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virtio_pci: harden MSI-X interrupts

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We used to synchronize pending MSI-X irq handlers via
synchronize_irq(), this may not work for the untrusted device which
may keep sending interrupts after reset which may lead unexpected
results. Similarly, we should not enable MSI-X interrupt until the
device is ready. So this patch fixes those two issues by:

1) switching to use disable_irq() to prevent the virtio interrupt
   handlers to be called after the device is reset.
2) using IRQF_NO_AUTOEN and enable the MSI-X irq during .ready()

This can make sure the virtio interrupt handler won't be called before
virtio_device_ready() and after reset.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Link: https://lore.kernel.org/r/20211019070152.8236-5-jasowang@redhat.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Jason Wang 2021-10-19 15:01:46 +08:00 • committed by Michael S. Tsirkin
parent d50497eb4e
commit 9e35276a53
4 changed files with 32 additions and 12 deletions
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27
drivers/virtio/virtio_pci_common.c
View file

@ -24,8 +24,8 @@ MODULE_PARM_DESC(force_legacy,
"Force legacy mode for transitional virtio 1 devices"); "Force legacy mode for transitional virtio 1 devices");
#endif #endif
/* wait for pending irq handlers */ /* disable irq handlers */
void vp_synchronize_vectors(struct virtio_device *vdev) void vp_disable_cbs(struct virtio_device *vdev)
{ {
struct virtio_pci_device *vp_dev = to_vp_device(vdev); struct virtio_pci_device *vp_dev = to_vp_device(vdev);
int i; int i;
@ -34,7 +34,20 @@ void vp_synchronize_vectors(struct virtio_device *vdev)
synchronize_irq(vp_dev->pci_dev->irq); synchronize_irq(vp_dev->pci_dev->irq);
for (i = 0; i < vp_dev->msix_vectors; ++i) for (i = 0; i < vp_dev->msix_vectors; ++i)
synchronize_irq(pci_irq_vector(vp_dev->pci_dev, i)); disable_irq(pci_irq_vector(vp_dev->pci_dev, i));
}
/* enable irq handlers */
void vp_enable_cbs(struct virtio_device *vdev)
{
struct virtio_pci_device *vp_dev = to_vp_device(vdev);
int i;
if (vp_dev->intx_enabled)
return;
for (i = 0; i < vp_dev->msix_vectors; ++i)
enable_irq(pci_irq_vector(vp_dev->pci_dev, i));
} }
/* the notify function used when creating a virt queue */ /* the notify function used when creating a virt queue */
@ -141,7 +154,8 @@ static int vp_request_msix_vectors(struct virtio_device *vdev, int nvectors,
snprintf(vp_dev->msix_names[v], sizeof *vp_dev->msix_names, snprintf(vp_dev->msix_names[v], sizeof *vp_dev->msix_names,
"%s-config", name); "%s-config", name);
err = request_irq(pci_irq_vector(vp_dev->pci_dev, v), err = request_irq(pci_irq_vector(vp_dev->pci_dev, v),
vp_config_changed, 0, vp_dev->msix_names[v], vp_config_changed, IRQF_NO_AUTOEN,
vp_dev->msix_names[v],
vp_dev); vp_dev);
if (err) if (err)
goto error; goto error;
@ -160,7 +174,8 @@ static int vp_request_msix_vectors(struct virtio_device *vdev, int nvectors,
snprintf(vp_dev->msix_names[v], sizeof *vp_dev->msix_names, snprintf(vp_dev->msix_names[v], sizeof *vp_dev->msix_names,
"%s-virtqueues", name); "%s-virtqueues", name);
err = request_irq(pci_irq_vector(vp_dev->pci_dev, v), err = request_irq(pci_irq_vector(vp_dev->pci_dev, v),
vp_vring_interrupt, 0, vp_dev->msix_names[v], vp_vring_interrupt, IRQF_NO_AUTOEN,
vp_dev->msix_names[v],
vp_dev); vp_dev);
if (err) if (err)
goto error; goto error;
@ -337,7 +352,7 @@ static int vp_find_vqs_msix(struct virtio_device *vdev, unsigned nvqs,
"%s-%s", "%s-%s",
dev_name(&vp_dev->vdev.dev), names[i]); dev_name(&vp_dev->vdev.dev), names[i]);
err = request_irq(pci_irq_vector(vp_dev->pci_dev, msix_vec), err = request_irq(pci_irq_vector(vp_dev->pci_dev, msix_vec),
vring_interrupt, 0, vring_interrupt, IRQF_NO_AUTOEN,
vp_dev->msix_names[msix_vec], vp_dev->msix_names[msix_vec],
vqs[i]); vqs[i]);
if (err) if (err)

