drm/i915: Remove logical HW ID

With the introduction of ctx->engines[] we allow multiple logical
contexts to be used on the same engine (e.g. with virtual engines).
According to bspec, aach logical context requires a unique tag in order
for context-switching to occur correctly between them. [Simple
experiments show that it is not so easy to trick the HW into performing
a lite-restore with matching logical IDs, though my memory from early
Broadwell experiments do suggest that it should be generating
lite-restores.]

We only need to keep a unique tag for the active lifetime of the
context, and for as long as we need to identify that context. The HW
uses the tag to determine if it should use a lite-restore (why not the
LRCA?) and passes the tag back for various status identifies. The only
status we need to track is for OA, so when using perf, we assign the
specific context a unique tag.

v2: Calculate required number of tags to fill ELSP.

Fixes: 976b55f0e1db ("drm/i915: Allow a context to define its set of engines")
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=111895
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Acked-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191004134015.13204-14-chris@chris-wilson.co.uk

18 files changed, 57 insertions, 302 deletions

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c
index 0ab416887fc2..cd4f327b23bd 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c
@@ -167,97 +167,6 @@ lookup_user_engine(struct i915_gem_context *ctx,
 	return i915_gem_context_get_engine(ctx, idx);
 }
 
-static inline int new_hw_id(struct drm_i915_private *i915, gfp_t gfp)
-{
-	unsigned int max;
-
-	lockdep_assert_held(&i915->contexts.mutex);
-
-	if (INTEL_GEN(i915) >= 12)
-		max = GEN12_MAX_CONTEXT_HW_ID;
-	else if (INTEL_GEN(i915) >= 11)
-		max = GEN11_MAX_CONTEXT_HW_ID;
-	else if (USES_GUC_SUBMISSION(i915))
-		/*
-		 * When using GuC in proxy submission, GuC consumes the
-		 * highest bit in the context id to indicate proxy submission.
-		 */
-		max = MAX_GUC_CONTEXT_HW_ID;
-	else
-		max = MAX_CONTEXT_HW_ID;
-
-	return ida_simple_get(&i915->contexts.hw_ida, 0, max, gfp);
-}
-
-static int steal_hw_id(struct drm_i915_private *i915)
-{
-	struct i915_gem_context *ctx, *cn;
-	LIST_HEAD(pinned);
-	int id = -ENOSPC;
-
-	lockdep_assert_held(&i915->contexts.mutex);
-
-	list_for_each_entry_safe(ctx, cn,
-				 &i915->contexts.hw_id_list, hw_id_link) {
-		if (atomic_read(&ctx->hw_id_pin_count)) {
-			list_move_tail(&ctx->hw_id_link, &pinned);
-			continue;
-		}
-
-		GEM_BUG_ON(!ctx->hw_id); /* perma-pinned kernel context */
-		list_del_init(&ctx->hw_id_link);
-		id = ctx->hw_id;
-		break;
-	}
-
-	/*
-	 * Remember how far we got up on the last repossesion scan, so the
-	 * list is kept in a "least recently scanned" order.
-	 */
-	list_splice_tail(&pinned, &i915->contexts.hw_id_list);
-	return id;
-}
-
-static int assign_hw_id(struct drm_i915_private *i915, unsigned int *out)
-{
-	int ret;
-
-	lockdep_assert_held(&i915->contexts.mutex);
-
-	/*
-	 * We prefer to steal/stall ourselves and our users over that of the
-	 * entire system. That may be a little unfair to our users, and
-	 * even hurt high priority clients. The choice is whether to oomkill
-	 * something else, or steal a context id.
-	 */
-	ret = new_hw_id(i915, GFP_KERNEL | __GFP_RETRY_MAYFAIL | __GFP_NOWARN);
-	if (unlikely(ret < 0)) {
-		ret = steal_hw_id(i915);
-		if (ret < 0) /* once again for the correct errno code */
-			ret = new_hw_id(i915, GFP_KERNEL);
-		if (ret < 0)
-			return ret;
-	}
-
-	*out = ret;
-	return 0;
-}
-
-static void release_hw_id(struct i915_gem_context *ctx)
-{
-	struct drm_i915_private *i915 = ctx->i915;
-
-	if (list_empty(&ctx->hw_id_link))
-		return;
-
-	mutex_lock(&i915->contexts.mutex);
-	if (!list_empty(&ctx->hw_id_link)) {
-		ida_simple_remove(&i915->contexts.hw_ida, ctx->hw_id);
-		list_del_init(&ctx->hw_id_link);
-	}
-	mutex_unlock(&i915->contexts.mutex);
-}
-
 static void __free_engines(struct i915_gem_engines *e, unsigned int count)
 {
 	while (count--) {
@@ -312,8 +221,6 @@ static void i915_gem_context_free(struct i915_gem_context *ctx)
 	lockdep_assert_held(&ctx->i915->drm.struct_mutex);
 	GEM_BUG_ON(!i915_gem_context_is_closed(ctx));
 
