Xen devel - Jul 2007 - [Xen-ia64-devel] [Patch] ARCH_HAS_DEV_MEM patch for Xwindow on IA64 machine

Hi all,

Attached patch modifies common code in files below, so I will post it
to xen-devel and xen-ia64-devel.

- drivers/xen/Kconfig
- drivers/xen/Makefile
- drivers/xen/char/mem.c

This patch makes architecture specific memory operations to be available
only if ARCH_HAS_DEV_MEM is defined.

Background why I posted the patch is as follows.

We would like to support Xwindow on IA64 by remapping machine address to
pseudo physical address at PCI device initialization (pci_acpi_scan_root()
in arch/ia64/pci/pci.c) but at "mmap /dev/mem" systemcall.
With the new scheme, we need no longer the archtecture specific memory
operations described above.

Please see 
http://lists.xensource.com/archives/html/xen-ia64-devel/2007-06/msg00167.html

Thanks

-----
Jun Kamada
Virtual Systems Development Div.
Platform Technology Development Unit
Fujitsu Ltd.
kama@jp.fujitsu.com


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>>> Jun Kamada <kama@jp.fujitsu.com> 04.07.07 13:43 >>>
>We would like to support Xwindow on IA64 by remapping machine address to
>pseudo physical address at PCI device initialization (pci_acpi_scan_root()
>in arch/ia64/pci/pci.c) but at "mmap /dev/mem" systemcall.
>With the new scheme, we need no longer the archtecture specific memory
>operations described above.
You only talk about X - isn''t it possible that there are other users of
this interface?

Also,
>--- a/drivers/xen/Kconfig	Thu Jun 21 15:12:20 2007 +0900
>+++ b/drivers/xen/Kconfig	Thu Jun 21 15:13:21 2007 +0900
>@@ -273,4 +273,8 @@ config XEN_SMPBOOT
> 	default y
> 	depends on SMP
> 
>+config XEN_DEVMEM
>+	bool
>+	default y
>+
> endif
This seems pretty useless unless ia64 doesn''t use drivers/xen/Kconfig
(which
would be a mistake I think).
>--- a/drivers/xen/Makefile	Thu Jun 21 15:12:20 2007 +0900
>+++ b/drivers/xen/Makefile	Thu Jun 21 15:13:21 2007 +0900
>@@ -5,9 +5,9 @@ obj-y	+= xenbus/
> obj-y	+= xenbus/
> obj-y	+= gntdev/
> obj-y	+= balloon/
>-obj-y	+= char/
> 
> obj-y	+= util.o
>+obj-$(CONFIG_XEN_DEVMEM)		+= char/
> obj-$(CONFIG_XEN_BLKDEV_BACKEND)	+= blkback/
> obj-$(CONFIG_XEN_BLKDEV_TAP)		+= blktap/
> obj-$(CONFIG_XEN_NETDEV_BACKEND)	+= netback/
This is certainly wrong. Even if driver/xen/char/ currently only has a
single file, you should descend into that directory. The conditional
(if needed at all) should then be in driver/xen/char/Makefile.

Jan


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Hi, Jan
>>>> Jun Kamada <kama@jp.fujitsu.com> 04.07.07 13:43
>>>
>>We would like to support Xwindow on IA64 by remapping machine address to
>>pseudo physical address at PCI device initialization
(pci_acpi_scan_root()
>>in arch/ia64/pci/pci.c) but at "mmap /dev/mem" systemcall.
>>With the new scheme, we need no longer the archtecture specific memory
>>operations described above.
>
>You only talk about X - isn''t it possible that there are other
users of this
> interface?
>
Yes, you''re right.
But if the following kama''s patches are applied,
Xen-ia64 use drivers/char/mem.c. 
So drivers/xen/char/mem.c will not be needed by Xen-ia64.
http://lists.xensource.com/archives/html/xen-ia64-devel/2007-06/msg00167.html
>Also,
>
>>--- a/drivers/xen/Kconfig	Thu Jun 21 15:12:20 2007 +0900
>>+++ b/drivers/xen/Kconfig	Thu Jun 21 15:13:21 2007 +0900
>>@@ -273,4 +273,8 @@ config XEN_SMPBOOT
>> 	default y
>> 	depends on SMP
>> 
>>+config XEN_DEVMEM
>>+	bool
>>+	default y
>>+
>> endif
>
>This seems pretty useless unless ia64 doesn''t use
drivers/xen/Kconfig (which
>would be a mistake I think).
Please see the following patch.
http://lists.xensource.com/archives/html/xen-ia64-devel/2007-06/msg00169.html

Currently drviers/xen/char is built by all archtecture.
But if the above kama''s patche is applied, it is not built by ia64.

diff -r a55f2df725a2 -r f3d513b91dea linux-2.6-xen-sparse/arch/ia64/Kconfig
--- a/linux-2.6-xen-sparse/arch/ia64/Kconfig	Wed Jun 13 12:28:14 2007 +0900
+++ b/linux-2.6-xen-sparse/arch/ia64/Kconfig	Wed Jun 13 12:35:24 2007 +0900
@@ -582,6 +582,9 @@ if XEN
 if XEN
 config XEN_SMPBOOT
 	default n
+
+config XEN_DEVMEM
+	default n
 endif
 
 source "drivers/xen/Kconfig"

Best Regards,

Akio Takebe


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Hi, Jan-san,

On Wed, 04 Jul 2007 13:04:50 +0100
"Jan Beulich" <jbeulich@novell.com>
wrote:
> >--- a/drivers/xen/Makefile	Thu Jun 21 15:12:20 2007 +0900
> >+++ b/drivers/xen/Makefile	Thu Jun 21 15:13:21 2007 +0900
> >@@ -5,9 +5,9 @@ obj-y	+= xenbus/
> > obj-y	+= xenbus/
> > obj-y	+= gntdev/
> > obj-y	+= balloon/
> >-obj-y	+= char/
> > 
> > obj-y	+= util.o
> >+obj-$(CONFIG_XEN_DEVMEM)		+= char/
> > obj-$(CONFIG_XEN_BLKDEV_BACKEND)	+= blkback/
> > obj-$(CONFIG_XEN_BLKDEV_TAP)		+= blktap/
> > obj-$(CONFIG_XEN_NETDEV_BACKEND)	+= netback/
> 
> This is certainly wrong. Even if driver/xen/char/ currently only has a
> single file, you should descend into that directory. The conditional
> (if needed at all) should then be in driver/xen/char/Makefile.
I modified the patch acording to your comment.

Thanks,

-----
Jun Kamada
Linux Technology Development Div.
Server Systems Unit
Fujitsu Ltd.
kama@jp.fujitsu.com


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