Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1259 insertions, 0 deletions

diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c
new file mode 100644
index 000000000..fb125b54e
--- /dev/null
+++ b/arch/x86/kvm/svm/avic.c
@@ -0,0 +1,1259 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Kernel-based Virtual Machine driver for Linux
+ *
+ * AMD SVM support
+ *
+ * Copyright (C) 2006 Qumranet, Inc.
+ * Copyright 2010 Red Hat, Inc. and/or its affiliates.
+ *
+ * Authors:
+ *   Yaniv Kamay  <yaniv@qumranet.com>
+ *   Avi Kivity   <avi@qumranet.com>
+ */
+
+#define pr_fmt(fmt) "SVM: " fmt
+
+#include <linux/kvm_types.h>
+#include <linux/hashtable.h>
+#include <linux/amd-iommu.h>
+#include <linux/kvm_host.h>
+
+#include <asm/irq_remapping.h>
+
+#include "trace.h"
+#include "lapic.h"
+#include "x86.h"
+#include "irq.h"
+#include "svm.h"
+
+/*
+ * Encode the arbitrary VM ID and the vCPU's default APIC ID, i.e the vCPU ID,
+ * into the GATag so that KVM can retrieve the correct vCPU from a GALog entry
+ * if an interrupt can't be delivered, e.g. because the vCPU isn't running.
+ *
+ * For the vCPU ID, use however many bits are currently allowed for the max
+ * guest physical APIC ID (limited by the size of the physical ID table), and
+ * use whatever bits remain to assign arbitrary AVIC IDs to VMs.  Note, the
+ * size of the GATag is defined by hardware (32 bits), but is an opaque value
+ * as far as hardware is concerned.
+ */
+#define AVIC_VCPU_ID_MASK		AVIC_PHYSICAL_MAX_INDEX_MASK
+
+#define AVIC_VM_ID_SHIFT		HWEIGHT32(AVIC_PHYSICAL_MAX_INDEX_MASK)
+#define AVIC_VM_ID_MASK			(GENMASK(31, AVIC_VM_ID_SHIFT) >> AVIC_VM_ID_SHIFT)
+
+#define AVIC_GATAG(x, y)		(((x & AVIC_VM_ID_MASK) << AVIC_VM_ID_SHIFT) | \
+						(y & AVIC_VCPU_ID_MASK))
+#define AVIC_GATAG_TO_VMID(x)		((x >> AVIC_VM_ID_SHIFT) & AVIC_VM_ID_MASK)
+#define AVIC_GATAG_TO_VCPUID(x)		(x & AVIC_VCPU_ID_MASK)
+
+static_assert(AVIC_GATAG(AVIC_VM_ID_MASK, AVIC_VCPU_ID_MASK) == -1u);
+
+static bool force_avic;
+module_param_unsafe(force_avic, bool, 0444);
+
+/* Note:
+ * This hash table is used to map VM_ID to a struct kvm_svm,
+ * when handling AMD IOMMU GALOG notification to schedule in
+ * a particular vCPU.
+ */
+#define SVM_VM_DATA_HASH_BITS	8
+static DEFINE_HASHTABLE(svm_vm_data_hash, SVM_VM_DATA_HASH_BITS);
+static u32 next_vm_id = 0;
+static bool next_vm_id_wrapped = 0;
+static DEFINE_SPINLOCK(svm_vm_data_hash_lock);
+enum avic_modes avic_mode;
+
+/*
+ * This is a wrapper of struct amd_iommu_ir_data.
+ */
+struct amd_svm_iommu_ir {
+	struct list_head node;	/* Used by SVM for per-vcpu ir_list */
+	void *data;		/* Storing pointer to struct amd_ir_data */
+};
+
+static void avic_activate_vmcb(struct vcpu_svm *svm)
+{
+	struct vmcb *vmcb = svm->vmcb01.ptr;
+
+	vmcb->control.int_ctl &= ~(AVIC_ENABLE_MASK | X2APIC_MODE_MASK);
+	vmcb->control.avic_physical_id &= ~AVIC_PHYSICAL_MAX_INDEX_MASK;
+
+	vmcb->control.int_ctl |= AVIC_ENABLE_MASK;
+
+	/* Note:
+	 * KVM can support hybrid-AVIC mode, where KVM emulates x2APIC
+	 * MSR accesses, while interrupt injection to a running vCPU
+	 * can be achieved using AVIC doorbell. The AVIC hardware still
+	 * accelerate MMIO accesses, but this does not cause any harm
+	 * as the guest is not supposed to access xAPIC mmio when uses x2APIC.
