Commit-ID: c3709e6734daa4d9b37fe31592ebb0eb57bae1bb
Gitweb: http://git.kernel.org/tip/c3709e6734daa4d9b37fe31592ebb0eb57bae1bb
Author: Alan Cox <[email protected]>
AuthorDate: Mon, 14 May 2012 18:41:09 +0100
Committer: H. Peter Anvin <[email protected]>
CommitDate: Mon, 14 May 2012 10:49:32 -0700
x86, kvm: KVM paravirt kernels don't check for CPUID being unavailable
We set cpuid_level to -1 if there is no CPUID instruction (only
possible on i386).
Signed-off-by: Alan Cox <[email protected]>
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 <[email protected]>
Cc: Marcelo Tosatti <[email protected]>
Signed-off-by: H. Peter Anvin <[email protected]>
---
arch/x86/include/asm/kvm_para.h | 3 +++
1 files changed, 3 insertions(+), 0 deletions(-)
diff --git a/arch/x86/include/asm/kvm_para.h b/arch/x86/include/asm/kvm_para.h
index 734c376..183922e 100644
--- a/arch/x86/include/asm/kvm_para.h
+++ b/arch/x86/include/asm/kvm_para.h
@@ -170,6 +170,9 @@ static inline int kvm_para_available(void)
unsigned int eax, ebx, ecx, edx;
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);
memcpy(signature + 0, &ebx, 4);
memcpy(signature + 4, &ecx, 4);