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virtio-devices: vmm: Signal NEEDS_RESET on activation failure

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When the guest writes DRIVER_OK and the device fails to activate, the
VMM previously bubbled the error up via VirtioActivate and never
released the activation barrier, leaving the vCPU that wrote DRIVER_OK
blocked on the barrier and effectively deadlocking the guest.

Per virtio 1.3 section 2.1.2, a device that has experienced an error
it cannot recover from should set DEVICE_NEEDS_RESET in its status and
notify the driver via a configuration change interrupt. Do that on
activation failure through the existing mark_device_needs_reset
helper, then release the activation barrier so the vCPU can resume.

DeviceManager::activate_virtio_devices now logs and continues instead
of aborting the whole pending list, so one failing device does not
take down the VMM or block pause and migration. The activator has
already reported the failure with the device id.

Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
This commit is contained in:
Anatol Belski
2026-05-26 16:19:46 +02:00
committed by Rob Bradford
parent d92e1ea77b
commit 2d2931a76e
2 changed files with 24 additions and 19 deletions
Download Patch File Download Diff File Expand all files Collapse all files

30
virtio-devices/src/transport/pci_device.rs
View File

@@ -40,9 +40,9 @@ use vmm_sys_util::eventfd::EventFd;
use super::pci_common_config::VirtioPciCommonConfigState;
use crate::transport::{VIRTIO_PCI_COMMON_CONFIG_ID, VirtioPciCommonConfig, VirtioTransport};
use crate::{
ActivateResult, DEVICE_ACKNOWLEDGE, DEVICE_DRIVER, DEVICE_DRIVER_OK, DEVICE_FAILED,
DEVICE_FEATURES_OK, DEVICE_INIT, GuestMemoryMmap, VirtioDevice, VirtioDeviceType,
VirtioInterrupt, VirtioInterruptType,
ActivateResult, ActivationContext, DEVICE_ACKNOWLEDGE, DEVICE_DRIVER, DEVICE_DRIVER_OK,
DEVICE_FAILED, DEVICE_FEATURES_OK, DEVICE_INIT, GuestMemoryMmap, VirtioDevice,
VirtioDeviceType, VirtioInterrupt, VirtioInterruptType, mark_device_needs_reset,
};
/// Vector value used to disable MSI for a queue.
@@ -331,22 +331,32 @@ pub struct VirtioPciDeviceActivator {
impl VirtioPciDeviceActivator {
pub fn activate(mut self) -> ActivateResult {
let mut locked_device = self.device.lock().unwrap();
locked_device.activate(crate::device::ActivationContext {
let result = self.device.lock().unwrap().activate(ActivationContext {
mem: self.memory.take().unwrap(),
interrupt_cb: self.interrupt,
interrupt_cb: self.interrupt.clone(),
queues: self.queues.take().unwrap(),
device_status: self.status,
})?;
self.device_activated.store(true, Ordering::SeqCst);
device_status: self.status.clone(),
});
if let Err(e) = &result {
mark_device_needs_reset(
&self.status,
self.interrupt.as_ref(),
format_args!("{}: virtio device activation failed: {e:?}", self.id),
);
} else {
self.device_activated.store(true, Ordering::SeqCst);
}
// Release the barrier regardless of outcome. A failing activate()
// would otherwise deadlock the vCPU that wrote DRIVER_OK.
if let Some(barrier) = self.barrier.take() {
info!("{}: Waiting for barrier", self.id);
barrier.wait();
info!("{}: Barrier released", self.id);
}
Ok(())
result
}
}