venus: add a new debug option to revive memory budget support

Signed-off-by: Yiwei Zhang <zzyiwei@chromium.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/33992>

src/virtio/vulkan/vn_common.c

@@ -34,6 +34,7 @@ static const struct debug_control vn_debug_options[] = {
    { "no_gpl", VN_DEBUG_NO_GPL },
    { "no_second_queue", VN_DEBUG_NO_SECOND_QUEUE },
    { "no_ray_tracing", VN_DEBUG_NO_RAY_TRACING },
+   { "mem_budget", VN_DEBUG_MEM_BUDGET },
    { NULL, 0 },
    /* clang-format on */
 };

src/virtio/vulkan/vn_common.h

@@ -114,6 +114,7 @@ enum vn_debug {
    VN_DEBUG_NO_GPL = 1ull << 8,
    VN_DEBUG_NO_SECOND_QUEUE = 1ull << 9,
    VN_DEBUG_NO_RAY_TRACING = 1ull << 10,
+   VN_DEBUG_MEM_BUDGET = 1ull << 11,
 };
 
 enum vn_perf {

src/virtio/vulkan/vn_physical_device.c

@@ -1303,8 +1303,7 @@ vn_physical_device_get_passthrough_extensions(
       .EXT_legacy_vertex_attributes = true,
       .EXT_line_rasterization = true,
       .EXT_load_store_op_none = true,
-      /* TODO: re-enable after generic app compat issues are resolved */
-      .EXT_memory_budget = false,
+      .EXT_memory_budget = VN_DEBUG(MEM_BUDGET),
       .EXT_multi_draw = true,
       .EXT_mutable_descriptor_type = true,
       .EXT_nested_command_buffer = true,