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RE: [Xen-devel] Help? Red Hat fails, Suse/Debian both work fine

To: "Akio Takebe" <takebe_akio@xxxxxxxxxxxxxx>, "Xu, Anthony" <anthony.xu@xxxxxxxxx>, "Magenheimer, Dan \(HP Labs Fort Collins\)" <dan.magenheimer@xxxxxx>, "xen-devel" <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: RE: [Xen-devel] Help? Red Hat fails, Suse/Debian both work fine
From: "Tian, Kevin" <kevin.tian@xxxxxxxxx>
Date: Thu, 2 Mar 2006 13:43:04 +0800
Cc: "yo.fujita" <yo.fujita@xxxxxxxxxxxxxxxx>, xen-ia64-devel@xxxxxxxxxxxxxxxxxxx
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Thread-topic: [Xen-devel] Help? Red Hat fails, Suse/Debian both work fine
Hi, Akio,
        Currently linux-2.6-xen-sparse/driver/xen/char/ is not included
in compilation for xen/ia64, so you're still using linux-style kmem 
path.

        Try to compile that directory into your xenlinux image, and 
define ARCH_HAS_DEV_MEM, and then see anything changed 
for you.

        However the interesting thing is, following Cset is only for 
changing way to map dom0's store page, instead of domU. DomU's 
store page is still mapped by foreign page map. If above hint is real 
cause, xend start can fail earlier due to incorrect mapping when 
introducing dom0 into xenstore. However you all observe the bug
bothering only when domU is booting...

