From: Sean Christopherson <sean.j.christopher...@intel.com>

Add a flag to disallow MCE injection and reject KVM_X86_SETUP_MCE with
-EINVAL when set.  TDX doesn't support injecting exceptions, including
(virtual) #MCs.

Signed-off-by: Kai Huang <kai.hu...@linux.intel.com>
Co-developed-by: Sean Christopherson <sean.j.christopher...@intel.com>
Signed-off-by: Sean Christopherson <sean.j.christopher...@intel.com>
---
 arch/x86/include/asm/kvm_host.h |  1 +
 arch/x86/kvm/x86.c              | 14 +++++++-------
 2 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index e8180a1fe610..70528102d865 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -996,6 +996,7 @@ struct kvm_arch {
 
        bool guest_state_protected;
        bool irq_injection_disallowed;
+       bool mce_injection_disallowed;
 
        struct kvm_pmu_event_filter *pmu_event_filter;
        struct task_struct *nx_lpage_recovery_thread;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index ec66d5d53a1a..2fb0d20c5788 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4095,15 +4095,16 @@ static int vcpu_ioctl_tpr_access_reporting(struct 
kvm_vcpu *vcpu,
 static int kvm_vcpu_ioctl_x86_setup_mce(struct kvm_vcpu *vcpu,
                                        u64 mcg_cap)
 {
-       int r;
        unsigned bank_num = mcg_cap & 0xff, bank;
 
-       r = -EINVAL;
+       if (vcpu->kvm->arch.mce_injection_disallowed)
+               return -EINVAL;
+
        if (!bank_num || bank_num > KVM_MAX_MCE_BANKS)
-               goto out;
+               return -EINVAL;
        if (mcg_cap & ~(kvm_mce_cap_supported | 0xff | 0xff0000))
-               goto out;
-       r = 0;
+               return -EINVAL;
+
        vcpu->arch.mcg_cap = mcg_cap;
        /* Init IA32_MCG_CTL to all 1s */
        if (mcg_cap & MCG_CTL_P)
@@ -4113,8 +4114,7 @@ static int kvm_vcpu_ioctl_x86_setup_mce(struct kvm_vcpu 
*vcpu,
                vcpu->arch.mce_banks[bank*4] = ~(u64)0;
 
        kvm_x86_ops.setup_mce(vcpu);
-out:
-       return r;
+       return 0;
 }
 
 static int kvm_vcpu_ioctl_x86_set_mce(struct kvm_vcpu *vcpu,
-- 
2.17.1

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