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

[Cornelia Huck <cohuck@redhat.com>]

On Thu, 19 Sep 2019 16:55:57 -0400
Matthew Rosato <mjrosato@linux.ibm.com> wrote:

> On 9/19/19 11:20 AM, Cornelia Huck wrote:
> > 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_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?
> >   
> 
> The structure itself is not mapped 1:1 to a hardware structure, but it
> does serve as a collection of information that was derived from other
> hardware structures.
> 
> "Used for passing hardware feature information about a zpci device
> between the host and guest" ?

"zPCI specific hardware feature information for a device"?

Are we reasonably sure that this is complete for now? I'm not sure if
expanding this structure would work; adding another should always be
possible, though (if a bit annoying).

> 
> >> + *
> >> + */
> >> +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  
> > 
> >   
>