Re: [PATCH] qemu-xen-3.4-testing: Fix read-only image file handling

[Michal Novotny <minovotn@redhat.com>]

Well, now the kernel is booting but when I'm trying to recompile tools 
and stubdom images it's not OK returning those errors:

...
qemu successfuly configured for Xen qemu-dm build
make -C ioemu-dir install
=== PCI passthrough capability has been enabled ===
make[3]: Entering directory 
`/home2/shared/xen-unstable.hg/tools/ioemu-remote'
=== PCI passthrough capability has been enabled ===
=== PCI passthrough capability has been enabled ===
make[4]: Entering directory 
`/home2/shared/xen-unstable.hg/tools/ioemu-remote/i386-dm'
CC i386-dm/vl.o
/home2/shared/xen-unstable.hg/tools/ioemu-dir/vl.c: In function ‘main’:
/home2/shared/xen-unstable.hg/tools/ioemu-dir/vl.c:5729: warning: 
implicit declaration of function ‘dma_helper_init’
/home2/shared/xen-unstable.hg/tools/ioemu-dir/vl.c:5731: error: too few 
arguments to function ‘xc_interface_open’
make[4]: *** [vl.o] Error 1
make[4]: Leaving directory 
`/home2/shared/xen-unstable.hg/tools/ioemu-remote/i386-dm'
make[3]: *** [subdir-i386-dm] Error 2
make[3]: Leaving directory 
`/home2/shared/xen-unstable.hg/tools/ioemu-remote'
make[2]: *** [subdir-install-ioemu-dir] Error 2
make[2]: Leaving directory `/home2/shared/xen-unstable.hg/tools'
make[1]: *** [subdirs-install] Error 2
make[1]: Leaving directory `/home2/shared/xen-unstable.hg/tools'
make: *** [install-tools] Error 2
#

The command I used for compilation is `make install-xen && make 
install-tools && make install-stubdom && make install-docs` on the 
latest updated xen-unstable staging mercurial tree so I need to 
investigate this further. Nevertheless, the dom0 2.6.31.13 is booting on 
RHEL-5 which is good. That links you gave me Pasi helped, thanks! Now I 
need to resolve those tools issues.

