15.04.2024 12:34, Michael S. Tsirkin wrote:
From: Cindy Lu <l...@redhat.com>
During the booting process of the non-standard image, the behavior of the
called function in qemu is as follows:
1. vhost_net_stop() was triggered by guest image. This will call the function
virtio_pci_set_guest_notifiers() with assgin= false,
virtio_pci_set_guest_notifiers(） will release the irqfd for vector 0
2. virtio_reset() was triggered, this will set configure vector to
VIRTIO_NO_VECTOR
3.vhost_net_start() was called (at this time, the configure vector is
still VIRTIO_NO_VECTOR) and then call virtio_pci_set_guest_notifiers() with
assgin=true, so the irqfd for vector 0 is still not "init" during this process
4. The system continues to boot and sets the vector back to 0. After that
msix_fire_vector_notifier() was triggered to unmask the vector 0 and meet the
crash
To fix the issue, we need to support changing the vector after
VIRTIO_CONFIG_S_DRIVER_OK is set.
This change breaks both 9.0 and stable-8.2.3:
https://gitlab.com/qemu-project/qemu/-/issues/2321
https://gitlab.com/qemu-project/qemu/-/issues/2334
So something's not right here.
Thanks,
/mjt
...
MST: coding style and typo fixups
Fixes: f9a09ca3ea ("vhost: add support for configure interrupt")
Cc: qemu-sta...@nongnu.org
Signed-off-by: Cindy Lu <l...@redhat.com>
Message-Id: <20240412062750.475180-1-l...@redhat.com>
Reviewed-by: Michael S. Tsirkin <m...@redhat.com>
Signed-off-by: Michael S. Tsirkin <m...@redhat.com>
Signed-off-by: Michael S. Tsirkin <m...@redhat.com>
---
hw/virtio/virtio-pci.c | 37 +++++++++++++++++++++++++++++++++++--
1 file changed, 35 insertions(+), 2 deletions(-)
v7->v8:
more cleanups, suggested by Philip
still untested, i just got involved to help address coding style
issues
diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index cb6940fc0e..cb159fd078 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -1424,6 +1424,38 @@ static int virtio_pci_add_mem_cap(VirtIOPCIProxy *proxy,
return offset;
}
+static void virtio_pci_set_vector(VirtIODevice *vdev,
+ VirtIOPCIProxy *proxy,
+ int queue_no, uint16_t old_vector,
+ uint16_t new_vector)
+{
+ bool kvm_irqfd = (vdev->status & VIRTIO_CONFIG_S_DRIVER_OK) &&
+ msix_enabled(&proxy->pci_dev) && kvm_msi_via_irqfd_enabled();
+
+ if (new_vector == old_vector) {
+ return;
+ }
+
+ /*
+ * If the device uses irqfd and the vector changes after DRIVER_OK is
+ * set, we need to release the old vector and set up the new one.
+ * Otherwise just need to set the new vector on the device.
+ */
+ if (kvm_irqfd && old_vector != VIRTIO_NO_VECTOR) {
+ kvm_virtio_pci_vector_release_one(proxy, queue_no);
+ }
+ /* Set the new vector on the device. */
+ if (queue_no == VIRTIO_CONFIG_IRQ_IDX) {
+ vdev->config_vector = new_vector;
+ } else {
+ virtio_queue_set_vector(vdev, queue_no, new_vector);
+ }
+ /* If the new vector changed need to set it up. */
+ if (kvm_irqfd && new_vector != VIRTIO_NO_VECTOR) {
+ kvm_virtio_pci_vector_use_one(proxy, queue_no);
+ }
+}
+
int virtio_pci_add_shm_cap(VirtIOPCIProxy *proxy,
uint8_t bar, uint64_t offset, uint64_t length,
uint8_t id)
@@ -1570,7 +1602,8 @@ static void virtio_pci_common_write(void *opaque, hwaddr
addr,
} else {
val = VIRTIO_NO_VECTOR;
}
- vdev->config_vector = val;
+ virtio_pci_set_vector(vdev, proxy, VIRTIO_CONFIG_IRQ_IDX,
+ vdev->config_vector, val);
break;
case VIRTIO_PCI_COMMON_STATUS:
if (!(val & VIRTIO_CONFIG_S_DRIVER_OK)) {
@@ -1610,7 +1643,7 @@ static void virtio_pci_common_write(void *opaque, hwaddr
addr,
} else {
val = VIRTIO_NO_VECTOR;
}
- virtio_queue_set_vector(vdev, vdev->queue_sel, val);
+ virtio_pci_set_vector(vdev, proxy, vdev->queue_sel, vector, val);
break;
case VIRTIO_PCI_COMMON_Q_ENABLE:
if (val == 1) {
--
GPG Key transition (from rsa2048 to rsa4096) since 2024-04-24.
New key: rsa4096/61AD3D98ECDF2C8E 9D8B E14E 3F2A 9DD7 9199 28F1 61AD 3D98
ECDF 2C8E
Old key: rsa2048/457CE0A0804465C5 6EE1 95D1 886E 8FFB 810D 4324 457C E0A0
8044 65C5
Transition statement: http://www.corpit.ru/mjt/gpg-transition-2024.txt