-	release_hw_id(ctx);
-
 	free_engines(rcu_access_pointer(ctx->engines));
 	mutex_destroy(&ctx->engines_mutex);
 
@@ -387,12 +294,6 @@ static void context_close(struct i915_gem_context *ctx)
 	ctx->file_priv = ERR_PTR(-EBADF);
 
 	/*
-	 * This context will never again be assinged to HW, so we can
-	 * reuse its ID for the next context.
-	 */
-	release_hw_id(ctx);
-
-	/*
 	 * The LUT uses the VMA as a backpointer to unref the object,
 	 * so we need to clear the LUT before we close all the VMA (inside
 	 * the ppgtt).
@@ -430,7 +331,6 @@ __create_context(struct drm_i915_private *i915)
 	RCU_INIT_POINTER(ctx->engines, e);
 
 	INIT_RADIX_TREE(&ctx->handles_vma, GFP_KERNEL);
-	INIT_LIST_HEAD(&ctx->hw_id_link);
 
 	/* NB: Mark all slices as needing a remap so that when the context first
 	 * loads it will restore whatever remap state already exists. If there
@@ -584,18 +484,11 @@ struct i915_gem_context *
 i915_gem_context_create_kernel(struct drm_i915_private *i915, int prio)
 {
 	struct i915_gem_context *ctx;
-	int err;
 
 	ctx = i915_gem_create_context(i915, 0);
 	if (IS_ERR(ctx))
 		return ctx;
 
-	err = i915_gem_context_pin_hw_id(ctx);
-	if (err) {
-		destroy_kernel_context(&ctx);
-		return ERR_PTR(err);
-	}
-
 	i915_gem_context_clear_bannable(ctx);
 	ctx->sched.priority = I915_USER_PRIORITY(prio);
 
@@ -609,12 +502,6 @@ static void init_contexts(struct drm_i915_private *i915)
 	mutex_init(&i915->contexts.mutex);
 	INIT_LIST_HEAD(&i915->contexts.list);
 
-	/* Using the simple ida interface, the max is limited by sizeof(int) */
-	BUILD_BUG_ON(MAX_CONTEXT_HW_ID > INT_MAX);
-	BUILD_BUG_ON(GEN11_MAX_CONTEXT_HW_ID > INT_MAX);
-	ida_init(&i915->contexts.hw_ida);
-	INIT_LIST_HEAD(&i915->contexts.hw_id_list);
-
 	INIT_WORK(&i915->contexts.free_work, contexts_free_worker);
 	init_llist_head(&i915->contexts.free_list);
 }
@@ -634,15 +521,6 @@ int i915_gem_contexts_init(struct drm_i915_private *dev_priv)
 		DRM_ERROR("Failed to create default global context\n");
 		return PTR_ERR(ctx);
 	}
-	/*
-	 * For easy recognisablity, we want the kernel context to be 0 and then
-	 * all user contexts will have non-zero hw_id. Kernel contexts are
-	 * permanently pinned, so that we never suffer a stall and can
-	 * use them from any allocation context (e.g. for evicting other
-	 * contexts and from inside the shrinker).
-	 */
-	GEM_BUG_ON(ctx->hw_id);
-	GEM_BUG_ON(!atomic_read(&ctx->hw_id_pin_count));
 	dev_priv->kernel_context = ctx;
 
 	DRM_DEBUG_DRIVER("%s context support initialized\n",
@@ -656,10 +534,6 @@ void i915_gem_contexts_fini(struct drm_i915_private *i915)
 	lockdep_assert_held(&i915->drm.struct_mutex);
 
 	destroy_kernel_context(&i915->kernel_context);
-
-	/* Must free all deferred contexts (via flush_workqueue) first */
-	GEM_BUG_ON(!list_empty(&i915->contexts.hw_id_list));
-	ida_destroy(&i915->contexts.hw_ida);
 }
 
 static int context_idr_cleanup(int id, void *p, void *data)
@@ -2316,33 +2190,6 @@ out:
 	return ret;
 }
 
-int __i915_gem_context_pin_hw_id(struct i915_gem_context *ctx)
-{
-	struct drm_i915_private *i915 = ctx->i915;
-	int err = 0;
-
-	mutex_lock(&i915->contexts.mutex);
-
-	GEM_BUG_ON(i915_gem_context_is_closed(ctx));
-
-	if (list_empty(&ctx->hw_id_link)) {
-		GEM_BUG_ON(atomic_read(&ctx->hw_id_pin_count));
-
-		err = assign_hw_id(i915, &ctx->hw_id);
-		if (err)
-			goto out_unlock;
-
-		list_add_tail(&ctx->hw_id_link, &i915->contexts.hw_id_list);
-	}
-
-	GEM_BUG_ON(atomic_read(&ctx->hw_id_pin_count) == ~0u);
-	atomic_inc(&ctx->hw_id_pin_count);
-
-out_unlock:
-	mutex_unlock(&i915->contexts.mutex);
-	return err;
-}
-
 /* GEM context-engines iterator: for_each_gem_engine() */
 struct intel_context *
 i915_gem_engines_iter_next(struct i915_gem_engines_iter *it)
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.h b/drivers/gpu/drm/i915/gem/i915_gem_context.h
index 176978608b6f..50bc27d30c03 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_context.h
+++ b/drivers/gpu/drm/i915/gem/i915_gem_context.h
@@ -112,21 +112,6 @@ i915_gem_context_clear_user_engines(struct i915_gem_context *ctx)
 	clear_bit(CONTEXT_USER_ENGINES, &ctx->flags);
 }
 
