drm/i915/gvt: scan non-privileged batch buffer for debug purpose

For perfomance purpose, scanning of non-privileged batch buffer is turned
off by default. But for debugging purpose, it can be turned on via debugfs.
After scanning, we submit the original non-privileged batch buffer into
hardware, so that the scanning is only a peeking window of guest submitted
commands and will not affect the execution results.

v4:
- refine debugfs print format&content (zhenyu wang)
- print engine id instread of engine name to prevent potential memory leak
  in debugfs warning message. (zhenyu wang)

v3:
- change vgpu->scan_nonprivbb from type bool to u32, so it is able to
  selectively turn on/off scanning of non-privileged batch buffer on engine
  level. e.g.
  if vgpu->scan_nonprivbb=3, then it will scan non-privileged batch buffer
  on engine 0 and 1.
- in debugfs interface to set vgpu->scan_nonprivbb, print warning message
  to warn user and explicitly tell state change in kernel log (zhenyu wang)
v2:
- rebase
- update comments for start_gma_offset (henry)
Signed-off-by: Zhao Yan <yan.y.zhao@intel.com>
Reviewed-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: Zhi Wang <zhi.a.wang@intel.com>

drivers/gpu/drm/i915/gvt/cmd_parser.c

@@ -1603,7 +1603,8 @@ static int batch_buffer_needs_scan(struct parser_exec_state *s)
 	if (IS_BROADWELL(gvt->dev_priv) || IS_SKYLAKE(gvt->dev_priv)
 		|| IS_KABYLAKE(gvt->dev_priv)) {
 		/* BDW decides privilege based on address space */
-		if (cmd_val(s, 0) & (1 << 8))
+		if (cmd_val(s, 0) & (1 << 8) &&
+			!(s->vgpu->scan_nonprivbb & (1 << s->ring_id)))
 			return 0;
 	}
 	return 1;
@@ -1617,6 +1618,8 @@ static int find_bb_size(struct parser_exec_state *s, unsigned long *bb_size)
 	bool bb_end = false;
 	struct intel_vgpu *vgpu = s->vgpu;
 	u32 cmd;
+	struct intel_vgpu_mm *mm = (s->buf_addr_type == GTT_BUFFER) ?
+		s->vgpu->gtt.ggtt_mm : s->workload->shadow_mm;
 
 	*bb_size = 0;
 
@@ -1628,18 +1631,22 @@ static int find_bb_size(struct parser_exec_state *s, unsigned long *bb_size)
 	cmd = cmd_val(s, 0);
 	info = get_cmd_info(s->vgpu->gvt, cmd, s->ring_id);
 	if (info == NULL) {
-		gvt_vgpu_err("unknown cmd 0x%x, opcode=0x%x\n",
-				cmd, get_opcode(cmd, s->ring_id));
+		gvt_vgpu_err("unknown cmd 0x%x, opcode=0x%x, addr_type=%s, ring %d, workload=%p\n",
+				cmd, get_opcode(cmd, s->ring_id),
+				(s->buf_addr_type == PPGTT_BUFFER) ?
+				"ppgtt" : "ggtt", s->ring_id, s->workload);
 		return -EBADRQC;
 	}
 	do {
-		if (copy_gma_to_hva(s->vgpu, s->vgpu->gtt.ggtt_mm,
+		if (copy_gma_to_hva(s->vgpu, mm,
 				gma, gma + 4, &cmd) < 0)
 			return -EFAULT;
 		info = get_cmd_info(s->vgpu->gvt, cmd, s->ring_id);
 		if (info == NULL) {
-			gvt_vgpu_err("unknown cmd 0x%x, opcode=0x%x\n",
-				cmd, get_opcode(cmd, s->ring_id));
+			gvt_vgpu_err("unknown cmd 0x%x, opcode=0x%x, addr_type=%s, ring %d, workload=%p\n",
+				cmd, get_opcode(cmd, s->ring_id),
+				(s->buf_addr_type == PPGTT_BUFFER) ?
+				"ppgtt" : "ggtt", s->ring_id, s->workload);
 			return -EBADRQC;
 		}
 
@@ -1665,6 +1672,9 @@ static int perform_bb_shadow(struct parser_exec_state *s)
 	unsigned long gma = 0;
 	unsigned long bb_size;
 	int ret = 0;
+	struct intel_vgpu_mm *mm = (s->buf_addr_type == GTT_BUFFER) ?
+		s->vgpu->gtt.ggtt_mm : s->workload->shadow_mm;
+	unsigned long gma_start_offset = 0;
 
