From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760442Ab3GSMKo (ORCPT ); Fri, 19 Jul 2013 08:10:44 -0400 Received: from mx1.redhat.com ([209.132.183.28]:60604 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760341Ab3GSMKm (ORCPT ); Fri, 19 Jul 2013 08:10:42 -0400 Message-ID: <51E92CAB.7020906@redhat.com> Date: Fri, 19 Jul 2013 14:10:19 +0200 From: Paolo Bonzini User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130625 Thunderbird/17.0.7 MIME-Version: 1.0 To: Jason Wang CC: gleb@redhat.com, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Vadim Rozenfeld , "K. Y. Srinivasan" Subject: Re: [PATCH] x86: properly handle KVM emulation of hyperv References: <1374229505-19470-1-git-send-email-jasowang@redhat.com> In-Reply-To: <1374229505-19470-1-git-send-email-jasowang@redhat.com> X-Enigmail-Version: 1.5.1 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 > Cc: Paolo Bonzini > Cc: Vadim Rozenfeld > Cc: K. Y. Srinivasan > Cc: Thomas Gleixner > Cc: Ingo Molnar > Cc: "H. Peter Anvin" > Signed-off-by: Jason Wang > --- > 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