dri-devel Archive on lore.kernel.org
 help / color / Atom feed
From: Mika Kuoppala <mika.kuoppala@linux.intel.com>
To: akeem.g.abodunrin@intel.com, intel-gfx@lists.freedesktop.org,
	dri-devel@lists.freedesktop.org, omer.aran@intel.com,
	pragyansri.pathi@intel.com, d.scott.phillips@intel.com,
	david.c.stewart@intel.com, tony.luck@intel.com,
	jon.bloomfield@intel.com, sudeep.dutt@intel.com,
	daniel.vetter@intel.com, joonas.lahtinen@intel.com,
	jani.nikula@intel.com, chris.p.wilson@intel.com
Cc: Balestrieri Francesco <francesco.balestrieri@intel.com>,
	Mika Kuoppala <mika.kuoppala@linux.intel.com>,
	Kumar Valsan Prathap <prathap.kumar.valsan@intel.com>
Subject: [PATCH 1/2] drm/i915: Add mechanism to submit a context WA on ring submission
Date: Thu, 16 Jan 2020 18:12:31 +0200
Message-ID: <20200116161231.26026-1-mika.kuoppala@linux.intel.com> (raw)
In-Reply-To: <20200114145136.65373-2-akeem.g.abodunrin@intel.com>

This patch adds framework to submit an arbitrary batchbuffer on each
context switch to clear residual state for render engine on Gen7/7.5
devices.

The idea of always emitting the context and vm setup around each request
is primary to make reset recovery easy, and not require rewriting the
ringbuffer. As each request would set up its own context, leaving it to
the HW to notice and elide no-op context switches, we could restart the
ring at any point, and reorder the requests freely.

However, to avoid emitting clear_residuals() between consecutive requests
in the ringbuffer of the same context, we do want to track the current
context in the ring. In doing so, we need to be careful to only record a
context switch when we are sure the next request will be emitted.

v2: elide optimization patch squashed, courtesy of Chris Wilson

Signed-off-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Signed-off-by: Akeem G Abodunrin <akeem.g.abodunrin@intel.com>
Cc: Kumar Valsan Prathap <prathap.kumar.valsan@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Balestrieri Francesco <francesco.balestrieri@intel.com>
Cc: Bloomfield Jon <jon.bloomfield@intel.com>
Cc: Dutt Sudeep <sudeep.dutt@intel.com>
---
 .../gpu/drm/i915/gt/intel_ring_submission.c   | 132 +++++++++++++++++-
 1 file changed, 129 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/intel_ring_submission.c b/drivers/gpu/drm/i915/gt/intel_ring_submission.c
index bc44fe8e5ffa..58500032c993 100644
--- a/drivers/gpu/drm/i915/gt/intel_ring_submission.c
+++ b/drivers/gpu/drm/i915/gt/intel_ring_submission.c
@@ -1384,7 +1384,9 @@ static int load_pd_dir(struct i915_request *rq,
 	return rq->engine->emit_flush(rq, EMIT_FLUSH);
 }
 
-static inline int mi_set_context(struct i915_request *rq, u32 flags)
+static inline int mi_set_context(struct i915_request *rq,
+				 struct intel_context *ce,
+				 u32 flags)
 {
 	struct drm_i915_private *i915 = rq->i915;
 	struct intel_engine_cs *engine = rq->engine;
@@ -1459,7 +1461,7 @@ static inline int mi_set_context(struct i915_request *rq, u32 flags)
 
 	*cs++ = MI_NOOP;
 	*cs++ = MI_SET_CONTEXT;
-	*cs++ = i915_ggtt_offset(rq->context->state) | flags;
+	*cs++ = i915_ggtt_offset(ce->state) | flags;
 	/*
 	 * w/a: MI_SET_CONTEXT must always be followed by MI_NOOP
 	 * WaMiSetContext_Hang:snb,ivb,vlv
@@ -1574,13 +1576,56 @@ static int switch_mm(struct i915_request *rq, struct i915_address_space *vm)
 	return rq->engine->emit_flush(rq, EMIT_INVALIDATE);
 }
 
