linux-kernel - [RFC PATCH 16/18] KVM: nVMX: Setup Intel MBEC in nested secondary controls

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Message-ID: <20250313203702.575156-17-jon@nutanix.com>
Date: Thu, 13 Mar 2025 13:36:55 -0700
From: Jon Kohler <jon@...anix.com>
To: seanjc@...gle.com, pbonzini@...hat.com, tglx@...utronix.de,
        mingo@...hat.com, bp@...en8.de, dave.hansen@...ux.intel.com,
        x86@...nel.org, hpa@...or.com, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Cc: Jon Kohler <jon@...anix.com>
Subject: [RFC PATCH 16/18] KVM: nVMX: Setup Intel MBEC in nested secondary controls

Setup Intel Mode Based Execution Control (bit 22) for nested
guest, gated on module parameter enablement.

Signed-off-by: Jon Kohler <jon@...anix.com>

---
 arch/x86/kvm/vmx/nested.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 931a7361c30f..ce3a6d6dfce7 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -7099,6 +7099,10 @@ static void nested_vmx_setup_secondary_ctls(u32 ept_caps,
 		 */
 		if (cpu_has_vmx_vmfunc())
 			msrs->vmfunc_controls = VMX_VMFUNC_EPTP_SWITCHING;
+
+		if (enable_pt_guest_exec_control)
+			msrs->secondary_ctls_high |=
+				SECONDARY_EXEC_MODE_BASED_EPT_EXEC;
 	}
 
 	/*
-- 
2.43.0