCI_FLAG_DISABLE_PCIE) &&
> > virtio_pci_modern(proxy)) {
> > pci_dev->cap_present |= QEMU_PCI_CAP_EXPRESS;
>
> Pardon my ignorance... is this a device-specific restriction, or is it
> the same for more (all?) virtio devices?
Yes this for all virtio devices.
But wait, I now realize that the check isn't done in the right place because
if we don't pass an explicit disable-legacy=on then proxy->disable_legacy gets
its final value in virtio_pci_realize() which gets called after
virtio_pci_dc_realize()...
I'll fix that.
Thanks !
--
Greg
[Qemu-devel] [PATCH 2/2] virtio-pci: error out when both legacy and modern modes are disabled, Greg Kurz, 2016/09/07