diff options
| -rw-r--r-- | drivers/s390/virtio/virtio_ccw.c | 4 | ||||
| -rw-r--r-- | drivers/virtio/virtio.c | 15 | ||||
| -rw-r--r-- | drivers/virtio/virtio_mmio.c | 5 | ||||
| -rw-r--r-- | drivers/virtio/virtio_pci_modern_dev.c | 5 | ||||
| -rw-r--r-- | drivers/virtio/virtio_ring.c | 11 | ||||
| -rw-r--r-- | include/linux/virtio_config.h | 20 |
6 files changed, 53 insertions, 7 deletions
diff --git a/drivers/s390/virtio/virtio_ccw.c b/drivers/s390/virtio/virtio_ccw.c index c188e4f20ca3..97e51c34e6cf 100644 --- a/drivers/s390/virtio/virtio_ccw.c +++ b/drivers/s390/virtio/virtio_ccw.c @@ -971,6 +971,10 @@ static void virtio_ccw_set_status(struct virtio_device *vdev, u8 status) ccw->flags = 0; ccw->count = sizeof(status); ccw->cda = (__u32)(unsigned long)&vcdev->dma_area->status; + /* We use ssch for setting the status which is a serializing + * instruction that guarantees the memory writes have + * completed before ssch. + */ ret = ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_WRITE_STATUS); /* Write failed? We assume status is unchanged. */ if (ret) diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c index aa1eb5132767..95fac4c97c8b 100644 --- a/drivers/virtio/virtio.c +++ b/drivers/virtio/virtio.c @@ -220,6 +220,15 @@ static int virtio_features_ok(struct virtio_device *dev) * */ void virtio_reset_device(struct virtio_device *dev) { + /* + * The below virtio_synchronize_cbs() guarantees that any + * interrupt for this line arriving after + * virtio_synchronize_vqs() has completed is guaranteed to see + * vq->broken as true. + */ + virtio_break_device(dev); + virtio_synchronize_cbs(dev); + dev->config->reset(dev); } EXPORT_SYMBOL_GPL(virtio_reset_device); @@ -428,6 +437,9 @@ int register_virtio_device(struct virtio_device *dev) dev->config_enabled = false; dev->config_change_pending = false; + INIT_LIST_HEAD(&dev->vqs); + spin_lock_init(&dev->vqs_list_lock); + /* We always start by resetting the device, in case a previous * driver messed it up. This also tests that code path a little. */ virtio_reset_device(dev); @@ -435,9 +447,6 @@ int register_virtio_device(struct virtio_device *dev) /* Acknowledge that we've seen the device. */ virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE); - INIT_LIST_HEAD(&dev->vqs); - spin_lock_init(&dev->vqs_list_lock); - /* * device_add() causes the bus infrastructure to look for a matching * driver. diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c index c9699a59f93c..f9a36bc7ac27 100644 --- a/drivers/virtio/virtio_mmio.c +++ b/drivers/virtio/virtio_mmio.c @@ -253,6 +253,11 @@ static void vm_set_status(struct virtio_device *vdev, u8 status) /* We should never be setting status to 0. */ BUG_ON(status == 0); + /* + * Per memory-barriers.txt, wmb() is not needed to guarantee + * that the the cache coherent memory writes have completed + * before writing to the MMIO region. + */ writel(status, vm_dev->base + VIRTIO_MMIO_STATUS); } diff --git a/drivers/virtio/virtio_pci_modern_dev.c b/drivers/virtio/virtio_pci_modern_dev.c index 4093f9cca7a6..a0fa14f28a7f 100644 --- a/drivers/virtio/virtio_pci_modern_dev.c +++ b/drivers/virtio/virtio_pci_modern_dev.c @@ -467,6 +467,11 @@ void vp_modern_set_status(struct virtio_pci_modern_device *mdev, { struct virtio_pci_common_cfg __iomem *cfg = mdev->common; + /* + * Per memory-barriers.txt, wmb() is not needed to guarantee + * that the the cache coherent memory writes have completed + * before writing to the MMIO region. + */ vp_iowrite8(status, &cfg->device_status); } EXPORT_SYMBOL_GPL(vp_modern_set_status); diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index 9c231e1fded7..13a7348cedff 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -1688,7 +1688,7 @@ static struct virtqueue *vring_create_virtqueue_packed( vq->we_own_ring = true; vq->notify = notify; vq->weak_barriers = weak_barriers; - vq->broken = false; + vq->broken = true; vq->last_used_idx = 0; vq->event_triggered = false; vq->num_added = 0; @@ -2134,8 +2134,11 @@ irqreturn_t vring_interrupt(int irq, void *_vq) return IRQ_NONE; } - if (unlikely(vq->broken)) - return IRQ_HANDLED; + if (unlikely(vq->broken)) { + dev_warn_once(&vq->vq.vdev->dev, + "virtio vring IRQ raised before DRIVER_OK"); + return IRQ_NONE; + } /* Just a hint for performance: so it's ok that this can be racy! */ if (vq->event) @@ -2177,7 +2180,7 @@ struct virtqueue *__vring_new_virtqueue(unsigned int index, vq->we_own_ring = false; vq->notify = notify; vq->weak_barriers = weak_barriers; - vq->broken = false; + vq->broken = true; vq->last_used_idx = 0; vq->event_triggered = false; vq->num_added = 0; diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h index 25be018810a7..d4edfd7d91bb 100644 --- a/include/linux/virtio_config.h +++ b/include/linux/virtio_config.h @@ -256,6 +256,26 @@ void virtio_device_ready(struct virtio_device *dev) unsigned status = dev->config->get_status(dev); BUG_ON(status & VIRTIO_CONFIG_S_DRIVER_OK); + + /* + * The virtio_synchronize_cbs() makes sure vring_interrupt() + * will see the driver specific setup if it sees vq->broken + * as false (even if the notifications come before DRIVER_OK). + */ + virtio_synchronize_cbs(dev); + __virtio_unbreak_device(dev); + /* + * The transport should ensure the visibility of vq->broken + * before setting DRIVER_OK. See the comments for the transport + * specific set_status() method. + * + * A well behaved device will only notify a virtqueue after + * DRIVER_OK, this means the device should "see" the coherenct + * memory write that set vq->broken as false which is done by + * the driver when it sees DRIVER_OK, then the following + * driver's vring_interrupt() will see vq->broken as false so + * we won't lose any notification. + */ dev->config->set_status(dev, status | VIRTIO_CONFIG_S_DRIVER_OK); } |