From mboxrd@z Thu Jan  1 00:00:00 1970
From: Avi Kivity <avi@qumranet.com>
Subject: Re: KVM Test result, kernel 81e4400..,
 userspace 08385e4.. , One new issue
Date: Mon, 25 Feb 2008 19:40:05 +0200
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Cc: kvm-devel@lists.sourceforge.net
To: Alexander Graf <alex@csgraf.de>
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Alexander Graf wrote:
>
> The ebx store was done because of PIC code, which does not allow ebx 
> to get clobbered. If we are not in PIC code, =r contains ebx as GPR 
> though, so the assumption that ebx needs to be restored was wrong 
> then. This new version only enables the store/restore code if i386 and 
> PIC code are used. There is no need to distinguish between x86_64 and 
> i386 for the other cases.
>
> So does this version work?
>

It probably will, but it seems fragile to depend on the details of PIC.  
I committed something more generic:

#ifdef __x86_64__
    asm volatile("cpuid"
         : "=a"(vec[0]), "=b"(vec[1]),
           "=c"(vec[2]), "=d"(vec[3])
         : "0"(function) : "cc");
#else
    asm volatile("pusha \n\t"
         "cpuid \n\t"
         "mov %%eax, 0(%1) \n\t"
         "mov %%ebx, 4(%1) \n\t"
         "mov %%ecx, 8(%1) \n\t"
         "mov %%edx, 12(%1) \n\t"
         "popa"
         : "a"(function), "S"(vec) : "memory", "cc");
#endif



-- 
error compiling committee.c: too many arguments to function


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