Re: Re:Re:Re: [Xen-devel] some errors of pvonhvm : xen-blkfront

[Pasi Kärkkäinen <pasik@xxxxxx>]

On Mon, Apr 25, 2011 at 11:15:45AM +0800, topperxin wrote:
>    Thank you, Stefano
>          I have known that the first linux kernel version which include the
>    PVONHVM feature is 2.6.36. But now, the question I have to face is our
>    clients always required us to support other linux version, which not
>    2.6.36, perhaps 2.6.35,
>    2.6.34, 2.6.32... so I have to porting the PV drivers to these kernel
>    version.
>          At first, if the target kernel version is
>    2.6.2X, I ported the pv-drivers based on 2.6.18,
>    these work not very hard, and I successfully. such ubuntu 8.04(2.6.24),
>    debian5.05(2.6.26)
>    But, if the target kernel version is 2.6.3X, these work seems very
>    difficult, I couldn't complete it, the biggest trouble is can't debug the
>    xen-blkfront.

Novell SLES/OpenSuse has a forward-port of the 2.6.18 based PVHVM drivers
to 2.6.2x and 2.6.3x. 

But I think it's better to use the new upstream-included PVHVM drivers these 
days.

-- Pasi

>          Since I known that the pv-drivers will be included in linux kernel
>    2.6.36, I studied the changes of it, and I try to port them to
>    ubuntu10.10(2.6.35), based on 2.6.36, the result is system can boot
>    successfully with xen-blkfront
>    disk, but when I execute some commands such as:
>    ls, mkdir...
>    the system will be blocked, the phenomena just like before I have stated
>    in this mail.
>         What should I do next? Is this method ok?
>    Could you please tell me, when you write the xen-blkfront disk drivers for
>    linux kernel 2.6.36, how do you debug it when you meet errors?
>         Thank you very much.
> 
> 
>  At 2011-04-21 01:24:25ÂÂ"Stefano Stabellini" 
> <stefano.stabellini@xxxxxxxxxxxxx> wrote:
> 
>  >On Tue, 19 Apr 2011, topperxin wrote:
>  >> hi Stefano
>  >>    thanks for your time
>  >>    As your method, I modified my /boo/grub/grub.cfg of ubuntu10.10 like 
> this:
>  >> ====================================================
>  >>    menuentry 'Ubuntu, with Linux 2.6.35.4.pvonhvm' --class ubuntu --class 
> gnu-linux --class gnu --class os {
>  >>         recordfail
>  >>         insmod part_msdos
>  >>         insmod ext2
>  >>         set root='(hd0,msdos1)'
>  >>         search --no-floppy --fs-uuid --set 
> 3336889c-576e-4088-a6ff-89e869289766
>  >>         linux   /boot/vmlinuz-2.6.35.4 
> root=UUID=3336889c-576e-4088-a6ff-89e869289766 ro 
> xen_emul_unplug=aux-ide-disks
>  >>         initrd  /boot/initrd.img-2.6.35.4.pvonhvm.0415
>  >> }
>  >> =======================================================
>  >>
>  >> then I reboot the Guest OS , I found the boot disk is still the 
> xen-blkfront, not the qemu emulate.
>  >
>  >aux-ide-disks means "do not unplug secondary emulated disks".
>  >
>  >
>  >> I reviewed the source of ./arch/x86/xen/platform-pci-unplug.c. there are 
> several parameters, such as:
>  >>
>  >> ===================================================================
>  >>                 if (!strncmp(p, "all", l))
>  >>                         xen_emul_unplug |= XEN_UNPLUG_ALL;
>  >>                 else if (!strncmp(p, "ide-disks", l))
>  >>                         xen_emul_unplug |= XEN_UNPLUG_ALL_IDE_DISKS;
>  >>                 else if (!strncmp(p, "aux-ide-disks", l))
>  >>                         xen_emul_unplug |= XEN_UNPLUG_AUX_IDE_DISKS;
>  >>                 else if (!strncmp(p, "nics", l))
>  >>                         xen_emul_unplug |= XEN_UNPLUG_ALL_NICS;
>  >>                 else if (!strncmp(p, "unnecessary", l))
>  >>                         xen_emul_unplug |= XEN_UNPLUG_UNNECESSARY;
>  >>                 else if (!strncmp(p, "never", l))                         
> xen_emul_unplug |= XEN_UNPLUG_NEVER;
>  >> =========================================================
>  >> In my opinion , If I want to use the emulated disk , I should set
>  >>
>  >>               xen_emul_unplug = XEN_UNPLUG_UNNECESSARY or
>  >>
>  >>               xen_emul_unplug = XEN_NEVER
>  >>
>  >> right? I try these two ways, but I still failed.
>  >
>  >If you specify xen_emul_unplug=XEN_UNPLUG_UNNECESSARY you prevent
>  >blkfront from hooking PV disks corresponding to emulated disks.
>  >Of course you have to make sure your root device is not /dev/xvda
>  >because that wouldn't work anymore, try root=/dev/sda if you want to
>  >make sure that you are using the emulated path.
>  >Also you need to specify hd* devices in your disk line in the VM config
>  >file, like this:
>  >
>  >disk = [ 'file:/root/images/debian_lenny_i386_small.raw,hda,w']
>  >
>  >
>  >>
>  >>   Could you please tell me where can I get the source of
>  >>
>  >>  kernel 2.6.35 with pvonhvm???
>  >
>  >The first Linux kernel to have PV on HVM support was Linux 2.6.36, so I
>  >don't have any 2.6.35 Linux tree with PV on HVM support. However a
>  >vanilla 2.6.36 (or 2.6.37 or 2.6.38) kernel should just work as PV on
>  >HVM kernel.
> 
>    --------------------------------------------------------------------------
> 
>    [1]ÃÃÃÃÃÃÃÃÃÃÃÃ2GÂÂÅÃÅÅÅÃÂÂÃÃÃÃÂÂÃÃÃÃÅÃÂÃÃÂÂÂÅÃÃÃÃÂÂÂÃÃÃÃ3ÂÂ!
> 
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