* [PATCH] drm/prime: Unbreak virtgpu dma-buf export @ 2024-03-22 21:48 Rob Clark 2024-03-25 22:38 ` Dominik Behr ` (2 more replies) 0 siblings, 3 replies; 8+ messages in thread From: Rob Clark @ 2024-03-22 21:48 UTC (permalink / raw) To: dri-devel Cc: Rob Clark, Dominik Behr, Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann, David Airlie, Daniel Vetter, Sumit Semwal, Christian König, Simon Ser, open list, open list:DMA BUFFER SHARING FRAMEWORK:Keyword:bdma_(?:buf|fence|resv)b, moderated list:DMA BUFFER SHARING FRAMEWORK:Keyword:bdma_(?:buf|fence|resv)b From: Rob Clark <robdclark@chromium.org> virtgpu "vram" GEM objects do not implement obj->get_sg_table(). But they also don't use drm_gem_map_dma_buf(). In fact they may not even have guest visible pages. But it is perfectly fine to export and share with other virtual devices. Reported-by: Dominik Behr <dbehr@chromium.org> Fixes: 207395da5a97 ("drm/prime: reject DMA-BUF attach when get_sg_table is missing") Signed-off-by: Rob Clark <robdclark@chromium.org> --- drivers/gpu/drm/drm_prime.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c index 7352bde299d5..64dd6276e828 100644 --- a/drivers/gpu/drm/drm_prime.c +++ b/drivers/gpu/drm/drm_prime.c @@ -582,7 +582,12 @@ int drm_gem_map_attach(struct dma_buf *dma_buf, { struct drm_gem_object *obj = dma_buf->priv; - if (!obj->funcs->get_sg_table) + /* + * drm_gem_map_dma_buf() requires obj->get_sg_table(), but drivers + * that implement their own ->map_dma_buf() do not. + */ + if ((dma_buf->ops->map_dma_buf == drm_gem_map_dma_buf) && + !obj->funcs->get_sg_table) return -ENOSYS; return drm_gem_pin(obj); -- 2.44.0 ^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH] drm/prime: Unbreak virtgpu dma-buf export 2024-03-22 21:48 [PATCH] drm/prime: Unbreak virtgpu dma-buf export Rob Clark @ 2024-03-25 22:38 ` Dominik Behr [not found] ` <CABUrSUAykXUoX0y6jzCw1s=E=E08Z54Ygo1TvBm49_iT88oDFg@mail.gmail.com> 2024-03-26 9:15 ` Simon Ser 2 siblings, 0 replies; 8+ messages in thread From: Dominik Behr @ 2024-03-25 22:38 UTC (permalink / raw) To: Rob Clark Cc: dri-devel, Rob Clark, Dominik Behr, Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann, David Airlie, Daniel Vetter, Sumit Semwal, Christian König, Simon Ser, open list, open list:DMA BUFFER SHARING FRAMEWORK:Keyword:bdma_(?:buf|fence|resv)b, moderated list:DMA BUFFER SHARING FRAMEWORK:Keyword:bdma_(?:buf|fence|resv)b It also fixes importing virtgpu blobs into real hardware, for instance amdgpu for DRI_PRIME rendering. On Fri, Mar 22, 2024 at 2:48 PM Rob Clark <robdclark@gmail.com> wrote: > > From: Rob Clark <robdclark@chromium.org> > > virtgpu "vram" GEM objects do not implement obj->get_sg_table(). But > they also don't use drm_gem_map_dma_buf(). In fact they may not even > have guest visible pages. But it is perfectly fine to export and share > with other virtual devices. > > Reported-by: Dominik Behr <dbehr@chromium.org> > Fixes: 207395da5a97 ("drm/prime: reject DMA-BUF attach when get_sg_table is missing") > Signed-off-by: Rob Clark <robdclark@chromium.org> > --- > drivers/gpu/drm/drm_prime.