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 | 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;
int i, fd;
+ bool inherit_owner;
/* If you are not the owner, you can become one */
if (ioctl == VHOST_SET_OWNER) {
@@ -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))
+ break;
+
+ 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)
+
+#define VHOST_SET_INHERIT_FROM_OWNER _IOW(VHOST_VIRTIO, 0x83, bool)
#endif
--
2.45.0On 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@redhat.com>
> ---
> 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;
> int i, fd;
> + bool inherit_owner;
>
> /* If you are not the owner, you can become one */
> if (ioctl == VHOST_SET_OWNER) {
> @@ -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*/
bad coding style
> + if (vhost_dev_has_owner(d))
> + break;
is this silently failing? should return EBUSY or something like this.
> +
> + if (copy_from_user(&inherit_owner, argp,
> + sizeof(inherit_owner))) {
not good,
> + r = -EFAULT;
> + break;
> + }
> + d->inherit_owner = inherit_owner;
> + break;
> default:
> r = -ENOIOCTLCMD;
> break;
This means any task can break out of jail
and steal root group system time by setting inherit_owner to 0
even if system is configured to inherit by default.
we need a modparam to block this.
> 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)
> +
> +#define VHOST_SET_INHERIT_FROM_OWNER _IOW(VHOST_VIRTIO, 0x83, bool)
do not put bool in interfaces. something like u8 and validate it is 0 or
1.
> #endif
> --
> 2.45.0
On Tue, Nov 05, 2024 at 03:25:26PM +0800, Cindy Lu wrote: > 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) > + > +#define VHOST_SET_INHERIT_FROM_OWNER _IOW(VHOST_VIRTIO, 0x83, bool) set with no get is also not great. > #endif > -- > 2.45.0
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@redhat.com>
>---
> 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
>
On Tue, Nov 5, 2024 at 6:32 PM Stefano Garzarella <sgarzare@redhat.com> wrote:
>
> 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@redhat.com>
> >---
> > 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?
>
r = 0 mean return successfully here.
Therefore, in the case VHOST_SET_INHERIT_FROM_OWNER function, I don't
need to set it again and can simply return.
....
if (vhost_dev_has_owner(d))
break;
.....
> >@@ -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.
>
Yes, in the function beginning, the code is
if (ioctl == VHOST_SET_OWNER) {
r = vhost_dev_set_owner(d);
goto done;
}
if the ioctl is not VHOST_SET_OWNER, then the code will not run the
function vhost_dev_set_owner.
This ioctl is used by userspace applications, so we cannot be certain
of the type and sequence of their calls; therefore, I added this
check.
> >+ break;
>
> Should we return an error (e.g. -EPERM) in this case?
>
sure，will add this back
thanks
Cindy
> >+
> >+ 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
> >
>
On Thu, Nov 07, 2024 at 03:12:49PM +0800, Cindy Lu wrote:
>On Tue, Nov 5, 2024 at 6:32 PM Stefano Garzarella <sgarzare@redhat.com> wrote:
>>
>> 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@redhat.com>
>> >---
>> > 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?
>>
>r = 0 mean return successfully here.
>Therefore, in the case VHOST_SET_INHERIT_FROM_OWNER function, I don't
>need to set it again and can simply return.
>....
> if (vhost_dev_has_owner(d))
> break;
>.....
Okay, but vhost_dev_check_owner() already set it to 0, so we can avoid
that, no?
>> >@@ -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.
>>
>Yes, in the function beginning, the code is
>if (ioctl == VHOST_SET_OWNER) {
>r = vhost_dev_set_owner(d);
>goto done;
>}
>if the ioctl is not VHOST_SET_OWNER, then the code will not run the
>function vhost_dev_set_owner.
Sorry, I meant vhost_dev_check_owner(), not vhost_dev_set_owner().
I'll try to explain again.
After applying this series we have this code:
long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp)
{
struct eventfd_ctx *ctx;
u64 p;
long r = 0;
int i, fd;
bool 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;
}
/* You must be the owner to do anything else */
r = vhost_dev_check_owner(d);
if (r)
goto done;
switch (ioctl) {
...
case VHOST_SET_INHERIT_FROM_OWNER:
/*inherit_owner can only be modified before owner is
* set*/
if (vhost_dev_has_owner(d))
break;
IIUC this check is always true, so we always call `break` because at
the beginning of this function we call vhost_dev_check_owner() which
if `dev->mm != current->mm` (so it can't be null I guess) jumps directly
into `done`, returning an error.
So I still don't understand in which condition we can run the code after
this check.
Thanks,
Stefano
if (copy_from_user(&inherit_owner, argp,
sizeof(inherit_owner))) {
r = -EFAULT;
break;
}
d->inherit_owner = inherit_owner;
break;
>This ioctl is used by userspace applications, so we cannot be certain
>of the type and sequence of their calls; therefore, I added this
>check.
>
>> >+ break;
>>
>> Should we return an error (e.g. -EPERM) in this case?
