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x86, kvm: KVM paravirt kernels don't check for CPUID being unavailable

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We set cpuid_level to -1 if there is no CPUID instruction (only
possible on i386).

Signed-off-by: Alan Cox <alan@linux.intel.com>
Link: http://lkml.kernel.org/r/20120514174059.30236.1064.stgit@bluebook
Resolves-bug: https://bugzilla.kernel.org/show_bug.cgi?id=12122
Cc: Avi Kivity <avi@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
This commit is contained in:
Alan Cox 2012-05-14 18:41:09 +01:00 committed by H. Peter Anvin
parent b2a3477727
commit c3709e6734
1 changed files with 3 additions and 0 deletions
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3
arch/x86/include/asm/kvm_para.h
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@ -170,6 +170,9 @@ static inline int kvm_para_available(void)
unsigned int eax, ebx, ecx, edx; unsigned int eax, ebx, ecx, edx;
char signature[13]; char signature[13];
if (boot_cpu_data.cpuid_level < 0)
return 0; /* So we don't blow up on old processors */
cpuid(KVM_CPUID_SIGNATURE, &eax, &ebx, &ecx, &edx); cpuid(KVM_CPUID_SIGNATURE, &eax, &ebx, &ecx, &edx);
memcpy(signature + 0, &ebx, 4); memcpy(signature + 0, &ebx, 4);
memcpy(signature + 4, &ecx, 4); memcpy(signature + 4, &ecx, 4);