On Tue, Aug 3, 2021 at 4:10 PM Jason Wang [off-list ref] wrote:

在 2021/7/29 下午3:34, Xie Yongji 写道:

quoted

Re-read the device status to ensure it's set to zero during
resetting. Otherwise, fail the vhost_vdpa_set_status() after timeout.

Signed-off-by: Xie Yongji <redacted>
---
  drivers/vhost/vdpa.c | 11 ++++++++++-
  1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index b07aa161f7ad..dd05c1e1133c 100644
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c

@@ -157,7 +157,7 @@ static long vhost_vdpa_set_status(struct vhost_vdpa *v, u8 __user *statusp)
      struct vdpa_device *vdpa = v->vdpa;
      const struct vdpa_config_ops *ops = vdpa->config;
      u8 status, status_old;
-     int nvqs = v->nvqs;
+     int timeout = 0, nvqs = v->nvqs;
      u16 i;

      if (copy_from_user(&status, statusp, sizeof(status)))

@@ -173,6 +173,15 @@ static long vhost_vdpa_set_status(struct vhost_vdpa *v, u8 __user *statusp)
              return -EINVAL;

      ops->set_status(vdpa, status);
+     if (status == 0) {
+             while (ops->get_status(vdpa)) {
+                     timeout += 20;
+                     if (timeout > VDPA_RESET_TIMEOUT_MS)
+                             return -EIO;
+
+                     msleep(20);
+             }

Spec has introduced the reset a one of the basic facility. And consider
we differ reset here.

This makes me think if it's better to introduce a dedicated vdpa ops for
reset?

Do you mean replace the ops.set_status(vdev, 0) with the ops.reset()?
Then we can remove the timeout processing which is device specific
stuff.

Thanks,
Yongji