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[PATCH v8 8/8] vhost: Add a KConfig knob to enable IOCTL VHOST_FORK_FROM_OWNER

Cindy Lu posted 8 patches 8 months, 3 weeks ago
There is a newer version of this series
[PATCH v8 8/8] vhost: Add a KConfig knob to enable IOCTL VHOST_FORK_FROM_OWNER
Posted by Cindy Lu 8 months, 3 weeks ago 
Introduce a new config knob `CONFIG_VHOST_ENABLE_FORK_OWNER_IOCTL`,
to control the availability of the `VHOST_FORK_FROM_OWNER` ioctl.
When CONFIG_VHOST_ENABLE_FORK_OWNER_IOCTL is set to n, the ioctl
is disabled, and any attempt to use it will result in failure.

Signed-off-by: Cindy Lu <lulu@redhat.com>
---
 drivers/vhost/Kconfig | 15 +++++++++++++++
 drivers/vhost/vhost.c |  3 +++
 2 files changed, 18 insertions(+)

diff --git a/drivers/vhost/Kconfig b/drivers/vhost/Kconfig
index b455d9ab6f3d..e5b9dcbf31b6 100644
--- a/drivers/vhost/Kconfig
+++ b/drivers/vhost/Kconfig
@@ -95,3 +95,18 @@ config VHOST_CROSS_ENDIAN_LEGACY
 	  If unsure, say "N".
 
 endif
+
+config VHOST_ENABLE_FORK_OWNER_IOCTL
+	bool "Enable IOCTL VHOST_FORK_FROM_OWNER"
+	default n
+	help
+	  This option enables the IOCTL VHOST_FORK_FROM_OWNER, which allows
+	  userspace applications to modify the thread mode for vhost devices.
+
+          By default, `CONFIG_VHOST_ENABLE_FORK_OWNER_IOCTL` is set to `n`,
+          meaning the ioctl is disabled and any operation using this ioctl
+          will fail.
+          When the configuration is enabled (y), the ioctl becomes
+          available, allowing users to set the mode if needed.
+
+	  If unsure, say "N".
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index fb0c7fb43f78..568e43cb54a9 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -2294,6 +2294,8 @@ long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp)
 		r = vhost_dev_set_owner(d);
 		goto done;
 	}
+
+#ifdef CONFIG_VHOST_ENABLE_FORK_OWNER_IOCTL
 	if (ioctl == VHOST_FORK_FROM_OWNER) {
 		u8 inherit_owner;
 		/*inherit_owner can only be modified before owner is set*/
@@ -2313,6 +2315,7 @@ long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp)
 		r = 0;
 		goto done;
 	}
+#endif
 	/* You must be the owner to do anything else */
 	r = vhost_dev_check_owner(d);
 	if (r)
-- 
2.45.0
Re: [PATCH v8 8/8] vhost: Add a KConfig knob to enable IOCTL VHOST_FORK_FROM_OWNER
Posted by Michael S. Tsirkin 8 months, 2 weeks ago 
On Fri, Mar 28, 2025 at 06:02:52PM +0800, Cindy Lu wrote:
> Introduce a new config knob `CONFIG_VHOST_ENABLE_FORK_OWNER_IOCTL`,
> to control the availability of the `VHOST_FORK_FROM_OWNER` ioctl.
> When CONFIG_VHOST_ENABLE_FORK_OWNER_IOCTL is set to n, the ioctl
> is disabled, and any attempt to use it will result in failure.
> 
> Signed-off-by: Cindy Lu <lulu@redhat.com>
> ---
>  drivers/vhost/Kconfig | 15 +++++++++++++++
>  drivers/vhost/vhost.c |  3 +++
>  2 files changed, 18 insertions(+)
> 
> diff --git a/drivers/vhost/Kconfig b/drivers/vhost/Kconfig
> index b455d9ab6f3d..e5b9dcbf31b6 100644
> --- a/drivers/vhost/Kconfig
> +++ b/drivers/vhost/Kconfig
> @@ -95,3 +95,18 @@ config VHOST_CROSS_ENDIAN_LEGACY
>  	  If unsure, say "N".
>  
>  endif
> +
> +config VHOST_ENABLE_FORK_OWNER_IOCTL
> +	bool "Enable IOCTL VHOST_FORK_FROM_OWNER"
> +	default n
> +	help
> +	  This option enables the IOCTL VHOST_FORK_FROM_OWNER, which allows
> +	  userspace applications to modify the thread mode for vhost devices.