-int __i915_gem_context_pin_hw_id(struct i915_gem_context *ctx);
-static inline int i915_gem_context_pin_hw_id(struct i915_gem_context *ctx)
-{
-	if (atomic_inc_not_zero(&ctx->hw_id_pin_count))
-		return 0;
-
-	return __i915_gem_context_pin_hw_id(ctx);
-}
-
-static inline void i915_gem_context_unpin_hw_id(struct i915_gem_context *ctx)
-{
-	GEM_BUG_ON(atomic_read(&ctx->hw_id_pin_count) == 0u);
-	atomic_dec(&ctx->hw_id_pin_count);
-}
-
 static inline bool i915_gem_context_is_kernel(struct i915_gem_context *ctx)
 {
 	return !ctx->file_priv;
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 260d59cc3de8..87be27877e22 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_context_types.h
+++ b/drivers/gpu/drm/i915/gem/i915_gem_context_types.h
@@ -147,24 +147,6 @@ struct i915_gem_context {
 #define CONTEXT_FORCE_SINGLE_SUBMISSION	2
 #define CONTEXT_USER_ENGINES		3
 
-	/**
-	 * @hw_id: - unique identifier for the context
-	 *
-	 * The hardware needs to uniquely identify the context for a few
-	 * functions like fault reporting, PASID, scheduling. The
-	 * &drm_i915_private.context_hw_ida is used to assign a unqiue
-	 * id for the lifetime of the context.
-	 *
-	 * @hw_id_pin_count: - number of times this context had been pinned
-	 * for use (should be, at most, once per engine).
-	 *
-	 * @hw_id_link: - all contexts with an assigned id are tracked
-	 * for possible repossession.
-	 */
-	unsigned int hw_id;
-	atomic_t hw_id_pin_count;
-	struct list_head hw_id_link;
-
 	struct mutex mutex;
 
 	struct i915_sched_attr sched;
diff --git a/drivers/gpu/drm/i915/gem/selftests/i915_gem_context.c b/drivers/gpu/drm/i915/gem/selftests/i915_gem_context.c
index 2288757808ae..2fb31ada2fa7 100644
--- a/drivers/gpu/drm/i915/gem/selftests/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/gem/selftests/i915_gem_context.c
@@ -660,9 +660,9 @@ static int igt_ctx_exec(void *arg)
 
 			err = gpu_fill(ce, obj, dw);
 			if (err) {
-				pr_err("Failed to fill dword %lu [%lu/%lu] with gpu (%s) in ctx %u [full-ppgtt? %s], err=%d\n",
+				pr_err("Failed to fill dword %lu [%lu/%lu] with gpu (%s) [full-ppgtt? %s], err=%d\n",
 				       ndwords, dw, max_dwords(obj),
-				       engine->name, ctx->hw_id,
+				       engine->name,
 				       yesno(!!ctx->vm), err);
 				intel_context_put(ce);
 				kernel_context_close(ctx);
@@ -798,9 +798,9 @@ static int igt_shared_ctx_exec(void *arg)
 
 			err = gpu_fill(ce, obj, dw);
 			if (err) {
-				pr_err("Failed to fill dword %lu [%lu/%lu] with gpu (%s) in ctx %u [full-ppgtt? %s], err=%d\n",
+				pr_err("Failed to fill dword %lu [%lu/%lu] with gpu (%s) [full-ppgtt? %s], err=%d\n",
 				       ndwords, dw, max_dwords(obj),
-				       engine->name, ctx->hw_id,
+				       engine->name,
 				       yesno(!!ctx->vm), err);
 				intel_context_put(ce);
 				kernel_context_close(ctx);
@@ -1382,10 +1382,9 @@ static int igt_ctx_readonly(void *arg)
 
 			err = gpu_fill(ce, obj, dw);
 			if (err) {
-				pr_err("Failed to fill dword %lu [%lu/%lu] with gpu (%s) in ctx %u [full-ppgtt? %s], err=%d\n",
+				pr_err("Failed to fill dword %lu [%lu/%lu] with gpu (%s) [full-ppgtt? %s], err=%d\n",
 				       ndwords, dw, max_dwords(obj),
-				       ce->engine->name, ctx->hw_id,
-				       yesno(!!ctx->vm), err);
+				       ce->engine->name, yesno(!!ctx->vm), err);
 				i915_gem_context_unlock_engines(ctx);
 				goto out_unlock;
 			}
diff --git a/drivers/gpu/drm/i915/gem/selftests/mock_context.c b/drivers/gpu/drm/i915/gem/selftests/mock_context.c
index be8974ccff24..0104f16b1327 100644
--- a/drivers/gpu/drm/i915/gem/selftests/mock_context.c
+++ b/drivers/gpu/drm/i915/gem/selftests/mock_context.c
@@ -13,7 +13,6 @@ mock_context(struct drm_i915_private *i915,
 {
 	struct i915_gem_context *ctx;
 	struct i915_gem_engines *e;
-	int ret;
 
