drm/i915/ttm: don't leak the ccs state

The kernel only manages the ccs state with lmem-only objects, however
the kernel should still take care not to leak the CCS state from the
previous user.

Fixes: 48760ffe923a ("drm/i915/gt: Clear compress metadata for Flat-ccs objects")
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Ramalingam C <ramalingam.c@intel.com>
Reviewed-by: Ramalingam C <ramalingam.c@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220727164346.282407-1-matthew.auld@intel.com

diff --git a/drivers/gpu/drm/i915/gt/intel_migrate.c b/drivers/gpu/drm/i915/gt/intel_migrate.c
index a69b244..9a08144 100644 (file)
--- a/drivers/gpu/drm/i915/gt/intel_migrate.c
+++ b/drivers/gpu/drm/i915/gt/intel_migrate.c
@@ -708,7 +708,7 @@ intel_context_migrate_copy(struct intel_context *ce,
        u8 src_access, dst_access;
        struct i915_request *rq;
        int src_sz, dst_sz;
-       bool ccs_is_src;
+       bool ccs_is_src, overwrite_ccs;
        int err;
 
        GEM_BUG_ON(ce->vm != ce->engine->gt->migrate.context->vm);
@@ -749,6 +749,8 @@ intel_context_migrate_copy(struct intel_context *ce,
                        get_ccs_sg_sgt(&it_ccs, bytes_to_cpy);
        }
 
+       overwrite_ccs = HAS_FLAT_CCS(i915) && !ccs_bytes_to_cpy && dst_is_lmem;
+
        src_offset = 0;
        dst_offset = CHUNK_SZ;
        if (HAS_64K_PAGES(ce->engine->i915)) {
@@ -852,6 +854,25 @@ intel_context_migrate_copy(struct intel_context *ce,
                        if (err)
                                goto out_rq;
                        ccs_bytes_to_cpy -= ccs_sz;
+               } else if (overwrite_ccs) {
+                       err = rq->engine->emit_flush(rq, EMIT_INVALIDATE);
+                       if (err)
+                               goto out_rq;
+
+                       /*
+                        * While we can't always restore/manage the CCS state,
+                        * we still need to ensure we don't leak the CCS state
+                        * from the previous user, so make sure we overwrite it
+                        * with something.
+                        */
+                       err = emit_copy_ccs(rq, dst_offset, INDIRECT_ACCESS,
+                                           dst_offset, DIRECT_ACCESS, len);
+                       if (err)
+                               goto out_rq;
+
+                       err = rq->engine->emit_flush(rq, EMIT_INVALIDATE);
+                       if (err)
+                               goto out_rq;
                }
 
                /* Arbitration is re-enabled between requests. */