ok

> +          By default, `CONFIG_VHOST_ENABLE_FORK_OWNER_IOCTL` is set to `n`,
> +          meaning the ioctl is disabled and any operation using this ioctl
> +          will fail.
> +          When the configuration is enabled (y), the ioctl becomes
> +          available, allowing users to set the mode if needed.

no need to be so verbose - the disabled beavious belongs in commit log
not here.

Also either ioctl or IOCTL but not both.

> +
> +	  If unsure, say "N".
> diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
> index fb0c7fb43f78..568e43cb54a9 100644
> --- a/drivers/vhost/vhost.c
> +++ b/drivers/vhost/vhost.c
> @@ -2294,6 +2294,8 @@ long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp)
>  		r = vhost_dev_set_owner(d);
>  		goto done;
>  	}
> +
> +#ifdef CONFIG_VHOST_ENABLE_FORK_OWNER_IOCTL
>  	if (ioctl == VHOST_FORK_FROM_OWNER) {
>  		u8 inherit_owner;
>  		/*inherit_owner can only be modified before owner is set*/
> @@ -2313,6 +2315,7 @@ long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp)
>  		r = 0;
>  		goto done;
>  	}
> +#endif
>  	/* You must be the owner to do anything else */
>  	r = vhost_dev_check_owner(d);
>  	if (r)
> -- 
> 2.45.0
Re: [PATCH v8 8/8] vhost: Add a KConfig knob to enable IOCTL VHOST_FORK_FROM_OWNER
Posted by Cindy Lu 8 months, 2 weeks ago 
On Tue, Apr 8, 2025 at 7:56 PM Michael S. Tsirkin <mst@redhat.com> wrote:
>
> On Fri, Mar 28, 2025 at 06:02:52PM +0800, Cindy Lu wrote:
> > Introduce a new config knob `CONFIG_VHOST_ENABLE_FORK_OWNER_IOCTL`,
> > to control the availability of the `VHOST_FORK_FROM_OWNER` ioctl.
> > When CONFIG_VHOST_ENABLE_FORK_OWNER_IOCTL is set to n, the ioctl
> > is disabled, and any attempt to use it will result in failure.
> >
> > Signed-off-by: Cindy Lu <lulu@redhat.com>
> > ---
> >  drivers/vhost/Kconfig | 15 +++++++++++++++
> >  drivers/vhost/vhost.c |  3 +++
> >  2 files changed, 18 insertions(+)
> >
> > diff --git a/drivers/vhost/Kconfig b/drivers/vhost/Kconfig
> > index b455d9ab6f3d..e5b9dcbf31b6 100644
> > --- a/drivers/vhost/Kconfig
> > +++ b/drivers/vhost/Kconfig
> > @@ -95,3 +95,18 @@ config VHOST_CROSS_ENDIAN_LEGACY
> >         If unsure, say "N".
> >
> >  endif
> > +
> > +config VHOST_ENABLE_FORK_OWNER_IOCTL
> > +     bool "Enable IOCTL VHOST_FORK_FROM_OWNER"
> > +     default n
> > +     help
> > +       This option enables the IOCTL VHOST_FORK_FROM_OWNER, which allows
> > +       userspace applications to modify the thread mode for vhost devices.
>
> ok
>
> > +          By default, `CONFIG_VHOST_ENABLE_FORK_OWNER_IOCTL` is set to `n`,
> > +          meaning the ioctl is disabled and any operation using this ioctl
> > +          will fail.
> > +          When the configuration is enabled (y), the ioctl becomes
> > +          available, allowing users to set the mode if needed.
>
> no need to be so verbose - the disabled beavious belongs in commit log
> not here.
>
> Also either ioctl or IOCTL but not both.
>
sure, will change this
Thanks
cindy
> > +
> > +       If unsure, say "N".
> > diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
> > index fb0c7fb43f78..568e43cb54a9 100644
> > --- a/drivers/vhost/vhost.c
> > +++ b/drivers/vhost/vhost.c
> > @@ -2294,6 +2294,8 @@ long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp)
> >               r = vhost_dev_set_owner(d);
> >               goto done;
> >       }
> > +
> > +#ifdef CONFIG_VHOST_ENABLE_FORK_OWNER_IOCTL
> >       if (ioctl == VHOST_FORK_FROM_OWNER) {
> >               u8 inherit_owner;
> >               /*inherit_owner can only be modified before owner is set*/
> > @@ -2313,6 +2315,7 @@ long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp)
> >               r = 0;
> >               goto done;
> >       }
> > +#endif
> >       /* You must be the owner to do anything else */
> >       r = vhost_dev_check_owner(d);
> >       if (r)
> > --
> > 2.45.0
>
Re: [PATCH v8 8/8] vhost: Add a KConfig knob to enable IOCTL VHOST_FORK_FROM_OWNER
Posted by Stefano Garzarella 8 months, 3 weeks ago 
On Fri, Mar 28, 2025 at 06:02:52PM +0800, Cindy Lu wrote:
>Introduce a new config knob `CONFIG_VHOST_ENABLE_FORK_OWNER_IOCTL`,
>to control the availability of the `VHOST_FORK_FROM_OWNER` ioctl.
>When CONFIG_VHOST_ENABLE_FORK_OWNER_IOCTL is set to n, the ioctl
>is disabled, and any attempt to use it will result in failure.
>
>Signed-off-by: Cindy Lu <lulu@redhat.com>
>---
> drivers/vhost/Kconfig | 15 +++++++++++++++
> drivers/vhost/vhost.c |  3 +++
> 2 files changed, 18 insertions(+)