 	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
 	if (!ctx)
@@ -30,13 +29,8 @@ mock_context(struct drm_i915_private *i915,
 	RCU_INIT_POINTER(ctx->engines, e);
 
 	INIT_RADIX_TREE(&ctx->handles_vma, GFP_KERNEL);
-	INIT_LIST_HEAD(&ctx->hw_id_link);
 	mutex_init(&ctx->mutex);
 
-	ret = i915_gem_context_pin_hw_id(ctx);
-	if (ret < 0)
-		goto err_engines;
-
 	if (name) {
 		struct i915_ppgtt *ppgtt;
 
@@ -54,8 +48,6 @@ mock_context(struct drm_i915_private *i915,
 
 	return ctx;
 
-err_engines:
-	free_engines(rcu_access_pointer(ctx->engines));
 err_free:
 	kfree(ctx);
 	return NULL;
diff --git a/drivers/gpu/drm/i915/gt/intel_context_types.h b/drivers/gpu/drm/i915/gt/intel_context_types.h
index bf9cedfccbf0..6959b05ae5f8 100644
--- a/drivers/gpu/drm/i915/gt/intel_context_types.h
+++ b/drivers/gpu/drm/i915/gt/intel_context_types.h
@@ -58,6 +58,7 @@ struct intel_context {
 
 	u32 *lrc_reg_state;
 	u64 lrc_desc;
+	u32 tag; /* cookie passed to HW to track this context on submission */
 
 	unsigned int active_count; /* protected by timeline->mutex */
 
diff --git a/drivers/gpu/drm/i915/gt/intel_engine_types.h b/drivers/gpu/drm/i915/gt/intel_engine_types.h
index 943f0663837e..6199064f332b 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine_types.h
+++ b/drivers/gpu/drm/i915/gt/intel_engine_types.h
@@ -303,10 +303,12 @@ struct intel_engine_cs {
 	u8 uabi_class;
 	u8 uabi_instance;
 
+	u32 uabi_capabilities;
 	u32 context_size;
 	u32 mmio_base;
 
-	u32 uabi_capabilities;
+	unsigned int context_tag;
+#define NUM_CONTEXT_TAG roundup_pow_of_two(2 * EXECLIST_MAX_PORTS)
 
 	struct rb_node uabi_node;
 
diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
index 3cfea1758fd2..468438fb47af 100644
--- a/drivers/gpu/drm/i915/gt/intel_lrc.c
+++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
@@ -440,12 +440,8 @@ assert_priority_queue(const struct i915_request *prev,
 static u64
 lrc_descriptor(struct intel_context *ce, struct intel_engine_cs *engine)
 {
-	struct i915_gem_context *ctx = ce->gem_context;
 	u64 desc;
 
-	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 = INTEL_LEGACY_32B_CONTEXT;
 	if (i915_vm_is_4lvl(ce->vm))
 		desc = INTEL_LEGACY_64B_CONTEXT;
@@ -463,20 +459,11 @@ lrc_descriptor(struct intel_context *ce, struct intel_engine_cs *engine)
 	 * anything below.
 	 */
 	if (INTEL_GEN(engine->i915) >= 11) {
-		GEM_BUG_ON(ctx->hw_id >= BIT(GEN11_SW_CTX_ID_WIDTH));
-		desc |= (u64)ctx->hw_id << GEN11_SW_CTX_ID_SHIFT;
-								/* bits 37-47 */
-
 		desc |= (u64)engine->instance << GEN11_ENGINE_INSTANCE_SHIFT;
 								/* bits 48-53 */
 
-		/* TODO: decide what to do with SW counter (bits 55-60) */
-
 		desc |= (u64)engine->class << GEN11_ENGINE_CLASS_SHIFT;
 								/* bits 61-63 */
-	} else {
-		GEM_BUG_ON(ctx->hw_id >= BIT(GEN8_CTX_ID_WIDTH));
-		desc |= (u64)ctx->hw_id << GEN8_CTX_ID_SHIFT;	/* bits 32-52 */
 	}
 
 	return desc;
@@ -985,6 +972,18 @@ __execlists_schedule_in(struct i915_request *rq)
 
 	intel_context_get(ce);
 
