3 Commits

Author SHA1 Message Date
Chris Wilson
9bad40a27d drm/i915/selftests: Always flush before unpining after writing
Be consistent, and even when we know we had used a WC, flush the mapped
object after writing into it. The flush understands the mapping type and
will only clflush if !I915_MAP_WC, but will always insert a wmb [sfence]
so that we can be sure that all writes are visible.

v2: Add the unconditional wmb so we are know that we always flush the
writes to memory/HW at that point.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200511141304.599-1-chris@chris-wilson.co.uk
2020-05-11 16:50:04 +01:00
Chris Wilson
cc328351e1 drm/i915/gt: Wait for the wa batch to be pinned
Be sure to wait for the vma to be in place before we tell the GPU to
execute from the wa batch. Since initialisation is mostly synchronous
(or rather at some point during start up we will need to sync anyway),
we can affort to do an explicit i915_vma_sync() during wa batch
construction rather than check for a required await on every context
switch. (We don't expect to change the wa bb at run time so paying the
cost once up front seems preferrable.)

Fixes: ee2413eeed76 ("drm/i915: Add mechanism to submit a context WA on ring submission")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200307122425.29114-1-chris@chris-wilson.co.uk
2020-03-07 17:10:35 +00:00
Mika Kuoppala
ee2413eeed drm/i915: Add mechanism to submit a context WA on ring submission
This patch adds framework to submit an arbitrary batchbuffer on each
context switch to clear residual state for render engine on Gen7/7.5
devices.

The idea of always emitting the context and vm setup around each request
is primary to make reset recovery easy, and not require rewriting the
ringbuffer. As each request would set up its own context, leaving it to
the HW to notice and elide no-op context switches, we could restart the
ring at any point, and reorder the requests freely.

However, to avoid emitting clear_residuals() between consecutive requests
in the ringbuffer of the same context, we do want to track the current
context in the ring. In doing so, we need to be careful to only record a
context switch when we are sure the next request will be emitted.

This security mitigation change does not trigger any performance
regression. Performance is on par with current mainline/drm-tip.

v2: Update vm_alias params to point to correct address space "vm" due to
changes made in the patch "f21613797bae98773"

v3-v4: none

Signed-off-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Signed-off-by: Prathap Kumar Valsan <prathap.kumar.valsan@intel.com>
Signed-off-by: Akeem G Abodunrin <akeem.g.abodunrin@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Balestrieri Francesco <francesco.balestrieri@intel.com>
Cc: Bloomfield Jon <jon.bloomfield@intel.com>
Cc: Dutt Sudeep <sudeep.dutt@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20200306000957.2836150-1-chris@chris-wilson.co.uk
2020-03-06 08:59:06 +00:00