| Message ID | 20241230124445.1850997-6-lulu@redhat.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
| Series | vhost: Add support of kthread API | expand |
| Context | Check | Description |
|---|---|---|
| netdev/tree_selection | success | Not a local patch |
On Mon, Dec 30, 2024 at 8:45 PM Cindy Lu <lulu@redhat.com> 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@redhat.com> > --- > drivers/vhost/vhost.c | 22 +++++++++++++++++++++- > include/uapi/linux/vhost.h | 19 +++++++++++++++++++ > 2 files changed, 40 insertions(+), 1 deletion(-) > > diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c > index ff17c42e2d1a..47c1329360ac 100644 > --- a/drivers/vhost/vhost.c > +++ b/drivers/vhost/vhost.c > @@ -2250,15 +2250,35 @@ 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; > + u8 inherit_owner; > > /* If you are not the owner, you can become one */ > if (ioctl == VHOST_SET_OWNER) { > r = vhost_dev_set_owner(d); > goto done; > } > + if (ioctl == VHOST_SET_INHERIT_FROM_OWNER) { > + /*inherit_owner can only be modified before owner is set*/ > + if (vhost_dev_has_owner(d)) { > + r = -EBUSY; > + goto done; > + } > + if (copy_from_user(&inherit_owner, argp, sizeof(u8))) { > + r = -EFAULT; > + goto done; > + } Not a native speaker but I wonder if "VHOST_FORK_FROM_OWNER" is better or not. > + /* Validate the inherit_owner value, ensuring it is either 0 or 1 */ > + if (inherit_owner > 1) { > + r = -EINVAL; > + goto done; > + } > + > + d->inherit_owner = (bool)inherit_owner; So this allows userspace to reset the owner and toggle the value. This seems to be fine, but I wonder if we need to some cleanup in vhost_dev_reset_owner() or not. Let's explain this somewhere (probably in the commit log). > > + goto done; > + } > /* You must be the owner to do anything else */ > r = vhost_dev_check_owner(d); > if (r) > diff --git a/include/uapi/linux/vhost.h b/include/uapi/linux/vhost.h > index b95dd84eef2d..f5fcf0b25736 100644 > --- a/include/uapi/linux/vhost.h > +++ b/include/uapi/linux/vhost.h > @@ -235,4 +235,23 @@ > */ > #define VHOST_VDPA_GET_VRING_SIZE _IOWR(VHOST_VIRTIO, 0x82, \ > struct vhost_vring_state) > + > +/** > + * VHOST_SET_INHERIT_FROM_OWNER - Set the inherit_owner flag for the vhost device > + * > + * @param inherit_owner: An 8-bit value that determines the vhost thread mode > + * > + * When inherit_owner is set to 1 (default behavior): > + * - The VHOST worker threads inherit their values/checks from > + * the thread that owns the VHOST device. The vhost threads will > + * be counted in the nproc rlimits. > + * > + * When inherit_owner is set to 0: > + * - The VHOST worker threads will use the traditional kernel thread (kthread) > + * implementation, which may be preferred by older userspace applications that > + * do not utilize the newer vhost_task concept. > + */ > + > +#define VHOST_SET_INHERIT_FROM_OWNER _IOW(VHOST_VIRTIO, 0x83, __u8) > + > #endif > -- > 2.45.0 Thanks
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index ff17c42e2d1a..47c1329360ac 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -2250,15 +2250,35 @@ 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; + u8 inherit_owner; /* If you are not the owner, you can become one */ if (ioctl == VHOST_SET_OWNER) { r = vhost_dev_set_owner(d); goto done; } + if (ioctl == VHOST_SET_INHERIT_FROM_OWNER) { + /*inherit_owner can only be modified before owner is set*/ + if (vhost_dev_has_owner(d)) { + r = -EBUSY; + goto done; + } + if (copy_from_user(&inherit_owner, argp, sizeof(u8))) { + r = -EFAULT; + goto done; + } + /* Validate the inherit_owner value, ensuring it is either 0 or 1 */ + if (inherit_owner > 1) { + r = -EINVAL; + goto done; + } + + d->inherit_owner = (bool)inherit_owner; + goto done; + } /* You must be the owner to do anything else */ r = vhost_dev_check_owner(d); if (r) diff --git a/include/uapi/linux/vhost.h b/include/uapi/linux/vhost.h index b95dd84eef2d..f5fcf0b25736 100644 --- a/include/uapi/linux/vhost.h +++ b/include/uapi/linux/vhost.h @@ -235,4 +235,23 @@ */ #define VHOST_VDPA_GET_VRING_SIZE _IOWR(VHOST_VIRTIO, 0x82, \ struct vhost_vring_state) + +/** + * VHOST_SET_INHERIT_FROM_OWNER - Set the inherit_owner flag for the vhost device + * + * @param inherit_owner: An 8-bit value that determines the vhost thread mode + * + * When inherit_owner is set to 1 (default behavior): + * - The VHOST worker threads inherit their values/checks from + * the thread that owns the VHOST device. The vhost threads will + * be counted in the nproc rlimits. + * + * When inherit_owner is set to 0: + * - The VHOST worker threads will use the traditional kernel thread (kthread) + * implementation, which may be preferred by older userspace applications that + * do not utilize the newer vhost_task concept. + */ + +#define VHOST_SET_INHERIT_FROM_OWNER _IOW(VHOST_VIRTIO, 0x83, __u8) + #endif
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@redhat.com> --- drivers/vhost/vhost.c | 22 +++++++++++++++++++++- include/uapi/linux/vhost.h | 19 +++++++++++++++++++ 2 files changed, 40 insertions(+), 1 deletion(-)