Re: [PATCH v6 09/10] vdpa: Add listener_shadow_vq to vhost_vdpa

[Jason Wang]

在 2022/11/11 21:12, Eugenio Perez Martin 写道:
> On Fri, Nov 11, 2022 at 8:49 AM Jason Wang <jasowang@redhat.com> wrote:
> > 在 2022/11/10 21:47, Eugenio Perez Martin 写道:
> > > On Thu, Nov 10, 2022 at 7:01 AM Jason Wang <jasowang@redhat.com> wrote:
> > > > On Wed, Nov 9, 2022 at 1:08 AM Eugenio Pérez <eperezma@redhat.com> wrote:
> > > > > The memory listener that thells the device how to convert GPA to qemu's
> > > > > va is registered against CVQ vhost_vdpa. This series try to map the
> > > > > memory listener translations to ASID 0, while it maps the CVQ ones to
> > > > > ASID 1.
> > > > >
> > > > > Let's tell the listener if it needs to register them on iova tree or
> > > > > not.
> > > > >
> > > > > Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
> > > > > ---
> > > > > v5: Solve conflict about vhost_iova_tree_remove accepting mem_region by
> > > > >       value.
> > > > > ---
> > > > >    include/hw/virtio/vhost-vdpa.h | 2 ++
> > > > >    hw/virtio/vhost-vdpa.c         | 6 +++---
> > > > >    net/vhost-vdpa.c               | 1 +
> > > > >    3 files changed, 6 insertions(+), 3 deletions(-)
> > > > >
> > > > > diff --git a/include/hw/virtio/vhost-vdpa.h b/include/hw/virtio/vhost-vdpa.h
> > > > > index 6560bb9d78..0c3ed2d69b 100644
> > > > > --- a/include/hw/virtio/vhost-vdpa.h
> > > > > +++ b/include/hw/virtio/vhost-vdpa.h
> > > > > @@ -34,6 +34,8 @@ typedef struct vhost_vdpa {
> > > > >        struct vhost_vdpa_iova_range iova_range;
> > > > >        uint64_t acked_features;
> > > > >        bool shadow_vqs_enabled;
> > > > > +    /* The listener must send iova tree addresses, not GPA */
> >
> > Btw, cindy's vIOMMU series will make it not necessarily GPA any more.
> Yes, this comment should be tuned then. But the SVQ iova_tree will not
> be equal to vIOMMU one because shadow vrings.
>
> But maybe SVQ can inspect both instead of having all the duplicated entries.
>
> > > > > +    bool listener_shadow_vq;
> > > > >        /* IOVA mapping used by the Shadow Virtqueue */
> > > > >        VhostIOVATree *iova_tree;
> > > > >        GPtrArray *shadow_vqs;
> > > > > diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
> > > > > index 8fd32ba32b..e3914fa40e 100644
> > > > > --- a/hw/virtio/vhost-vdpa.c
> > > > > +++ b/hw/virtio/vhost-vdpa.c
> > > > > @@ -220,7 +220,7 @@ static void vhost_vdpa_listener_region_add(MemoryListener 
> > > > > *listener,
> > > > >                                             vaddr, section->readonly);
> > > > >
> > > > >        llsize = int128_sub(llend, int128_make64(iova));
> > > > > -    if (v->shadow_vqs_enabled) {
> > > > > +    if (v->listener_shadow_vq) {
> > > > >            int r;
> > > > >
> > > > >            mem_region.translated_addr = (hwaddr)(uintptr_t)vaddr,
> > > > > @@ -247,7 +247,7 @@ static void vhost_vdpa_listener_region_add(MemoryListener 
> > > > > *listener,
> > > > >        return;
> > > > >
> > > > >    fail_map:
> > > > > -    if (v->shadow_vqs_enabled) {
> > > > > +    if (v->listener_shadow_vq) {
> > > > >            vhost_iova_tree_remove(v->iova_tree, mem_region);
> > > > >        }
> > > > >
> > > > > @@ -292,7 +292,7 @@ static void vhost_vdpa_listener_region_del(MemoryListener 
> > > > > *listener,
> > > > >
> > > > >        llsize = int128_sub(llend, int128_make64(iova));
> > > > >
> > > > > -    if (v->shadow_vqs_enabled) {
> > > > > +    if (v->listener_shadow_vq) {
> > > > >            const DMAMap *result;
> > > > >            const void *vaddr = memory_region_get_ram_ptr(section->mr) +
> > > > >                section->offset_within_region +
> > > > > diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c
> > > > > index 85a318faca..02780ee37b 100644
> > > > > --- a/net/vhost-vdpa.c
> > > > > +++ b/net/vhost-vdpa.c
> > > > > @@ -570,6 +570,7 @@ static NetClientState *net_vhost_vdpa_init(NetClientState 
> > > > > *peer,
> > > > >        s->vhost_vdpa.index = queue_pair_index;
> > > > >        s->always_svq = svq;
> > > > >        s->vhost_vdpa.shadow_vqs_enabled = svq;
> > > > > +    s->vhost_vdpa.listener_shadow_vq = svq;
> > > > Any chance those above two can differ?
> > > If CVQ is shadowed but data VQs are not, shadow_vqs_enabled is true
> > > but listener_shadow_vq is not.
> > >
> > > It is more clear in the next commit, where only shadow_vqs_enabled is
> > > set to true at vhost_vdpa_net_cvq_start.
> >
> > Ok, the name looks a little bit confusing. I wonder if it's better to
> > use shadow_cvq and shadow_data ?
> I'm ok with renaming it, but struct vhost_vdpa is generic across all
> kind of devices, and it does not know if it is a datapath or not for
> the moment.
>
> Maybe listener_uses_iova_tree?


I think "iova_tree" is something that is internal to svq implementation, 
it's better to define the name from the view of vhost_vdpa level.

Thanks


> Thanks!