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

[Akio Takebe <takebe_akio@xxxxxxxxxxxxxx>]

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\xF3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?
>>> >> >
>>> >>
>>> >>
>>> >>
>>>
>>>
>>>
>>
>>_______________________________________________
>>Xen-devel mailing list
>>Xen-devel@xxxxxxxxxxxxxxxxxxx
>>http://lists.xensource.com/xen-devel


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