linux-kernel - [PATCH v19 126/130] KVM: TDX: Inhibit APICv for TDX guest

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Message-Id: <38e2f8a77e89301534d82325946eb74db3e47815.1708933498.git.isaku.yamahata@intel.com>
Date: Mon, 26 Feb 2024 00:27:08 -0800
From: isaku.yamahata@...el.com
To: kvm@...r.kernel.org,
	linux-kernel@...r.kernel.org
Cc: isaku.yamahata@...el.com,
	isaku.yamahata@...il.com,
	Paolo Bonzini <pbonzini@...hat.com>,
	erdemaktas@...gle.com,
	Sean Christopherson <seanjc@...gle.com>,
	Sagi Shahar <sagis@...gle.com>,
	Kai Huang <kai.huang@...el.com>,
	chen.bo@...el.com,
	hang.yuan@...el.com,
	tina.zhang@...el.com
Subject: [PATCH v19 126/130] KVM: TDX: Inhibit APICv for TDX guest

From: Isaku Yamahata <isaku.yamahata@...el.com>

TDX doesn't support APICV, inhibit APICv for TDX guest.  Follow how SEV
does it.  Define a new inhibit reason for TDX, set it on TD
initialization, and add the flag to kvm_x86_ops.required_apicv_inhibits.

Signed-off-by: Isaku Yamahata <isaku.yamahata@...el.com>
---
 arch/x86/include/asm/kvm_host.h | 9 +++++++++
 arch/x86/kvm/vmx/main.c         | 3 ++-
 arch/x86/kvm/vmx/tdx.c          | 4 ++++
 3 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 2686c080820b..920fb771246b 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1300,6 +1300,15 @@ enum kvm_apicv_inhibit {
 	 * mapping between logical ID and vCPU.
 	 */
 	APICV_INHIBIT_REASON_LOGICAL_ID_ALIASED,
+
+	/*********************************************************/
+	/* INHIBITs that are relevant only to the Intel's APICv. */
+	/*********************************************************/
+
+	/*
+	 * APICv is disabled because TDX doesn't support it.
+	 */
+	APICV_INHIBIT_REASON_TDX,
 };
 
 struct kvm_arch {
diff --git a/arch/x86/kvm/vmx/main.c b/arch/x86/kvm/vmx/main.c
index c46c860be0f2..2cd404fd7176 100644
--- a/arch/x86/kvm/vmx/main.c
+++ b/arch/x86/kvm/vmx/main.c
@@ -1022,7 +1022,8 @@ static void vt_post_memory_mapping(struct kvm_vcpu *vcpu,
 	 BIT(APICV_INHIBIT_REASON_BLOCKIRQ) |			\
 	 BIT(APICV_INHIBIT_REASON_PHYSICAL_ID_ALIASED) |	\
 	 BIT(APICV_INHIBIT_REASON_APIC_ID_MODIFIED) |		\
-	 BIT(APICV_INHIBIT_REASON_APIC_BASE_MODIFIED))
+	 BIT(APICV_INHIBIT_REASON_APIC_BASE_MODIFIED) |		\
+	 BIT(APICV_INHIBIT_REASON_TDX))
 
 struct kvm_x86_ops vt_x86_ops __initdata = {
 	.name = KBUILD_MODNAME,
diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index f706c346eea4..7be1be161dc2 100644
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -2488,6 +2488,8 @@ static int __tdx_td_init(struct kvm *kvm, struct td_params *td_params,
 		goto teardown;
 	}
 
+	kvm_set_apicv_inhibit(kvm, APICV_INHIBIT_REASON_TDX);
+
 	return 0;
 
 	/*
@@ -2821,6 +2823,8 @@ static int tdx_td_vcpu_init(struct kvm_vcpu *vcpu, u64 vcpu_rcx)
 		return -EIO;
 	}
 
+	WARN_ON_ONCE(kvm_apicv_activated(vcpu->kvm));
+	vcpu->arch.apic->apicv_active = false;
 	vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE;
 	tdx->td_vcpu_created = true;
 	return 0;
-- 
2.25.1