linux-kernel - [PATCH RFC 1/3] x86/kvm/hyper-v: remove stale evmcs_already_enabled check from nested_enable

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Date:   Wed, 15 Jan 2020 18:10:12 +0100
From:   Vitaly Kuznetsov <vkuznets@...hat.com>
To:     kvm@...r.kernel.org
Cc:     Paolo Bonzini <pbonzini@...hat.com>,
        Sean Christopherson <sean.j.christopherson@...el.com>,
        Jim Mattson <jmattson@...gle.com>,
        linux-kernel@...r.kernel.org, Liran Alon <liran.alon@...cle.com>,
        Roman Kagan <rkagan@...tuozzo.com>
Subject: [PATCH RFC 1/3] x86/kvm/hyper-v: remove stale evmcs_already_enabled check from nested_enable_evmcs()

In nested_enable_evmcs() evmcs_already_enabled check doesn't really do
anything: controls are already sanitized and we return '0' regardless.
Just drop the check.

Signed-off-by: Vitaly Kuznetsov <vkuznets@...hat.com>
---
 arch/x86/kvm/vmx/evmcs.c | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/arch/x86/kvm/vmx/evmcs.c b/arch/x86/kvm/vmx/evmcs.c
index 72359709cdc1..89c3e0caf39f 100644
--- a/arch/x86/kvm/vmx/evmcs.c
+++ b/arch/x86/kvm/vmx/evmcs.c
@@ -350,17 +350,12 @@ int nested_enable_evmcs(struct kvm_vcpu *vcpu,
 			uint16_t *vmcs_version)
 {
 	struct vcpu_vmx *vmx = to_vmx(vcpu);
-	bool evmcs_already_enabled = vmx->nested.enlightened_vmcs_enabled;
 
 	vmx->nested.enlightened_vmcs_enabled = true;
 
 	if (vmcs_version)
 		*vmcs_version = nested_get_evmcs_version(vcpu);
 
-	/* We don't support disabling the feature for simplicity. */
-	if (evmcs_already_enabled)
-		return 0;
-
 	vmx->nested.msrs.pinbased_ctls_high &= ~EVMCS1_UNSUPPORTED_PINCTRL;
 	vmx->nested.msrs.entry_ctls_high &= ~EVMCS1_UNSUPPORTED_VMENTRY_CTRL;
 	vmx->nested.msrs.exit_ctls_high &= ~EVMCS1_UNSUPPORTED_VMEXIT_CTRL;
-- 
2.24.1