From: Halil Pasic <pasic@linux.ibm.com>
To: Cornelia Huck <cohuck@redhat.com>
Cc: Eric Auger <eric.auger@redhat.com>,
qemu-s390x@nongnu.org, qemu-devel@nongnu.org,
"Michael S. Tsirkin" <mst@redhat.com>
Subject: Re: [PATCH 0/2] virtio: non-legacy device handling
Date: Mon, 20 Jul 2020 11:54:06 +0200 [thread overview]
Message-ID: <20200720115406.508f2115.pasic@linux.ibm.com> (raw)
In-Reply-To: <20200707105446.677966-1-cohuck@redhat.com>
On Tue, 7 Jul 2020 12:54:44 +0200
Cornelia Huck <cohuck@redhat.com> wrote:
> As discussed in "virtio-fs: force virtio 1.x usage", it seems like
> a good idea to make sure that any new virtio device (which does not
> support legacy virtio) is indeed a non-transitional device, just to
> catch accidental misconfigurations. We can easily compile a list
> of virtio devices with legacy support and have transports verify
> in their plugged callbacks that legacy support is off for any device
> not in that list.
>
> Most new virtio devices force non-transitional already, so nothing
> changes for them. vhost-user-fs-pci even does not allow to configure
> a non-transitional device, so it is fine as well.
>
> One problematic device, however, is virtio-iommu-pci. It currently
> offers both the transitional and the non-transitional variety of the
> device, and does not force anything. I'm unsure whether we should
> consider transitional virtio-iommu unsupported, or if we should add
> some compat handling. (The support for legacy or not generally may
> change based upon the bus, IIUC, so I'm unsure how to come up with
> something generic.)
>
Both patches look good to me (Acked-by: Halil Pasic
<pasic@linux.ibm.com>). I tend to agree with Davids comment on how
this information is coded: the more object oriented way would have
been to store this at the something like VirtioDeviceClass, but
Michael's argument stands.
Another OO option would be to expose this as a virtio property. Would
enable introspection, and would also give the host admin means to
force non-legacy for transitional devices. But the juice is probably not
worth the squeeze.
Regards,
Halil
next prev parent reply other threads:[~2020-07-20 9:54 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-07 10:54 [PATCH 0/2] virtio: non-legacy device handling Cornelia Huck
2020-07-07 10:54 ` [PATCH 1/2] virtio: list legacy-capable devices Cornelia Huck
2020-07-07 10:54 ` [PATCH 2/2] virtio: verify that legacy support is not accidentally on Cornelia Huck
2020-07-16 13:43 ` [PATCH 0/2] virtio: non-legacy device handling Cornelia Huck
2020-07-20 8:09 ` David Hildenbrand
2020-07-20 9:03 ` Michael S. Tsirkin
2020-07-20 9:07 ` David Hildenbrand
2020-07-23 6:33 ` Cornelia Huck
2020-07-23 11:57 ` David Hildenbrand
2020-07-23 12:15 ` Cornelia Huck
2020-07-23 12:54 ` Michael S. Tsirkin
2020-07-20 9:54 ` Halil Pasic [this message]
2020-07-23 6:35 ` Cornelia Huck
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