在 2022/7/1 14:31, Michael S. Tsirkin 写道:

On Wed, Jun 29, 2022 at 02:56:41PM +0800, Xuan Zhuo wrote:

quoted

This patch allows the new introduced
__virtqueue_break()/__virtqueue_unbreak() to break/unbreak the
virtqueue.

Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>

I wonder how this interacts with the hardening patches.
Jason?

Consider we've marked it as broken, I think we don't need to care about 
the hardening in this series. Just make it work without hardening.

And I will handle vq reset when rework the IRQ hardening.

Thanks

quoted

---
  drivers/virtio/virtio_ring.c | 24 ++++++++++++++++++++++++
  include/linux/virtio.h       |  3 +++
  2 files changed, 27 insertions(+)

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 5ec43607cc15..7b02be7fce67 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c

@@ -2744,6 +2744,30 @@ unsigned int virtqueue_get_vring_size(struct virtqueue *_vq)
  }
  EXPORT_SYMBOL_GPL(virtqueue_get_vring_size);
  
+/*
+ * This function should only be called by the core, not directly by the driver.
+ */
+void __virtqueue_break(struct virtqueue *_vq)
+{
+	struct vring_virtqueue *vq = to_vvq(_vq);
+
+	/* Pairs with READ_ONCE() in virtqueue_is_broken(). */
+	WRITE_ONCE(vq->broken, true);
+}
+EXPORT_SYMBOL_GPL(__virtqueue_break);
+
+/*
+ * This function should only be called by the core, not directly by the driver.
+ */
+void __virtqueue_unbreak(struct virtqueue *_vq)
+{
+	struct vring_virtqueue *vq = to_vvq(_vq);
+
+	/* Pairs with READ_ONCE() in virtqueue_is_broken(). */
+	WRITE_ONCE(vq->broken, false);
+}

I don't think these "Pairs" comments have any value.

quoted

+EXPORT_SYMBOL_GPL(__virtqueue_unbreak);
+
  bool virtqueue_is_broken(struct virtqueue *_vq)
  {
  	struct vring_virtqueue *vq = to_vvq(_vq);

diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index 1272566adec6..dc474a0d48d1 100644
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h

@@ -138,6 +138,9 @@ bool is_virtio_device(struct device *dev);
  void virtio_break_device(struct virtio_device *dev);
  void __virtio_unbreak_device(struct virtio_device *dev);
  
+void __virtqueue_break(struct virtqueue *_vq);
+void __virtqueue_unbreak(struct virtqueue *_vq);
+
  void virtio_config_changed(struct virtio_device *dev);
  #ifdef CONFIG_PM_SLEEP
  int virtio_device_freeze(struct virtio_device *dev);

-- 
2.31.0