[PATCH 08/17] drm/i915: Remove lrc default desc from GEM context

Chris Wilson
2019-07-30T13:30:55Z

We only compute the lrc_descriptor() on pinning the context, i.e.
infrequently, so we do not benefit from storing the template as the
addressing mode is also fixed for the lifetime of the intel_context.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
---
drivers/gpu/drm/i915/gem/i915_gem_context.c | 28 ++-----------------
.../gpu/drm/i915/gem/i915_gem_context_types.h | 2 --
drivers/gpu/drm/i915/gt/intel_lrc.c | 12 +++++---
drivers/gpu/drm/i915/gvt/scheduler.c | 3 --
4 files changed, 10 insertions(+), 35 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c
index b28c7ca681a8..1b3dc7258ef2 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c
@@ -397,30 +397,6 @@ static void context_close(struct i915_gem_context *ctx)
i915_gem_context_put(ctx);
}

-static u32 default_desc_template(const struct drm_i915_private *i915,
- const struct i915_address_space *vm)
-{
- u32 address_mode;
- u32 desc;
-
- desc = GEN8_CTX_VALID | GEN8_CTX_PRIVILEGE;
-
- address_mode = INTEL_LEGACY_32B_CONTEXT;
- if (vm && i915_vm_is_4lvl(vm))
- address_mode = INTEL_LEGACY_64B_CONTEXT;
- desc |= address_mode << GEN8_CTX_ADDRESSING_MODE_SHIFT;
-
- if (IS_GEN(i915, 8))
- desc |= GEN8_CTX_L3LLC_COHERENT;
-
- /* TODO: WaDisableLiteRestore when we start using semaphore
- * signalling between Command Streamers
- * ring->ctx_desc_template |= GEN8_CTX_FORCE_RESTORE;
- */
-
- return desc;
-}
-
static struct i915_gem_context *
__create_context(struct drm_i915_private *i915)
{
@@ -459,7 +435,6 @@ __create_context(struct drm_i915_private *i915)
i915_gem_context_set_recoverable(ctx);

ctx->ring_size = 4 * PAGE_SIZE;
- ctx->desc_template = default_desc_template(i915, NULL);

for (i = 0; i < ARRAY_SIZE(ctx->hang_timestamp); i++)
ctx->hang_timestamp[i] = jiffies - CONTEXT_FAST_HANG_JIFFIES;
@@ -478,8 +453,9 @@ __set_ppgtt(struct i915_gem_context *ctx, struct i915_address_space *vm)
struct i915_gem_engines_iter it;
struct intel_context *ce;

+ GEM_BUG_ON(old && i915_vm_is_4lvl(vm) != i915_vm_is_4lvl(old));
+
ctx->vm = i915_vm_get(vm);
- ctx->desc_template = default_desc_template(ctx->i915, vm);

for_each_gem_engine(ce, i915_gem_context_lock_engines(ctx), it) {
i915_vm_put(ce->vm);
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context_types.h b/drivers/gpu/drm/i915/gem/i915_gem_context_types.h
index 0ee61482ef94..a02d98494078 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_context_types.h
+++ b/drivers/gpu/drm/i915/gem/i915_gem_context_types.h
@@ -171,8 +171,6 @@ struct i915_gem_context {

/** ring_size: size for allocating the per-engine ring buffer */
u32 ring_size;
- /** desc_template: invariant fields for the HW context descriptor */
- u32 desc_template;

/** guilty_count: How many times this context has caused a GPU hang. */
atomic_t guilty_count;
diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
index 5181d29d272e..232f40fcb490 100644
--- a/drivers/gpu/drm/i915/gt/intel_lrc.c
+++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
@@ -417,13 +417,17 @@ lrc_descriptor(struct intel_context *ce, struct intel_engine_cs *engine)
BUILD_BUG_ON(MAX_CONTEXT_HW_ID > (BIT(GEN8_CTX_ID_WIDTH)));
BUILD_BUG_ON(GEN11_MAX_CONTEXT_HW_ID > (BIT(GEN11_SW_CTX_ID_WIDTH)));

- desc = ctx->desc_template; /* bits 0-11 */
- GEM_BUG_ON(desc & GENMASK_ULL(63, 12));
+ desc = INTEL_LEGACY_32B_CONTEXT;
+ if (i915_vm_is_4lvl(ce->vm))
+ desc = INTEL_LEGACY_64B_CONTEXT;
+ desc <<= GEN8_CTX_ADDRESSING_MODE_SHIFT;
+
+ desc |= GEN8_CTX_VALID | GEN8_CTX_PRIVILEGE;
+ if (IS_GEN(engine->i915, 8))
+ desc |= GEN8_CTX_L3LLC_COHERENT;

desc |= i915_ggtt_offset(ce->state) + LRC_HEADER_PAGES * PAGE_SIZE;
/* bits 12-31 */
- GEM_BUG_ON(desc & GENMASK_ULL(63, 32));
-
/*
* The following 32bits are copied into the OA reports (dword 2).
* Consider updating oa_get_render_ctx_id in i915_perf.c when changing
diff --git a/drivers/gpu/drm/i915/gvt/scheduler.c b/drivers/gpu/drm/i915/gvt/scheduler.c
index f40524b0e300..32ae6b5b7e16 100644
--- a/drivers/gpu/drm/i915/gvt/scheduler.c
+++ b/drivers/gpu/drm/i915/gvt/scheduler.c
@@ -291,9 +291,6 @@ shadow_context_descriptor_update(struct intel_context *ce,
* Update bits 0-11 of the context descriptor which includes flags
* like GEN8_CTX_* cached in desc_template
*/
- desc &= U64_MAX << 12;
- desc |= ce->gem_context->desc_template & ((1ULL << 12) - 1);
-
desc &= ~(0x3 << GEN8_CTX_ADDRESSING_MODE_SHIFT);
desc |= workload->ctx_desc.addressing_mode <<
GEN8_CTX_ADDRESSING_MODE_SHIFT;
--
2.22.0