Il 19/07/2013 12:25, Jason Wang ha scritto:
> Recent kvm has some basic support of hyperv, this will cause the guest to
> identify itself running on top of hyperv instead of kvm which will disable kvm
> pv functionality. Solve this by check kvm para platform first and also check
> KVM_CPUID_SIGNATURE_NEXT which were set when kvm emulate hyperv.
>
> Cc: Gleb Natapov <g...@redhat.com>
> Cc: Paolo Bonzini <pbonz...@redhat.com>
> Cc: Vadim Rozenfeld <vroze...@redhat.com>
> Cc: K. Y. Srinivasan <k...@microsoft.com>
> Cc: Thomas Gleixner <t...@linutronix.de>
> Cc: Ingo Molnar <mi...@redhat.com>
> Cc: "H. Peter Anvin" <h...@zytor.com>
> Signed-off-by: Jason Wang <jasow...@redhat.com>
> ---
> arch/x86/include/asm/kvm_para.h | 25 +++++++++++++++++--------
> arch/x86/include/uapi/asm/kvm_para.h | 1 +
> arch/x86/kernel/cpu/hypervisor.c | 2 +-
> 3 files changed, 19 insertions(+), 9 deletions(-)
>
> diff --git a/arch/x86/include/asm/kvm_para.h b/arch/x86/include/asm/kvm_para.h
> index 695399f..aa8f3a7 100644
> --- a/arch/x86/include/asm/kvm_para.h
> +++ b/arch/x86/include/asm/kvm_para.h
> @@ -85,22 +85,31 @@ static inline long kvm_hypercall4(unsigned int nr,
> unsigned long p1,
> return ret;
> }
>
> -static inline bool kvm_para_available(void)
> +static inline bool kvm_para_available_function(unsigned int function)
> {
> unsigned int eax, ebx, ecx, edx;
> char signature[13];
>
> + cpuid(function, &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 true;
> +
> + return false;
> +}
> +
> +static inline bool kvm_para_available(void)
> +{
> if (boot_cpu_data.cpuid_level < 0)
> return false; /* So we don't blow up on old processors */
>
> 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)
> + if (kvm_para_available_function(KVM_CPUID_SIGNATURE) ||
> + kvm_para_available_function(KVM_CPUID_SIGNATURE_NEXT))
> return true;
> }
Nice catch. Just one small thing, you should loop until 0x40010000, as
done in arch/x86/include/asm/xen/hypervisor.h, in case one day a third
hypervisor implements three extensions (Hyper-V, KVM and its own set).
Paolo
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