Michal

On 06/04/2010 12:57 PM, Michal Novotny wrote:
> On 06/04/2010 12:42 PM, Pasi Kärkkäinen wrote:
>> On Fri, Jun 04, 2010 at 11:37:51AM +0200, Michal Novotny wrote:
>>> Oh, one more thing I've discovered now. Since the codebase for
>>> qemu-xen-unstable is looking the same like for qemu-xen-3.4-testing and
>>> the patch is applicable without any modifications it could be working
>>> for xen-4.1 unstable as well, unfortunately I was not able to boot 
>>> PVOPS
>>> kernel since it always ends up in kernel panic, maybe the missing
>>> drivers or something like that.
>>>
>> What kernel version? Did you use xen/stable-2.6.32.x branch from 
>> xen.git?
>
> It's the one that's being automatically downloaded from git as 
> linux-2.6-pvops.git. The URL is 
> git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen.git with the 
> "fetch" being set to "+refs/heads/*:refs/remotes/xen/*". This is the 
> .git/config automatically created by `make world` in xen-unstable tree:
>
> [core]
> repositoryformatversion = 0
> filemode = true
> bare = false
> logallrefupdates = true
> [remote "xen"]
> url = git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen.git
> fetch = +refs/heads/*:refs/remotes/xen/*
> [branch "xen/stable-2.6.31.x"]
> remote = xen
> merge = refs/heads/xen/stable-2.6.31.x
>
> By default it's using uhci-hcd/ehci-hcd and ohci-hcd as builtins but I 
> needed to change it to be modules since otherwise it's being stuck. 
> I'm trying this on RHEL-5 dom0 (I'm having second partition RHEL-5 
> with upstream xen).
>> See my example .config files from:
>> http://wiki.xensource.com/xenwiki/XenParavirtOps in the 
>> "troubleshooting" section.
>
> I'll have a look, thanks for the link.
>
>> Works on F12/F13 dom0's.
>>
>> For el5 dom0 you might need these:
>> http://wiki.xensource.com/xenwiki/2.6.18-to-2.6.31-and-higher
>
> Oh, ok, this may be very useful since I'm trying this on RHEL-5. Thanks!
>
>> aka
>> CONFIG_SYSFS_DEPRECATED=y
>> CONFIG_SYSFS_DEPRECATED_V2=y
>>
>> Also atm I think you need CONFIG_XEN_XENBUS_FRONTEND=y in the .config
>> because of the recently added pv-on-hvm drivers (you'll get build 
>> failure without that option),
>> so you need XEN_PCIDEV_FRONTEND XEN_BLKDEV_FRONTEND or 
>> XEN_NETDEV_FRONTEND or XEN_FBDEV_FRONTEND needs to be =y.
>>
>
> Great! Thanks for your help Pasi! If anything I'll let you know.
>
> Michal
>
>> -- Pasi
>>
>>
>>> On 06/03/2010 04:12 PM, Michal Novotny wrote:
>>>> Oh, just one more thing that should be mentioned:
>>>>
>>>> When you want to mount an image that is set as read-only in the domain
>>>> configuration file but you omit to set mode to read-only it results
>>>> into I/O errors when processing the requests. Remounting as read-only
>>>> or unmounting and remounting using the `mount /dev/* /path/to/mount -o
>>>> ro` shall do the mounting the correct way, i.e. with no I/O errors, so
>>>> make sure you mount those disks as read-only otherwise you can be
>>>> getting errors like:
>>>>
>>>> end_request: I/O error, dev hdb, sector 52
>>>>
>>>> Buffer I/O error on device hdb1, logical block 1
>>>>
>>>> lost page write due to I/O error on hdb1
>>>>
>>>>
>>>> and for IDE devices you'll be getting several additional DeviceFault
>>>> errors since mounting the device read-write (default setting) writes
>>>> some data onto a disk at the mount-time.
>>>>
>>>> Michal
>>>>
>>>> On 06/03/2010 04:04 PM, Michal Novotny wrote:
>>>>> [Well, I did send an e-mail to the list using git but it's not here
>>>>> so I'm forwarding the e-mail to the list for sure:]
>>>>>
>>>>> Hi,
>>>>> this is the patch for qemu-xen-3.4-testing to fix the read-only
>>>>> image file handling since the image file was always treated as
>>>>> read-write which means that all the HVM guests were able to
>>>>> write to all the disk images available in domain configuration
>>>>> file no matter what the mode of the image was defined. This
>>>>> patch fixes this functionality to honor the O_RDONLY in the
>>>>> BDRV_O_ACCESS flag in block.c and also fixes the IDE and SCSI
>>>>> interfaces that uses it.
>>>>>
>>>>> It's been tested on RHEL-5 with xen-3.4-testing version of
>>>>> upstream xen with xen-3.4-testing qemu implementation.
>>>>>
>>>>> For SCSI devices the DATA PROTECT request sense has been added
>>>>> as found at: http://en.wikipedia.org/wiki/SCSI_Request_Sense_Command
>>>>>
>>>>> file no matter what the mode of the image was defined. This
>>>>> patch fixes this functionality to honor the O_RDONLY in the
>>>>> BDRV_O_ACCESS flag in block.c and also fixes the IDE and SCSI
>>>>> interfaces that uses it.
>>>>>
>>>>> It's been tested on RHEL-5 with xen-3.4-testing version of
>>>>> Michal
>>>>>
>>>>> Signed-off-by: Michal Novotny<minovotn@redhat.com>
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> Xen-devel mailing list
>>>>> Xen-devel@lists.xensource.com
>>>>> http://lists.xensource.com/xen-devel
>>>>
>>>
>>> -- 
>>> Michal Novotny<minovotn@redhat.com>, RHCE
>>> Virtualization Team (xen userspace), Red Hat
>>>
>>>
>>> _______________________________________________
>>> Xen-devel mailing list
>>> Xen-devel@lists.xensource.com
>>> http://lists.xensource.com/xen-devel
>
>


-- 
Michal Novotny<minovotn@redhat.com>, RHCE
Virtualization Team (xen userspace), Red Hat