+static int clear_residuals(struct i915_request *rq)
+{
+	struct intel_engine_cs *engine = rq->engine;
+	int ret;
+
+	GEM_BUG_ON(!engine->kernel_context->state);
+
+	ret = switch_mm(rq, vm_alias(engine->kernel_context));
+	if (ret)
+		return ret;
+
+	ret = mi_set_context(rq,
+			     engine->kernel_context,
+			     MI_MM_SPACE_GTT | MI_RESTORE_INHIBIT);
+	if (ret)
+		return ret;
+
+	ret = engine->emit_bb_start(rq,
+				    engine->wa_ctx.vma->node.start, 0,
+				    0);
+	if (ret)
+		return ret;
+
+	ret = engine->emit_flush(rq, EMIT_FLUSH);
+	if (ret)
+		return ret;
+
+	/* Always invalidate before the next switch_mm() */
+	return engine->emit_flush(rq, EMIT_INVALIDATE);
+}
+
 static int switch_context(struct i915_request *rq)
 {
+	struct intel_engine_cs *engine = rq->engine;
 	struct intel_context *ce = rq->context;
+	void **residuals = NULL;
 	int ret;
 
 	GEM_BUG_ON(HAS_EXECLISTS(rq->i915));
 
+	if (engine->wa_ctx.vma && ce != engine->kernel_context) {
+		if (engine->wa_ctx.vma->private != ce) {
+			ret = clear_residuals(rq);
+			if (ret)
+				return ret;
+
+			residuals = &engine->wa_ctx.vma->private;
+		}
+	}
+
 	ret = switch_mm(rq, vm_alias(ce));
 	if (ret)
 		return ret;
@@ -1600,7 +1645,7 @@ static int switch_context(struct i915_request *rq)
 		else
 			flags |= MI_RESTORE_INHIBIT;
 
-		ret = mi_set_context(rq, flags);
+		ret = mi_set_context(rq, ce, flags);
 		if (ret)
 			return ret;
 	}
@@ -1609,6 +1654,20 @@ static int switch_context(struct i915_request *rq)
 	if (ret)
 		return ret;
 
+	/*
+	 * Now past the point of no return, this request _will_ be emitted.
+	 *
+	 * Or at least this preamble will be emitted, the request may be
+	 * interrupted prior to submitting the user payload. If so, we
+	 * still submit the "empty" request in order to preserve global
+	 * state tracking such as this, our tracking of the current
+	 * dirty context.
+	 */
+	if (residuals) {
+		intel_context_put(*residuals);
+		*residuals = intel_context_get(ce);
+	}
+
 	return 0;
 }
 
@@ -1792,6 +1851,11 @@ static void ring_release(struct intel_engine_cs *engine)
 
 	intel_engine_cleanup_common(engine);
 
+	if (engine->wa_ctx.vma) {
+		intel_context_put(engine->wa_ctx.vma->private);
+		i915_vma_unpin_and_release(&engine->wa_ctx.vma, 0);
+	}
+
 	intel_ring_unpin(engine->legacy.ring);
 	intel_ring_put(engine->legacy.ring);
 
@@ -1939,6 +2003,60 @@ static void setup_vecs(struct intel_engine_cs *engine)
 	engine->emit_fini_breadcrumb = gen7_xcs_emit_breadcrumb;
 }
 
+static int gen7_ctx_switch_bb_setup(struct intel_engine_cs * const engine,
+				    struct i915_vma * const vma)
+{
+	return 0;
+}
+
+static int gen7_ctx_switch_bb_init(struct intel_engine_cs *engine)
+{
+	struct drm_i915_gem_object *obj;
+	struct i915_vma *vma;
+	int size;
+	int err;
+
+	size = gen7_ctx_switch_bb_setup(engine, NULL /* probe size */);
+	if (size <= 0)
+		return size;
+
+	size = ALIGN(size, PAGE_SIZE);
+	obj = i915_gem_object_create_internal(engine->i915, size);
+	if (IS_ERR(obj))
+		return PTR_ERR(obj);
+
+	vma = i915_vma_instance(obj, engine->gt->vm, NULL);
+	if (IS_ERR(vma)) {
+		err = PTR_ERR(vma);
+		goto err_obj;
+	}
+
+	vma->private = intel_context_create(engine); /* dummy residuals */
+	if (IS_ERR(vma->private)) {
+		err = PTR_ERR(vma->private);
+		goto err_obj;
+	}
+
+	err = i915_vma_pin(vma, 0, 0, PIN_USER | PIN_HIGH);
+	if (err)
+		goto err_private;
+
+	err = gen7_ctx_switch_bb_setup(engine, vma);
+	if (err)
+		goto err_unpin;
+
+	engine->wa_ctx.vma = vma;
+	return 0;
+
+err_unpin:
+	i915_vma_unpin(vma);
+err_private:
+	intel_context_put(vma->private);
+err_obj:
+	i915_gem_object_put(obj);
+	return err;
+}
+
 int intel_ring_submission_setup(struct intel_engine_cs *engine)
 {
 	struct intel_timeline *timeline;
@@ -1992,11 +2110,19 @@ int intel_ring_submission_setup(struct intel_engine_cs *engine)
 
