vrend: Add possibility for the guest to add debug flags

For this to work to host will have to add "guestallow" to the
debug flags.

Reviewed-by: Gurchetan Singh <gurchetansingh@chromium.org>
Tested-by: Jakob Bornecrantz <jakob@collabora.com>
Signed-off-by: Gert Wollny <gert.wollny@collabora.com>
Signed-off-by: Jakob Bornecrantz <jakob@collabora.com>

src/virgl_hw.h

@@ -231,6 +231,7 @@ enum virgl_formats {
 #define VIRGL_CAP_SHADER_CLOCK         (1 << 11)
 #define VIRGL_CAP_TEXTURE_BARRIER      (1 << 12)
 #define VIRGL_CAP_TGSI_COMPONENTS      (1 << 13)
+#define VIRGL_CAP_GUEST_MAY_INIT_LOG   (1 << 14)
 
 /* virgl bind flags - these are compatible with mesa 10.5 gallium.
  * but are fixed, no other should be passed to virgl either.

src/virgl_protocol.h

@@ -23,6 +23,8 @@
 #ifndef VIRGL_PROTOCOL_H
 #define VIRGL_PROTOCOL_H
 
+#include <stdint.h>
+
 #define VIRGL_QUERY_STATE_NEW 0
 #define VIRGL_QUERY_STATE_DONE 1
 #define VIRGL_QUERY_STATE_WAIT_HOST 2
@@ -94,7 +96,8 @@ enum virgl_context_cmd {
    VIRGL_CCMD_SET_FRAMEBUFFER_STATE_NO_ATTACH,
    VIRGL_CCMD_TEXTURE_BARRIER,
    VIRGL_CCMD_SET_ATOMIC_BUFFERS,
-   VIRGL_MAX_COMMANDS,
+   VIRGL_CCMD_SET_DEBUG_FLAGS,
+   VIRGL_MAX_COMMANDS
 };
 
 /*
@@ -556,4 +559,8 @@ enum virgl_context_cmd {
 #define VIRGL_SET_ATOMIC_BUFFER_LENGTH(x) ((x) * VIRGL_SET_ATOMIC_BUFFER_ELEMENT_SIZE + 3)
 #define VIRGL_SET_ATOMIC_BUFFER_RES_HANDLE(x) ((x) * VIRGL_SET_ATOMIC_BUFFER_ELEMENT_SIZE + 4)
 
+/* set debug flags */
+#define VIRGL_SET_DEBUG_FLAGS_MIN_SIZE 2
+#define VIRGL_SET_DEBUG_FLAGSTRING_OFFSET 1
+
 #endif

src/vrend_debug.c

@@ -112,11 +112,31 @@ static const struct debug_named_value vrend_debug_options[] = {
    {"copyres", dbg_copy_resource, "Debug copy resource code path"},
    {"feat", dbg_features, "Log features found"},
    {"tex", dbg_tex, "Log texture operations"},
+   {"guestallow", dbg_allow_guest_override, "Allow the guest to override the debug flags"},
    DEBUG_NAMED_VALUE_END
 };
 
 static uint64_t vrend_debug_flags = 0;
 static int vrend_debug_flags_initalized = 0;
+
+int vrend_get_debug_flags(const char *flagstring)
+{
+   int retval;
+   char buf[1024] = "";
+
+   /* Unfortunately the available function to scan the flags take the string
+    * from the environment. The alternative to using setenv would be to
+    * duplicate code or to change the gallium/util intefaces and diverge more
+    * from mesa. So just stick to the environment variable. */
+   snprintf(buf, 1024, "VREND_TEMP_DEBUG_STRING_%d", getpid());
+   setenv(buf, flagstring, 1);
+
+   retval = (int)debug_get_flags_option(buf,
+                                        vrend_debug_options, 0);
+   unsetenv(buf);
+   return retval;
+}
+
 void vrend_init_debug_flags()
 {
    if (!vrend_debug_flags_initalized)  {
@@ -135,3 +155,8 @@ void vrend_debug_add_flag(enum virgl_debug_flags flag)
 {
    vrend_debug_flags |= flag;
 }
+
+int  vrend_debug_can_override(void)
+{
+   return vrend_debug_flags & dbg_allow_guest_override;
+}

src/vrend_debug.h

@@ -41,6 +41,7 @@ enum virgl_debug_flags {
    dbg_copy_resource = 1 << 6,
    dbg_features = 1 << 7,
    dbg_tex = 1 << 8,
+   dbg_allow_guest_override = 1 << 16,
    dbg_feature_use = 1 << 17,
 };
 
