Re: [PATCH v4 3/4] vfio: zpci: defining the VFIO headers

[Cornelia Huck <cohuck@redhat.com>]

On Fri,  6 Sep 2019 20:13:50 -0400
Matthew Rosato <mjrosato@linux.ibm.com> wrote:

> From: Pierre Morel <pmorel@linux.ibm.com>
> 
> We define a new device region in vfio.h to be able to
> get the ZPCI CLP information by reading this region from
> userland.
> 
> We create a new file, vfio_zdev.h to define the structure
> of the new region we defined in vfio.h
> 
> Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
> Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
> ---
>  include/uapi/linux/vfio.h      |  1 +
>  include/uapi/linux/vfio_zdev.h | 35 +++++++++++++++++++++++++++++++++++
>  2 files changed, 36 insertions(+)
>  create mode 100644 include/uapi/linux/vfio_zdev.h
> 
> diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
> index 8f10748..8328c87 100644
> --- a/include/uapi/linux/vfio.h
> +++ b/include/uapi/linux/vfio.h
> @@ -371,6 +371,7 @@ struct vfio_region_gfx_edid {
>   * to do TLB invalidation on a GPU.
>   */
>  #define VFIO_REGION_SUBTYPE_IBM_NVLINK2_ATSD	(1)
> +#define VFIO_REGION_SUBTYPE_ZDEV_CLP		(2)

Using a subtype is fine, but maybe add a comment what this is for?

>  
>  /*
>   * The MSIX mappable capability informs that MSIX data of a BAR can be mmapped
> diff --git a/include/uapi/linux/vfio_zdev.h b/include/uapi/linux/vfio_zdev.h
> new file mode 100644
> index 0000000..55e0d6d
> --- /dev/null
> +++ b/include/uapi/linux/vfio_zdev.h
> @@ -0,0 +1,35 @@
> +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
> +/*
> + * Region definition for ZPCI devices
> + *
> + * Copyright IBM Corp. 2019
> + *
> + * Author(s): Pierre Morel <pmorel@linux.ibm.com>
> + */
> +
> +#ifndef _VFIO_ZDEV_H_
> +#define _VFIO_ZDEV_H_
> +
> +#include <linux/types.h>
> +
> +/**
> + * struct vfio_region_zpci_info - ZPCI information.

Hm... probably should also get some more explanation. E.g. is that
derived from a hardware structure?

> + *
> + */
> +struct vfio_region_zpci_info {
> +	__u64 dasm;
> +	__u64 start_dma;
> +	__u64 end_dma;
> +	__u64 msi_addr;
> +	__u64 flags;
> +	__u16 pchid;
> +	__u16 mui;
> +	__u16 noi;
> +	__u16 maxstbl;
> +	__u8 version;
> +	__u8 gid;
> +#define VFIO_PCI_ZDEV_FLAGS_REFRESH 1
> +	__u8 util_str[];
> +} __packed;
> +
> +#endif