>>
>sure，will add this back
>thanks
>Cindy
>> >+
>> >+ 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
>> >
>>
>
On Thu, Nov 7, 2024 at 6:03 PM Stefano Garzarella <sgarzare@redhat.com> wrote:
>
> On Thu, Nov 07, 2024 at 03:12:49PM +0800, Cindy Lu wrote:
> >On Tue, Nov 5, 2024 at 6:32 PM Stefano Garzarella <sgarzare@redhat.com> wrote:
> >>
> >> 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@redhat.com>
> >> >---
> >> > 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?
> >>
> >r = 0 mean return successfully here.
> >Therefore, in the case VHOST_SET_INHERIT_FROM_OWNER function, I don't
> >need to set it again and can simply return.
> >....
> > if (vhost_dev_has_owner(d))
> > break;
> >.....
>
> Okay, but vhost_dev_check_owner() already set it to 0, so we can avoid
> that, no?
>
> >> >@@ -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.
> >>
> >Yes, in the function beginning, the code is
> >if (ioctl == VHOST_SET_OWNER) {
> >r = vhost_dev_set_owner(d);
> >goto done;
> >}
> >if the ioctl is not VHOST_SET_OWNER, then the code will not run the
> >function vhost_dev_set_owner.
>
> Sorry, I meant vhost_dev_check_owner(), not vhost_dev_set_owner().
>
> I'll try to explain again.
>
> After applying this series we have this code:
>
> long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp)
> {
> struct eventfd_ctx *ctx;
> u64 p;
> long r = 0;
> int i, fd;
> bool 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;
> }
>
> /* You must be the owner to do anything else */
> r = vhost_dev_check_owner(d);
> if (r)
> goto done;
>
> switch (ioctl) {
> ...
> case VHOST_SET_INHERIT_FROM_OWNER:
> /*inherit_owner can only be modified before owner is
> * set*/
> if (vhost_dev_has_owner(d))
> break;
>
> IIUC this check is always true, so we always call `break` because at
> the beginning of this function we call vhost_dev_check_owner() which
> if `dev->mm != current->mm` (so it can't be null I guess) jumps directly
> into `done`, returning an error.
>
> So I still don't understand in which condition we can run the code after
> this check.
>
oh sorry I missed that check. I will move the new case back to the top
of function,
I didn't think it through before making this change; I just wanted to
clean up the code but forgot about the status.
Thanks
cindy
> Thanks,
> Stefano
>
> if (copy_from_user(&inherit_owner, argp,
> sizeof(inherit_owner))) {
> r = -EFAULT;
> break;
> }
> d->inherit_owner = inherit_owner;
> break;
>
>
> >This ioctl is used by userspace applications, so we cannot be certain
> >of the type and sequence of their calls; therefore, I added this
> >check.
> >
> >> >+ break;
> >>
> >> Should we return an error (e.g. -EPERM) in this case?
> >>
> >sure，will add this back
> >thanks
> >Cindy
> >> >+
> >> >+ 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
> >> >
> >>
> >
>
On Tue, Nov 5, 2024 at 3:28 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 | 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;
> int i, fd;
> + bool inherit_owner;
>
> /* If you are not the owner, you can become one */
> if (ioctl == VHOST_SET_OWNER) {
> @@ -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))
> + break;
> +
> + if (copy_from_user(&inherit_owner, argp,
> + sizeof(inherit_owner))) {
> + r = -EFAULT;
> + break;
> + }
> + d->inherit_owner = inherit_owner;
> + break;
Is there any case that we need to switch from owner back to kthread?
If not I would choose a more simplified API that is just
VHOST_INHERIT_OWNER.
> 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)
> +
> +#define VHOST_SET_INHERIT_FROM_OWNER _IOW(VHOST_VIRTIO, 0x83, bool)
> #endif
> --
> 2.45.0
Thanks
>
On 11/5/24 3:39 AM, Jason Wang wrote:
> On Tue, Nov 5, 2024 at 3:28 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 | 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;
>> int i, fd;
>> + bool inherit_owner;
>>
>> /* If you are not the owner, you can become one */
>> if (ioctl == VHOST_SET_OWNER) {
>> @@ -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))
>> + break;
>> +
>> + if (copy_from_user(&inherit_owner, argp,
>> + sizeof(inherit_owner))) {
>> + r = -EFAULT;
>> + break;
>> + }
>> + d->inherit_owner = inherit_owner;
>> + break;
>
> Is there any case that we need to switch from owner back to kthread?
> If not I would choose a more simplified API that is just
> VHOST_INHERIT_OWNER.
I can't think of any need to be able to switch back and forth for
general use.
However for this patchset, I think in patch 9/9 we set the default as:
inherit_owner_default = true
so the default is to use vhost_tasks.
With that code, we would need VHOST_SET_INHERIT_FROM_OWNER so userspace
can set the kernel to use kthreads.
I'm not sure if in the past emails it was resolved what the default would
be.
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