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c > index 7352bde299d5..64dd6276e828 100644 > --- a/drivers/gpu/drm/drm_prime.c > +++ b/drivers/gpu/drm/drm_prime.c > @@ -582,7 +582,12 @@ int drm_gem_map_attach(struct dma_buf *dma_buf, > { > struct drm_gem_object *obj = dma_buf->priv; > > - if (!obj->funcs->get_sg_table) > + /* > + * drm_gem_map_dma_buf() requires obj->get_sg_table(), but drivers > + * that implement their own ->map_dma_buf() do not. > + */ > + if ((dma_buf->ops->map_dma_buf == drm_gem_map_dma_buf) && > + !obj->funcs->get_sg_table) > return -ENOSYS; > > return drm_gem_pin(obj); > -- > 2.44.0 > ^ permalink raw reply [flat|nested] 8+ messages in thread
[parent not found: <CABUrSUAykXUoX0y6jzCw1s=E=E08Z54Ygo1TvBm49_iT88oDFg@mail.gmail.com>]
* Re: [PATCH] drm/prime: Unbreak virtgpu dma-buf export [not found] ` <CABUrSUAykXUoX0y6jzCw1s=E=E08Z54Ygo1TvBm49_iT88oDFg@mail.gmail.com> @ 2024-03-26 2:38 ` Rob Clark 2024-03-27 23:15 ` Dominik Behr 0 siblings, 1 reply; 8+ messages in thread From: Rob Clark @ 2024-03-26 2:38 UTC (permalink / raw) To: Dominik Behr Cc: dri-devel, Rob Clark, Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann, David Airlie, Daniel Vetter, Sumit Semwal, Christian König, Simon Ser, open list, open list:DMA BUFFER SHARING FRAMEWORK:Keyword:bdma_(?:buf|fence|resv)b, moderated list:DMA BUFFER SHARING FRAMEWORK:Keyword:bdma_(?:buf|fence|resv)b This is actually a bit concerning.. importing a host page backed buffer without guest mapping into a passthru device probably doesn't work and should be rejected earlier. I do think we should relax the restriction (either taking my patch or reverting the commit it fixes) until we work this out properly (because the original patch is a regression), but importing a buffer without guest pages into a passthru device can't possibly work properly. Maybe it works by chance if the host buffer is mapped to the guest, but that is not guaranteed. BR, -R On Mon, Mar 25, 2024 at 3:35 PM Dominik Behr <dbehr@chromium.org> wrote: > > It also fixes importing virtgpu blobs into real hardware, for instance amdgpu for DRI_PRIME rendering. > > On Fri, Mar 22, 2024 at 2:48 PM Rob Clark <robdclark@gmail.com> wrote: >> >> From: Rob Clark <robdclark@chromium.org> >> >> virtgpu "vram" GEM objects do not implement obj->get_sg_table(). But >> they also don't use drm_gem_map_dma_buf(). In fact they may not even >> have guest visible pages. But it is perfectly fine to export and share >> with other virtual devices. >> >> Reported-by: Dominik Behr <dbehr@chromium.org> >> Fixes: 207395da5a97 ("drm/prime: reject DMA-BUF attach when get_sg_table is missing") >> Signed-off-by: Rob Clark <robdclark@chromium.org> >> --- >> drivers/gpu/drm/drm_prime.c | 7 ++++++- >> 1 file changed, 6 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c >> index 7352bde299d5..64dd6276e828 100644 >> --- a/drivers/gpu/drm/drm_prime.c >> +++ b/drivers/gpu/drm/drm_prime.c >> @@ -582,7 +582,12 @@ int drm_gem_map_attach(struct dma_buf *dma_buf, >> { >> struct drm_gem_object *obj = dma_buf->priv; >> >> - if (!obj->funcs->get_sg_table) >> + /* >> + * drm_gem_map_dma_buf() requires obj->get_sg_table(), but drivers >> + * that implement their own ->map_dma_buf() do not. >> + */ >> + if ((dma_buf->ops->map_dma_buf == drm_gem_map_dma_buf) && >> + !obj->funcs->get_sg_table) >> return -ENOSYS; >> >> return drm_gem_pin(obj); >> -- >> 2.44.0 >> ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] drm/prime: Unbreak virtgpu dma-buf export 2024-03-26 2:38 ` Rob Clark @ 2024-03-27 23:15 ` Dominik Behr 0 siblings, 0 replies; 8+ messages in thread From: Dominik Behr @ 2024-03-27 23:15 UTC (permalink / raw) To: Rob Clark Cc: Dominik Behr, dri-devel, Rob Clark, Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann, David Airlie, Daniel Vetter, Sumit Semwal, Christian König, Simon Ser, open list, open list:DMA BUFFER SHARING FRAMEWORK:Keyword:bdma_(?:buf|fence|resv)b, moderated list:DMA BUFFER SHARING FRAMEWORK:Keyword:bdma_(?:buf|fence|resv)b It is mapped, via iommu interface (vfio-iommu) when map_dma is called. -- Dominik On Mon, Mar 25, 2024 at 7:38 PM Rob Clark <robdclark@gmail.com> wrote: > > This is actually a bit concerning.. importing a host page backed > buffer without guest mapping into a passthru device probably doesn't > work and should be rejected earlier. > > I do think we should relax the restriction (either taking my patch or > reverting the commit it fixes) until we work this out properly > (because the original patch is a regression), but importing a buffer > without guest pages into a passthru device can't possibly work > properly. Maybe it works by chance if the host buffer is mapped to > the guest, but that is not guaranteed. > > BR, > -R > > On Mon, Mar 25, 2024 at 3:35 PM Dominik Behr <dbehr@chromium.org> wrote: > > > > It also fixes importing virtgpu blobs into real hardware, for instance amdgpu for DRI_PRIME rendering. > > > > On Fri, Mar 22, 2024 at 2:48 PM Rob Clark <robdclark@gmail.com> wrote: > >> > >> From: Rob Clark <robdclark@chromium.org> > >> > >> virtgpu "vram" GEM objects do not implement obj->get_sg_table(). But > >> they also don't use drm_gem_map_dma_buf(). In fact they may not even > >> have guest visible pages. But it is perfectly fine to export and share > >> with other virtual devices. > >> > >> Reported-by: Dominik Behr <dbehr@chromium.org> > >> Fixes: 207395da5a97 ("drm/prime: reject DMA-BUF attach when get_sg_table is missing") > >> Signed-off-by: Rob Clark <robdclark@chromium.org> > >> --- > >> drivers/gpu/drm/drm_prime.c | 7 ++++++- > >> 1 file changed, 6 insertions(+), 1 deletion(-) > >> > >> diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c > >> index 7352bde299d5..64dd6276e828 100644 > >> --- a/drivers/gpu/drm/drm_prime.c > >> +++ b/drivers/gpu/drm/drm_prime.c > >> @@ -582,7 +582,12 @@ int drm_gem_map_attach(struct dma_buf *dma_buf, > >> { > >> struct drm_gem_object *obj = dma_buf->priv; > >> > >> - if (!obj->funcs->get_sg_table) > >> + /* > >> + * drm_gem_map_dma_buf() requires obj->get_sg_table(), but drivers > >> + * that implement their own ->map_dma_buf() do not. > >> + */ > >> + if ((dma_buf->ops->map_dma_buf == drm_gem_map_dma_buf) && > >> + !obj->funcs->get_sg_table) > >> return -ENOSYS; > >> > >> return drm_gem_pin(obj); > >> -- > >> 2.44.0 > >> ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] drm/prime: Unbreak virtgpu dma-buf export 2024-03-22 21:48 [PATCH] drm/prime: Unbreak virtgpu dma-buf export Rob Clark 2024-03-25 22:38 ` Dominik Behr [not found] ` <CABUrSUAykXUoX0y6jzCw1s=E=E08Z54Ygo1TvBm49_iT88oDFg@mail.gmail.com> @ 2024-03-26 9:15 ` Simon Ser 2024-03-28 18:47 ` Rob Clark 2 siblings, 1 reply; 8+ messages in thread From: Simon Ser @ 2024-03-26 9:15 UTC (permalink / raw) To: Rob Clark Cc: dri-devel, Rob Clark, Dominik Behr, Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann, David Airlie, Daniel Vetter, Sumit Semwal, Christian König, linux-kernel, linux-media, linaro-mm-sig Makes sense to me! Reviewed-by: Simon Ser <contact@emersion.fr> ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] drm/prime: Unbreak virtgpu dma-buf export 2024-03-26 9:15 ` Simon Ser @ 2024-03-28 18:47 ` Rob Clark 2024-03-28 18:54 ` Simon Ser 0 siblings, 1 reply; 8+ messages in thread From: Rob Clark @ 2024-03-28 18:47 UTC (permalink / raw) To: Simon Ser Cc: dri-devel, Rob Clark, Dominik Behr, Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann, David Airlie, Daniel Vetter, Sumit Semwal, Christian König, linux-kernel, linux-media, linaro-mm-sig On Tue, Mar 26, 2024 at 2:15 AM Simon Ser <contact@emersion.fr> wrote: > > Makes sense to me! > > Reviewed-by: Simon Ser <contact@emersion.fr> Thanks.. any chance I could talk you into pushing to drm-misc-fixes? BR, -R ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] drm/prime: Unbreak virtgpu dma-buf export 2024-03-28 18:47 ` Rob Clark @ 2024-03-28 18:54 ` Simon Ser 2024-03-28 18:59 ` Rob Clark 0 siblings, 1 reply; 8+ messages in thread From: Simon Ser @ 2024-03-28 18:54 UTC (permalink / raw) To: Rob Clark Cc: dri-devel, Rob Clark, Dominik Behr, Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann, David Airlie, Daniel Vetter, Sumit Semwal, Christian König, linux-kernel, linux-media, linaro-mm-sig On Thursday, March 28th, 2024 at 19:47, Rob Clark <robdclark@gmail.com> wrote: > any chance I could talk you into pushing to drm-misc-fixes? Oh sorry, I thought you had access… Pushed with a minor edit to remove unnecessary parentheses to make checkpatch happy! ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] drm/prime: Unbreak virtgpu dma-buf export 2024-03-28 18:54 ` Simon Ser @ 2024-03-28 18:59 ` Rob Clark 0 siblings, 0 replies; 8+ messages in thread From: Rob Clark @ 2024-03-28 18:59 UTC (permalink / raw) To: Simon Ser Cc: dri-devel, Rob Clark, Dominik Behr, Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann, David Airlie, Daniel Vetter, Sumit Semwal, Christian König, linux-kernel, linux-media, linaro-mm-sig On Thu, Mar 28, 2024 at 11:54 AM Simon Ser <contact@emersion.fr> wrote: > > On Thursday, March 28th, 2024 at 19:47, Rob Clark <robdclark@gmail.com> wrote: > > > any chance I could talk you into pushing to drm-misc-fixes? > > Oh sorry, I thought you had access… Pushed with a minor edit to remove > unnecessary parentheses to make checkpatch happy! Thanks! BR, -R ^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2024-03-28 18:59 UTC | newest] Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2024-03-22 21:48 [PATCH] drm/prime: Unbreak virtgpu dma-buf export Rob Clark 2024-03-25 22:38 ` Dominik Behr [not found] ` <CABUrSUAykXUoX0y6jzCw1s=E=E08Z54Ygo1TvBm49_iT88oDFg@mail.gmail.com> 2024-03-26 2:38 ` Rob Clark 2024-03-27 23:15 ` Dominik Behr 2024-03-26 9:15 ` Simon Ser 2024-03-28 18:47 ` Rob Clark 2024-03-28 18:54 ` Simon Ser 2024-03-28 18:59 ` Rob Clark
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