vrend: forward the host renderer hardware info

Some game engines rely on the real hardware info to adjust default
graphics quality and other attributes.

Signed-off-by: Yiwei Zhang <zzyiwei@chromium.org>
Reviewed-by: Gert Wollny <gert.wollny@collabora.com>

src/virgl_hw.h

@@ -595,6 +595,7 @@ struct virgl_caps_v2 {
         struct virgl_supported_format_mask scanout;
         uint32_t capability_bits_v2;
         uint32_t max_video_memory;
+        char renderer[64];
 };
 
 union virgl_caps {

src/vrend_renderer.c

@@ -10210,13 +10210,17 @@ static void vrend_renderer_fill_caps_v2(int gl_ver, int gles_ver,  union virgl_c
    GLint max;
    GLfloat range[2];
    uint32_t video_memory;
+   const char *renderer = (const char *)glGetString(GL_RENDERER);
 
    /* Count this up when you add a feature flag that is used to set a CAP in
     * the guest that was set unconditionally before. Then check that flag and
     * this value to avoid regressions when a guest with a new mesa version is
     * run on an old virgl host. Use it also to indicate non-cap fixes on the
     * host that help enable features in the guest. */
-   caps->v2.host_feature_check_version = 4;
+   caps->v2.host_feature_check_version = 5;
+
+   /* Forward host GL_RENDERER to the guest. */
+   strncpy(caps->v2.renderer, renderer, sizeof(caps->v2.renderer) - 1);
 
    glGetFloatv(GL_ALIASED_POINT_SIZE_RANGE, range);
    caps->v2.min_aliased_point_size = range[0];
@@ -10475,7 +10479,6 @@ static void vrend_renderer_fill_caps_v2(int gl_ver, int gles_ver,  union virgl_c
 
    if (has_feature(feat_arb_buffer_storage) && !vrend_state.use_external_blob) {
       const char *vendor = (const char *)glGetString(GL_VENDOR);
-      const char *renderer = (const char*)glGetString(GL_RENDERER);
       bool is_mesa = ((strstr(renderer, "Mesa") != NULL) || (strstr(renderer, "DRM") != NULL));
       /*
        * Intel GPUs (aside from Atom, which doesn't expose GL4.5) are cache-coherent.