On 6/6/25 4:20 PM, David Marchand wrote:
On Thu, Jun 5, 2025 at 4:55 PM Eugenio Perez Martin <epere...@redhat.com> wrote:
On Thu, Jun 5, 2025 at 1:50 PM David Marchand <david.march...@redhat.com> wrote:
On Thu, Jun 5, 2025 at 1:36 PM Eugenio Pérez <epere...@redhat.com> wrote:
QEMU's shadow virtqueue and VDUSE exposes these areas as read-only. If
we don't change it, vhost_iova_to_vva do not consider them as valid and
returns that they're not found.
Eugenio Pérez (2):
vhost: search the split vq desc and avail in RO areas
vhost: search the packed vq driver area in RO areas
lib/vhost/vhost.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
At a quick glance, no need for two patches.
Sure I can respin with both squashed.
Sorry, the implication of this issue is not clear to me.
What is the impact from a user pov?
QEMU maps the CVQ descriptors and avail vring through as read only
maps in the case of vDPA. But DPDK is looking for them with RW
permissions, so the vhost_iova_to_vva function never selects the right
one as valid.
Looking for them with RO still picks the map if it is mapped as RW,
but the reverse is not true.
Ok, thanks.
Well, it's better, but still hard to tell how this impacts existing
usecases :-).
After discussing with Maxime, I understand that the shadow CVQ just
can't work => blocking multi queue support with vduse for example.
This is the type of high level impact I was looking for.
Let me know if you want me to respin the series with this comment too!
Ideally yes, but maybe Maxime can do it when applying.
Yes, I can rework the commit message while applying.
Thanks,
Maxime