 	/* get the start gm address of the batch buffer */
 	gma = get_gma_bb_from_cmd(s, 1);
@@ -1679,8 +1689,24 @@ static int perform_bb_shadow(struct parser_exec_state *s)
 	if (!bb)
 		return -ENOMEM;
 
+	bb->ppgtt = (s->buf_addr_type == GTT_BUFFER) ? false : true;
+
+	/* the gma_start_offset stores the batch buffer's start gma's
+	 * offset relative to page boundary. so for non-privileged batch
+	 * buffer, the shadowed gem object holds exactly the same page
+	 * layout as original gem object. This is for the convience of
+	 * replacing the whole non-privilged batch buffer page to this
+	 * shadowed one in PPGTT at the same gma address. (this replacing
+	 * action is not implemented yet now, but may be necessary in
+	 * future).
+	 * for prileged batch buffer, we just change start gma address to
+	 * that of shadowed page.
+	 */
+	if (bb->ppgtt)
+		gma_start_offset = gma & ~I915_GTT_PAGE_MASK;
+
 	bb->obj = i915_gem_object_create(s->vgpu->gvt->dev_priv,
-					 roundup(bb_size, PAGE_SIZE));
+			 roundup(bb_size + gma_start_offset, PAGE_SIZE));
 	if (IS_ERR(bb->obj)) {
 		ret = PTR_ERR(bb->obj);
 		goto err_free_bb;
@@ -1701,9 +1727,9 @@ static int perform_bb_shadow(struct parser_exec_state *s)
 		bb->clflush &= ~CLFLUSH_BEFORE;
 	}
 
-	ret = copy_gma_to_hva(s->vgpu, s->vgpu->gtt.ggtt_mm,
+	ret = copy_gma_to_hva(s->vgpu, mm,
 			      gma, gma + bb_size,
-			      bb->va);
+			      bb->va + gma_start_offset);
 	if (ret < 0) {
 		gvt_vgpu_err("fail to copy guest ring buffer\n");
 		ret = -EFAULT;
@@ -1729,7 +1755,7 @@ static int perform_bb_shadow(struct parser_exec_state *s)
 	 * buffer's gma in pair. After all, we don't want to pin the shadow
 	 * buffer here (too early).
 	 */
-	s->ip_va = bb->va;
+	s->ip_va = bb->va + gma_start_offset;
 	s->ip_gma = gma;
 	return 0;
 err_unmap:
@@ -2468,15 +2494,18 @@ static int cmd_parser_exec(struct parser_exec_state *s)
 
 	info = get_cmd_info(s->vgpu->gvt, cmd, s->ring_id);
 	if (info == NULL) {
-		gvt_vgpu_err("unknown cmd 0x%x, opcode=0x%x\n",
-				cmd, get_opcode(cmd, s->ring_id));
+		gvt_vgpu_err("unknown cmd 0x%x, opcode=0x%x, addr_type=%s, ring %d, workload=%p\n",
+				cmd, get_opcode(cmd, s->ring_id),
+				(s->buf_addr_type == PPGTT_BUFFER) ?
+				"ppgtt" : "ggtt", s->ring_id, s->workload);
 		return -EBADRQC;
 	}
 
 	s->info = info;
 
 	trace_gvt_command(vgpu->id, s->ring_id, s->ip_gma, s->ip_va,
-			  cmd_length(s), s->buf_type);
+			  cmd_length(s), s->buf_type, s->buf_addr_type,
+			  s->workload, info->name);
 
 	if (info->handler) {
 		ret = info->handler(s);

drivers/gpu/drm/i915/gvt/debugfs.c

@@ -124,6 +124,68 @@ static int vgpu_mmio_diff_show(struct seq_file *s, void *unused)
 }
 DEFINE_SHOW_ATTRIBUTE(vgpu_mmio_diff);
 