 	GEM_BUG_ON(timeline->hwsp_ggtt != engine->status_page.vma);
 
+	if (IS_GEN(engine->i915, 7) && engine->class == RENDER_CLASS) {
+		err = gen7_ctx_switch_bb_init(engine);
+		if (err)
+			goto err_ring_unpin;
+	}
+
 	/* Finally, take ownership and responsibility for cleanup! */
 	engine->release = ring_release;
 
 	return 0;
 
+err_ring_unpin:
+	intel_ring_unpin(ring);
 err_ring:
 	intel_ring_put(ring);
 err_timeline_unpin:
-- 
2.17.1

_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

  reply index

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-14 14:51 [RFC PATCH 0/2] Security mitigation for Intel Gen7 and Gen7.5 Akeem G Abodunrin
2020-01-14 14:51 ` [RFC PATCH 1/2] drm/i915: Add mechanism to submit a context WA on ring submission Akeem G Abodunrin
2020-01-16 16:12   ` Mika Kuoppala [this message]
2020-01-14 14:51 ` [RFC PATCH 2/2] drm/i915/gen7: Clear all EU/L3 residual contexts Akeem G Abodunrin
2020-01-14 22:35   ` Chris Wilson
2020-01-14 17:45 [RFC PATCH v2 1/2] drm/i915: Add mechanism to submit a context WA on ring submission Akeem G Abodunrin
2020-01-16 16:16 ` [PATCH " Mika Kuoppala
2020-01-16 16:47   ` Mika Kuoppala
2020-01-30 16:57 [PATCH 0/2] Security mitigation for Intel Gen7/7.5 HWs Akeem G Abodunrin
2020-01-30 16:57 ` [PATCH 1/2] drm/i915: Add mechanism to submit a context WA on ring submission Akeem G Abodunrin
2020-02-20 22:57 [PATCH 0/2] Security mitigation for Intel Gen7/7.5 HWs Akeem G Abodunrin
2020-02-20 22:57 ` [PATCH 1/2] drm/i915: Add mechanism to submit a context WA on ring submission Akeem G Abodunrin

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200116161231.26026-1-mika.kuoppala@linux.intel.com \
    --to=mika.kuoppala@linux.intel.com \
    --cc=akeem.g.abodunrin@intel.com \
    --cc=chris.p.wilson@intel.com \
    --cc=d.scott.phillips@intel.com \
    --cc=daniel.vetter@intel.com \
    --cc=david.c.stewart@intel.com \
    --cc=dri-devel@lists.freedesktop.org \
    --cc=francesco.balestrieri@intel.com \
    --cc=intel-gfx@lists.freedesktop.org \
    --cc=jani.nikula@intel.com \
    --cc=jon.bloomfield@intel.com \
    --cc=joonas.lahtinen@intel.com \
    --cc=omer.aran@intel.com \
    --cc=pragyansri.pathi@intel.com \
    --cc=prathap.kumar.valsan@intel.com \
    --cc=sudeep.dutt@intel.com \
    --cc=tony.luck@intel.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

dri-devel Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/dri-devel/0 dri-devel/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 dri-devel dri-devel/ https://lore.kernel.org/dri-devel \
		dri-devel@lists.freedesktop.org
	public-inbox-index dri-devel

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.freedesktop.lists.dri-devel


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git