vhost-device-gpu: Make Adapter new() return Result

Change all GPU adapter new() methods to return
io::Result<Self>. This allows callers to decide
how to handle initialization failures.

Signed-off-by: Dorinda Bassey <dbassey@redhat.com>

vhost-device-gpu/src/backend/gfxstream.rs

@@ -7,7 +7,7 @@
 use std::{
     cell::RefCell,
     collections::BTreeMap,
-    io::IoSliceMut,
+    io::{self, IoSliceMut},
     os::{fd::FromRawFd, raw::c_void},
     sync::{Arc, Mutex},
 };
@@ -103,7 +103,11 @@ pub struct GfxstreamAdapter {
 }
 
 impl GfxstreamAdapter {
-    pub fn new(queue_ctl: &VringRwLock, gpu_config: &GpuConfig, gpu_backend: GpuBackend) -> Self {
+    pub fn new(
+        queue_ctl: &VringRwLock,
+        gpu_config: &GpuConfig,
+        gpu_backend: GpuBackend,
+    ) -> io::Result<Self> {
         let fence_state = Arc::new(Mutex::new(FenceState::default()));
         let fence = Self::create_fence_handler(queue_ctl.clone(), fence_state.clone());
 
@@ -116,12 +120,12 @@ impl GfxstreamAdapter {
             }
         });
 
-        Self {
+        Ok(Self {
             gpu_backend,
             fence_state,
             resources: BTreeMap::new(),
             scanouts: Default::default(),
-        }
+        })
     }
 
     fn create_fence_handler(

vhost-device-gpu/src/backend/null.rs

@@ -3,6 +3,8 @@
 //
 // SPDX-License-Identifier: Apache-2.0 or BSD-3-Clause
 
+use std::io;
+
 use log::trace;
 use rutabaga_gfx::RutabagaFence;
 use vhost::vhost_user::{
@@ -28,11 +30,11 @@ impl NullAdapter {
         _queue_ctl: &vhost_user_backend::VringRwLock,
         _config: &GpuConfig,
         gpu_backend: GpuBackend,
-    ) -> Self {
+    ) -> io::Result<Self> {
         trace!("NullAdapter created");
-        Self {
+        Ok(Self {
             _gpu_backend: gpu_backend,
-        }
+        })
     }
 }
 
@@ -264,7 +266,7 @@ mod tests {
         let vring = VringRwLock::new(mem, 0x100).unwrap();
         let config = GpuConfig::new(GpuMode::Null, None, GpuFlags::default()).unwrap();
 
-        NullAdapter::new(&vring, &config, gpu_backend)
+        NullAdapter::new(&vring, &config, gpu_backend).unwrap()
     }
 
     #[test]

vhost-device-gpu/src/backend/virgl.rs

@@ -6,7 +6,7 @@
 
 use std::{
     collections::BTreeMap,
-    io::IoSliceMut,
+    io::{self, IoSliceMut},
     os::fd::{AsFd, FromRawFd, IntoRawFd, RawFd},
     sync::{Arc, Mutex},
 };
@@ -142,7 +142,11 @@ pub struct VirglRendererAdapter {
 }
 
 impl VirglRendererAdapter {
-    pub fn new(queue_ctl: &VringRwLock, config: &GpuConfig, gpu_backend: GpuBackend) -> Self {
+    pub fn new(
+        queue_ctl: &VringRwLock,
+        config: &GpuConfig,
+        gpu_backend: GpuBackend,
+    ) -> io::Result<Self> {
         let virglrenderer_flags = VirglRendererFlags::new()
             .use_virgl(true)
             .use_venus(true)
@@ -161,14 +165,14 @@ impl VirglRendererAdapter {
 
         let renderer = VirglRenderer::init(virglrenderer_flags, fence_handler, None)
             .expect("Failed to initialize virglrenderer");
-        Self {
+        Ok(Self {
             renderer,
             gpu_backend,
             fence_state,
             resources: BTreeMap::new(),
             contexts: BTreeMap::new(),
             scanouts: Default::default(),
-        }
+        })
     }
 }
 
@@ -758,7 +762,7 @@ mod virgl_cov_tests {
                 create_vring(&mem, &[] as &[TestingDescChainArgs], GuestAddress(0x2000), GuestAddress(0x4000), 64);
 
             let backend = dummy_gpu_backend();
-            let mut gpu = VirglRendererAdapter::new(&vring, &cfg, backend);
+            let mut gpu = VirglRendererAdapter::new(&vring, &cfg, backend).unwrap();
 
             gpu.event_poll();
             let edid_req = VhostUserGpuEdidRequest {

vhost-device-gpu/src/device.rs

@@ -24,7 +24,7 @@ macro_rules! handle_adapter {
                     // Pass $vrings to the call
                     let (control_vring, gpu_backend) = $self.extract_backend_and_vring($vrings)?;
 
-                    let renderer = $new_adapter(control_vring, gpu_backend);
+                    let renderer = $new_adapter(control_vring, gpu_backend)?;
 
                     event_poll_fd = renderer.get_event_poll_fd();
                     maybe_renderer.insert(renderer)