IMHO this patch should be squashed with "[PATCH v8 6/8] vhost: uapi to
control task mode (owner vs kthread)".

It might break the bisection to support an ioctl, and after a few
commits enable or disable it depending on a kernel configuration.

>
>diff --git a/drivers/vhost/Kconfig b/drivers/vhost/Kconfig
>index b455d9ab6f3d..e5b9dcbf31b6 100644
>--- a/drivers/vhost/Kconfig
>+++ b/drivers/vhost/Kconfig
>@@ -95,3 +95,18 @@ config VHOST_CROSS_ENDIAN_LEGACY
> 	  If unsure, say "N".
>
> endif

nit: there is a mix of tabs and spaces in the next block, should we
fix it?

>+
>+config VHOST_ENABLE_FORK_OWNER_IOCTL
>+	bool "Enable IOCTL VHOST_FORK_FROM_OWNER"
>+	default n
>+	help
>+	  This option enables the IOCTL VHOST_FORK_FROM_OWNER, which allows
>+	  userspace applications to modify the thread mode for vhost devices.
   ^
   tabs

>+
>+          By default, `CONFIG_VHOST_ENABLE_FORK_OWNER_IOCTL` is set to `n`,
>+          meaning the ioctl is disabled and any operation using this ioctl
>+          will fail.
>+          When the configuration is enabled (y), the ioctl becomes
>+          available, allowing users to set the mode if needed.
   ^
   spaces
>+
>+	  If unsure, say "N".
   ^
   tabs

>diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
>index fb0c7fb43f78..568e43cb54a9 100644
>--- a/drivers/vhost/vhost.c
>+++ b/drivers/vhost/vhost.c
>@@ -2294,6 +2294,8 @@ long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp)
> 		r = vhost_dev_set_owner(d);
> 		goto done;
> 	}
>+
>+#ifdef CONFIG_VHOST_ENABLE_FORK_OWNER_IOCTL
> 	if (ioctl == VHOST_FORK_FROM_OWNER) {
> 		u8 inherit_owner;
> 		/*inherit_owner can only be modified before owner is set*/
>@@ -2313,6 +2315,7 @@ long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp)
> 		r = 0;
> 		goto done;
> 	}
>+#endif
> 	/* You must be the owner to do anything else */
> 	r = vhost_dev_check_owner(d);
> 	if (r)
>-- 
>2.45.0
>
Re: [PATCH v8 8/8] vhost: Add a KConfig knob to enable IOCTL VHOST_FORK_FROM_OWNER
Posted by Cindy Lu 8 months, 2 weeks ago 
On Tue, Apr 1, 2025 at 9:21 PM Stefano Garzarella <sgarzare@redhat.com> wrote:
>
> On Fri, Mar 28, 2025 at 06:02:52PM +0800, Cindy Lu wrote:
> >Introduce a new config knob `CONFIG_VHOST_ENABLE_FORK_OWNER_IOCTL`,
> >to control the availability of the `VHOST_FORK_FROM_OWNER` ioctl.
> >When CONFIG_VHOST_ENABLE_FORK_OWNER_IOCTL is set to n, the ioctl
> >is disabled, and any attempt to use it will result in failure.
> >
> >Signed-off-by: Cindy Lu <lulu@redhat.com>
> >---
> > drivers/vhost/Kconfig | 15 +++++++++++++++
> > drivers/vhost/vhost.c |  3 +++
> > 2 files changed, 18 insertions(+)
>
> IMHO this patch should be squashed with "[PATCH v8 6/8] vhost: uapi to
> control task mode (owner vs kthread)".
>
> It might break the bisection to support an ioctl, and after a few
> commits enable or disable it depending on a kernel configuration.
>
> >
> >diff --git a/drivers/vhost/Kconfig b/drivers/vhost/Kconfig
> >index b455d9ab6f3d..e5b9dcbf31b6 100644
> >--- a/drivers/vhost/Kconfig
> >+++ b/drivers/vhost/Kconfig
> >@@ -95,3 +95,18 @@ config VHOST_CROSS_ENDIAN_LEGACY
> >         If unsure, say "N".
> >
> > endif
>
> nit: there is a mix of tabs and spaces in the next block, should we
> fix it?
>
sure ,will fix this
Thanks
Cindy
> >+
> >+config VHOST_ENABLE_FORK_OWNER_IOCTL
> >+      bool "Enable IOCTL VHOST_FORK_FROM_OWNER"
> >+      default n
> >+      help
> >+        This option enables the IOCTL VHOST_FORK_FROM_OWNER, which allows
> >+        userspace applications to modify the thread mode for vhost devices.
>    ^
>    tabs
>
> >+
> >+          By default, `CONFIG_VHOST_ENABLE_FORK_OWNER_IOCTL` is set to `n`,
> >+          meaning the ioctl is disabled and any operation using this ioctl
> >+          will fail.
> >+          When the configuration is enabled (y), the ioctl becomes
> >+          available, allowing users to set the mode if needed.
>    ^
>    spaces
> >+
> >+        If unsure, say "N".
>    ^
>    tabs
>
will fix this
Thanks
Cindy
> >diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
> >index fb0c7fb43f78..568e43cb54a9 100644
> >--- a/drivers/vhost/vhost.c
> >+++ b/drivers/vhost/vhost.c
> >@@ -2294,6 +2294,8 @@ long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp)
> >               r = vhost_dev_set_owner(d);
> >               goto done;
> >       }
> >+
> >+#ifdef CONFIG_VHOST_ENABLE_FORK_OWNER_IOCTL
> >       if (ioctl == VHOST_FORK_FROM_OWNER) {
> >               u8 inherit_owner;
> >               /*inherit_owner can only be modified before owner is set*/
> >@@ -2313,6 +2315,7 @@ long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp)
> >               r = 0;
> >               goto done;
> >       }
> >+#endif
> >       /* You must be the owner to do anything else */
> >       r = vhost_dev_check_owner(d);
> >       if (r)
> >--
> >2.45.0
> >
>

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