Re: [RFC v1 3/8] vhost: Add 3 new uapi to support iommufd

[Cindy Lu]

On Mon, Nov 6, 2023 at 3:30 PM Jason Wang <jasowang@xxxxxxxxxx> wrote:
>
> On Sat, Nov 4, 2023 at 1:17 AM Cindy Lu <lulu@xxxxxxxxxx> wrote:
> >
> > VHOST_VDPA_SET_IOMMU_FD: bind the device to iommufd device
> >
> > VDPA_DEVICE_ATTACH_IOMMUFD_AS: Attach a vdpa device to an iommufd
> > address space specified by IOAS id.
> >
> > VDPA_DEVICE_DETACH_IOMMUFD_AS: Detach a vdpa device
> > from the iommufd address space
> >
> > Signed-off-by: Cindy Lu <lulu@xxxxxxxxxx>
> > ---
>
> [...]
>
> > diff --git a/include/uapi/linux/vhost.h b/include/uapi/linux/vhost.h
> > index f5c48b61ab62..07e1b2c443ca 100644
> > --- a/include/uapi/linux/vhost.h
> > +++ b/include/uapi/linux/vhost.h
> > @@ -219,4 +219,70 @@
> >   */
> >  #define VHOST_VDPA_RESUME              _IO(VHOST_VIRTIO, 0x7E)
> >
> > +/* vhost_vdpa_set_iommufd
> > + * Input parameters:
> > + * @iommufd: file descriptor from /dev/iommu; pass -1 to unset
> > + * @iommufd_ioasid: IOAS identifier returned from ioctl(IOMMU_IOAS_ALLOC)
> > + * Output parameters:
> > + * @out_dev_id: device identifier
> > + */
> > +struct vhost_vdpa_set_iommufd {
> > +       __s32 iommufd;
> > +       __u32 iommufd_ioasid;
> > +       __u32 out_dev_id;
> > +};
> > +
> > +#define VHOST_VDPA_SET_IOMMU_FD \
> > +       _IOW(VHOST_VIRTIO, 0x7F, struct vhost_vdpa_set_iommufd)
> > +
> > +/*
> > + * VDPA_DEVICE_ATTACH_IOMMUFD_AS -
> > + * _IOW(VHOST_VIRTIO, 0x7f, struct vdpa_device_attach_iommufd_as)
> > + *
> > + * Attach a vdpa device to an iommufd address space specified by IOAS
> > + * id.
> > + *
> > + * Available only after a device has been bound to iommufd via
> > + * VHOST_VDPA_SET_IOMMU_FD
> > + *
> > + * Undo by VDPA_DEVICE_DETACH_IOMMUFD_AS or device fd close.
> > + *
> > + * @argsz:     user filled size of this data.
> > + * @flags:     must be 0.
> > + * @ioas_id:   Input the target id which can represent an ioas
> > + *             allocated via iommufd subsystem.
> > + *
> > + * Return: 0 on success, -errno on failure.
> > + */
> > +struct vdpa_device_attach_iommufd_as {
> > +       __u32 argsz;
> > +       __u32 flags;
> > +       __u32 ioas_id;
> > +};
>
> I think we need to map ioas to vDPA AS, so there should be an ASID
> from the view of vDPA?
>
> Thanks
>
The qemu will have a structure save and  maintain this information,So
I didn't add this
 in kernel，we can add this but maybe only for check?
this in
Thanks
Cindy
> > +
> > +#define VDPA_DEVICE_ATTACH_IOMMUFD_AS \
> > +       _IOW(VHOST_VIRTIO, 0x82, struct vdpa_device_attach_iommufd_as)
> > +
> > +/*
> > + * VDPA_DEVICE_DETACH_IOMMUFD_AS
> > + *
> > + * Detach a vdpa device from the iommufd address space it has been
> > + * attached to. After it, device should be in a blocking DMA state.
> > + *
> > + * Available only after a device has been bound to iommufd via
> > + * VHOST_VDPA_SET_IOMMU_FD
> > + *
> > + * @argsz:     user filled size of this data.
> > + * @flags:     must be 0.
> > + *
> > + * Return: 0 on success, -errno on failure.
> > + */
> > +struct vdpa_device_detach_iommufd_as {
> > +       __u32 argsz;
> > +       __u32 flags;
> > +};
> > +
> > +#define VDPA_DEVICE_DETACH_IOMMUFD_AS \
> > +       _IOW(VHOST_VIRTIO, 0x83, struct vdpa_device_detach_iommufd_as)
> > +
> >  #endif
> > --
> > 2.34.3
> >
>