From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vitaly Kuznetsov Subject: Re: [PATCH] x86/kvm/hyper-v: tweak HYPERV_CPUID_ENLIGHTMENT_INFO Date: Thu, 24 Jan 2019 18:39:21 +0100 Message-ID: <8736pigdkm.fsf@vitty.brq.redhat.com> References: <20190124171516.23626-1-vkuznets@redhat.com> <805B7B08-734E-4A96-AF98-D33065C59105@oracle.com> Mime-Version: 1.0 Content-Type: text/plain Cc: kvm@vger.kernel.org, Paolo Bonzini , Radim =?utf-8?B?S3LEjW3DocWZ?= , Roman Kagan , linux-kernel@vger.kernel.org To: Liran Alon Return-path: In-Reply-To: <805B7B08-734E-4A96-AF98-D33065C59105@oracle.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org Liran Alon writes: >> On 24 Jan 2019, at 19:15, Vitaly Kuznetsov wrote: >> >> We shouldn't probably be suggesting using Enlightened VMCS when it's not >> enabled (not supported from guest's point of view). System reset through >> synthetic MSR is not recommended neither by genuine Hyper-V nor my QEMU. >> >> Windows seems to be fine either way but let's be consistent. >> >> Fixes: 2bc39970e932 ("x86/kvm/hyper-v: Introduce KVM_GET_SUPPORTED_HV_CPUID") >> Signed-off-by: Vitaly Kuznetsov >> --- >> arch/x86/kvm/hyperv.c | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c >> index ac44a681f065..4730fcaa70cf 100644 >> --- a/arch/x86/kvm/hyperv.c >> +++ b/arch/x86/kvm/hyperv.c >> @@ -1847,11 +1847,11 @@ int kvm_vcpu_ioctl_get_hv_cpuid(struct kvm_vcpu *vcpu, struct kvm_cpuid2 *cpuid, >> case HYPERV_CPUID_ENLIGHTMENT_INFO: >> ent->eax |= HV_X64_REMOTE_TLB_FLUSH_RECOMMENDED; >> ent->eax |= HV_X64_APIC_ACCESS_RECOMMENDED; >> - ent->eax |= HV_X64_SYSTEM_RESET_RECOMMENDED; >> 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 >> -- >> 2.20.1 >> > > Seems to me that there are 2 unrelated separated patches here. Why not > split them? They seem to be too small :-) No problem, I'll split them up in v2. > For content itself: Reviewed-by: Liran Alon > Thanks! -- Vitaly