From 5d1808ecbc370ce6a083947f8866c8e857671914 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Thu, 28 Apr 2016 09:56:51 +0100 Subject: [PATCH] drm/i915: Assign every HW context a unique ID The hardware tracks contexts and expects all live contexts (those active on the hardware) to have a unique identifier. This is used by the hardware to assign pagefaults and the like to a particular context. v2: Reorder to make sure ctx->link is not left dangling if the assignment of a hw_id fails (Mika). v3: We have 21bits of context space, not 20. Signed-off-by: Chris Wilson Reviewed-by: Tvrtko Ursulin Link: http://patchwork.freedesktop.org/patch/msgid/1461833819-3991-17-git-send-email-chris@chris-wilson.co.uk --- drivers/gpu/drm/i915/i915_debugfs.c | 2 +- drivers/gpu/drm/i915/i915_drv.h | 10 +++++++++ drivers/gpu/drm/i915/i915_gem_context.c | 36 +++++++++++++++++++++++++++++++++ 3 files changed, 47 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c index e1bc5ec..e35d0cc 100644 --- a/drivers/gpu/drm/i915/i915_debugfs.c +++ b/drivers/gpu/drm/i915/i915_debugfs.c @@ -2001,7 +2001,7 @@ static int i915_context_status(struct seq_file *m, void *unused) ctx->legacy_hw_ctx.rcs_state == NULL) continue; - seq_puts(m, "HW context "); + seq_printf(m, "HW context %u ", ctx->hw_id); describe_ctx(m, ctx); if (ctx == dev_priv->kernel_context) seq_printf(m, "(kernel context) "); diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h index 831da9f..0f75752 100644 --- a/drivers/gpu/drm/i915/i915_drv.h +++ b/drivers/gpu/drm/i915/i915_drv.h @@ -851,6 +851,9 @@ struct intel_context { struct i915_ctx_hang_stats hang_stats; struct i915_hw_ppgtt *ppgtt; + /* Unique identifier for this context, used by the hw for tracking */ + unsigned hw_id; + /* Legacy ring buffer submission */ struct { struct drm_i915_gem_object *rcs_state; @@ -1838,6 +1841,13 @@ struct drm_i915_private { DECLARE_HASHTABLE(mm_structs, 7); struct mutex mm_lock; + /* 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 context_hw_ida; +#define MAX_CONTEXT_HW_ID (1<<21) /* exclusive */ + /* Kernel Modesetting */ struct drm_crtc *plane_to_crtc_mapping[I915_MAX_PIPES]; diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c index 2fea74b..25a9a14 100644 --- a/drivers/gpu/drm/i915/i915_gem_context.c +++ b/drivers/gpu/drm/i915/i915_gem_context.c @@ -171,6 +171,8 @@ void i915_gem_context_free(struct kref *ctx_ref) if (ctx->legacy_hw_ctx.rcs_state) drm_gem_object_unreference(&ctx->legacy_hw_ctx.rcs_state->base); list_del(&ctx->link); + + ida_simple_remove(&ctx->i915->context_hw_ida, ctx->hw_id); kfree(ctx); } @@ -211,6 +213,28 @@ i915_gem_alloc_context_obj(struct drm_device *dev, size_t size) return obj; } +static int assign_hw_id(struct drm_i915_private *dev_priv, unsigned *out) +{ + int ret; + + ret = ida_simple_get(&dev_priv->context_hw_ida, + 0, MAX_CONTEXT_HW_ID, GFP_KERNEL); + if (ret < 0) { + /* Contexts are only released when no longer active. + * Flush any pending retires to hopefully release some + * stale contexts and try again. + */ + i915_gem_retire_requests(dev_priv->dev); + ret = ida_simple_get(&dev_priv->context_hw_ida, + 0, MAX_CONTEXT_HW_ID, GFP_KERNEL); + if (ret < 0) + return ret; + } + + *out = ret; + return 0; +} + static struct intel_context * __create_hw_context(struct drm_device *dev, struct drm_i915_file_private *file_priv) @@ -223,6 +247,12 @@ __create_hw_context(struct drm_device *dev, if (ctx == NULL) return ERR_PTR(-ENOMEM); + ret = assign_hw_id(dev_priv, &ctx->hw_id); + if (ret) { + kfree(ctx); + return ERR_PTR(ret); + } + kref_init(&ctx->ref); list_add_tail(&ctx->link, &dev_priv->context_list); ctx->i915 = dev_priv; @@ -366,6 +396,10 @@ int i915_gem_context_init(struct drm_device *dev) } } + /* Using the simple ida interface, the max is limited by sizeof(int) */ + BUILD_BUG_ON(MAX_CONTEXT_HW_ID > INT_MAX); + ida_init(&dev_priv->context_hw_ida); + if (i915.enable_execlists) { /* NB: intentionally left blank. We will allocate our own * backing objects as we need them, thank you very much */ @@ -429,6 +463,8 @@ void i915_gem_context_fini(struct drm_device *dev) i915_gem_context_unreference(dctx); dev_priv->kernel_context = NULL; + + ida_destroy(&dev_priv->context_hw_ida); } static int context_idr_cleanup(int id, void *p, void *data) -- 2.7.4