drm/i915/guc: Keep the ctx_pool_vaddr mapped, for easy access

The GuC descriptor is big in size. If we use a local definition of
guc_desc we have a chance to overflow stack, so avoid it.

Also, Chris abhors scatterlists :)

v2: Rebased, helper function to retrieve the context descriptor,
s/ctx_pool_vma/ctx_pool/

v3: Zero out guc_context_desc before initialization

v4: Do not do arithmetic on void pointers (Daniele)

v5: Nicer than arithmetic on pointers (Chris, Joonas)

Signed-off-by: Oscar Mateo <oscar.mateo@intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>

diff --git a/drivers/gpu/drm/i915/i915_guc_submission.c b/drivers/gpu/drm/i915/i915_guc_submission.c
index be88bbe..9ba6927 100644 (file)
--- a/drivers/gpu/drm/i915/i915_guc_submission.c
+++ b/drivers/gpu/drm/i915/i915_guc_submission.c
@@ -133,6 +133,13 @@ static int __guc_deallocate_doorbell(struct intel_guc *guc, u32 ctx_index)
        return intel_guc_send(guc, action, ARRAY_SIZE(action));
 }
 
+static struct guc_context_desc *__get_context_desc(struct i915_guc_client *client)
+{
+       struct guc_context_desc *base = client->guc->ctx_pool_vaddr;
+
+       return &base[client->ctx_index];
+}
+
 /*
  * Initialise, update, or clear doorbell data shared with the GuC
  *
@@ -142,21 +149,11 @@ static int __guc_deallocate_doorbell(struct intel_guc *guc, u32 ctx_index)
 
 static int __update_doorbell_desc(struct i915_guc_client *client, u16 new_id)
 {
-       struct sg_table *sg = client->guc->ctx_pool_vma->pages;
-       struct guc_context_desc desc;
-       size_t len;
+       struct guc_context_desc *desc;
 
        /* Update the GuC's idea of the doorbell ID */
-       len = sg_pcopy_to_buffer(sg->sgl, sg->nents, &desc, sizeof(desc),
-                                sizeof(desc) * client->ctx_index);
-       if (len != sizeof(desc))
-               return -EFAULT;
-
-       desc.db_id = new_id;
-       len = sg_pcopy_from_buffer(sg->sgl, sg->nents, &desc, sizeof(desc),
-                                  sizeof(desc) * client->ctx_index);
-       if (len != sizeof(desc))
-               return -EFAULT;
+       desc = __get_context_desc(client);
+       desc->db_id = new_id;
 
        return 0;
 }
@@ -271,29 +268,28 @@ static void guc_proc_desc_init(struct intel_guc *guc,
  * data structures relating to this client (doorbell, process descriptor,
  * write queue, etc).
  */
-
 static void guc_ctx_desc_init(struct intel_guc *guc,
                              struct i915_guc_client *client)
 {
        struct drm_i915_private *dev_priv = guc_to_i915(guc);
        struct intel_engine_cs *engine;
        struct i915_gem_context *ctx = client->owner;
-       struct guc_context_desc desc;
-       struct sg_table *sg;
+       struct guc_context_desc *desc;
        unsigned int tmp;
        u32 gfx_addr;
 
-       memset(&desc, 0, sizeof(desc));
+       desc = __get_context_desc(client);
+       memset(desc, 0, sizeof(*desc));
 
-       desc.attribute = GUC_CTX_DESC_ATTR_ACTIVE | GUC_CTX_DESC_ATTR_KERNEL;
-       desc.context_id = client->ctx_index;
-       desc.priority = client->priority;
-       desc.db_id = client->doorbell_id;
+       desc->attribute = GUC_CTX_DESC_ATTR_ACTIVE | GUC_CTX_DESC_ATTR_KERNEL;
+       desc->context_id = client->ctx_index;
+       desc->priority = client->priority;
+       desc->db_id = client->doorbell_id;
 
        for_each_engine_masked(engine, dev_priv, client->engines, tmp) {
                struct intel_context *ce = &ctx->engine[engine->id];
                uint32_t guc_engine_id = engine->guc_id;
-               struct guc_execlist_context *lrc = &desc.lrc[guc_engine_id];
+               struct guc_execlist_context *lrc = &desc->lrc[guc_engine_id];
 
                /* TODO: We have a design issue to be solved here. Only when we
                 * receive the first batch, we know which engine is used by the
@@ -318,49 +314,40 @@ static void guc_ctx_desc_init(struct intel_guc *guc,
                lrc->ring_next_free_location = lrc->ring_begin;
                lrc->ring_current_tail_pointer_value = 0;
 
-               desc.engines_used |= (1 << guc_engine_id);
+               desc->engines_used |= (1 << guc_engine_id);
        }
 
        DRM_DEBUG_DRIVER("Host engines 0x%x => GuC engines used 0x%x\n",
-                       client->engines, desc.engines_used);
-       WARN_ON(desc.engines_used == 0);
+                       client->engines, desc->engines_used);
+       WARN_ON(desc->engines_used == 0);
 