+	if (ce->tag) {
+		/* Use a fixed tag for OA and friends */
+		ce->lrc_desc |= (u64)ce->tag << 32;
+	} else {
+		/* We don't need a strict matching tag, just different values */
+		ce->lrc_desc &= ~GENMASK_ULL(47, 37);
+		ce->lrc_desc |=
+			(u64)(engine->context_tag++ % NUM_CONTEXT_TAG) <<
+			GEN11_SW_CTX_ID_SHIFT;
+		BUILD_BUG_ON(NUM_CONTEXT_TAG > GEN12_MAX_CONTEXT_HW_ID);
+	}
+
 	intel_gt_pm_get(engine->gt);
 	execlists_context_status_change(rq, INTEL_CONTEXT_SCHEDULE_IN);
 	intel_engine_context_in(engine);
@@ -2114,7 +2113,6 @@ static void execlists_context_unpin(struct intel_context *ce)
 	check_redzone((void *)ce->lrc_reg_state - LRC_STATE_PN * PAGE_SIZE,
 		      ce->engine);
 
-	i915_gem_context_unpin_hw_id(ce->gem_context);
 	i915_gem_object_unpin_map(ce->state->obj);
 	intel_ring_reset(ce->ring, ce->ring->tail);
 }
@@ -2164,18 +2162,12 @@ __execlists_context_pin(struct intel_context *ce,
 		goto unpin_active;
 	}
 
-	ret = i915_gem_context_pin_hw_id(ce->gem_context);
-	if (ret)
-		goto unpin_map;
-
 	ce->lrc_desc = lrc_descriptor(ce, engine);
 	ce->lrc_reg_state = vaddr + LRC_STATE_PN * PAGE_SIZE;
 	__execlists_update_reg_state(ce, engine);
 
 	return 0;
 
-unpin_map:
-	i915_gem_object_unpin_map(ce->state->obj);
 unpin_active:
 	intel_context_active_release(ce);
 err:
diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.h b/drivers/gpu/drm/i915/gt/intel_lrc.h
index 66ac616361c1..99dc576a4e25 100644
--- a/drivers/gpu/drm/i915/gt/intel_lrc.h
+++ b/drivers/gpu/drm/i915/gt/intel_lrc.h
@@ -66,6 +66,12 @@ struct intel_engine_cs;
 #define GEN11_CSB_READ_PTR_MASK (GEN11_CSB_PTR_MASK << 8)
 #define GEN11_CSB_WRITE_PTR_MASK (GEN11_CSB_PTR_MASK << 0)
 
+#define MAX_CONTEXT_HW_ID (1<<21) /* exclusive */
+#define MAX_GUC_CONTEXT_HW_ID (1 << 20) /* exclusive */
+#define GEN11_MAX_CONTEXT_HW_ID (1<<11) /* exclusive */
+/* in Gen12 ID 0x7FF is reserved to indicate idle */
+#define GEN12_MAX_CONTEXT_HW_ID	(GEN11_MAX_CONTEXT_HW_ID - 1)
+
 enum {
 	INTEL_CONTEXT_SCHEDULE_IN = 0,
 	INTEL_CONTEXT_SCHEDULE_OUT,
diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
index 343d79c1cb7e..04a5a0d90823 100644
--- a/drivers/gpu/drm/i915/gvt/kvmgt.c
+++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
@@ -1564,27 +1564,10 @@ vgpu_id_show(struct device *dev, struct device_attribute *attr,
 	return sprintf(buf, "\n");
 }
 
-static ssize_t
-hw_id_show(struct device *dev, struct device_attribute *attr,
-	   char *buf)
-{
-	struct mdev_device *mdev = mdev_from_dev(dev);
-
-	if (mdev) {
-		struct intel_vgpu *vgpu = (struct intel_vgpu *)
-			mdev_get_drvdata(mdev);
-		return sprintf(buf, "%u\n",
-			       vgpu->submission.shadow[0]->gem_context->hw_id);
-	}
-	return sprintf(buf, "\n");
-}
-
 static DEVICE_ATTR_RO(vgpu_id);
-static DEVICE_ATTR_RO(hw_id);
 
 static struct attribute *intel_vgpu_attrs[] = {
 	&dev_attr_vgpu_id.attr,
-	&dev_attr_hw_id.attr,
 	NULL
 };
 
diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 2afc41e43b6e..0e90ac608e07 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -1593,9 +1593,6 @@ static int i915_context_status(struct seq_file *m, void *unused)
 		struct intel_context *ce;
 
 		seq_puts(m, "HW context ");
-		if (!list_empty(&ctx->hw_id_link))
-			seq_printf(m, "%x [pin %u]", ctx->hw_id,
-				   atomic_read(&ctx->hw_id_pin_count));
 		if (ctx->pid) {
 			struct task_struct *task;
 
