Messages in this thread | | | Date | Wed, 26 Jul 2023 13:25:15 +0200 | From | Greg KH <> | Subject | Re: [PATCH 2/2 v4] vfio-cdx: add ioctl support for bus master enable |
| |
On Wed, Jul 26, 2023 at 04:32:20PM +0530, Nipun Gupta wrote: > add VFIO_DEVICE_CDX_CTRL IOCTL to expose control operations for CDX > devices to VFIO users. Support Bus master enable and Bus master disable > on CDX bus control. > > Signed-off-by: Shubham Rohila <shubham.rohila@amd.com> > Signed-off-by: Nipun Gupta <nipun.gupta@amd.com>
Who wrote this? The signed-off-by ordering seems odd.
> --- > > Changes in v4: > - This patch is newly added which uses cdx_set_master() and > cdx_clear_master() APIs. > > drivers/vfio/cdx/main.c | 26 ++++++++++++++++++++++++++ > include/uapi/linux/vfio.h | 14 ++++++++++++++ > 2 files changed, 40 insertions(+) > > diff --git a/drivers/vfio/cdx/main.c b/drivers/vfio/cdx/main.c > index c376a69d2db2..c39a965716f4 100644 > --- a/drivers/vfio/cdx/main.c > +++ b/drivers/vfio/cdx/main.c > @@ -98,6 +98,30 @@ static int vfio_cdx_ioctl_get_region_info(struct vfio_cdx_device *vdev, > return copy_to_user(arg, &info, minsz) ? -EFAULT : 0; > } > > +static int vfio_cdx_ioctl_ctrl(struct vfio_cdx_device *vdev, > + struct vfio_device_cdx_ctrl __user *arg) > +{ > + unsigned long minsz = offsetofend(struct vfio_device_cdx_ctrl, op); > + struct cdx_device *cdx_dev = to_cdx_device(vdev->vdev.dev); > + struct vfio_device_cdx_ctrl ops; > + > + if (copy_from_user(&ops, arg, minsz)) > + return -EFAULT; > + > + if (ops.argsz < minsz) > + return -EINVAL; > + > + switch (ops.op) { > + case VFIO_CDX_CTRL_CLEAR_MASTER: > + cdx_clear_master(cdx_dev); > + return 0; > + case VFIO_CDX_CTRL_SET_MASTER: > + return cdx_set_master(cdx_dev); > + default: > + return -EINVAL; > + } > +} > + > static long vfio_cdx_ioctl(struct vfio_device *core_vdev, > unsigned int cmd, unsigned long arg) > { > @@ -112,6 +136,8 @@ static long vfio_cdx_ioctl(struct vfio_device *core_vdev, > return vfio_cdx_ioctl_get_region_info(vdev, uarg); > case VFIO_DEVICE_RESET: > return cdx_dev_reset(core_vdev->dev); > + case VFIO_DEVICE_CDX_CTRL: > + return vfio_cdx_ioctl_ctrl(vdev, uarg); > default: > return -ENOTTY; > } > diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h > index 20c804bdc09c..5f6a58f9f8e2 100644 > --- a/include/uapi/linux/vfio.h > +++ b/include/uapi/linux/vfio.h > @@ -1649,6 +1649,20 @@ struct vfio_iommu_spapr_tce_remove { > }; > #define VFIO_IOMMU_SPAPR_TCE_REMOVE _IO(VFIO_TYPE, VFIO_BASE + 20) > > +/** > + * VFIO_DEVICE_CDX_CTRL - _IO(VFIO_TYPE, VFIO_BASE + 21) > + * > + * Control CDX device. > + * Variable op is set as per the operation required
But what is argsz set to?
> + */ > +struct vfio_device_cdx_ctrl { > + __u32 argsz; > + __u32 op; > +#define VFIO_CDX_CTRL_SET_MASTER 0 /* Set Bus Master */ > +#define VFIO_CDX_CTRL_CLEAR_MASTER 1 /* Clear Bus Master */ > +}; > +#define VFIO_DEVICE_CDX_CTRL _IO(VFIO_TYPE, VFIO_BASE + 21) > +
Doesn't vfio stuff require a spec and agreement on the interface somewhere? Has that happened here already?
And why an ioctl? Why would userspace care about this type of control?
thanks,
greg k-h
| |