drm/i915/gvt: Fix BDW command parser regression

On BDW new Windows driver has brought extra registers to handle for
LRM/LRR command in WA ctx. Add allowed registers in cmd parser for BDW.

Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Yan Zhao <yan.y.zhao@intel.com>
Cc: stable@vger.kernel.org
Tested-by: Alex Williamson <alex.williamson@redhat.com>
Reviewed-by: Colin Xu <colin.xu@intel.com>
Fixes: 73a37a4 ("drm/i915/gvt: filter cmds "lrr-src" and "lrr-dst" in cmd_handler")
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20210414084813.3763353-1-zhenyuw@linux.intel.com

Author: zhenyw

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

@@ -916,19 +916,26 @@ static int cmd_reg_handler(struct parser_exec_state *s,
 
 	if (!strncmp(cmd, "srm", 3) ||
 			!strncmp(cmd, "lrm", 3)) {
-		if (offset != i915_mmio_reg_offset(GEN8_L3SQCREG4) &&
-				offset != 0x21f0) {
+		if (offset == i915_mmio_reg_offset(GEN8_L3SQCREG4) ||
+		    offset == 0x21f0 ||
+		    (IS_BROADWELL(gvt->gt->i915) &&
+		     offset == i915_mmio_reg_offset(INSTPM)))
+			return 0;
+		else {
 			gvt_vgpu_err("%s access to register (%x)\n",
 					cmd, offset);
 			return -EPERM;
-		} else
-			return 0;
+		}
 	}
 
 	if (!strncmp(cmd, "lrr-src", 7) ||
 			!strncmp(cmd, "lrr-dst", 7)) {
-		gvt_vgpu_err("not allowed cmd %s\n", cmd);
-		return -EPERM;
+		if (IS_BROADWELL(gvt->gt->i915) && offset == 0x215c)
+			return 0;
+		else {
+			gvt_vgpu_err("not allowed cmd %s reg (%x)\n", cmd, offset);
+			return -EPERM;
+		}
 	}
 
 	if (!strncmp(cmd, "pipe_ctrl", 9)) {