vkr: add vkr_log

It automatically prefixes the message with "vkr: ".

Signed-off-by: Chia-I Wu <olvaffe@gmail.com>
Reviewed-by: Ryan Neph <ryanneph@google.com>
Acked-by: Gert Wollny <gert.wollny@collabora.com>

src/venus/vkr_common.c

@@ -5,8 +5,47 @@
 
 #include "vkr_common.h"
 
+#include <stdarg.h>
+#include <stdio.h>
+
 #include "vkr_cs.h"
 
+void
+vkr_log(const char *fmt, ...)
+{
+   const char prefix[] = "vkr: ";
+   char line[1024];
+   size_t len;
+   va_list va;
+   int ret;
+
+   len = ARRAY_SIZE(prefix) - 1;
+   memcpy(line, prefix, len);
+
+   va_start(va, fmt);
+   ret = vsnprintf(line + len, ARRAY_SIZE(line) - len, fmt, va);
+   va_end(va);
+
+   if (ret < 0) {
+      const char log_error[] = "log error";
+      memcpy(line + len, log_error, ARRAY_SIZE(log_error) - 1);
+      len += ARRAY_SIZE(log_error) - 1;
+   } else if ((size_t)ret < ARRAY_SIZE(line) - len) {
+      len += ret;
+   } else {
+      len = ARRAY_SIZE(line) - 1;
+   }
+
+   /* make room for newline */
+   if (len + 1 >= ARRAY_SIZE(line))
+      len--;
+
+   line[len++] = '\n';
+   line[len] = '\0';
+
+   virgl_log(line);
+}
+
 void
 object_array_fini(struct object_array *arr)
 {

src/venus/vkr_common.h

@@ -288,6 +288,9 @@ struct object_array {
 extern uint32_t vkr_renderer_flags;
 extern uint32_t vkr_debug_flags;
 
+void
+vkr_log(const char *fmt, ...);
+
 bool
 object_array_init(struct object_array *arr,
                   uint32_t count,