From mboxrd@z Thu Jan 1 00:00:00 1970 From: "H. Peter Anvin" Subject: Re: [PATCH] x86: properly handle KVM emulation of hyperv Date: Fri, 19 Jul 2013 14:03:54 -0700 Message-ID: <51E9A9BA.1070805@zytor.com> References: <1374229505-19470-1-git-send-email-jasowang@redhat.com> <51E92CAB.7020906@redhat.com> <51E9A896.8070408@zytor.com> <51E9A8E0.8080404@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: Jason Wang , gleb@redhat.com, tglx@linutronix.de, mingo@redhat.com, x86@kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Vadim Rozenfeld , "K. Y. Srinivasan" To: Paolo Bonzini Return-path: In-Reply-To: <51E9A8E0.8080404@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On 07/19/2013 02:00 PM, Paolo Bonzini wrote: > Il 19/07/2013 22:59, H. Peter Anvin ha scritto: >>>>>> - 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). >>>> >> Any way we can centralize this stuff? > > I guess a function cpuid_hypervisor_base("KVMKVMKVM") that does the scan? > Something like that. -hpa