6
drivers/virtio/virtio_pci_common.h
View file

@ -101,8 +101,10 @@ static struct virtio_pci_device *to_vp_device(struct virtio_device *vdev)
return container_of(vdev, struct virtio_pci_device, vdev); return container_of(vdev, struct virtio_pci_device, vdev);
} }
/* wait for pending irq handlers */ /* disable irq handlers */
void vp_synchronize_vectors(struct virtio_device *vdev); void vp_disable_cbs(struct virtio_device *vdev);
/* enable irq handlers */
void vp_enable_cbs(struct virtio_device *vdev);
/* the notify function used when creating a virt queue */ /* the notify function used when creating a virt queue */
bool vp_notify(struct virtqueue *vq); bool vp_notify(struct virtqueue *vq);
/* the config->del_vqs() implementation */ /* the config->del_vqs() implementation */

5
drivers/virtio/virtio_pci_legacy.c
View file

@ -98,8 +98,8 @@ static void vp_reset(struct virtio_device *vdev)
/* Flush out the status write, and flush in device writes, /* Flush out the status write, and flush in device writes,
* including MSi-X interrupts, if any. */ * including MSi-X interrupts, if any. */
vp_legacy_get_status(&vp_dev->ldev); vp_legacy_get_status(&vp_dev->ldev);
/* Flush pending VQ/configuration callbacks. */ /* Disable VQ/configuration callbacks. */
vp_synchronize_vectors(vdev); vp_disable_cbs(vdev);
} }
static u16 vp_config_vector(struct virtio_pci_device *vp_dev, u16 vector) static u16 vp_config_vector(struct virtio_pci_device *vp_dev, u16 vector)
@ -185,6 +185,7 @@ static void del_vq(struct virtio_pci_vq_info *info)
} }
static const struct virtio_config_ops virtio_pci_config_ops = { static const struct virtio_config_ops virtio_pci_config_ops = {
.enable_cbs = vp_enable_cbs,
.get = vp_get, .get = vp_get,
.set = vp_set, .set = vp_set,
.get_status = vp_get_status, .get_status = vp_get_status,

6
drivers/virtio/virtio_pci_modern.c
View file

@ -172,8 +172,8 @@ static void vp_reset(struct virtio_device *vdev)
*/ */
while (vp_modern_get_status(mdev)) while (vp_modern_get_status(mdev))
msleep(1); msleep(1);
/* Flush pending VQ/configuration callbacks. */ /* Disable VQ/configuration callbacks. */
vp_synchronize_vectors(vdev); vp_disable_cbs(vdev);
} }
static u16 vp_config_vector(struct virtio_pci_device *vp_dev, u16 vector) static u16 vp_config_vector(struct virtio_pci_device *vp_dev, u16 vector)
@ -380,6 +380,7 @@ static bool vp_get_shm_region(struct virtio_device *vdev,
} }
static const struct virtio_config_ops virtio_pci_config_nodev_ops = { static const struct virtio_config_ops virtio_pci_config_nodev_ops = {
.enable_cbs = vp_enable_cbs,
.get = NULL, .get = NULL,
.set = NULL, .set = NULL,
.generation = vp_generation, .generation = vp_generation,
@ -397,6 +398,7 @@ static const struct virtio_config_ops virtio_pci_config_nodev_ops = {
}; };
static const struct virtio_config_ops virtio_pci_config_ops = { static const struct virtio_config_ops virtio_pci_config_ops = {
.enable_cbs = vp_enable_cbs,
.get = vp_get, .get = vp_get,
.set = vp_set, .set = vp_set,
.generation = vp_generation, .generation = vp_generation,