| Message ID | 20241105072642.898710-8-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 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 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 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 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 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.
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
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(-)