devices: virtio: enable MSI-X for all devices

All virtio devices can use the same generic calculation for number of
MSI-X vectors required: number of queues plus one for configuration
changes.  Move this calculation to the VirtioPciDevice implementation
and remove the Option to unconditionally enable MSI-X support for all
PCI virtio devices.

BUG=chromium:854765
TEST=Verify all virtio interrupts in /proc/interrupts are PCI-MSI

Change-Id: I5905ab52840e7617b0b342ec6ca3f75dccd16e4d
Signed-off-by: Daniel Verkamp <dverkamp@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/1925169
Reviewed-by: Zide Chen <zide.chen@intel.com>
Reviewed-by: Dylan Reid <dgreid@chromium.org>
Tested-by: kokoro <noreply+kokoro@google.com>

2 files changed, 2 insertions, 12 deletions

diff --git a/devices/src/virtio/vhost/net.rs b/devices/src/virtio/vhost/net.rs
index 5834aa7..2082a0f 100644
--- a/devices/src/virtio/vhost/net.rs
+++ b/devices/src/virtio/vhost/net.rs
@@ -21,7 +21,6 @@ use crate::virtio::{Interrupt, Queue, VirtioDevice, TYPE_NET};
 const QUEUE_SIZE: u16 = 256;
 const NUM_QUEUES: usize = 2;
 const QUEUE_SIZES: &[u16] = &[QUEUE_SIZE; NUM_QUEUES];
-const NUM_MSIX_VECTORS: u16 = NUM_QUEUES as u16;
 
 pub struct Net<T: TapT, U: VhostNetT<T>> {
     workers_kill_evt: Option<EventFd>,
@@ -82,7 +81,7 @@ where
             | 1 << virtio_sys::vhost::VIRTIO_F_VERSION_1;
 
         let mut vhost_interrupt = Vec::new();
-        for _ in 0..NUM_MSIX_VECTORS {
+        for _ in 0..NUM_QUEUES {
             vhost_interrupt.push(EventFd::new().map_err(Error::VhostIrqCreate)?);
         }
 
@@ -150,10 +149,6 @@ where
         TYPE_NET
     }
 
-    fn msix_vectors(&self) -> u16 {
-        NUM_MSIX_VECTORS
-    }
-
     fn queue_max_sizes(&self) -> &[u16] {
         QUEUE_SIZES
     }
diff --git a/devices/src/virtio/vhost/vsock.rs b/devices/src/virtio/vhost/vsock.rs
index 231e134..32f2c99 100644
--- a/devices/src/virtio/vhost/vsock.rs
+++ b/devices/src/virtio/vhost/vsock.rs
@@ -17,7 +17,6 @@ use crate::virtio::{copy_config, Interrupt, Queue, VirtioDevice, TYPE_VSOCK};
 const QUEUE_SIZE: u16 = 256;
 const NUM_QUEUES: usize = 3;
 const QUEUE_SIZES: &[u16] = &[QUEUE_SIZE; NUM_QUEUES];
-const NUM_MSIX_VECTORS: u16 = NUM_QUEUES as u16;
 
 pub struct Vsock {
     worker_kill_evt: Option<EventFd>,
@@ -43,7 +42,7 @@ impl Vsock {
             | 1 << virtio_sys::vhost::VIRTIO_F_VERSION_1;
 
         let mut interrupts = Vec::new();
-        for _ in 0..NUM_MSIX_VECTORS {
+        for _ in 0..NUM_QUEUES {
             interrupts.push(EventFd::new().map_err(Error::VhostIrqCreate)?);
         }
 
@@ -112,10 +111,6 @@ impl VirtioDevice for Vsock {
         TYPE_VSOCK
     }
 
-    fn msix_vectors(&self) -> u16 {
-        NUM_MSIX_VECTORS
-    }
-
     fn queue_max_sizes(&self) -> &[u16] {
         QUEUE_SIZES
     }