+static int
+vgpu_scan_nonprivbb_get(void *data, u64 *val)
+{
+	struct intel_vgpu *vgpu = (struct intel_vgpu *)data;
+	*val = vgpu->scan_nonprivbb;
+	return 0;
+}
+
+/*
+ * set/unset bit engine_id of vgpu->scan_nonprivbb to turn on/off scanning
+ * of non-privileged batch buffer. e.g.
+ * if vgpu->scan_nonprivbb=3, then it will scan non-privileged batch buffer
+ * on engine 0 and 1.
+ */
+static int
+vgpu_scan_nonprivbb_set(void *data, u64 val)
+{
+	struct intel_vgpu *vgpu = (struct intel_vgpu *)data;
+	struct drm_i915_private *dev_priv = vgpu->gvt->dev_priv;
+	enum intel_engine_id id;
+	char buf[128], *s;
+	int len;
+
+	val &= (1 << I915_NUM_ENGINES) - 1;
+
+	if (vgpu->scan_nonprivbb == val)
+		return 0;
+
+	if (!val)
+		goto done;
+
+	len = sprintf(buf,
+		"gvt: vgpu %d turns on non-privileged batch buffers scanning on Engines:",
+		vgpu->id);
+
+	s = buf + len;
+
+	for (id = 0; id < I915_NUM_ENGINES; id++) {
+		struct intel_engine_cs *engine;
+
+		engine = dev_priv->engine[id];
+		if (engine && (val & (1 << id))) {
+			len = snprintf(s, 4, "%d, ", engine->id);
+			s += len;
+		} else
+			val &=  ~(1 << id);
+	}
+
+	if (val)
+		sprintf(s, "low performance expected.");
+
+	pr_warn("%s\n", buf);
+
+done:
+	vgpu->scan_nonprivbb = val;
+	return 0;
+}
+
+DEFINE_SIMPLE_ATTRIBUTE(vgpu_scan_nonprivbb_fops,
+			vgpu_scan_nonprivbb_get, vgpu_scan_nonprivbb_set,
+			"0x%llx\n");
+
 /**
  * intel_gvt_debugfs_add_vgpu - register debugfs entries for a vGPU
  * @vgpu: a vGPU
@@ -151,6 +213,11 @@ int intel_gvt_debugfs_add_vgpu(struct intel_vgpu *vgpu)
 	if (!ent)
 		return -ENOMEM;
 
+	ent = debugfs_create_file("scan_nonprivbb", 0644, vgpu->debugfs,
+				 vgpu, &vgpu_scan_nonprivbb_fops);
+	if (!ent)
+		return -ENOMEM;
+
 	return 0;
 }
 

drivers/gpu/drm/i915/gvt/gvt.h

@@ -226,6 +226,7 @@ struct intel_vgpu {
 
 	struct completion vblank_done;
 
+	u32 scan_nonprivbb;
 };
 
 /* validating GM healthy status*/

drivers/gpu/drm/i915/gvt/scheduler.c

@@ -452,12 +452,6 @@ static int prepare_shadow_batch_buffer(struct intel_vgpu_workload *workload)
 	int ret;
 
 	list_for_each_entry(bb, &workload->shadow_bb, list) {
-		bb->vma = i915_gem_object_ggtt_pin(bb->obj, NULL, 0, 0, 0);
-		if (IS_ERR(bb->vma)) {
-			ret = PTR_ERR(bb->vma);
-			goto err;
-		}
-
 		/* For privilge batch buffer and not wa_ctx, the bb_start_cmd_va
 		 * is only updated into ring_scan_buffer, not real ring address
 		 * allocated in later copy_workload_to_ring_buffer. pls be noted
@@ -469,6 +463,31 @@ static int prepare_shadow_batch_buffer(struct intel_vgpu_workload *workload)
 			bb->bb_start_cmd_va = workload->shadow_ring_buffer_va
 				+ bb->bb_offset;
 
+		if (bb->ppgtt) {
+			/* for non-priv bb, scan&shadow is only for
+			 * debugging purpose, so the content of shadow bb
+			 * is the same as original bb. Therefore,
+			 * here, rather than switch to shadow bb's gma
+			 * address, we directly use original batch buffer's
+			 * gma address, and send original bb to hardware
+			 * directly
+			 */
+			if (bb->clflush & CLFLUSH_AFTER) {
+				drm_clflush_virt_range(bb->va,
+						bb->obj->base.size);
+				bb->clflush &= ~CLFLUSH_AFTER;
+			}
+			i915_gem_obj_finish_shmem_access(bb->obj);
+			bb->accessing = false;
+
+		} else {
+			bb->vma = i915_gem_object_ggtt_pin(bb->obj,
+					NULL, 0, 0, 0);
+			if (IS_ERR(bb->vma)) {
+				ret = PTR_ERR(bb->vma);
+				goto err;
+			}
+
 			/* relocate shadow batch buffer */
 			bb->bb_start_cmd_va[1] = i915_ggtt_offset(bb->vma);
 			if (gmadr_bytes == 8)
@@ -476,11 +495,13 @@ static int prepare_shadow_batch_buffer(struct intel_vgpu_workload *workload)
 