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index cb63b2bd0ce8..6bdcffbf1b9b 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1541,18 +1541,6 @@ struct drm_i915_private {
 		struct list_head list;
 		struct llist_head free_list;
 		struct work_struct free_work;
-
-		/* The hw wants to have a stable context identifier for the
-		 * lifetime of the context (for OA, PASID, faults, etc).
-		 * This is limited in execlists to 21 bits.
-		 */
-		struct ida hw_ida;
-#define MAX_CONTEXT_HW_ID (1<<21) /* exclusive */
-#define MAX_GUC_CONTEXT_HW_ID (1 << 20) /* exclusive */
-#define GEN11_MAX_CONTEXT_HW_ID (1<<11) /* exclusive */
-/* in Gen12 ID 0x7FF is reserved to indicate idle */
-#define GEN12_MAX_CONTEXT_HW_ID	(GEN11_MAX_CONTEXT_HW_ID - 1)
-		struct list_head hw_id_list;
 	} contexts;
 
 	u32 fdi_rx_config;
diff --git a/drivers/gpu/drm/i915/i915_gpu_error.c b/drivers/gpu/drm/i915/i915_gpu_error.c
index a28ee754b7b4..5cf4eed5add8 100644
--- a/drivers/gpu/drm/i915/i915_gpu_error.c
+++ b/drivers/gpu/drm/i915/i915_gpu_error.c
@@ -471,9 +471,9 @@ static void error_print_context(struct drm_i915_error_state_buf *m,
 				const char *header,
 				const struct drm_i915_error_context *ctx)
 {
-	err_printf(m, "%s%s[%d] hw_id %d, prio %d, guilty %d active %d\n",
-		   header, ctx->comm, ctx->pid, ctx->hw_id,
-		   ctx->sched_attr.priority, ctx->guilty, ctx->active);
+	err_printf(m, "%s%s[%d] prio %d, guilty %d active %d\n",
+		   header, ctx->comm, ctx->pid, ctx->sched_attr.priority,
+		   ctx->guilty, ctx->active);
 }
 
 static void error_print_engine(struct drm_i915_error_state_buf *m,
@@ -1271,7 +1271,6 @@ static bool record_context(struct drm_i915_error_context *e,
 		rcu_read_unlock();
 	}
 
-	e->hw_id = ctx->hw_id;
 	e->sched_attr = ctx->sched;
 	e->guilty = atomic_read(&ctx->guilty_count);
 	e->active = atomic_read(&ctx->active_count);
diff --git a/drivers/gpu/drm/i915/i915_gpu_error.h b/drivers/gpu/drm/i915/i915_gpu_error.h
index 63cf387411e0..7f1cd0b1fef7 100644
--- a/drivers/gpu/drm/i915/i915_gpu_error.h
+++ b/drivers/gpu/drm/i915/i915_gpu_error.h
@@ -119,7 +119,6 @@ struct i915_gpu_state {
 		struct drm_i915_error_context {
 			char comm[TASK_COMM_LEN];
 			pid_t pid;
-			u32 hw_id;
 			int active;
 			int guilty;
 			struct i915_sched_attr sched_attr;
diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c
index 80055501eccb..ecfbc37b738b 100644
--- a/drivers/gpu/drm/i915/i915_perf.c
+++ b/drivers/gpu/drm/i915/i915_perf.c
@@ -1283,22 +1283,15 @@ static int oa_get_render_ctx_id(struct i915_perf_stream *stream)
 		} else {
 			stream->specific_ctx_id_mask =
 				(1U << GEN8_CTX_ID_WIDTH) - 1;
-			stream->specific_ctx_id =
-				upper_32_bits(ce->lrc_desc);
-			stream->specific_ctx_id &=
-				stream->specific_ctx_id_mask;
+			stream->specific_ctx_id = stream->specific_ctx_id_mask;
 		}
 		break;
 
 	case 11:
 	case 12: {
 		stream->specific_ctx_id_mask =
-			((1U << GEN11_SW_CTX_ID_WIDTH) - 1) << (GEN11_SW_CTX_ID_SHIFT - 32) |
-			((1U << GEN11_ENGINE_INSTANCE_WIDTH) - 1) << (GEN11_ENGINE_INSTANCE_SHIFT - 32) |
-			((1 << GEN11_ENGINE_CLASS_WIDTH) - 1) << (GEN11_ENGINE_CLASS_SHIFT - 32);
-		stream->specific_ctx_id = upper_32_bits(ce->lrc_desc);
-		stream->specific_ctx_id &=
-			stream->specific_ctx_id_mask;
+			((1U << GEN11_SW_CTX_ID_WIDTH) - 1) << (GEN11_SW_CTX_ID_SHIFT - 32);
+		stream->specific_ctx_id = stream->specific_ctx_id_mask;
 		break;
 	}
 
@@ -1306,6 +1299,8 @@ static int oa_get_render_ctx_id(struct i915_perf_stream *stream)
 		MISSING_CASE(INTEL_GEN(i915));
 	}
 
+	ce->tag = stream->specific_ctx_id_mask;
+
 	DRM_DEBUG_DRIVER("filtering on ctx_id=0x%x ctx_id_mask=0x%x\n",
 			 stream->specific_ctx_id,
 			 stream->specific_ctx_id_mask);
@@ -1324,12 +1319,14 @@ static void oa_put_render_ctx_id(struct i915_perf_stream *stream)
 {
 	struct intel_context *ce;
 
