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Work around a QEMU bug in virtio console pasting

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This commit is contained in:
Ruihan Li
2024-07-06 22:36:13 +08:00
committed by Tate, Hongliang Tian
parent ceb0ef67e1
commit a465ec1346
1 changed files with 15 additions and 9 deletions
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24
kernel/comps/virtio/src/device/console/device.rs
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@ -106,14 +106,7 @@ impl ConsoleDevice {
callbacks: RwLock::new(Vec::new()), callbacks: RwLock::new(Vec::new()),
}); });
let mut receive_queue = device.receive_queue.lock_irq_disabled(); device.activate_receive_buffer(&mut device.receive_queue.lock_irq_disabled());
receive_queue
.add_dma_buf(&[], &[&device.receive_buffer])
.unwrap();
if receive_queue.should_notify() {
receive_queue.notify();
}
drop(receive_queue);
// Register irq callbacks // Register irq callbacks
let mut transport = device.transport.lock_irq_disabled(); let mut transport = device.transport.lock_irq_disabled();
@ -149,9 +142,22 @@ impl ConsoleDevice {
let reader = self.receive_buffer.reader().unwrap().limit(len as usize); let reader = self.receive_buffer.reader().unwrap().limit(len as usize);
callback(reader); callback(reader);
} }
self.activate_receive_buffer(&mut receive_queue);
}
fn activate_receive_buffer(&self, receive_queue: &mut VirtQueue) {
receive_queue receive_queue
.add_dma_buf(&[], &[&self.receive_buffer]) // We limit the buffer length to one to work around a QEMU bug that causes incorrect
// results when pasting more than 32 bytes into the virtio console. This has no
// performance penalty, since QEMU always gets one byte at a time, regardless of
// whether we have this limit or not.
//
// For the QEMU bug, see details at
// <https://lore.kernel.org/qemu-devel/20240707111940.232549-3-lrh2000@pku.edu.cn/T/#u>.
.add_dma_buf(&[], &[&DmaStreamSlice::new(&self.receive_buffer, 0, 1)])
.unwrap(); .unwrap();
if receive_queue.should_notify() { if receive_queue.should_notify() {
receive_queue.notify(); receive_queue.notify();
} }