* vdpa: handling of VIRTIO_F_ACCESS_PLATFORM/VIRTIO_F_ORDER_PLATFORM
@ 2020-08-11 9:52 Michael S. Tsirkin
2020-08-12 2:07 ` Jason Wang
0 siblings, 1 reply; 2+ messages in thread
From: Michael S. Tsirkin @ 2020-08-11 9:52 UTC (permalink / raw)
To: Jason Wang, virtualization
Hi!
I'd like to raise the question of whether we can drop the requirement
of VIRTIO_F_ACCESS_PLATFORM from vdpa?
As far as I can see, it is merely required for virtio vdpa -
so should we not enforce it there?
The point is support for legacy guests - which mostly just works
on x86.
Also, what is the plan for VIRTIO_F_ORDER_PLATFORM?
--
MST
_______________________________________________
Virtualization mailing list
Virtualization@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/virtualization
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: vdpa: handling of VIRTIO_F_ACCESS_PLATFORM/VIRTIO_F_ORDER_PLATFORM
2020-08-11 9:52 vdpa: handling of VIRTIO_F_ACCESS_PLATFORM/VIRTIO_F_ORDER_PLATFORM Michael S. Tsirkin
@ 2020-08-12 2:07 ` Jason Wang
0 siblings, 0 replies; 2+ messages in thread
From: Jason Wang @ 2020-08-12 2:07 UTC (permalink / raw)
To: Michael S. Tsirkin, virtualization
On 2020/8/11 下午5:52, Michael S. Tsirkin wrote:
> Hi!
> I'd like to raise the question of whether we can drop the requirement
> of VIRTIO_F_ACCESS_PLATFORM from vdpa?
> As far as I can see, it is merely required for virtio vdpa -
> so should we not enforce it there?
If we don't enforce it, virtio will use PA which breaks the setup when
IOMMU is enabled. As discussed in the past, mandating DMA API for virito
can just solve this issue.
>
> The point is support for legacy guests - which mostly just works
> on x86.
Legacy guest should work even if we mandate ACCESS_PLATFORM.
This is because we don't simply pass through guest features (qemu will
always set ACCESS_PLATFORM to vhost-vdpa).
>
> Also, what is the plan for VIRTIO_F_ORDER_PLATFORM?
I think we should mandate ORDER_PLATFORM, (even for guest).
Thanks
>
_______________________________________________
Virtualization mailing list
Virtualization@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/virtualization
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2020-08-12 2:07 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-08-11 9:52 vdpa: handling of VIRTIO_F_ACCESS_PLATFORM/VIRTIO_F_ORDER_PLATFORM Michael S. Tsirkin
2020-08-12 2:07 ` Jason Wang
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.