[PATCH] drm/panfrost: Implement per FD address spaces

[Rob Herring]

On Thu, Aug 8, 2019 at 5:18 PM Matthew Auld
<matthew.william.auld at gmail.com> wrote:
>
> On Thu, 8 Aug 2019 at 23:29, Rob Herring <robh at kernel.org> wrote:
> >
> > Up until now, a single shared GPU address space was used. This is not
> > ideal as there's no protection between processes and doesn't work for
> > supporting the same GPU/CPU VA feature. Most importantly, this will
> > hopefully mitigate Alyssa's fear of WebGL, whatever that is.
> >
> > Most of the changes here are moving struct drm_mm and struct
> > panfrost_mmu objects from the per device struct to the per FD struct.
> > The critical function is panfrost_mmu_as_get() which handles allocating
> > and switching the h/w address spaces.
> >
> > Cc: Tomeu Vizoso <tomeu.vizoso at collabora.com>
> > Cc: David Airlie <airlied at linux.ie>
> > Cc: Daniel Vetter <daniel at ffwll.ch>
> > Cc: Robin Murphy <robin.murphy at arm.com>
> > Cc: Steven Price <steven.price at arm.com>
> > Cc: Alyssa Rosenzweig <alyssa.rosenzweig at collabora.com>
> > Signed-off-by: Rob Herring <robh at kernel.org>
> > ---
> > This depends on madvise support (now in drm-misc) and the heap/no-exec
> > series (just the rework). Seeems to be working pretty well for me, but
> > more testing would be helpful. I've run multiple 'glmark2-es2-drm
> > --off-screen' instances and Gnome Shell. Running more than 8 clients (at
> > least for T860) will hit the address space switch code paths.
> >
> > Rob
> >
> >  drivers/gpu/drm/panfrost/TODO              |   4 -
> >  drivers/gpu/drm/panfrost/panfrost_device.c |   2 +
> >  drivers/gpu/drm/panfrost/panfrost_device.h |  24 ++-
> >  drivers/gpu/drm/panfrost/panfrost_drv.c    |  31 ++-
> >  drivers/gpu/drm/panfrost/panfrost_gem.c    |  15 +-
> >  drivers/gpu/drm/panfrost/panfrost_gem.h    |   3 +
> >  drivers/gpu/drm/panfrost/panfrost_job.c    |  12 +-
> >  drivers/gpu/drm/panfrost/panfrost_mmu.c    | 220 +++++++++++++++------
> >  drivers/gpu/drm/panfrost/panfrost_mmu.h    |   8 +
> >  9 files changed, 239 insertions(+), 80 deletions(-)
>
> [snip]
>
> > @@ -413,7 +414,28 @@ panfrost_open(struct drm_device *dev, struct drm_file *file)
> >         panfrost_priv->pfdev = pfdev;
> >         file->driver_priv = panfrost_priv;
> >
> > -       return panfrost_job_open(panfrost_priv);
> > +       spin_lock_init(&panfrost_priv->mm_lock);
> > +
> > +       /* 4G enough for now. can be 48-bit */
> > +       panfrost_priv->mm.color_adjust = panfrost_drm_mm_color_adjust;
> > +       drm_mm_init(&panfrost_priv->mm, SZ_32M >> PAGE_SHIFT, (SZ_4G - SZ_32M) >> PAGE_SHIFT);
>
> Drive-by-comment: drm_mm_init will trample your color_adjust. Intentional?

No, thanks. I must have switched them at some point.

Rob