 			/* No one is going to touch shadow bb from now on. */
 			if (bb->clflush & CLFLUSH_AFTER) {
-			drm_clflush_virt_range(bb->va, bb->obj->base.size);
+				drm_clflush_virt_range(bb->va,
+						bb->obj->base.size);
 				bb->clflush &= ~CLFLUSH_AFTER;
 			}
 
-		ret = i915_gem_object_set_to_gtt_domain(bb->obj, false);
+			ret = i915_gem_object_set_to_gtt_domain(bb->obj,
+					false);
 			if (ret)
 				goto err;
 
@@ -489,6 +510,7 @@ static int prepare_shadow_batch_buffer(struct intel_vgpu_workload *workload)
 
 			i915_vma_move_to_active(bb->vma, workload->req, 0);
 		}
+	}
 	return 0;
 err:
 	release_shadow_batch_buffer(workload);

drivers/gpu/drm/i915/gvt/scheduler.h

@@ -125,6 +125,7 @@ struct intel_vgpu_shadow_bb {
 	unsigned int clflush;
 	bool accessing;
 	unsigned long bb_offset;
+	bool ppgtt;
 };
 
 #define workload_q_head(vgpu, ring_id) \

drivers/gpu/drm/i915/gvt/trace.h

@@ -224,19 +224,25 @@ TRACE_EVENT(oos_sync,
 	TP_printk("%s", __entry->buf)
 );
 
+#define GVT_CMD_STR_LEN 40
 TRACE_EVENT(gvt_command,
-	TP_PROTO(u8 vgpu_id, u8 ring_id, u32 ip_gma, u32 *cmd_va, u32 cmd_len,
-		 u32 buf_type),
+	TP_PROTO(u8 vgpu_id, u8 ring_id, u32 ip_gma, u32 *cmd_va,
+		u32 cmd_len,  u32 buf_type, u32 buf_addr_type,
+		void *workload, char *cmd_name),
 
-	TP_ARGS(vgpu_id, ring_id, ip_gma, cmd_va, cmd_len, buf_type),
+	TP_ARGS(vgpu_id, ring_id, ip_gma, cmd_va, cmd_len, buf_type,
+		buf_addr_type, workload, cmd_name),
 
 	TP_STRUCT__entry(
 		__field(u8, vgpu_id)
 		__field(u8, ring_id)
 		__field(u32, ip_gma)
 		__field(u32, buf_type)
+		__field(u32, buf_addr_type)
 		__field(u32, cmd_len)
+		__field(void*, workload)
 		__dynamic_array(u32, raw_cmd, cmd_len)
+		__array(char, cmd_name, GVT_CMD_STR_LEN)
 	),
 
 	TP_fast_assign(
@@ -244,17 +250,25 @@ TRACE_EVENT(gvt_command,
 		__entry->ring_id = ring_id;
 		__entry->ip_gma = ip_gma;
 		__entry->buf_type = buf_type;
+		__entry->buf_addr_type = buf_addr_type;
 		__entry->cmd_len = cmd_len;
+		__entry->workload = workload;
+		snprintf(__entry->cmd_name, GVT_CMD_STR_LEN, "%s", cmd_name);
 		memcpy(__get_dynamic_array(raw_cmd), cmd_va, cmd_len * sizeof(*cmd_va));
 	),
 
 
-	TP_printk("vgpu%d ring %d: buf_type %u, ip_gma %08x, raw cmd %s",
+	TP_printk("vgpu%d ring %d: address_type %u, buf_type %u, ip_gma %08x,cmd (name=%s,len=%u,raw cmd=%s), workload=%p\n",
 		__entry->vgpu_id,
 		__entry->ring_id,
+		__entry->buf_addr_type,
 		__entry->buf_type,
 		__entry->ip_gma,
-		__print_array(__get_dynamic_array(raw_cmd), __entry->cmd_len, 4))
+		__entry->cmd_name,
+		__entry->cmd_len,
+		__print_array(__get_dynamic_array(raw_cmd),
+			__entry->cmd_len, 4),
+		__entry->workload)
 );
 
 #define GVT_TEMP_STR_LEN 10