We need set log when updating used flags and avail event. Otherwise guest may see stale values after migration and then do not exit or exit unexpectedly.
Signed-off-by: Jason Wang <[email protected]> --- drivers/vhost/vhost.c | 61 +++++++++++++++++++++++++++++++++++++++---------- 1 files changed, 48 insertions(+), 13 deletions(-) diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index 43a3fc6..c344d4f 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -578,16 +578,6 @@ static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m) return 0; } -int init_used(struct vhost_virtqueue *vq) -{ - int r = put_user(vq->used_flags, &vq->used->flags); - - if (r) - return r; - vq->signalled_used_valid = false; - return get_user(vq->last_used_idx, &vq->used->idx); -} - static long vhost_set_vring(struct vhost_dev *d, int ioctl, void __user *argp) { struct file *eventfp, *filep = NULL, @@ -954,6 +944,51 @@ int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log, return 0; } +static int vhost_update_used_flags(struct vhost_virtqueue *vq) +{ + if (put_user(vq->used_flags, &vq->used->flags) < 0) + return -EFAULT; + if (unlikely(vq->log_used)) { + /* Make sure the flag is seen before log. */ + smp_wmb(); + /* Log used flag write. */ + log_write(vq->log_base, + vq->log_addr + offsetof(struct vring_used, flags), + sizeof vq->used->flags); + if (vq->log_ctx) + eventfd_signal(vq->log_ctx, 1); + } + return 0; +} + +static int vhost_update_avail_event(struct vhost_virtqueue *vq, u16 avail_event) +{ + if (put_user(vq->avail_idx, vhost_avail_event(vq))) + return -EFAULT; + if (unlikely(vq->log_used)) { + /* Make sure the event is seen before log. */ + smp_wmb(); + /* Log avail event write */ + log_write(vq->log_base, + vq->log_addr + offsetof(struct vring_used, + ring[vq->num]), + sizeof avail_event); + if (vq->log_ctx) + eventfd_signal(vq->log_ctx, 1); + } + return 0; +} + +int init_used(struct vhost_virtqueue *vq) +{ + int r = vhost_update_used_flags(vq); + + if (r) + return r; + vq->signalled_used_valid = false; + return get_user(vq->last_used_idx, &vq->used->idx); +} + static int translate_desc(struct vhost_dev *dev, u64 addr, u32 len, struct iovec iov[], int iov_size) { @@ -1425,14 +1460,14 @@ bool vhost_enable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq) return false; vq->used_flags &= ~VRING_USED_F_NO_NOTIFY; if (!vhost_has_feature(dev, VIRTIO_RING_F_EVENT_IDX)) { - r = put_user(vq->used_flags, &vq->used->flags); + r = vhost_update_used_flags(vq); if (r) { vq_err(vq, "Failed to enable notification at %p: %d\n", &vq->used->flags, r); return false; } } else { - r = put_user(vq->avail_idx, vhost_avail_event(vq)); + r = vhost_update_avail_event(vq, vq->avail_idx); if (r) { vq_err(vq, "Failed to update avail event index at %p: %d\n", vhost_avail_event(vq), r); @@ -1475,7 +1510,7 @@ void vhost_disable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq) return; vq->used_flags |= VRING_USED_F_NO_NOTIFY; if (!vhost_has_feature(dev, VIRTIO_RING_F_EVENT_IDX)) { - r = put_user(vq->used_flags, &vq->used->flags); + r = vhost_update_used_flags(vq); if (r) vq_err(vq, "Failed to enable notification at %p: %d\n", &vq->used->flags, r); _______________________________________________ Virtualization mailing list [email protected] https://lists.linux-foundation.org/mailman/listinfo/virtualization
