From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vitaly Kuznetsov Subject: Re: [PATCH v2 2/2] x86/kvm/hyper-v: recommend using eVMCS only when it is enabled Date: Fri, 25 Jan 2019 12:43:33 +0100 Message-ID: <87h8dxnesa.fsf@vitty.brq.redhat.com> References: <20190125111934.28782-1-vkuznets@redhat.com> <20190125111934.28782-3-vkuznets@redhat.com> Mime-Version: 1.0 Content-Type: text/plain Cc: Paolo Bonzini , Radim =?utf-8?B?S3LEjW3DocWZ?= , Roman Kagan , Liran Alon , linux-kernel@vger.kernel.org To: kvm@vger.kernel.org Return-path: In-Reply-To: <20190125111934.28782-3-vkuznets@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org Vitaly Kuznetsov writes: > We shouldn't probably be suggesting using Enlightened VMCS when it's not > enabled (not supported from guest's point of view). Hyper-V on KVM seems > to be fine either way but let's be consistent. > Fixes: 2bc39970e932 ("x86/kvm/hyper-v: Introduce KVM_GET_SUPPORTED_HV_CPUID") is missing here. Hope it can be added upon commit. > Reviewed-by: Liran Alon > Signed-off-by: Vitaly Kuznetsov > --- > arch/x86/kvm/hyperv.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c > index 4840f5b3c88f..4730fcaa70cf 100644 > --- a/arch/x86/kvm/hyperv.c > +++ b/arch/x86/kvm/hyperv.c > @@ -1850,7 +1850,8 @@ int kvm_vcpu_ioctl_get_hv_cpuid(struct kvm_vcpu *vcpu, struct kvm_cpuid2 *cpuid, > ent->eax |= HV_X64_RELAXED_TIMING_RECOMMENDED; > ent->eax |= HV_X64_CLUSTER_IPI_RECOMMENDED; > ent->eax |= HV_X64_EX_PROCESSOR_MASKS_RECOMMENDED; > - ent->eax |= HV_X64_ENLIGHTENED_VMCS_RECOMMENDED; > + if (evmcs_ver) > + ent->eax |= HV_X64_ENLIGHTENED_VMCS_RECOMMENDED; > > /* > * Default number of spinlock retry attempts, matches -- Vitaly