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From: Farhan Ali <alifm@linux.ibm.com>
To: Cornelia Huck <cohuck@redhat.com>,
	Halil Pasic <pasic@linux.ibm.com>,
	Eric Farman <farman@linux.ibm.com>,
	Pierre Morel <pmorel@linux.ibm.com>
Cc: linux-s390@vger.kernel.org, qemu-s390x@nongnu.org,
	Alex Williamson <alex.williamson@redhat.com>,
	qemu-devel@nongnu.org, kvm@vger.kernel.org
Subject: Re: [PATCH 1/3] vfio-ccw: add capabilities chain
Date: Tue, 27 Nov 2018 14:04:49 -0500	[thread overview]
Message-ID: <a3a73709-e354-758a-a7f0-219eafd593ab@linux.ibm.com> (raw)
In-Reply-To: <20181122165432.4437-2-cohuck@redhat.com>



On 11/22/2018 11:54 AM, Cornelia Huck wrote:
> diff --git a/drivers/s390/cio/vfio_ccw_private.h b/drivers/s390/cio/vfio_ccw_private.h
> index 078e46f9623d..a6f9f84526e2 100644
> --- a/drivers/s390/cio/vfio_ccw_private.h
> +++ b/drivers/s390/cio/vfio_ccw_private.h
> @@ -3,9 +3,11 @@
>    * Private stuff for vfio_ccw driver
>    *
>    * Copyright IBM Corp. 2017
> + * Copyright Red Hat, Inc. 2018
>    *
>    * Author(s): Dong Jia Shi<bjsdjshi@linux.vnet.ibm.com>
>    *            Xiao Feng Ren<renxiaof@linux.vnet.ibm.com>
> + *            Cornelia Huck<cohuck@redhat.com>
>    */
>   
>   #ifndef_VFIO_CCW_PRIVATE_H_
> @@ -19,6 +21,38 @@
>   #include "css.h"
>   #include "vfio_ccw_cp.h"
>   
> +#define VFIO_CCW_OFFSET_SHIFT   40
> +#define VFIO_CCW_OFFSET_TO_INDEX(off)	(off >> VFIO_CCW_OFFSET_SHIFT)
> +#define VFIO_CCW_INDEX_TO_OFFSET(index)	((u64)(index) << VFIO_CCW_OFFSET_SHIFT)
> +#define VFIO_CCW_OFFSET_MASK	(((u64)(1) << VFIO_CCW_OFFSET_SHIFT) - 1)
> +

Why is the offset shift 40? I know vfio-pci is also using the same 
offset shift, but I am curious about the reasoning behind why we are 
using this? :)

  parent reply	other threads:[~2018-11-27 19:04 UTC|newest]

Thread overview: 54+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-22 16:54 [PATCH 0/3] vfio-ccw: support hsch/csch (kernel part) Cornelia Huck
2018-11-22 16:54 ` [PATCH 1/3] vfio-ccw: add capabilities chain Cornelia Huck
2018-11-23 12:28   ` Pierre Morel
2018-11-23 12:45     ` Cornelia Huck
2018-11-23 13:26       ` Pierre Morel
2018-11-27 19:04   ` Farhan Ali [this message]
2018-11-28  9:05     ` Cornelia Huck
2018-12-17 21:53   ` Eric Farman
2018-12-18 17:24     ` Cornelia Huck
2018-12-18 17:56       ` Eric Farman
2018-12-19 16:28       ` Alex Williamson
2018-12-21 11:12         ` Cornelia Huck
2018-11-22 16:54 ` [PATCH 2/3] s390/cio: export hsch to modules Cornelia Huck
2018-11-23 12:30   ` Pierre Morel
2018-11-22 16:54 ` [PATCH 3/3] vfio-ccw: add handling for asnyc channel instructions Cornelia Huck
2018-11-23 13:08   ` Pierre Morel
2018-11-26  9:47     ` Cornelia Huck
2018-11-27 19:09   ` Farhan Ali
2018-11-28  9:02     ` Cornelia Huck
2018-11-28 14:31       ` Farhan Ali
2018-11-28 14:52         ` Cornelia Huck
2018-11-28 15:00           ` Farhan Ali
2018-11-28 15:35             ` Cornelia Huck
2018-11-28 15:55               ` Farhan Ali
2019-01-18 13:53                 ` Cornelia Huck
2018-11-27 19:57   ` Farhan Ali
2018-11-28  8:41     ` Cornelia Huck
2018-11-28 16:36   ` [qemu-s390x] " Halil Pasic
2018-11-29 16:52     ` Cornelia Huck
2018-11-29 17:24       ` Halil Pasic
2018-12-17 21:54   ` Eric Farman
2018-12-18 16:45     ` Cornelia Huck
2018-11-24 21:07 ` [qemu-s390x] [PATCH 0/3] vfio-ccw: support hsch/csch (kernel part) Halil Pasic
2018-11-26  9:26   ` Cornelia Huck
2018-11-26 18:57 ` Farhan Ali
2018-11-26 19:00   ` Cornelia Huck
2018-12-04 12:38 ` Halil Pasic
2018-12-04 13:11   ` Cornelia Huck
2018-12-04 15:02     ` Halil Pasic
2018-12-05 12:54       ` Cornelia Huck
2018-12-05 18:34         ` Farhan Ali
2018-12-06 14:39           ` Cornelia Huck
2018-12-06 15:26             ` Farhan Ali
2018-12-06 16:21               ` Cornelia Huck
2018-12-06 17:50                 ` Farhan Ali
2018-12-07  9:34                   ` Cornelia Huck
2018-12-06 18:47         ` Halil Pasic
2018-12-07 10:05           ` Cornelia Huck
2018-12-07 15:49             ` Halil Pasic
2018-12-07 16:54             ` Halil Pasic
2018-12-19 11:54               ` Cornelia Huck
2018-12-19 14:17                 ` Halil Pasic
2018-12-21 11:23                   ` Cornelia Huck
2018-12-21 12:42                     ` Halil Pasic

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