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Re: [Xen-devel] xsave=0 workaround needed on 3.2 kernels with Xen 4.1 or Xen-unstable.

On 05/09/2012 11:38 AM, Konrad Rzeszutek Wilk wrote:

Which would imply that the OSXSAVE is not set (but Fedora Core 17 64-bit PV 
still crashes on that machine) - which means that in multi-lib the 
is _not_ set. But then looking at the sources I see:
What's even more amusing? Just after installing the incorrect feature check and introducing bit_YMM_Usable, Uli reverted all the tests which had been checking for usable YMM regs and made them check AVX again.


Perhaps this is needed:

--- glibc-2.15-a316c1f/sysdeps/x86_64/multiarch/init-arch.c.orig        
2012-05-09 13:32:10.832000122 -0400
+++ glibc-2.15-a316c1f/sysdeps/x86_64/multiarch/init-arch.c     2012-05-09 
13:33:31.043000138 -0400
@@ -154,6 +154,8 @@ __init_cpu_features (void)
                     : "=a" (xcrlow), "=d" (xcrhigh) : "c" (0));
                (xcrlow&  6) == 6; }))
        __cpu_features.feature[index_YMM_Usable] |= bit_YMM_Usable;
+       else
+       __cpu_features.cpuid[COMMON_CPUID_INDEX_1].ecx&= ~bit_AVX;

    __cpu_features.family = family;
I certainly agree. The big problem here is testing... I still can't test it :( Against my better judgment I may have to throw a glibc with that change over the wall and hope. There's been far too much of that already.


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