linux-kernel - [PATCH AUTOSEL for 4.14 098/135] KVM: nVMX: Fix EPT switching advertising

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Date:   Thu, 7 Dec 2017 15:45:54 +0000
From:   alexander.levin@...izon.com
To:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "stable@...r.kernel.org" <stable@...r.kernel.org>
Cc:     Wanpeng Li <wanpeng.li@...mail.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Radim Krčmář <rkrcmar@...hat.com>,
        Jim Mattson <jmattson@...gle.com>, alexander.levin@...izon.com
Subject: [PATCH AUTOSEL for 4.14 098/135] KVM: nVMX: Fix EPT switching
 advertising

From: Wanpeng Li <wanpeng.li@...mail.com>

[ Upstream commit 575b3a2cb439b03fd603ea77c73c76f3ed237596 ]

I can use vmxcap tool to observe "EPTP Switching   yes" even if EPT is not
exposed to L1.

EPT switching is advertised unconditionally since it is emulated, however,
it can be treated as an extended feature for EPT and it should not be
advertised if EPT itself is not exposed. This patch fixes it.

Reviewed-by: David Hildenbrand <david@...hat.com>
Cc: Paolo Bonzini <pbonzini@...hat.com>
Cc: Radim Krčmář <rkrcmar@...hat.com>
Cc: Jim Mattson <jmattson@...gle.com>
Signed-off-by: Wanpeng Li <wanpeng.li@...mail.com>
Signed-off-by: Radim Krčmář <rkrcmar@...hat.com>
Signed-off-by: Sasha Levin <alexander.levin@...izon.com>
---
 arch/x86/kvm/vmx.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index b21113bcf227..4b853d201943 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -2845,8 +2845,9 @@ static void nested_vmx_setup_ctls_msrs(struct vcpu_vmx *vmx)
 		 * Advertise EPTP switching unconditionally
 		 * since we emulate it
 		 */
-		vmx->nested.nested_vmx_vmfunc_controls =
-			VMX_VMFUNC_EPTP_SWITCHING;
+		if (enable_ept)
+			vmx->nested.nested_vmx_vmfunc_controls =
+				VMX_VMFUNC_EPTP_SWITCHING;
 	}
 
 	/*
-- 
2.11.0