diff options
| author | Jason Wang | 2021-10-19 15:01:47 +0800 |
|---|---|---|
| committer | Michael S. Tsirkin | 2021-11-01 05:26:48 -0400 |
| commit | 080cd7c3ac8701081d143a15ba17dd9475313188 (patch) | |
| tree | 4f05ff73855daeacdd2bad9098b1c9ee4a22e9b2 /drivers/virtio | |
| parent | 9e35276a5344f74d4a3600fc4100b3dd251d5c56 (diff) | |
virtio-pci: harden INTX interrupts
This patch tries to make sure the virtio interrupt handler for INTX
won't be called after a reset and before virtio_device_ready(). We
can't use IRQF_NO_AUTOEN since we're using shared interrupt
(IRQF_SHARED). So this patch tracks the INTX enabling status in a new
intx_soft_enabled variable and toggle it during in
vp_disable/enable_vectors(). The INTX interrupt handler will check
intx_soft_enabled before processing the actual interrupt.
Cc: Boqun Feng <boqun.feng@gmail.com>
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/20211019070152.8236-6-jasowang@redhat.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Diffstat (limited to 'drivers/virtio')
| -rw-r--r-- | drivers/virtio/virtio_pci_common.c | 23 | ||||
| -rw-r--r-- | drivers/virtio/virtio_pci_common.h | 1 |
2 files changed, 22 insertions, 2 deletions
diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio_pci_common.c index 3f51fdb7be45..fdbde1db5ec5 100644 --- a/drivers/virtio/virtio_pci_common.c +++ b/drivers/virtio/virtio_pci_common.c @@ -30,8 +30,16 @@ void vp_disable_cbs(struct virtio_device *vdev) struct virtio_pci_device *vp_dev = to_vp_device(vdev); int i; - if (vp_dev->intx_enabled) + if (vp_dev->intx_enabled) { + /* + * The below synchronize() guarantees that any + * interrupt for this line arriving after + * synchronize_irq() has completed is guaranteed to see + * intx_soft_enabled == false. + */ + WRITE_ONCE(vp_dev->intx_soft_enabled, false); synchronize_irq(vp_dev->pci_dev->irq); + } for (i = 0; i < vp_dev->msix_vectors; ++i) disable_irq(pci_irq_vector(vp_dev->pci_dev, i)); @@ -43,8 +51,16 @@ 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) + if (vp_dev->intx_enabled) { + disable_irq(vp_dev->pci_dev->irq); + /* + * The above disable_irq() provides TSO ordering and + * as such promotes the below store to store-release. + */ + WRITE_ONCE(vp_dev->intx_soft_enabled, true); + enable_irq(vp_dev->pci_dev->irq); return; + } for (i = 0; i < vp_dev->msix_vectors; ++i) enable_irq(pci_irq_vector(vp_dev->pci_dev, i)); @@ -97,6 +113,9 @@ static irqreturn_t vp_interrupt(int irq, void *opaque) struct virtio_pci_device *vp_dev = opaque; u8 isr; + if (!READ_ONCE(vp_dev->intx_soft_enabled)) + return IRQ_NONE; + /* reading the ISR has the effect of also clearing it so it's very * important to save off the value. */ isr = ioread8(vp_dev->isr); diff --git a/drivers/virtio/virtio_pci_common.h b/drivers/virtio/virtio_pci_common.h index d3c6f72c7390..23f6c5c678d5 100644 --- a/drivers/virtio/virtio_pci_common.h +++ b/drivers/virtio/virtio_pci_common.h @@ -63,6 +63,7 @@ struct virtio_pci_device { /* MSI-X support */ int msix_enabled; int intx_enabled; + bool intx_soft_enabled; cpumask_var_t *msix_affinity_masks; /* Name strings for interrupts. This size should be enough, * and I'm too lazy to allocate each name separately. */ |