linux-kernel - [PATCH 07/11] KVM: x86: Disable SMM for TDX

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Date:   Fri, 12 Nov 2021 23:37:29 +0800
From:   Xiaoyao Li <xiaoyao.li@...el.com>
To:     Paolo Bonzini <pbonzini@...hat.com>,
        Sean Christopherson <seanjc@...gle.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>
Cc:     xiaoyao.li@...el.com, erdemaktas@...gle.com,
        Connor Kuehl <ckuehl@...hat.com>, x86@...nel.org,
        linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        isaku.yamahata@...el.com, Kai Huang <kai.huang@...el.com>
Subject: [PATCH 07/11] KVM: x86: Disable SMM for TDX

SMM is not supported for TDX VM, nor can KVM emulate it for TDX VM.

Signed-off-by: Xiaoyao Li <xiaoyao.li@...el.com>
---
 arch/x86/kvm/irq_comm.c | 2 ++
 arch/x86/kvm/x86.c      | 6 ++++++
 arch/x86/kvm/x86.h      | 5 +++++
 3 files changed, 13 insertions(+)

diff --git a/arch/x86/kvm/irq_comm.c b/arch/x86/kvm/irq_comm.c
index f9f643e31893..705fc0dc0272 100644
--- a/arch/x86/kvm/irq_comm.c
+++ b/arch/x86/kvm/irq_comm.c
@@ -128,6 +128,8 @@ static inline bool kvm_msi_route_invalid(struct kvm *kvm,
 			       .data = e->msi.data };
 	return  (kvm_eoi_intercept_disallowed(kvm) &&
 		 msg.arch_data.is_level) ||
+		(kvm_smm_unsupported(kvm) &&
+		 msg.arch_data.delivery_mode == APIC_DELIVERY_MODE_SMI) ||
 		(kvm->arch.x2apic_format && (msg.address_hi & 0xff));
 }
 
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 113ed9aa5c82..1f3cc2a2d844 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4132,6 +4132,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 			r |= KVM_X86_DISABLE_EXITS_MWAIT;
 		break;
 	case KVM_CAP_X86_SMM:
+		if (kvm && kvm_smm_unsupported(kvm))
+			break;
+
 		/* SMBASE is usually relocated above 1M on modern chipsets,
 		 * and SMM handlers might indeed rely on 4G segment limits,
 		 * so do not report SMM to be available if real mode is
@@ -4500,6 +4503,9 @@ static int kvm_vcpu_ioctl_nmi(struct kvm_vcpu *vcpu)
 
 static int kvm_vcpu_ioctl_smi(struct kvm_vcpu *vcpu)
 {
+	if (kvm_smm_unsupported(vcpu->kvm))
+		return -EINVAL;
+
 	kvm_make_request(KVM_REQ_SMI, vcpu);
 
 	return 0;
diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
index 65c8c77e507b..ab7c91ca2478 100644
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h
@@ -456,6 +456,11 @@ static __always_inline bool kvm_eoi_intercept_disallowed(struct kvm *kvm)
 	return kvm->arch.vm_type == KVM_X86_TDX_VM;
 }
 
+static __always_inline bool kvm_smm_unsupported(struct kvm *kvm)
+{
+	return kvm->arch.vm_type == KVM_X86_TDX_VM;
+}
+
 void kvm_load_guest_xsave_state(struct kvm_vcpu *vcpu);
 void kvm_load_host_xsave_state(struct kvm_vcpu *vcpu);
 int kvm_spec_ctrl_test_value(u64 value);
-- 
2.27.0