-	stream->specific_ctx_id = INVALID_CTX_ID;
-	stream->specific_ctx_id_mask = 0;
-
 	ce = fetch_and_zero(&stream->pinned_ctx);
-	if (ce)
+	if (ce) {
+		ce->tag = 0; /* recomputed on next submission after parking */
 		intel_context_unpin(ce);
+	}
+
+	stream->specific_ctx_id = INVALID_CTX_ID;
+	stream->specific_ctx_id_mask = 0;
 }
 
 static void
diff --git a/drivers/gpu/drm/i915/i915_trace.h b/drivers/gpu/drm/i915/i915_trace.h
index 24f2944da09d..1f2cf6cfafb5 100644
--- a/drivers/gpu/drm/i915/i915_trace.h
+++ b/drivers/gpu/drm/i915/i915_trace.h
@@ -665,7 +665,6 @@ TRACE_EVENT(i915_request_queue,
 
 	    TP_STRUCT__entry(
 			     __field(u32, dev)
-			     __field(u32, hw_id)
 			     __field(u64, ctx)
 			     __field(u16, class)
 			     __field(u16, instance)
@@ -675,7 +674,6 @@ TRACE_EVENT(i915_request_queue,
 
 	    TP_fast_assign(
 			   __entry->dev = rq->i915->drm.primary->index;
-			   __entry->hw_id = rq->gem_context->hw_id;
 			   __entry->class = rq->engine->uabi_class;
 			   __entry->instance = rq->engine->uabi_instance;
 			   __entry->ctx = rq->fence.context;
@@ -683,10 +681,9 @@ TRACE_EVENT(i915_request_queue,
 			   __entry->flags = flags;
 			   ),
 
-	    TP_printk("dev=%u, engine=%u:%u, hw_id=%u, ctx=%llu, seqno=%u, flags=0x%x",
+	    TP_printk("dev=%u, engine=%u:%u, ctx=%llu, seqno=%u, flags=0x%x",
 		      __entry->dev, __entry->class, __entry->instance,
-		      __entry->hw_id, __entry->ctx, __entry->seqno,
-		      __entry->flags)
+		      __entry->ctx, __entry->seqno, __entry->flags)
 );
 
 DECLARE_EVENT_CLASS(i915_request,
@@ -695,7 +692,6 @@ DECLARE_EVENT_CLASS(i915_request,
 
 	    TP_STRUCT__entry(
 			     __field(u32, dev)
-			     __field(u32, hw_id)
 			     __field(u64, ctx)
 			     __field(u16, class)
 			     __field(u16, instance)
@@ -704,16 +700,15 @@ DECLARE_EVENT_CLASS(i915_request,
 
 	    TP_fast_assign(
 			   __entry->dev = rq->i915->drm.primary->index;
-			   __entry->hw_id = rq->gem_context->hw_id;
 			   __entry->class = rq->engine->uabi_class;
 			   __entry->instance = rq->engine->uabi_instance;
 			   __entry->ctx = rq->fence.context;
 			   __entry->seqno = rq->fence.seqno;
 			   ),
 
-	    TP_printk("dev=%u, engine=%u:%u, hw_id=%u, ctx=%llu, seqno=%u",
+	    TP_printk("dev=%u, engine=%u:%u, ctx=%llu, seqno=%u",
 		      __entry->dev, __entry->class, __entry->instance,
-		      __entry->hw_id, __entry->ctx, __entry->seqno)
+		      __entry->ctx, __entry->seqno)
 );
 
 DEFINE_EVENT(i915_request, i915_request_add,
@@ -738,7 +733,6 @@ TRACE_EVENT(i915_request_in,
 
 	    TP_STRUCT__entry(
 			     __field(u32, dev)
-			     __field(u32, hw_id)
 			     __field(u64, ctx)
 			     __field(u16, class)
 			     __field(u16, instance)
@@ -749,7 +743,6 @@ TRACE_EVENT(i915_request_in,
 
 	    TP_fast_assign(
 			   __entry->dev = rq->i915->drm.primary->index;
-			   __entry->hw_id = rq->gem_context->hw_id;
 			   __entry->class = rq->engine->uabi_class;
 			   __entry->instance = rq->engine->uabi_instance;
 			   __entry->ctx = rq->fence.context;
@@ -758,9 +751,9 @@ TRACE_EVENT(i915_request_in,
 			   __entry->port = port;
 			   ),
 
-	    TP_printk("dev=%u, engine=%u:%u, hw_id=%u, ctx=%llu, seqno=%u, prio=%u, port=%u",
+	    TP_printk("dev=%u, engine=%u:%u, ctx=%llu, seqno=%u, prio=%u, port=%u",
 		      __entry->dev, __entry->class, __entry->instance,
-		      __entry->hw_id, __entry->ctx, __entry->seqno,
+		      __entry->ctx, __entry->seqno,
 		      __entry->prio, __entry->port)
 );
 
@@ -770,7 +763,6 @@ TRACE_EVENT(i915_request_out,
 
 	    TP_STRUCT__entry(
 			     __field(u32, dev)
-			     __field(u32, hw_id)
 			     __field(u64, ctx)
 			     __field(u16, class)
 			     __field(u16, instance)
@@ -780,7 +772,6 @@ TRACE_EVENT(i915_request_out,
 
