Re: linux-next: manual merge of the kvm tree with the tip tree

From: Gleb Natapov
Date: Wed May 16 2012 - 03:53:45 EST


On Wed, May 16, 2012 at 05:14:35PM +1000, Stephen Rothwell wrote:
> Hi all,
>
> Today's linux-next merge of the kvm tree got a conflict in
> arch/x86/include/asm/kvm_para.h between commit c3709e6734da ("x86, kvm:
> KVM paravirt kernels don't check for CPUID being unavailable") from the
> tip tree and commit 9b72d3b07dd9 ("KVM guest: make kvm_para_available()
> check hypervisor bit reading cpuid leaf") from the kvm tree.
>
> Just context changes. I fixed it up (see below) and can carry the fix as
> necessary.
Fix looks good to me.

> --
> Cheers,
> Stephen Rothwell sfr@xxxxxxxxxxxxxxxx
>
> diff --cc arch/x86/include/asm/kvm_para.h
> index 183922e,a7a7a94..0000000
> --- a/arch/x86/include/asm/kvm_para.h
> +++ b/arch/x86/include/asm/kvm_para.h
> @@@ -170,17 -178,16 +178,19 @@@ static inline int kvm_para_available(vo
> 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);
> - memcpy(signature + 8, &edx, 4);
> - signature[12] = 0;
> + if (cpu_has_hypervisor) {
> + cpuid(KVM_CPUID_SIGNATURE, &eax, &ebx, &ecx, &edx);
> + memcpy(signature + 0, &ebx, 4);
> + memcpy(signature + 4, &ecx, 4);
> + memcpy(signature + 8, &edx, 4);
> + signature[12] = 0;
>
> - if (strcmp(signature, "KVMKVMKVM") == 0)
> - return 1;
> + if (strcmp(signature, "KVMKVMKVM") == 0)
> + return 1;
> + }
>
> return 0;
> }



--
Gleb.
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