Re: [Xen-ia64-devel] RE: [Xen-devel] Help? Red Hat fails, Suse/Debian both work fine

["Yoshi.Oguchi" <y-oguchi@xxxxxxxxxxxxxx>]

Hi Kevin, 

>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...
>

As you suspect, we observed xenstored behaves incorrectly
from the start.
After booting Dom0, typing "xenstore-list /"  results in
"bad_client" error (or just hangs).
Apparently, xenstored can't read mapped ring buffer.

Akio is now debugging on it, also he'll try to see if 
anything changes when /driver/xen/char is included.

Thanks, 
Yoshi Oguchi
--
Tian, Kevin wrote:
>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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>
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