+	 */
+	if (apic_x2apic_mode(svm->vcpu.arch.apic) &&
+	    avic_mode == AVIC_MODE_X2) {
+		vmcb->control.int_ctl |= X2APIC_MODE_MASK;
+		vmcb->control.avic_physical_id |= X2AVIC_MAX_PHYSICAL_ID;
+		/* Disabling MSR intercept for x2APIC registers */
+		svm_set_x2apic_msr_interception(svm, false);
+	} else {
+		/*
+		 * Flush the TLB, the guest may have inserted a non-APIC
+		 * mapping into the TLB while AVIC was disabled.
+		 */
+		kvm_make_request(KVM_REQ_TLB_FLUSH_CURRENT, &svm->vcpu);
+
+		/* For xAVIC and hybrid-xAVIC modes */
+		vmcb->control.avic_physical_id |= AVIC_MAX_PHYSICAL_ID;
+		/* Enabling MSR intercept for x2APIC registers */
+		svm_set_x2apic_msr_interception(svm, true);
+	}
+}
+
+static void avic_deactivate_vmcb(struct vcpu_svm *svm)
+{
+	struct vmcb *vmcb = svm->vmcb01.ptr;
+
+	vmcb->control.int_ctl &= ~(AVIC_ENABLE_MASK | X2APIC_MODE_MASK);
+	vmcb->control.avic_physical_id &= ~AVIC_PHYSICAL_MAX_INDEX_MASK;
+
+	/*
+	 * If running nested and the guest uses its own MSR bitmap, there
+	 * is no need to update L0's msr bitmap
+	 */
+	if (is_guest_mode(&svm->vcpu) &&
+	    vmcb12_is_intercept(&svm->nested.ctl, INTERCEPT_MSR_PROT))
+		return;
+
+	/* Enabling MSR intercept for x2APIC registers */
+	svm_set_x2apic_msr_interception(svm, true);
+}
+
+/* Note:
+ * This function is called from IOMMU driver to notify
+ * SVM to schedule in a particular vCPU of a particular VM.
+ */
+int avic_ga_log_notifier(u32 ga_tag)
+{
+	unsigned long flags;
+	struct kvm_svm *kvm_svm;
+	struct kvm_vcpu *vcpu = NULL;
+	u32 vm_id = AVIC_GATAG_TO_VMID(ga_tag);
+	u32 vcpu_id = AVIC_GATAG_TO_VCPUID(ga_tag);
+
+	pr_debug("SVM: %s: vm_id=%#x, vcpu_id=%#x\n", __func__, vm_id, vcpu_id);
+	trace_kvm_avic_ga_log(vm_id, vcpu_id);
+
+	spin_lock_irqsave(&svm_vm_data_hash_lock, flags);
+	hash_for_each_possible(svm_vm_data_hash, kvm_svm, hnode, vm_id) {
+		if (kvm_svm->avic_vm_id != vm_id)
+			continue;
+		vcpu = kvm_get_vcpu_by_id(&kvm_svm->kvm, vcpu_id);
+		break;
+	}
+	spin_unlock_irqrestore(&svm_vm_data_hash_lock, flags);
+
+	/* Note:
+	 * At this point, the IOMMU should have already set the pending
+	 * bit in the vAPIC backing page. So, we just need to schedule
+	 * in the vcpu.