Thanks,
Kevin

>-----Original Message-----
>From: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
>[mailto:xen-devel-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Akio Takebe
>Sent: 2006年3月2日 8:44
>To: Xu, Anthony; Magenheimer, Dan (HP Labs Fort Collins); xen-devel
>Cc: yo.fujita; Akio Takebe; xen-ia64-devel@xxxxxxxxxxxxxxxxxxx
>Subject: RE: [Xen-devel] Help? Red Hat fails, Suse/Debian both work fine
>
>Hi, Anthony
>
>Thank you for your advice.
>I checked retun value of mmap(), and it is not NULL.
>I'll check vcpu_translate().
>
>Best Regards,
>
>Akio Takebe
>
>>>It is likely some subtle difference (or bug), perhaps in mmap?
>>
>>As I know, in Redhat, mmap can return NULL address, but seems xen
>>can't handle this situation, see below code segment:
>>
>>In function vcpu_translate() of vcpu.c file
>>
>>    else if (!region && warn_region0_address) {
>>        REGS *regs = vcpu_regs(vcpu);
>>        unsigned long viip = PSCB(vcpu,iip);
>>        unsigned long vipsr = PSCB(vcpu,ipsr);
>>        unsigned long iip = regs->cr_iip;
>>        unsigned long ipsr = regs->cr_ipsr;
>>        printk("vcpu_translate: bad address %p, viip=%p, vipsr=%p, iip=%p,
>>ipsr=%p continuing\n", address, viip, vipsr, iip, ipsr);
>>    }
>>warn_region0_address is turned off by default,
>>so maybe we can turn on warn_region0_address to see whether this is the
>>root cause.
>>
>>Thanks,
>>-Anthony
>>
>>>-----Original Message-----
>>>From: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
>>>[mailto:xen-devel-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of
>Magenheimer, Dan
>>>(HP Labs Fort Collins)
>>>Sent: 2006ト・ヤツ1ネユ 5:45
>>>To: xen-devel
>>>Cc: yo.fujita; Akio Takebe; xen-ia64-devel@xxxxxxxxxxxxxxxxxxx
>>>Subject: [Xen-devel] Help? Red Hat fails, Suse/Debian both work fine
>>>
>>>Hi all --
>>>
>>>We are seeing a strange problem where a recent cset causes
>>>Red Hat to fail domU boot on ia64 complaining of a hotplug
>>>problem but doesn't cause any problem for Suse or Debian.
>>>It is likely some subtle difference (or bug), perhaps in mmap?
>>>Suggestions/advice from anyone more familiar with distro
>>>differences (on ia64) would be appreciated.
>>>
>>>Changeset is xen-unstable 8783 ("Use /dev/kmem to map dom0
>>>xenstore page instead of abusing the foreign mapping interface.",
>>>Feb 8, committed by Christian).  Backing out this changeset
>>>or using the small patch below causes the problem to go away,
>>>so we have a workaround, but a root cause would be nice
>>>to know and fix.
>>>
>>>Full thread of discussion can be found here:
>>>http://lists.xensource.com/archives/html/xen-ia64-devel/2006-02/msg00104
>>>.html
>>>
>>>Thanks,
>>>Dan
>>>
>>>> -----Original Message-----
>>>> From: Akio Takebe [mailto:takebe_akio@xxxxxxxxxxxxxx]
>>>> Sent: Tuesday, February 28, 2006 2:47 AM
>>>> To: Magenheimer, Dan (HP Labs Fort Collins); yo.fujita;
>>>> xen-ia64-devel@xxxxxxxxxxxxxxxxxxx
>>>> Cc: Akio Takebe
>>>> Subject: RE: [Xen-ia64-devel] Weekly benchmark results [2/3rd week]
>>>>
>>>> Hi, Dan
>>>>
>>>> I'm still debuging, but it is very difficult...
>>>> Much advice is welcome. :-)
>>>>
>>>> Now I can boot domU by using the following patch.
>>>>
>>>> diff -r 6c43118bdba8 tools/xenstore/xenstored_domain.c
>>>> --- a/tools/xenstore/xenstored_domain.c Fri Feb 24 15:41:08 2006 -0700
>>>> +++ b/tools/xenstore/xenstored_domain.c Tue Feb 28 18:20:16 2006
>+0900
>>>> @@ -467,6 +467,7 @@ static int dom0_init(void)
>>>>         int rc, fd;
>>>>         evtchn_port_t port;
>>>>         unsigned long kva;
>>>> +       unsigned long mfn;
>>>>         char str[20];
>>>>         struct domain *dom0;
>>>>
>>>> @@ -500,9 +501,16 @@ static int dom0_init(void)
>>>>         if (fd == -1)
>>>>                 return -1;
>>>>
>>>> -       dom0->interface = mmap(NULL, getpagesize(),
>>>> PROT_READ|PROT_WRITE,
>>>> -                              MAP_SHARED, fd, kva);
>>>> -       if (dom0->interface == MAP_FAILED)
>>>> +       mfn=((0x0fffffffffffffff & kva) >>14);
>>>> +/*
>>>> +        dom0->interface = mmap(NULL, getpagesize(),
>>>> PROT_READ|PROT_WRITE,
>>>> +                               MAP_SHARED, fd, kva);
>>>> +*/
>>>> +       dom0->interface = xc_map_foreign_range(
>>>> +               *xc_handle, 0,
>>>> +               getpagesize(), PROT_READ|PROT_WRITE, mfn);
>>>> +       if (!dom0->interface)
>>>> +//     if (dom0->interface == MAP_FAILED)
>>>>                 goto outfd;
>>>>
>>>>         close(fd);
>>>>
>>>> Best Regards,
>>>>
>>>> Akio Takebe
>>>>
>>>> >Hi Akio --
>>>> >
>>>> >Any more progress on this issue?  If you are stuck,
>>>> >maybe we should post the problem to xen-devel to
>>>> >see if we can get help from a Red Hat person (since
>>>> >the problem doesn't occur on Suse or Debian).
>>>> >
>>>> >Thanks,
>>>> >Dan
>>>> >
>>>> >> -----Original Message-----
>>>> >> From: Akio Takebe [mailto:takebe_akio@xxxxxxxxxxxxxx]
>>>> >> Sent: Thursday, February 23, 2006 8:45 PM
>>>> >> To: Magenheimer, Dan (HP Labs Fort Collins); yo.fujita;
>>>> >> xen-ia64-devel@xxxxxxxxxxxxxxxxxxx
>>>> >> Cc: Akio Takebe
>>>> >> Subject: RE: [Xen-ia64-devel] Weekly benchmark results [2/3rd week]
>>>> >>
>>>> >> Hi, Dan and Alex
>>>> >>
>>>> >> I think this issue is only on ia64.
>>>> >> I seem that kmem_map@drivers/char/mem.c is used on ia64,
>>>> >> but mem_map@drivers/xen/char/mem.c is used on x86.
>>>> >> So I think pfn or kva aren't set correctly.
>>>> >> We tried to boot domU with revesing cset xen-ia64-ustable.8790
>>>> >> and it was good work.
>>>> >>
>>>> >> I'm still debugging it. :-<
>>>> >>
>>>> >> Best Regards,
>>>> >>
>>>> >> Akio Takebe
>>>> >>
>>>> >> >Confirmed cset xen-unstable 8783 fails while 8782 succeeds.
>>>> >> >
>>>> >> >Perhaps there's something different about mmap on RH
>>>> >> >vs Suse and Debian?  Perhaps only on ia64?
>>>> >> >
>>>> >>
>>>> >>
>>>> >>
>>>>
>>>>
>>>>
>>>
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>
>
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