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Revert "x86: Force-disable (f)xsave"

This reverts commit aab0d67ef7.

After investigating, it turns out that the culprit is not xsave, but
xsaves (or rather xrstors64).  This is a CPL=0 instruction which
therefore cannot be executed by L4Linux.

Passing the command line option "noxsaves" fixes the issue.  I am not
sure whether it makes any sense to even consider using xsaves/xrstors
when L4Linux is running in user space, but maybe there are environments
where it is running with CPL=0 in a VM, so I will leave it as it is.
Max Reitz 6 months ago
parent
commit
be95ad17a0
1 changed files with 0 additions and 2 deletions
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    2
      arch/x86/include/asm/cpufeature.h

+ 0
- 2
arch/x86/include/asm/cpufeature.h View File

@@ -205,8 +205,6 @@ t_no:
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 #define static_cpu_has(bit)					\
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 (								\
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-	(bit == X86_FEATURE_FXSR || bit == X86_FEATURE_XSAVE) ? \
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-		false : 					\
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 	__builtin_constant_p(boot_cpu_has(bit)) ?		\
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 		boot_cpu_has(bit) :				\
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 		_static_cpu_has(bit)				\

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