+	 */
+	if (vcpu)
+		kvm_vcpu_wake_up(vcpu);
+
+	return 0;
+}
+
+void avic_vm_destroy(struct kvm *kvm)
+{
+	unsigned long flags;
+	struct kvm_svm *kvm_svm = to_kvm_svm(kvm);
+
+	if (!enable_apicv)
+		return;
+
+	if (kvm_svm->avic_logical_id_table_page)
+		__free_page(kvm_svm->avic_logical_id_table_page);
+	if (kvm_svm->avic_physical_id_table_page)
+		__free_page(kvm_svm->avic_physical_id_table_page);
+
+	spin_lock_irqsave(&svm_vm_data_hash_lock, flags);
+	hash_del(&kvm_svm->hnode);
+	spin_unlock_irqrestore(&svm_vm_data_hash_lock, flags);
+}
+
+int avic_vm_init(struct kvm *kvm)
+{
+	unsigned long flags;
+	int err = -ENOMEM;
+	struct kvm_svm *kvm_svm = to_kvm_svm(kvm);
+	struct kvm_svm *k2;
+	struct page *p_page;
+	struct page *l_page;
+	u32 vm_id;
+
+	if (!enable_apicv)
+		return 0;
+
+	/* Allocating physical APIC ID table (4KB) */
+	p_page = alloc_page(GFP_KERNEL_ACCOUNT | __GFP_ZERO);
+	if (!p_page)
+		goto free_avic;
+
+	kvm_svm->avic_physical_id_table_page = p_page;
+
+	/* Allocating logical APIC ID table (4KB) */
+	l_page = alloc_page(GFP_KERNEL_ACCOUNT | __GFP_ZERO);
+	if (!l_page)
+		goto free_avic;
+
+	kvm_svm->avic_logical_id_table_page = l_page;
+
+	spin_lock_irqsave(&svm_vm_data_hash_lock, flags);
+ again:
+	vm_id = next_vm_id = (next_vm_id + 1) & AVIC_VM_ID_MASK;
+	if (vm_id == 0) { /* id is 1-based, zero is not okay */
+		next_vm_id_wrapped = 1;
+		goto again;
+	}
+	/* Is it still in use? Only possible if wrapped at least once */
+	if (next_vm_id_wrapped) {
+		hash_for_each_possible(svm_vm_data_hash, k2, hnode, vm_id) {
+			if (k2->avic_vm_id == vm_id)
+				goto again;
+		}
+	}
+	kvm_svm->avic_vm_id = vm_id;
+	hash_add(svm_vm_data_hash, &kvm_svm->hnode, kvm_svm->avic_vm_id);
+	spin_unlock_irqrestore(&svm_vm_data_hash_lock, flags);
+
+	return 0;
+
+free_avic:
+	avic_vm_destroy(kvm);
+	return err;
+}
+
+void avic_init_vmcb(struct vcpu_svm *svm, struct vmcb *vmcb)
+{
+	struct kvm_svm *kvm_svm = to_kvm_svm(svm->vcpu.kvm);
+	phys_addr_t bpa = __sme_set(page_to_phys(svm->avic_backing_page));
+	phys_addr_t lpa = __sme_set(page_to_phys(kvm_svm->avic_logical_id_table_page));
+	phys_addr_t ppa = __sme_set(page_to_phys(kvm_svm->avic_physical_id_table_page));
+
+	vmcb->control.avic_backing_page = bpa & AVIC_HPA_MASK;
+	vmcb->control.avic_logical_id = lpa & AVIC_HPA_MASK;
+	vmcb->control.avic_physical_id = ppa & AVIC_HPA_MASK;
+	vmcb->control.avic_vapic_bar = APIC_DEFAULT_PHYS_BASE & VMCB_AVIC_APIC_BAR_MASK;
+
+	if (kvm_apicv_activated(svm->vcpu.kvm))
+		avic_activate_vmcb(svm);
+	else
+		avic_deactivate_vmcb(svm);
+}
+
+static u64 *avic_get_physical_id_entry(struct kvm_vcpu *vcpu,
+				       unsigned int index)
+{
+	u64 *avic_physical_id_table;
+	struct kvm_svm *kvm_svm = to_kvm_svm(vcpu->kvm);
+
+	if ((avic_mode == AVIC_MODE_X1 && index > AVIC_MAX_PHYSICAL_ID) ||
+	    (avic_mode == AVIC_MODE_X2 && index > X2AVIC_MAX_PHYSICAL_ID))
+		return NULL;
+
+	avic_physical_id_table = page_address(kvm_svm->avic_physical_id_table_page);
+
+	return &avic_physical_id_table[index];
+}
+
+/*
+ * Note:
+ * AVIC hardware walks the nested page table to check permissions,
+ * but does not use the SPA address specified in the leaf page
+ * table entry since it uses  address in the AVIC_BACKING_PAGE pointer
+ * field of the VMCB. Therefore, we set up the
+ * APIC_ACCESS_PAGE_PRIVATE_MEMSLOT (4KB) here.