 	    TP_fast_assign(
 			   __entry->dev = rq->i915->drm.primary->index;
-			   __entry->hw_id = rq->gem_context->hw_id;
 			   __entry->class = rq->engine->uabi_class;
 			   __entry->instance = rq->engine->uabi_instance;
 			   __entry->ctx = rq->fence.context;
@@ -788,10 +779,9 @@ TRACE_EVENT(i915_request_out,
 			   __entry->completed = i915_request_completed(rq);
 			   ),
 
-		    TP_printk("dev=%u, engine=%u:%u, hw_id=%u, ctx=%llu, seqno=%u, completed?=%u",
+		    TP_printk("dev=%u, engine=%u:%u, ctx=%llu, seqno=%u, completed?=%u",
 			      __entry->dev, __entry->class, __entry->instance,
-			      __entry->hw_id, __entry->ctx, __entry->seqno,
-			      __entry->completed)
+			      __entry->ctx, __entry->seqno, __entry->completed)
 );
 
 #else
@@ -829,7 +819,6 @@ TRACE_EVENT(i915_request_wait_begin,
 
 	    TP_STRUCT__entry(
 			     __field(u32, dev)
-			     __field(u32, hw_id)
 			     __field(u64, ctx)
 			     __field(u16, class)
 			     __field(u16, instance)
@@ -845,7 +834,6 @@ TRACE_EVENT(i915_request_wait_begin,
 	     */
 	    TP_fast_assign(
 			   __entry->dev = rq->i915->drm.primary->index;
-			   __entry->hw_id = rq->gem_context->hw_id;
 			   __entry->class = rq->engine->uabi_class;
 			   __entry->instance = rq->engine->uabi_instance;
 			   __entry->ctx = rq->fence.context;
@@ -853,9 +841,9 @@ TRACE_EVENT(i915_request_wait_begin,
 			   __entry->flags = flags;
 			   ),
 
-	    TP_printk("dev=%u, engine=%u:%u, hw_id=%u, ctx=%llu, seqno=%u, flags=0x%x",
+	    TP_printk("dev=%u, engine=%u:%u, ctx=%llu, seqno=%u, flags=0x%x",
 		      __entry->dev, __entry->class, __entry->instance,
-		      __entry->hw_id, __entry->ctx, __entry->seqno,
+		      __entry->ctx, __entry->seqno,
 		      __entry->flags)
 );
 
@@ -958,19 +946,17 @@ DECLARE_EVENT_CLASS(i915_context,
 	TP_STRUCT__entry(
 			__field(u32, dev)
 			__field(struct i915_gem_context *, ctx)
-			__field(u32, hw_id)
 			__field(struct i915_address_space *, vm)
 	),
 
 	TP_fast_assign(
 			__entry->dev = ctx->i915->drm.primary->index;
 			__entry->ctx = ctx;
-			__entry->hw_id = ctx->hw_id;
 			__entry->vm = ctx->vm;
 	),
 
-	TP_printk("dev=%u, ctx=%p, ctx_vm=%p, hw_id=%u",
-		  __entry->dev, __entry->ctx, __entry->vm, __entry->hw_id)
+	TP_printk("dev=%u, ctx=%p, ctx_vm=%p",
+		  __entry->dev, __entry->ctx, __entry->vm)
 )
 
 DEFINE_EVENT(i915_context, i915_context_create,
diff --git a/drivers/gpu/drm/i915/selftests/i915_gem_evict.c b/drivers/gpu/drm/i915/selftests/i915_gem_evict.c
index 52d2df843148..f39f0282e78c 100644
--- a/drivers/gpu/drm/i915/selftests/i915_gem_evict.c
+++ b/drivers/gpu/drm/i915/selftests/i915_gem_evict.c
@@ -491,8 +491,8 @@ static int igt_evict_contexts(void *arg)
 			if (IS_ERR(rq)) {
 				/* When full, fail_if_busy will trigger EBUSY */
 				if (PTR_ERR(rq) != -EBUSY) {
-					pr_err("Unexpected error from request alloc (ctx hw id %u, on %s): %d\n",
-					       ctx->hw_id, engine->name,
+					pr_err("Unexpected error from request alloc (on %s): %d\n",
+					       engine->name,
 					       (int)PTR_ERR(rq));
 					err = PTR_ERR(rq);
 				}
diff --git a/drivers/gpu/drm/i915/selftests/i915_vma.c b/drivers/gpu/drm/i915/selftests/i915_vma.c
index 1c9db08f7c28..ac1ff558eb90 100644
--- a/drivers/gpu/drm/i915/selftests/i915_vma.c
+++ b/drivers/gpu/drm/i915/selftests/i915_vma.c
@@ -170,7 +170,7 @@ static int igt_vma_create(void *arg)
 		}
 
 		nc = 0;
-		for_each_prime_number(num_ctx, MAX_CONTEXT_HW_ID) {
+		for_each_prime_number(num_ctx, 2 * NUM_CONTEXT_TAG) {
 			for (; nc < num_ctx; nc++) {
 				ctx = mock_context(i915, "mock");
 				if (!ctx)