Commit ef99a60f authored by Chris Wilson's avatar Chris Wilson Committed by Jani Nikula
Browse files

drm/i915/gt: Clear CACHE_MODE prior to clearing residuals 

Since we do a bare context switch with no restore, the clear residual
kernel runs on dirty state, and we must be careful to avoid executing
with bad state from context registers inherited from a malicious client.

Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/2955


Fixes: 09aa9e45 ("drm/i915/gt: Restore clear-residual mitigations for Ivybridge, Baytrail")
Testcase: igt/gem_ctx_isolation # ivb,vlv
Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Akeem G Abodunrin <akeem.g.abodunrin@intel.com>
Reviewed-by: default avatarAkeem G Abodunrin <akeem.g.abodunrin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210117093015.29143-1-chris@chris-wilson.co.uk


(cherry picked from commit ace44e13)
Signed-off-by: default avatarJani Nikula <jani.nikula@intel.com>
parent 6ee1d745

drivers/gpu/drm/i915/gt/gen7_renderclear.c

+12 −0
Original line number Diff line number Diff line
@@ -390,6 +390,16 @@ static void emit_batch(struct i915_vma * const vma, 
						     &cb_kernel_ivb,

						     desc_count);



	/* Reset inherited context registers */

	gen7_emit_pipeline_invalidate(&cmds);

	batch_add(&cmds, MI_LOAD_REGISTER_IMM(2));

	batch_add(&cmds, i915_mmio_reg_offset(CACHE_MODE_0_GEN7));

	batch_add(&cmds, 0xffff0000);

	batch_add(&cmds, i915_mmio_reg_offset(CACHE_MODE_1));

	batch_add(&cmds, 0xffff0000 | PIXEL_SUBSPAN_COLLECT_OPT_DISABLE);

	gen7_emit_pipeline_flush(&cmds);



	/* Switch to the media pipeline and our base address */

	gen7_emit_pipeline_invalidate(&cmds);

	batch_add(&cmds, PIPELINE_SELECT | PIPELINE_SELECT_MEDIA);

	batch_add(&cmds, MI_NOOP);
@@ -399,9 +409,11 @@ static void emit_batch(struct i915_vma * const vma, 
	gen7_emit_state_base_address(&cmds, descriptors);

	gen7_emit_pipeline_invalidate(&cmds);



	/* Set the clear-residual kernel state */

	gen7_emit_vfe_state(&cmds, bv, urb_size - 1, 0, 0);

	gen7_emit_interface_descriptor_load(&cmds, descriptors, desc_count);



	/* Execute the kernel on all HW threads */

	for (i = 0; i < num_primitives(bv); i++)

		gen7_emit_media_object(&cmds, i);