From a73b6522c41a7fab77417e1b471b79d2fcd29b92 Mon Sep 17 00:00:00 2001
From: Dylan Reid <dgreid@chromium.org>
Date: Wed, 6 Jan 2021 15:22:15 -0800
Subject: [PATCH] virtio: switch to accessor for msix config

Convert the pub member to private and provide an accessor.
Prevents the spread of poking in to a private member from vhost.

Change-Id: Ib2070e990dc91c532164cc83f5af72bfbc9b2e89
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/2795283
Tested-by: kokoro <noreply+kokoro@google.com>
Commit-Queue: Dylan Reid <dgreid@chromium.org>
Reviewed-by: Daniel Verkamp <dverkamp@chromium.org>
Reviewed-by: Keiichi Watanabe <keiichiw@chromium.org>
---
 devices/src/virtio/interrupt.rs          | 7 ++++++-
 devices/src/virtio/vhost/user/handler.rs | 8 ++++----
 devices/src/virtio/vhost/worker.rs       | 4 ++--
 3 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/devices/src/virtio/interrupt.rs b/devices/src/virtio/interrupt.rs
index 2ddff08f6e..dac8aaad0c 100644
--- a/devices/src/virtio/interrupt.rs
+++ b/devices/src/virtio/interrupt.rs
@@ -13,7 +13,7 @@ pub struct Interrupt {
     interrupt_status: Arc<AtomicUsize>,
     interrupt_evt: Event,
     interrupt_resample_evt: Event,
-    pub msix_config: Option<Arc<Mutex<MsixConfig>>>,
+    msix_config: Option<Arc<Mutex<MsixConfig>>>,
     config_msix_vector: u16,
 }
 
@@ -91,4 +91,9 @@ impl Interrupt {
     pub fn get_resample_evt(&self) -> &Event {
         &self.interrupt_resample_evt
     }
+
+    /// Get a reference to the msix configuration
+    pub fn get_msix_config(&self) -> &Option<Arc<Mutex<MsixConfig>>> {
+        &self.msix_config
+    }
 }
diff --git a/devices/src/virtio/vhost/user/handler.rs b/devices/src/virtio/vhost/user/handler.rs
index 14fdb16fcc..f3797ae8e4 100644
--- a/devices/src/virtio/vhost/user/handler.rs
+++ b/devices/src/virtio/vhost/user/handler.rs
@@ -173,11 +173,11 @@ impl VhostUserHandler {
             .set_vring_base(queue_index, 0)
             .map_err(Error::SetVringBase)?;
 
-        let msix_config = interrupt
-            .msix_config
+        let msix_config_opt = interrupt
+            .get_msix_config()
             .as_ref()
-            .ok_or(Error::MsixConfigUnavailable)?
-            .lock();
+            .ok_or(Error::MsixConfigUnavailable)?;
+        let msix_config = msix_config_opt.lock();
         let irqfd = msix_config
             .get_irqfd(queue.vector as usize)
             .ok_or(Error::MsixIrqfdUnavailable)?;
diff --git a/devices/src/virtio/vhost/worker.rs b/devices/src/virtio/vhost/worker.rs
index c166c933d4..225d880e12 100644
--- a/devices/src/virtio/vhost/worker.rs
+++ b/devices/src/virtio/vhost/worker.rs
@@ -199,7 +199,7 @@ impl<T: Vhost> Worker<T> {
         // with the msix. Due to this, cannot use the direct irq fd but
         // should fall back to indirect irq fd.
         if self.response_tube.is_some() {
-            if let Some(msix_config) = &self.interrupt.msix_config {
+            if let Some(msix_config) = self.interrupt.get_msix_config() {
                 let msix_config = msix_config.lock();
                 let msix_masked = msix_config.masked();
                 if msix_masked {
@@ -227,7 +227,7 @@ impl<T: Vhost> Worker<T> {
     }
 
     fn set_vring_calls(&self) -> Result<()> {
-        if let Some(msix_config) = &self.interrupt.msix_config {
+        if let Some(msix_config) = self.interrupt.get_msix_config() {
             let msix_config = msix_config.lock();
             if msix_config.masked() {
                 for (queue_index, _) in self.queues.iter().enumerate() {