On Fri, Aug 14, 2026 at 03:29:01PM +0800, Jia Jia wrote:
The device IOTLB is shared by vhost backends, but clearing it requires
dropping each virtqueue's IOTLB pointer and metadata cache before the
old table is freed. Add a common helper for this teardown sequence so
backend-specific feature code only needs to decide when the table must
be cleared.
The caller must hold the device mutex. The helper does not update
acked_features; backends continue to update that state in their own
virtqueue loops.
Signed-off-by: Jia Jia <[email protected]>
---
drivers/vhost/vhost.c | 24 ++++++++++++++++++++++++
drivers/vhost/vhost.h | 1 +
2 files changed, 25 insertions(+)
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 269efad90369..7eaa61d9ceeb 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -2283,6 +2283,30 @@ long vhost_vring_ioctl(struct vhost_dev *d, unsigned int
ioctl, void __user *argp)
}
EXPORT_SYMBOL_GPL(vhost_vring_ioctl);
+/* Caller must hold the device mutex. */
+void vhost_clear_device_iotlb(struct vhost_dev *d)
+{
+ struct vhost_iotlb *iotlb;
+ int i;
Should we move the check of `d->iotlb` here? so the callers doesn't need
to access to an internal details.
Stefano
+
+ iotlb = d->iotlb;
+ d->iotlb = NULL;
+
+ for (i = 0; i < d->nvqs; ++i) {
+ struct vhost_virtqueue *vq = d->vqs[i];
+
+ mutex_lock(&vq->mutex);
+ vq->iotlb = NULL;
+ __vhost_vq_meta_reset(vq);
+ mutex_unlock(&vq->mutex);
+ }
+
+ vhost_clear_msg(d);
+ vhost_iotlb_free(iotlb);
+ wake_up_interruptible_poll(&d->wait, EPOLLIN | EPOLLRDNORM);
+}
+EXPORT_SYMBOL_GPL(vhost_clear_device_iotlb);
+
int vhost_init_device_iotlb(struct vhost_dev *d)
{
struct vhost_iotlb *niotlb, *oiotlb;
diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
index 0192ade6e749..3c75e8089373 100644
--- a/drivers/vhost/vhost.h
+++ b/drivers/vhost/vhost.h
@@ -277,6 +277,7 @@ ssize_t vhost_chr_read_iter(struct vhost_dev *dev, struct
iov_iter *to,
int noblock);
ssize_t vhost_chr_write_iter(struct vhost_dev *dev,
struct iov_iter *from);
+void vhost_clear_device_iotlb(struct vhost_dev *d);
int vhost_init_device_iotlb(struct vhost_dev *d);
void vhost_iotlb_map_free(struct vhost_iotlb *iotlb,
--
2.34.1
