On Tue, Nov 05, 2024 at 03:25:26PM +0800, Cindy Lu wrote:
Add a new UAPI to enable setting the vhost device to task mode.
The userspace application can use VHOST_SET_INHERIT_FROM_OWNER
to configure the mode if necessary.
This setting must be applied before VHOST_SET_OWNER, as the worker
will be created in the VHOST_SET_OWNER function
Signed-off-by: Cindy Lu <lulu@xxxxxxxxxx>
---
drivers/vhost/vhost.c | 15 ++++++++++++++-
include/uapi/linux/vhost.h | 2 ++
2 files changed, 16 insertions(+), 1 deletion(-)
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index c17dc01febcc..70c793b63905 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -2274,8 +2274,9 @@ long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp)
{
struct eventfd_ctx *ctx;
u64 p;
- long r;
+ long r = 0;
I don't know if something is missing in this patch, but I am confused:
`r` is set few lines below...
int i, fd;
+ bool inherit_owner;
/* If you are not the owner, you can become one */
if (ioctl == VHOST_SET_OWNER) {
...
/* You must be the owner to do anything else */
r = vhost_dev_check_owner(d);
if (r)
goto done;
So, why we are now initializing it to 0?
@@ -2332,6 +2333,18 @@ long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp)
if (ctx)
eventfd_ctx_put(ctx);
break;
+ case VHOST_SET_INHERIT_FROM_OWNER:
+ /*inherit_owner can only be modified before owner is set*/
+ if (vhost_dev_has_owner(d))
And here, how this check can be false, if at the beginning of the
function we call vhost_dev_check_owner()?
Maybe your intention was to add this code before the
`vhost_dev_check_owner()` call, so this should explain why initialize
`r` to 0, but I'm not sure.
+ break;
Should we return an error (e.g. -EPERM) in this case?
+
+ if (copy_from_user(&inherit_owner, argp,
+ sizeof(inherit_owner))) {
+ r = -EFAULT;
+ break;
+ }
+ d->inherit_owner = inherit_owner;
+ break;
default:
r = -ENOIOCTLCMD;
break;
diff --git a/include/uapi/linux/vhost.h b/include/uapi/linux/vhost.h
index b95dd84eef2d..1e192038633d 100644
--- a/include/uapi/linux/vhost.h
+++ b/include/uapi/linux/vhost.h
@@ -235,4 +235,6 @@
*/
#define VHOST_VDPA_GET_VRING_SIZE _IOWR(VHOST_VIRTIO, 0x82, \
struct vhost_vring_state)
+
Please add a documentation here, this is UAPI, so the user should
know what this ioctl does based on the parameter.
Thanks,
Stefano
+#define VHOST_SET_INHERIT_FROM_OWNER _IOW(VHOST_VIRTIO, 0x83, bool)
#endif
--
2.45.0
