virtio: Use spin_lock_irqsave/restore for virtio-pci
virtio-pci acquires its spin lock in an interrupt context so it's necessary
to use spin_lock_irqsave/restore variants. This patch fixes guest SMP when
using virtio devices in KVM.
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
diff --git a/drivers/virtio/virtio_pci.c b/drivers/virtio/virtio_pci.c
index 26f787d..59a8f73 100644
--- a/drivers/virtio/virtio_pci.c
+++ b/drivers/virtio/virtio_pci.c
@@ -177,6 +177,7 @@
struct virtio_pci_device *vp_dev = opaque;
struct virtio_pci_vq_info *info;
irqreturn_t ret = IRQ_NONE;
+ unsigned long flags;
u8 isr;
/* reading the ISR has the effect of also clearing it so it's very
@@ -197,12 +198,12 @@
drv->config_changed(&vp_dev->vdev);
}
- spin_lock(&vp_dev->lock);
+ spin_lock_irqsave(&vp_dev->lock, flags);
list_for_each_entry(info, &vp_dev->virtqueues, node) {
if (vring_interrupt(irq, info->vq) == IRQ_HANDLED)
ret = IRQ_HANDLED;
}
- spin_unlock(&vp_dev->lock);
+ spin_unlock_irqrestore(&vp_dev->lock, flags);
return ret;
}
@@ -214,6 +215,7 @@
struct virtio_pci_device *vp_dev = to_vp_device(vdev);
struct virtio_pci_vq_info *info;
struct virtqueue *vq;
+ unsigned long flags;
u16 num;
int err;
@@ -255,9 +257,9 @@
vq->priv = info;
info->vq = vq;
- spin_lock(&vp_dev->lock);
+ spin_lock_irqsave(&vp_dev->lock, flags);
list_add(&info->node, &vp_dev->virtqueues);
- spin_unlock(&vp_dev->lock);
+ spin_unlock_irqrestore(&vp_dev->lock, flags);
return vq;
@@ -274,10 +276,11 @@
{
struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev);
struct virtio_pci_vq_info *info = vq->priv;
+ unsigned long flags;
- spin_lock(&vp_dev->lock);
+ spin_lock_irqsave(&vp_dev->lock, flags);
list_del(&info->node);
- spin_unlock(&vp_dev->lock);
+ spin_unlock_irqrestore(&vp_dev->lock, flags);
vring_del_virtqueue(vq);