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

From: Xiaoyao Li
Date: Fri Nov 12 2021 - 10:38:48 EST


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

Signed-off-by: Xiaoyao Li <xiaoyao.li@xxxxxxxxx>
---
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