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From: Vitaly Kuznetsov <vkuznets@redhat.com>
To: kvm@vger.kernel.org
Cc: "Paolo Bonzini" <pbonzini@redhat.com>,
	"Radim Krčmář" <rkrcmar@redhat.com>,
	"Roman Kagan" <rkagan@virtuozzo.com>,
	"Liran Alon" <liran.alon@oracle.com>,
	linux-kernel@vger.kernel.org
Subject: [PATCH v2 2/2] x86/kvm/hyper-v: recommend using eVMCS only when it is enabled
Date: Fri, 25 Jan 2019 12:19:34 +0100	[thread overview]
Message-ID: <20190125111934.28782-3-vkuznets@redhat.com> (raw)
In-Reply-To: <20190125111934.28782-1-vkuznets@redhat.com>

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.

Reviewed-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
 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
-- 
2.20.1


  parent reply	other threads:[~2019-01-25 11:19 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-25 11:19 [PATCH v2 0/2] tweak HYPERV_CPUID_ENLIGHTMENT_INFO Vitaly Kuznetsov
2019-01-25 11:19 ` [PATCH v2 1/2] x86/kvm/hyper-v: don't recommend doing reset via synthetic MSR Vitaly Kuznetsov
2019-01-25 11:19 ` Vitaly Kuznetsov [this message]
2019-01-25 11:43   ` [PATCH v2 2/2] x86/kvm/hyper-v: recommend using eVMCS only when it is enabled Vitaly Kuznetsov
2019-01-25 18:11     ` Paolo Bonzini
2019-01-25 17:51 ` [PATCH v2 0/2] tweak HYPERV_CPUID_ENLIGHTMENT_INFO Paolo Bonzini

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