Quoting Akeem G Abodunrin (2020-02-20 23:00:22)
From: Mika Kuoppala mika.kuoppala@linux.intel.com
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.p.wilson@intel.com -Chris --------------------------------------------------------------------- Intel Corporation (UK) Limited Registered No. 1134945 (England) Registered Office: Pipers Way, Swindon SN3 1RJ VAT No: 860 2173 47
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