From 885950c2a4a65486524ac53e40f6b6515d7ebd3a Mon Sep 17 00:00:00 2001
From: Cautreoxit <huk@stu.pku.edu.cn>
Date: Thu, 14 Nov 2024 21:10:55 +0800
Subject: [PATCH] Add VirtioBlockFeature to cache virtio-blk's features

---
 kernel/comps/virtio/src/device/block/device.rs |  7 +++++--
 kernel/comps/virtio/src/device/block/mod.rs    | 13 +++++++++++++
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/kernel/comps/virtio/src/device/block/device.rs b/kernel/comps/virtio/src/device/block/device.rs
index 885453357..4d842dccb 100644
--- a/kernel/comps/virtio/src/device/block/device.rs
+++ b/kernel/comps/virtio/src/device/block/device.rs
@@ -19,7 +19,7 @@ use ostd::{
     Pod,
 };
 
-use super::{BlockFeatures, VirtioBlockConfig};
+use super::{BlockFeatures, VirtioBlockConfig, VirtioBlockFeature};
 use crate::{
     device::{
         block::{ReqType, RespStatus},
@@ -92,6 +92,7 @@ impl aster_block::BlockDevice for BlockDevice {
 #[derive(Debug)]
 struct DeviceInner {
     config: SafePtr<VirtioBlockConfig, IoMem>,
+    features: VirtioBlockFeature,
     queue: SpinLock<VirtQueue>,
     transport: SpinLock<Box<dyn VirtioTransport>>,
     block_requests: DmaStream,
@@ -122,6 +123,7 @@ impl DeviceInner {
                 "Not supporting Multi-Queue Block IO Queueing Mechanism, only using the first queue"
             );
         }
+        let features = VirtioBlockFeature::new(transport.as_ref());
         let queue = VirtQueue::new(0, Self::QUEUE_SIZE, transport.as_mut())
             .expect("create virtqueue failed");
         let block_requests = {
@@ -137,6 +139,7 @@ impl DeviceInner {
 
         let device = Arc::new(Self {
             config,
+            features,
             queue: SpinLock::new(queue),
             transport: SpinLock::new(transport),
             block_requests,
@@ -410,7 +413,7 @@ impl DeviceInner {
     /// Flushes any cached data from the guest to the persistent storage on the host.
     /// This will be ignored if the device doesn't support the `VIRTIO_BLK_F_FLUSH` feature.
     fn flush(&self, bio_request: BioRequest) {
-        if self.transport.lock().read_device_features() & BlockFeatures::FLUSH.bits() == 0 {
+        if self.features.support_flush {
             bio_request.bios().for_each(|bio| {
                 bio.complete(BioStatus::Complete);
             });
diff --git a/kernel/comps/virtio/src/device/block/mod.rs b/kernel/comps/virtio/src/device/block/mod.rs
index 31fbef271..36b157af3 100644
--- a/kernel/comps/virtio/src/device/block/mod.rs
+++ b/kernel/comps/virtio/src/device/block/mod.rs
@@ -111,6 +111,12 @@ pub struct VirtioBlockTopology {
     opt_io_size: u32,
 }
 
+#[derive(Debug, Copy, Clone)]
+#[repr(C)]
+pub struct VirtioBlockFeature {
+    support_flush: bool,
+}
+
 impl VirtioBlockConfig {
     pub(self) fn new(transport: &dyn VirtioTransport) -> SafePtr<Self, IoMem> {
         let memory = transport.device_config_memory();
@@ -135,3 +141,10 @@ impl VirtioBlockConfig {
             .map(|val| val as usize)
     }
 }
+
+impl VirtioBlockFeature {
+    pub(self) fn new(transport: &dyn VirtioTransport) -> Self {
+        let support_flush = transport.read_device_features() & BlockFeatures::FLUSH.bits() == 1;
+        VirtioBlockFeature { support_flush }
+    }
+}