drm/i915/gvt: load host render mocs once in mocs switch

Load host render mocs registers once for delta update of mocs switch, it
reduces mmio read times obviously, then brings performance improvement
during multi-vms switch.
Signed-off-by: Weinan Li <weinan.z.li@intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>

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

@@ -149,8 +149,41 @@ static struct engine_mmio gen9_engine_mmio_list[] __cacheline_aligned = {
 	{ /* Terminated */ }
 };
 
-static u32 gen9_render_mocs[I915_NUM_ENGINES][64];
-static u32 gen9_render_mocs_L3[32];
+static struct {
+	bool initialized;
+	u32 control_table[I915_NUM_ENGINES][64];
+	u32 l3cc_table[32];
+} gen9_render_mocs;
+
+static void load_render_mocs(struct drm_i915_private *dev_priv)
+{
+	i915_reg_t offset;
+	u32 regs[] = {
+		[RCS] = 0xc800,
+		[VCS] = 0xc900,
+		[VCS2] = 0xca00,
+		[BCS] = 0xcc00,
+		[VECS] = 0xcb00,
+	};
+	int ring_id, i;
+
+	for (ring_id = 0; ring_id < I915_NUM_ENGINES; ring_id++) {
+		offset.reg = regs[ring_id];
+		for (i = 0; i < 64; i++) {
+			gen9_render_mocs.control_table[ring_id][i] =
+				I915_READ_FW(offset);
+			offset.reg += 4;
+		}
+	}
+
+	offset.reg = 0xb020;
+	for (i = 0; i < 32; i++) {
+		gen9_render_mocs.l3cc_table[i] =
+			I915_READ_FW(offset);
+		offset.reg += 4;
+	}
+	gen9_render_mocs.initialized = true;
+}
 
 static void handle_tlb_pending_event(struct intel_vgpu *vgpu, int ring_id)
 {
@@ -218,18 +251,19 @@ static void switch_mocs(struct intel_vgpu *pre, struct intel_vgpu *next,
 	if (WARN_ON(ring_id >= ARRAY_SIZE(regs)))
 		return;
 
-	offset.reg = regs[ring_id];
+	if (!pre && !gen9_render_mocs.initialized)
+		load_render_mocs(dev_priv);
 
+	offset.reg = regs[ring_id];
 	for (i = 0; i < 64; i++) {
 		if (pre)
 			old_v = vgpu_vreg(pre, offset);
 		else
-			old_v = gen9_render_mocs[ring_id][i]
-			      = I915_READ_FW(offset);
+			old_v = gen9_render_mocs.control_table[ring_id][i];
 		if (next)
 			new_v = vgpu_vreg(next, offset);
 		else
-			new_v = gen9_render_mocs[ring_id][i];
+			new_v = gen9_render_mocs.control_table[ring_id][i];
 
 		if (old_v != new_v)
 			I915_WRITE_FW(offset, new_v);
@@ -243,12 +277,11 @@ static void switch_mocs(struct intel_vgpu *pre, struct intel_vgpu *next,
 			if (pre)
 				old_v = vgpu_vreg(pre, l3_offset);
 			else
-				old_v = gen9_render_mocs_L3[i]
-				      = I915_READ_FW(offset);
+				old_v = gen9_render_mocs.l3cc_table[i];
 			if (next)
 				new_v = vgpu_vreg(next, l3_offset);
 			else
-				new_v = gen9_render_mocs_L3[i];
+				new_v = gen9_render_mocs.l3cc_table[i];
 
 			if (old_v != new_v)
 				I915_WRITE_FW(l3_offset, new_v);