rutabaga_gfx: Query cachability from minigbm

Drop the hack hard-coding cachability based on driver name, and replace
with querying from minigbm.  This allows other drivers to use cached
minigbm/gralloc allocated buffers in cases where it is beneficial (such
as with sw encoders)

BUG=b:239718180, b:306548532
TEST=cts-tradefed run cts -m CtsVideoTestCases -t android.video.cts.VideoEncoderDecoderTest#testAvcGoog0Perf0320x0240
     no artifact in Camera FOV Calibration of CtsVerifier on rex

Change-Id: I854e2f00b993310716f64a3c568ed8c6f2665469
Reviewed-on: https://chromium-review.googlesource.com/c/crosvm/crosvm/+/3780218
Reviewed-by: Dawn Han <dawnhan@google.com>
Reviewed-by: Ryan Neph <ryanneph@google.com>
Reviewed-by: Yiwei Zhang <zzyiwei@chromium.org>
Reviewed-by: Daniel Verkamp <dverkamp@chromium.org>
Commit-Queue: Chia-I Wu <olv@google.com>

rutabaga_gfx/src/rutabaga_gralloc/minigbm.rs

@@ -8,13 +8,11 @@
 
 #![cfg(feature = "minigbm")]
 
-use std::ffi::CStr;
 use std::fs::File;
 use std::io::Error;
 use std::io::Seek;
 use std::io::SeekFrom;
 use std::os::fd::FromRawFd;
-use std::os::raw::c_char;
 use std::sync::Arc;
 
 use crate::rutabaga_gralloc::formats::DrmFormat;
@@ -52,7 +50,6 @@ impl Drop for MinigbmDeviceInner {
 pub struct MinigbmDevice {
     minigbm_device: Arc<MinigbmDeviceInner>,
     last_buffer: Option<Arc<MinigbmBuffer>>,
-    device_name: &'static str,
 }
 
 impl MinigbmDevice {
@@ -60,7 +57,6 @@ impl MinigbmDevice {
     /// the minigbm library.
     pub fn init() -> RutabagaResult<Box<dyn Gralloc>> {
         let descriptor: File;
-        let device_name: &str;
         let gbm: *mut gbm_device;
         // SAFETY:
         // Safe because minigbm_create_default_device is safe to call with an unused fd,
@@ -76,22 +72,12 @@ impl MinigbmDevice {
             descriptor = File::from_raw_fd(fd);
         }
 
-        // SAFETY:
-        // Safe because the string returned by gbm_device_get_backend_name() exists at least
-        // as long as the associated gbm_device.
-        unsafe {
-            let backend_name: *const c_char = gbm_device_get_backend_name(gbm);
-            let c_str: &CStr = CStr::from_ptr(backend_name);
-            device_name = c_str.to_str()?;
-        }
-
         Ok(Box::new(MinigbmDevice {
             minigbm_device: Arc::new(MinigbmDeviceInner {
                 _fd: descriptor,
                 gbm,
             }),
             last_buffer: None,
-            device_name,
         }))
     }
 }
@@ -127,11 +113,7 @@ impl Gralloc for MinigbmDevice {
         let mut reqs: ImageMemoryRequirements = Default::default();
         let gbm_buffer = MinigbmBuffer(bo, self.clone());
 
-        // Intel GPUs typically only use cached memory buffers.  This will change with dGPUs, but
-        // perhaps minigbm will be deprecated by then.  Other display drivers (rockchip, mediatek,
-        // amdgpu) typically use write combine memory.  We can also consider use flags too if this
-        // heuristic proves insufficient.
-        if self.device_name == "i915" {
+        if gbm_buffer.cached() {
             reqs.map_info = RUTABAGA_MAP_CACHE_CACHED;
         } else {
             reqs.map_info = RUTABAGA_MAP_CACHE_WC;
@@ -261,6 +243,14 @@ impl MinigbmBuffer {
         unsafe { gbm_bo_get_stride_for_plane(self.0, plane) }
     }
 
+    /// Should buffer use cached mapping to guest
+    pub fn cached(&self) -> bool {
+        // SAFETY:
+        // This is always safe to call with a valid gbm_bo pointer.
+        let mode = unsafe { gbm_bo_get_map_info(self.0) };
+        mode == gbm_bo_map_cache_mode::GBM_BO_MAP_CACHE_CACHED
+    }
+
     /// Exports a new dmabuf/prime file descriptor.
     pub fn export(&self) -> RutabagaResult<File> {
         // SAFETY:

rutabaga_gfx/src/rutabaga_gralloc/minigbm_bindings.rs

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// Generated with bindgen --allowlist-function='gbm_.*' --allowlist-type='gbm_.*' minigbm/gbm.h
+// Generated with bindgen --default-enum-style=rust --allowlist-function='gbm_.*' --allowlist-type='gbm_.*' minigbm/gbm.h
 // Then modified manually
 
 #![cfg(feature = "minigbm")]
@@ -149,6 +149,21 @@ pub type gbm_bo_transfer_flags = u32;
 extern "C" {
     pub fn gbm_bo_unmap(bo: *mut gbm_bo, map_data: *mut c_void);
 }
+#[repr(u32)]
+#[doc = " Enum to indicate the cache attributes of CPU mapping returned by"]
+#[doc = " gbm_bo_map()"]
+#[doc = ""]
+#[doc = " Note that definition aligns with VIRTIO_GPU_MAP_CACHE_*, RUTABAGA_MAP_CACHE_*,"]
+#[doc = " and VIRGL_RENDERER_MAP_CACHE_* (but skipping the _NONE and _UNCACHED values as"]
+#[doc = " those don't actually make sense to use)."]
+#[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
+pub enum gbm_bo_map_cache_mode {
+    GBM_BO_MAP_CACHE_CACHED = 1,
+    GBM_BO_MAP_CACHE_WC = 3,
+}
+extern "C" {
+    pub fn gbm_bo_get_map_info(bo: *mut gbm_bo) -> gbm_bo_map_cache_mode;
+}
 extern "C" {
     pub fn gbm_bo_get_width(bo: *mut gbm_bo) -> u32;
 }

third_party/minigbm

@@ -1 +1 @@
-Subproject commit 90b2d4773273b3ea180aff8f995d58e7b7604eb5
+Subproject commit e701ddbf02a6d590586f813a2ee9a132cfc1ea40