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// Copyright 2019 The Chromium OS Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
use super::{INTERRUPT_STATUS_CONFIG_CHANGED, INTERRUPT_STATUS_USED_RING, VIRTIO_MSI_NO_VECTOR};
use crate::pci::MsixConfig;
use std::sync::atomic::{AtomicUsize, Ordering};
use std::sync::Arc;
use sync::Mutex;
use sys_util::EventFd;
pub struct Interrupt {
interrupt_status: Arc<AtomicUsize>,
interrupt_evt: EventFd,
interrupt_resample_evt: EventFd,
msix_config: Option<Arc<Mutex<MsixConfig>>>,
config_msix_vector: u16,
}
impl Interrupt {
pub fn new(
interrupt_status: Arc<AtomicUsize>,
interrupt_evt: EventFd,
interrupt_resample_evt: EventFd,
msix_config: Option<Arc<Mutex<MsixConfig>>>,
config_msix_vector: u16,
) -> Interrupt {
Interrupt {
interrupt_status,
interrupt_evt,
interrupt_resample_evt,
msix_config,
config_msix_vector,
}
}
/// Virtqueue Interrupts From The Device
///
/// If MSI-X is enabled in this device, MSI-X interrupt is preferred.
/// Write to the irqfd to VMM to deliver virtual interrupt to the guest
fn signal(&self, vector: u16, interrupt_status_mask: u32) {
// Don't need to set ISR for MSI-X interrupts
if let Some(msix_config) = &self.msix_config {
let mut msix_config = msix_config.lock();
if msix_config.enabled() {
if vector != VIRTIO_MSI_NO_VECTOR {
msix_config.trigger(vector);
}
return;
}
}
// Set bit in ISR and inject the interrupt if it was not already pending.
// Don't need to inject the interrupt if the guest hasn't processed it.
if self
.interrupt_status
.fetch_or(interrupt_status_mask as usize, Ordering::SeqCst)
== 0
{
// Write to irqfd to inject INTx interrupt
self.interrupt_evt.write(1).unwrap();
}
}
/// Notify the driver that buffers have been placed in the used queue.
pub fn signal_used_queue(&self, vector: u16) {
self.signal(vector, INTERRUPT_STATUS_USED_RING)
}
/// Notify the driver that the device configuration has changed.
pub fn signal_config_changed(&self) {
self.signal(self.config_msix_vector, INTERRUPT_STATUS_CONFIG_CHANGED)
}
/// Handle interrupt resampling event
pub fn interrupt_resample(&self) {
let _ = self.interrupt_resample_evt.read();
if self.interrupt_status.load(Ordering::SeqCst) != 0 {
self.interrupt_evt.write(1).unwrap();
}
}
/// Return the reference of interrupt_resample_evt
/// To keep the interface clean, this member is private.
pub fn get_resample_evt(&self) -> &EventFd {
&self.interrupt_resample_evt
}
}
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