[Intel-xe] [PATCH] drm/xe: Disallow pinning dma-bufs in VRAM

[Oded Gabbay]

On Wed, Sep 20, 2023 at 12:52 PM Thomas Hellström
<thomas.hellstrom at linux.intel.com> wrote:
>
>
> On 9/20/23 11:35, Oded Gabbay wrote:
> > On Tue, Sep 19, 2023 at 11:46 AM Thomas Hellström
> > <thomas.hellstrom at linux.intel.com> wrote:
> >> For now only support pinning in TT memory, for two reasons:
> >> 1) Avoid pinning in a placement not accessible to some importers.
> >> 2) Pinning in VRAM requires PIN accounting which is a to-do.
> >>
> >> Suggested-by: Oded Gabbay <ogabbay at kernel.org>
> >> Signed-off-by: Thomas Hellström <thomas.hellstrom at linux.intel.com>
> >> ---
> >>   drivers/gpu/drm/xe/xe_dma_buf.c | 25 +++++++++++++++++++++----
> >>   1 file changed, 21 insertions(+), 4 deletions(-)
> >>
> >> diff --git a/drivers/gpu/drm/xe/xe_dma_buf.c b/drivers/gpu/drm/xe/xe_dma_buf.c
> >> index 09343b8b3e96..bd8d51e7f93f 100644
> >> --- a/drivers/gpu/drm/xe/xe_dma_buf.c
> >> +++ b/drivers/gpu/drm/xe/xe_dma_buf.c
> >> @@ -49,13 +49,30 @@ static int xe_dma_buf_pin(struct dma_buf_attachment *attach)
> >>   {
> >>          struct drm_gem_object *obj = attach->dmabuf->priv;
> >>          struct xe_bo *bo = gem_to_xe_bo(obj);
> >> +       struct xe_device *xe = xe_bo_device(bo);
> >> +       int ret;
> >>
> >>          /*
> >> -        * Migrate to TT first to increase the chance of non-p2p clients
> >> -        * can attach.
> >> +        * For now only support pinning in TT memory, for two reasons:
> >> +        * 1) Avoid pinning in a placement not accessible to some importers.
> >> +        * 2) Pinning in VRAM requires PIN accounting which is a to-do.
> >>           */
> >> -       (void)xe_bo_migrate(bo, XE_PL_TT);
> >> -       xe_bo_pin_external(bo);
> >> +       if (xe_bo_is_pinned(bo) && bo->ttm.resource->placement != XE_PL_TT) {
> >> +               drm_dbg(&xe->drm, "Can't migrate pinned bo for dma-buf pin.\n");
> >> +               return -EINVAL;
> >> +       }
> >> +
> >> +       ret = xe_bo_migrate(bo, XE_PL_TT);
> >> +       if (ret) {
> >> +               if (ret != -EINTR && ret != -ERESTARTSYS)
> >> +                       drm_dbg(&xe->drm,
> >> +                               "Failed migrating dma-buf to TT memory: %pe\n",
> >> +                               ERR_PTR(ret));
> >> +               return ret;
> >> +       }
> >> +
> >> +       ret = xe_bo_pin_external(bo);
> >> +       xe_assert(xe, !ret);
> >>
> >>          return 0;
> >>   }
> >> --
> >> 2.41.0
> >>
> > Reviewed-by: Oded Gabbay <ogabbay at kernel.org>
>
> Thanks for revieiwing, Oded. Just sent a v2 with a kunit test update to
> reflect the changes. Please let me know if there are any issues with that.
>
No issues, looks fine.
Oded

> /Thomas
>
> > Thanks,
> > Oded