On Wed, Mar 27, 2024 at 3:16 PM Xuan Zhuo <xuanz...@linux.alibaba.com> wrote:
>
> On Tue, 26 Mar 2024 14:35:21 +0800, Jason Wang <jasow...@redhat.com> wrote:
> > On Mon, Mar 25, 2024 at 4:54 PM Xuan Zhuo <xuanz...@linux.alibaba.com>
> > wrote:
> > >
> > > As discussed:
> > >
> > > http://lore.kernel.org/all/cacgkmevq0no8qgc46u4mgsmtud44fd_cflcpavmj3rhyqrz...@mail.gmail.com
> > >
> > > If the virtio is premapped mode, the driver should manage the dma info by
> > > self.
> > > So the virtio core should not store the dma info. We can release the
> > > memory used
> > > to store the dma info.
> > >
> > > For virtio-net xmit queue, if the virtio-net maintains the dma info,
> > > the virtio-net must allocate too much memory(19 * queue_size for
> > > per-queue), so
> > > we do not plan to make the virtio-net to maintain the dma info by
> > > default. The
> > > virtio-net xmit queue only maintain the dma info when premapped mode is
> > > enable
> > > (such as AF_XDP is enable).
> > >
> > > So this patch set try to do:
> > >
> > > 1. make the virtio core to do not store the dma info when driver can do
> > > that
> > > - But if the desc_extra has not dma info, we face a new question,
> > > it is hard to get the dma info of the desc with indirect flag.
> > > For split mode, that is easy from desc, but for the packed mode,
> > > it is hard to get the dma info from the desc. And hardening
> > > the dma unmap is safe, we should store the dma info of indirect
> > > descs when the virtio core does not store the bufer dma info.
> > >
> > > The follow patches to this:
> > > * virtio_ring: packed: structure the indirect desc table
> > > * virtio_ring: split: structure the indirect desc table
> > >
> > > - On the other side, in the umap handle, we mix the indirect descs
> > > with
> > > other descs. That make things too complex. I found if we we
> > > distinguish
> > > the descs with VRING_DESC_F_INDIRECT before unmap, thing will be
> > > clearer.
> > >
> > > The follow patches do this.
> > > * virtio_ring: packed: remove double check of the unmap ops
> > > * virtio_ring: split: structure the indirect desc table
> > >
> > > 2. make the virtio core to enable premapped mode by find_vqs() params
> > > - Because the find_vqs() will try to allocate memory for the dma info.
> > > If we set the premapped mode after find_vqs() and release the
> > > dma info, that is odd.
> > >
> > >
> > > Please review.
> > >
> > > Thanks
> >
> > This doesn't apply cleany on vhost.git linux-next branch.
> >
> > Which tree is this based on?
>
>
> Sorry. That is on the top of "[PATCH vhost v5 0/6] refactor the params of
> find_vqs()".
>
> Lore-URL:
> http://lore.kernel.org/all/20240325090419.33677-1-xuanz...@linux.alibaba.com
>
> Thanks.
I've tried that but it doesn't work:
% git am ~/Downloads/\[PATCH\ vhost\ v5\ 01_10\]\ virtio_ring_\
introduce\ vring_need_unmap_buffer.eml
Applying: virtio_ring: introduce vring_need_unmap_buffer
error: patch failed: drivers/virtio/virtio_ring.c:2080
error: drivers/virtio/virtio_ring.c: patch does not apply
Patch failed at 0001 virtio_ring: introduce vring_need_unmap_buffer
hint: Use 'git am --show-current-patch=diff' to see the failed patch
When you have resolved this problem, run "git am --continue".
If you prefer to skip this patch, run "git am --skip" instead.
To restore the original branch and stop patching, run "git am --abort".
I'm using vhost.git linux-next branch, HEAD is
commit 56e71885b0349241c07631a7b979b61e81afab6a
Author: Maxime Coquelin <maxime.coque...@redhat.com>
Date: Tue Jan 9 12:10:24 2024 +0100
vduse: Temporarily fail if control queue feature requested
Thanks
>
> >
> > Thanks
> >
>
