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

Mukesh R
2026-01-24T00:36:30Z

On 1/23/26 10:25, Nuno Das Neves wrote:
> 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.
>

Correct, I switched it because the next patch won't compile without it as
it needs the declarations here. It could be combined into one big patch,
but I think normally one would not expect full functionality until the
release is certified to be that feature compliant anyways. Hope that
makes sense.

Thanks,
-Mukesh

>> /*
>> ********************************
>> @@ -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