        /*
         * The doorbell, process descriptor, and workqueue are all parts
         * of the client object, which the GuC will reference via the GGTT
         */
        gfx_addr = guc_ggtt_offset(client->vma);
-       desc.db_trigger_phy = sg_dma_address(client->vma->pages->sgl) +
+       desc->db_trigger_phy = sg_dma_address(client->vma->pages->sgl) +
                                client->doorbell_offset;
-       desc.db_trigger_cpu = (uintptr_t)__get_doorbell(client);
-       desc.db_trigger_uk = gfx_addr + client->doorbell_offset;
-       desc.process_desc = gfx_addr + client->proc_desc_offset;
-       desc.wq_addr = gfx_addr + client->wq_offset;
-       desc.wq_size = client->wq_size;
+       desc->db_trigger_cpu = (uintptr_t)__get_doorbell(client);
+       desc->db_trigger_uk = gfx_addr + client->doorbell_offset;
+       desc->process_desc = gfx_addr + client->proc_desc_offset;
+       desc->wq_addr = gfx_addr + client->wq_offset;
+       desc->wq_size = client->wq_size;
 
        /*
         * XXX: Take LRCs from an existing context if this is not an
         * IsKMDCreatedContext client
         */
-       desc.desc_private = (uintptr_t)client;
-
-       /* Pool context is pinned already */
-       sg = guc->ctx_pool_vma->pages;
-       sg_pcopy_from_buffer(sg->sgl, sg->nents, &desc, sizeof(desc),
-                            sizeof(desc) * client->ctx_index);
+       desc->desc_private = (uintptr_t)client;
 }
 
 static void guc_ctx_desc_fini(struct intel_guc *guc,
                              struct i915_guc_client *client)
 {
-       struct guc_context_desc desc;
-       struct sg_table *sg;
+       struct guc_context_desc *desc;
 
-       memset(&desc, 0, sizeof(desc));
-
-       sg = guc->ctx_pool_vma->pages;
-       sg_pcopy_from_buffer(sg->sgl, sg->nents, &desc, sizeof(desc),
-                            sizeof(desc) * client->ctx_index);
+       desc = __get_context_desc(client);
+       memset(desc, 0, sizeof(*desc));
 }
 
 /**
@@ -1023,6 +1010,7 @@ int i915_guc_submission_init(struct drm_i915_private *dev_priv)
        const size_t gemsize = round_up(poolsize, PAGE_SIZE);
        struct intel_guc *guc = &dev_priv->guc;
        struct i915_vma *vma;
+       void *vaddr;
 
        if (!HAS_GUC_SCHED(dev_priv))
                return 0;
@@ -1034,14 +1022,21 @@ int i915_guc_submission_init(struct drm_i915_private *dev_priv)
        if (!i915.enable_guc_submission)
                return 0; /* not enabled  */
 
-       if (guc->ctx_pool_vma)
+       if (guc->ctx_pool)
                return 0; /* already allocated */
 
        vma = intel_guc_allocate_vma(guc, gemsize);
        if (IS_ERR(vma))
                return PTR_ERR(vma);
 
-       guc->ctx_pool_vma = vma;
+       guc->ctx_pool = vma;
+
+       vaddr = i915_gem_object_pin_map(vma->obj, I915_MAP_WB);
+       if (IS_ERR(vaddr))
+               goto err;
+
+       guc->ctx_pool_vaddr = vaddr;
+
        ida_init(&guc->ctx_ids);
        intel_guc_log_create(guc);
        guc_addon_create(guc);
@@ -1216,9 +1211,12 @@ void i915_guc_submission_fini(struct drm_i915_private *dev_priv)
        i915_vma_unpin_and_release(&guc->ads_vma);
        i915_vma_unpin_and_release(&guc->log.vma);
 
-       if (guc->ctx_pool_vma)
+       if (guc->ctx_pool_vaddr) {
                ida_destroy(&guc->ctx_ids);
-       i915_vma_unpin_and_release(&guc->ctx_pool_vma);
+               i915_gem_object_unpin_map(guc->ctx_pool->obj);
+       }
+
+       i915_vma_unpin_and_release(&guc->ctx_pool);
 }
 
 /**

diff --git a/drivers/gpu/drm/i915/intel_guc_loader.c b/drivers/gpu/drm/i915/intel_guc_loader.c
index 2f270d0..1a6e478 100644 (file)
--- a/drivers/gpu/drm/i915/intel_guc_loader.c
+++ b/drivers/gpu/drm/i915/intel_guc_loader.c
@@ -156,7 +156,7 @@ static void guc_params_init(struct drm_i915_private *dev_priv)
 
        /* If GuC submission is enabled, set up additional parameters here */
        if (i915.enable_guc_submission) {
-               u32 pgs = guc_ggtt_offset(dev_priv->guc.ctx_pool_vma);
+               u32 pgs = guc_ggtt_offset(dev_priv->guc.ctx_pool);
                u32 ctx_in_16 = GUC_MAX_GPU_CONTEXTS / 16;
 
                pgs >>= PAGE_SHIFT;

diff --git a/drivers/gpu/drm/i915/intel_uc.h b/drivers/gpu/drm/i915/intel_uc.h
index c3a3843..77f7153 100644 (file)
--- a/drivers/gpu/drm/i915/intel_uc.h
+++ b/drivers/gpu/drm/i915/intel_uc.h
@@ -153,7 +153,8 @@ struct intel_guc {
        bool interrupts_enabled;
 
        struct i915_vma *ads_vma;
-       struct i915_vma *ctx_pool_vma;
+       struct i915_vma *ctx_pool;
+       void *ctx_pool_vaddr;
        struct ida ctx_ids;
 
        struct i915_guc_client *execbuf_client;