On Fri, Oct 04, 2024 at 09:58:21AM GMT, Cindy Lu wrote:
Add a new UAPI to support setting the vhost device to
use task mode. The user space application needs to use
VHOST_SET_INHERIT_FROM_OWNER to set the mode.
This setting must be set before VHOST_SET_OWNER is set.
Why?
Signed-off-by: Cindy Lu <l...@redhat.com>
---
drivers/vhost/vhost.c | 18 +++++++++++++++++-
include/uapi/linux/vhost.h | 2 ++
2 files changed, 19 insertions(+), 1 deletion(-)
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 08c9e77916ca..0e5c81026acd 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -2341,8 +2341,24 @@ 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;
int i, fd;
+ bool inherit_owner;
^
This can be moved ...
+
+ if (ioctl == VHOST_SET_INHERIT_FROM_OWNER) {
^
... here.
+ /* Is there an owner already? */
This comment is superfluous, I would instead explain why there has to be
an owner, what problem would we have if not?
+ if (vhost_dev_has_owner(d)) {
+ r = -EBUSY;
+ goto done;
+ }
+ if (copy_from_user(&inherit_owner, argp,
+ sizeof(inherit_owner))) {
+ r = -EFAULT;
+ goto done;
+ }
+ enforce_inherit_owner = inherit_owner;
mmmm, I'm confused.
IIUC with this change, an user, for example, can call
VHOST_SET_INHERIT_FROM_OWNER on /dev/vhost-vsock and change the
behaviour of /dev/vhost-net.
Is that really what we want?
Maybe it's better if the module parameter controls the default of any
device, but the ioctl changes the behavior only for that device.
+ goto done;
+ }
/* If you are not the owner, you can become one */
if (ioctl == VHOST_SET_OWNER) {
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 documentation here.
+#define VHOST_SET_INHERIT_FROM_OWNER _IOW(VHOST_VIRTIO, 0x83, bool)
^
Please, add a tab like we did
for all previous definitions.
Thanks,
Stefano
