linux-kernel - [PATCH v2 2/2] KVM: nVMX: Simplify the setting of SECONDARY_EXEC_ENABLE

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Message-Id: <20221109075413.1405803-3-yu.c.zhang@linux.intel.com>
Date:   Wed,  9 Nov 2022 15:54:13 +0800
From:   Yu Zhang <yu.c.zhang@...ux.intel.com>
To:     pbonzini@...hat.com, seanjc@...gle.com, kvm@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org
Subject: [PATCH v2 2/2] KVM: nVMX: Simplify the setting of SECONDARY_EXEC_ENABLE_VMFUNC for nested.

Values of base settings for nested proc-based VM-Execution control MSR come
from the ones for non-nested. And for SECONDARY_EXEC_ENABLE_VMFUNC flag,
KVM currently a) first mask off it from vmcs_conf->cpu_based_2nd_exec_ctrl;
b) then check it against the same source; c) and reset it again if host has
it.

So just simplify this, by not masking off SECONDARY_EXEC_ENABLE_VMFUNC in
the first place.

No functional change.

Signed-off-by: Sean Christopherson <seanjc@...gle.com>
Signed-off-by: Yu Zhang <yu.c.zhang@...ux.intel.com>
---
 arch/x86/kvm/vmx/nested.c | 14 +++++---------
 1 file changed, 5 insertions(+), 9 deletions(-)

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 1acb81c2be11..2bad79985c10 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -6806,6 +6806,7 @@ void nested_vmx_setup_ctls_msrs(struct vmcs_config *vmcs_conf, u32 ept_caps)
 		SECONDARY_EXEC_VIRTUAL_INTR_DELIVERY |
 		SECONDARY_EXEC_RDRAND_EXITING |
 		SECONDARY_EXEC_ENABLE_INVPCID |
+		SECONDARY_EXEC_ENABLE_VMFUNC |
 		SECONDARY_EXEC_RDSEED_EXITING |
 		SECONDARY_EXEC_XSAVES |
 		SECONDARY_EXEC_TSC_SCALING;
@@ -6837,18 +6838,13 @@ void nested_vmx_setup_ctls_msrs(struct vmcs_config *vmcs_conf, u32 ept_caps)
 				SECONDARY_EXEC_ENABLE_PML;
 			msrs->ept_caps |= VMX_EPT_AD_BIT;
 		}
-	}

-	if (cpu_has_vmx_vmfunc()) {
-		msrs->secondary_ctls_high |=
-			SECONDARY_EXEC_ENABLE_VMFUNC;
 		/*
-		 * Advertise EPTP switching unconditionally
-		 * since we emulate it
+		 * Advertise EPTP switching irrespective of hardware support,
+		 * KVM emulates it in software so long as VMFUNC is supported.
 		 */
-		if (enable_ept)
-			msrs->vmfunc_controls =
-				VMX_VMFUNC_EPTP_SWITCHING;
+		if (cpu_has_vmx_vmfunc())
+			msrs->vmfunc_controls = VMX_VMFUNC_EPTP_SWITCHING;
 	}

 	/*
-- 
2.17.1