[PATCH v2 4/4] KVM: x86: Add support for MCG_CMCI_P and handling of injected UCNAs.

[Jue Wang <juew@google.com>]

Note prior to this patch, the UCNA type of signaling can already be
processed by kvm_vcpu_ioctl_x86_set_mce and does not result in correct
CMCI signaling semantic.

Signed-off-by: Jue Wang <juew@google.com>
---
 arch/x86/kvm/vmx/vmx.c |  1 +
 arch/x86/kvm/x86.c     | 48 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 49 insertions(+)

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index b730d799c26e..63aa2b3d30ca 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -8035,6 +8035,7 @@ static __init int hardware_setup(void)
 	}
 
 	kvm_mce_cap_supported |= MCG_LMCE_P;
+	kvm_mce_cap_supported |= MCG_CMCI_P;
 
 	if (pt_mode != PT_MODE_SYSTEM && pt_mode != PT_MODE_HOST_GUEST)
 		return -EINVAL;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 73c64d2b9e60..eb6058ca1e70 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4775,6 +4775,50 @@ static int kvm_vcpu_ioctl_x86_setup_mce(struct kvm_vcpu *vcpu,
 	return r;
 }
 
+static bool is_ucna(u64 mcg_status, u64 mci_status)
+{
+	return !mcg_status &&
+		!(mci_status & (MCI_STATUS_PCC | MCI_STATUS_S | MCI_STATUS_AR));
+}
+
+static int kvm_vcpu_x86_set_ucna(struct kvm_vcpu *vcpu,
+		struct kvm_x86_mce *mce)
+{
+	u64 mcg_cap = vcpu->arch.mcg_cap;
+	unsigned int bank_num = mcg_cap & 0xff;
+	u64 *banks = vcpu->arch.mce_banks;
+
+	/* Check for legal bank number in guest */
+	if (mce->bank >= bank_num)
+		return -EINVAL;
+
+	/*
+	 * UCNA signals should not set bits that are only used for machine check
+	 * exceptions.
+	 */
+	if (mce->mcg_status ||
+		(mce->status & (MCI_STATUS_PCC | MCI_STATUS_S | MCI_STATUS_AR)))
+		return -EINVAL;
+
+	/* UCNA must have VAL and UC bits set */
+	if (!(mce->status & MCI_STATUS_VAL) || !(mce->status & MCI_STATUS_UC))
+		return -EINVAL;
+
+	banks += 4 * mce->bank;
+	banks[1] = mce->status;
+	banks[2] = mce->addr;
+	banks[3] = mce->misc;
+	vcpu->arch.mcg_status = mce->mcg_status;
+
+	if (!(mcg_cap & MCG_CMCI_P) || !(vcpu->arch.mci_ctl2_banks[mce->bank] & MCI_CTL2_CMCI_EN))
+		return 0;
+
+	if (lapic_in_kernel(vcpu))
+		kvm_apic_local_deliver(vcpu->arch.apic, APIC_LVTCMCI);
+
+	return 0;
+}
+
 static int kvm_vcpu_ioctl_x86_set_mce(struct kvm_vcpu *vcpu,
 				      struct kvm_x86_mce *mce)
 {
@@ -4784,6 +4828,10 @@ static int kvm_vcpu_ioctl_x86_set_mce(struct kvm_vcpu *vcpu,
 
 	if (mce->bank >= bank_num || !(mce->status & MCI_STATUS_VAL))
 		return -EINVAL;
+
+	if (is_ucna(mce->mcg_status, mce->status))
+		return kvm_vcpu_x86_set_ucna(vcpu, mce);
+
 	/*
 	 * if IA32_MCG_CTL is not all 1s, the uncorrected error
 	 * reporting is disabled
-- 
2.35.1.1178.g4f1659d476-goog