Re: [PATCH v0 05/15] mshv: Declarations and definitions for VFIO-MSHV bridge device

Nuno Das Neves
2026-01-23T18:25:38Z

On 1/19/2026 10:42 PM, Mukesh R wrote:
> From: Mukesh Rathor <mrathor@linux.microsoft.com>
>
> Add data structs needed by the subsequent patch that introduces a new
> module to implement VFIO-MSHV pseudo device.
>
> Signed-off-by: Mukesh Rathor <mrathor@linux.microsoft.com>
> ---
> drivers/hv/mshv_root.h | 23 +++++++++++++++++++++++
> include/uapi/linux/mshv.h | 31 +++++++++++++++++++++++++++++++
> 2 files changed, 54 insertions(+)
>
> diff --git a/drivers/hv/mshv_root.h b/drivers/hv/mshv_root.h
> index c3753b009fd8..42e1da1d545b 100644
> --- a/drivers/hv/mshv_root.h
> +++ b/drivers/hv/mshv_root.h
> @@ -220,6 +220,29 @@ struct port_table_info {
> };
> };
>
> +struct mshv_device {
> + const struct mshv_device_ops *device_ops;
> + struct mshv_partition *device_pt;
> + void *device_private;
> + struct hlist_node device_ptnode;
> +};
> +
> +struct mshv_device_ops {
> + const char *device_name;
> + long (*device_create)(struct mshv_device *dev, u32 type);
> + void (*device_release)(struct mshv_device *dev);
> + long (*device_set_attr)(struct mshv_device *dev,
> + struct mshv_device_attr *attr);
> + long (*device_has_attr)(struct mshv_device *dev,
> + struct mshv_device_attr *attr);
> +};
> +
> +extern struct mshv_device_ops mshv_vfio_device_ops;
> +int mshv_vfio_ops_init(void);
> +void mshv_vfio_ops_exit(void);
> +long mshv_partition_ioctl_create_device(struct mshv_partition *partition,
> + void __user *user_args);
> +
> int mshv_update_routing_table(struct mshv_partition *partition,
> const struct mshv_user_irq_entry *entries,
> unsigned int numents);
> diff --git a/include/uapi/linux/mshv.h b/include/uapi/linux/mshv.h
> index dee3ece28ce5..b7b10f9e2896 100644
> --- a/include/uapi/linux/mshv.h
> +++ b/include/uapi/linux/mshv.h
> @@ -252,6 +252,7 @@ struct mshv_root_hvcall {
> #define MSHV_GET_GPAP_ACCESS_BITMAP _IOWR(MSHV_IOCTL, 0x06, struct mshv_gpap_access_bitmap)
> /* Generic hypercall */
> #define MSHV_ROOT_HVCALL _IOWR(MSHV_IOCTL, 0x07, struct mshv_root_hvcall)
> +#define MSHV_CREATE_DEVICE _IOWR(MSHV_IOCTL, 0x08, struct mshv_create_device)
>

With this commit, the IOCTL number is exposed to userspace but it doesn't work.
Ideally the IOCTL number should be added in the commit where it becomes usable.

> /*
> ********************************
> @@ -402,4 +403,34 @@ struct mshv_sint_mask {
> /* hv_hvcall device */
> #define MSHV_HVCALL_SETUP _IOW(MSHV_IOCTL, 0x1E, struct mshv_vtl_hvcall_setup)
> #define MSHV_HVCALL _IOWR(MSHV_IOCTL, 0x1F, struct mshv_vtl_hvcall)
> +
> +/* device passhthru */
> +#define MSHV_CREATE_DEVICE_TEST 1
> +
> +enum {
> + MSHV_DEV_TYPE_VFIO,
> + MSHV_DEV_TYPE_MAX,
> +};
> +
> +struct mshv_create_device {
> + __u32 type; /* in: MSHV_DEV_TYPE_xxx */
> + __u32 fd; /* out: device handle */
> + __u32 flags; /* in: MSHV_CREATE_DEVICE_xxx */
> +};
> +
> +#define MSHV_DEV_VFIO_FILE 1
> +#define MSHV_DEV_VFIO_FILE_ADD 1
> +#define MSHV_DEV_VFIO_FILE_DEL 2
> +
> +struct mshv_device_attr {
> + __u32 flags; /* no flags currently defined */
> + __u32 group; /* device-defined */
> + __u64 attr; /* group-defined */
> + __u64 addr; /* userspace address of attr data */
> +};
> +
> +/* Device fds created with MSHV_CREATE_DEVICE */
> +#define MSHV_SET_DEVICE_ATTR _IOW(MSHV_IOCTL, 0x00, struct mshv_device_attr)
> +#define MSHV_HAS_DEVICE_ATTR _IOW(MSHV_IOCTL, 0x01, struct mshv_device_attr)
> +
> #endif