@@ -51,6 +52,12 @@ const char *vrend_get_object_type_name(enum virgl_object_type cmd);
 
 void vrend_init_debug_flags(void);
 
+int  vrend_debug_can_override(void);
+
+int vrend_get_debug_flags(const char *flagstring);
+
+void vrend_context_set_debug_flags(struct vrend_context *ctx, const char *flags);
+
 unsigned vrend_debug(struct vrend_context *ctx, enum virgl_debug_flags flag);
 
 void vrend_debug_add_flag(enum virgl_debug_flags flag);

src/vrend_decode.c

@@ -1262,6 +1262,32 @@ static int vrend_decode_texture_barrier(struct vrend_decode_ctx *ctx, uint16_t l
    return 0;
 }
 
+static int vrend_decode_set_debug_mask(struct vrend_decode_ctx *ctx, int length)
+{
+   char *flagstring;
+   int slen = sizeof(uint32_t) * length;
+   uint32_t *buf;
+
+   if (length < VIRGL_SET_DEBUG_FLAGS_MIN_SIZE)
+      return EINVAL;
+
+   buf = get_buf_ptr(ctx, VIRGL_SET_DEBUG_FLAGSTRING_OFFSET);
+   flagstring = malloc(slen+1);
+
+   if (!flagstring) {
+      return ENOMEM;
+   }
+
+   memcpy(flagstring, buf, slen);
+   flagstring[slen] = 0;
+   vrend_context_set_debug_flags(ctx->grctx, flagstring);
+
+   free(flagstring);
+
+   return 0;
+}
+
+
 void vrend_renderer_context_create_internal(uint32_t handle, uint32_t nlen,
                                             const char *debug_name)
 {
@@ -1493,6 +1519,9 @@ int vrend_decode_block(uint32_t ctx_id, uint32_t *block, int ndw)
       case VIRGL_CCMD_TEXTURE_BARRIER:
          ret = vrend_decode_texture_barrier(gdctx, len);
          break;
+      case VIRGL_CCMD_SET_DEBUG_FLAGS:
+         ret = vrend_decode_set_debug_mask(gdctx, len);
+         break;
       default:
          ret = EINVAL;
       }

src/vrend_renderer.c

@@ -8402,6 +8402,9 @@ static void vrend_renderer_fill_caps_v2(int gl_ver, int gles_ver,  union virgl_c
     * of the caps setting */
    if (vrend_debug(NULL, dbg_features))
       vrend_debug_add_flag(dbg_feature_use);
+
+   /* always enable, only indicates that the CMD is supported */
+   caps->v2.capability_bits |= VIRGL_CAP_GUEST_MAY_INIT_LOG;
 }
 
 void vrend_renderer_fill_caps(uint32_t set, UNUSED uint32_t version,
@@ -8611,6 +8614,15 @@ static struct vrend_resource *vrend_renderer_ctx_res_lookup(struct vrend_context
    return res;
 }
 
+void vrend_context_set_debug_flags(struct vrend_context *ctx, const char *flagstring)
+{
+   if (vrend_debug_can_override()) {
+      ctx->debug_flags |= vrend_get_debug_flags(flagstring);
+      if (ctx->debug_flags & dbg_features)
+         vrend_debug_add_flag(dbg_feature_use);
+   }
+}
+
 int vrend_renderer_resource_get_info(int res_handle,
                                      struct vrend_renderer_resource_info *info)
 {