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[Xen-ia64-devel] RE: vcpu_translate issue

To: "Magenheimer, Dan \(HP Labs Fort Collins\)" <dan.magenheimer@xxxxxx>
Subject: [Xen-ia64-devel] RE: vcpu_translate issue
From: "Xu, Anthony" <anthony.xu@xxxxxxxxx>
Date: Sat, 5 Nov 2005 14:55:45 +0800
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I just want to run some testcases like ltp to make dom0 more stable. If this is 
the case I have no choice but to defer those tests.


>-----Original Message-----
>From: Magenheimer, Dan (HP Labs Fort Collins) [mailto:dan.magenheimer@xxxxxx]
>Sent: 2005年11月4日 22:13
>To: Xu, Anthony
>Cc: xen-ia64-devel@xxxxxxxxxxxxxxxxxxx
>Subject: RE: vcpu_translate issue
>The warning is there because the current code doesn't yet
>work properly for a region 0 virtual address.  Even
>if you remove the printf, I don't think ltp mmap09 will
>work properly because the current code assumes
>incorrectly that every region 0 access is a guest
>physical access.  Bug!  I think this is the first time
>we have seen a region 0 virtual address.
>Also, the printf is very good at catching problems when
>there is a new bug in Xen so it would be nice to
>keep the printf.  Perhaps it could be tied to a
>Xen command line option: warnregion0.  E.g.
>if (metaphysical) {
>       if (address >> 61)
>               panic_domain(("bad metaphysical address")
>       else {
>               ... existing phys translate code
>       }
>else if (!(address >> 61) && warnregion0) {
>       printf
>I think this code will also fix region 0 virtual addresses
>(because it properly falls through to the rest of
>> -----Original Message-----
>> From: Xu, Anthony [mailto:anthony.xu@xxxxxxxxx]
>> Sent: Friday, November 04, 2005 3:20 AM
>> To: Magenheimer, Dan (HP Labs Fort Collins)
>> Cc: xen-ia64-devel@xxxxxxxxxxxxxxxxxxx
>> Subject: vcpu_translate issue
>> Dan,
>> In vcpu_translate function, if guest address is within region
>> 0 and guest is in virtual mode, vcpu_translate will print
>> warning message and don't translate. It seems you assume
>> guest will not access this kind of address, but actually
>> guest application can allocate region 0 address spaces by
>> using system call mmap.
>> You can try testcase mmap09 of ltp on both native and xen0 to
>> find out this.
>> So, Can we remove this code segment in vcpu_translate?
>> Thanks,
>> Anthony.

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