devices: convert virtio features to a u64

The virtio specification only defines feature bits in the 0-63 range
currently, so we can represent the features as a u64.  The Linux kernel
makes the same simplifying assumption, and very few features have been
defined beyond the first 32 bits, so this is probably safe for a while.

This allows the device models to be simplified, since they no longer
need to deal with the features paging mechanism (it is handled by the
generic virtio transport code).

BUG=None
TEST=build_test; boot termina on kevin

Change-Id: I6fd86907b2bdf494466c205e85072ebfeb7f5b73
Signed-off-by: Daniel Verkamp <dverkamp@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/1313012
Commit-Ready: ChromeOS CL Exonerator Bot <chromiumos-cl-exonerator@appspot.gserviceaccount.com>
Reviewed-by: Dylan Reid <dgreid@chromium.org>
Reviewed-by: Zach Reizner <zachr@chromium.org>

1 files changed, 3 insertions, 9 deletions

diff --git a/devices/src/virtio/gpu/mod.rs b/devices/src/virtio/gpu/mod.rs
index 5ef90c9..5c1806b 100644
--- a/devices/src/virtio/gpu/mod.rs
+++ b/devices/src/virtio/gpu/mod.rs
@@ -632,17 +632,11 @@ impl VirtioDevice for Gpu {
         QUEUE_SIZES
     }
 
-    fn features(&self, page: u32) -> u32 {
-        let avail_features: u64 = 1 << VIRTIO_GPU_F_VIRGL | 1 << VIRTIO_F_VERSION_1;
-        match page {
-            0 => avail_features as u32,
-            1 => (avail_features >> 32) as u32,
-            _ => 0,
-        }
+    fn features(&self) -> u64 {
+        1 << VIRTIO_GPU_F_VIRGL | 1 << VIRTIO_F_VERSION_1
     }
 
-    fn ack_features(&mut self, page: u32, value: u32) {
-        let _ = page;
+    fn ack_features(&mut self, value: u64) {
         let _ = value;
     }