+ */
+static int avic_alloc_access_page(struct kvm *kvm)
+{
+	void __user *ret;
+	int r = 0;
+
+	mutex_lock(&kvm->slots_lock);
+
+	if (kvm->arch.apic_access_memslot_enabled)
+		goto out;
+
+	ret = __x86_set_memory_region(kvm,
+				      APIC_ACCESS_PAGE_PRIVATE_MEMSLOT,
+				      APIC_DEFAULT_PHYS_BASE,
+				      PAGE_SIZE);
+	if (IS_ERR(ret)) {
+		r = PTR_ERR(ret);
+		goto out;
+	}
+
+	kvm->arch.apic_access_memslot_enabled = true;
+out:
+	mutex_unlock(&kvm->slots_lock);
+	return r;
+}
+
+static int avic_init_backing_page(struct kvm_vcpu *vcpu)
+{
+	u64 *entry, new_entry;
+	int id = vcpu->vcpu_id;
+	struct vcpu_svm *svm = to_svm(vcpu);
+
+	if ((avic_mode == AVIC_MODE_X1 && id > AVIC_MAX_PHYSICAL_ID) ||
+	    (avic_mode == AVIC_MODE_X2 && id > X2AVIC_MAX_PHYSICAL_ID))
+		return -EINVAL;
+
+	if (!vcpu->arch.apic->regs)
+		return -EINVAL;
+
+	if (kvm_apicv_activated(vcpu->kvm)) {
+		int ret;
+
+		ret = avic_alloc_access_page(vcpu->kvm);
+		if (ret)
+			return ret;
+	}
+
+	svm->avic_backing_page = virt_to_page(vcpu->arch.apic->regs);
+
+	/* Setting AVIC backing page address in the phy APIC ID table */
+	entry = avic_get_physical_id_entry(vcpu, id);
+	if (!entry)
+		return -EINVAL;
+
+	new_entry = __sme_set((page_to_phys(svm->avic_backing_page) &
+			      AVIC_PHYSICAL_ID_ENTRY_BACKING_PAGE_MASK) |
+			      AVIC_PHYSICAL_ID_ENTRY_VALID_MASK);
+	WRITE_ONCE(*entry, new_entry);
+
+	svm->avic_physical_id_cache = entry;
+
+	return 0;
+}
+
+void avic_ring_doorbell(struct kvm_vcpu *vcpu)
+{
+	/*
+	 * Note, the vCPU could get migrated to a different pCPU at any point,
+	 * which could result in signalling the wrong/previous pCPU.  But if
+	 * that happens the vCPU is guaranteed to do a VMRUN (after being
+	 * migrated) and thus will process pending interrupts, i.e. a doorbell
+	 * is not needed (and the spurious one is harmless).
+	 */
+	int cpu = READ_ONCE(vcpu->cpu);
+
+	if (cpu != get_cpu()) {
+		wrmsrl(MSR_AMD64_SVM_AVIC_DOORBELL, kvm_cpu_get_apicid(cpu));
+		trace_kvm_avic_doorbell(vcpu->vcpu_id, kvm_cpu_get_apicid(cpu));
+	}
+	put_cpu();
+}
+
+/*
+ * A fast-path version of avic_kick_target_vcpus(), which attempts to match
+ * destination APIC ID to vCPU without looping through all vCPUs.
+ */
+static int avic_kick_target_vcpus_fast(struct kvm *kvm, struct kvm_lapic *source,
+				       u32 icrl, u32 icrh, u32 index)
+{
+	u32 l1_physical_id, dest;
+	struct kvm_vcpu *target_vcpu;
+	int dest_mode = icrl & APIC_DEST_MASK;
+	int shorthand = icrl & APIC_SHORT_MASK;
+	struct kvm_svm *kvm_svm = to_kvm_svm(kvm);
+
+	if (shorthand != APIC_DEST_NOSHORT)
+		return -EINVAL;
+
+	if (apic_x2apic_mode(source))
+		dest = icrh;
+	else
+		dest = GET_XAPIC_DEST_FIELD(icrh);
+
+	if (dest_mode == APIC_DEST_PHYSICAL) {
+		/* broadcast destination, use slow path */
+		if (apic_x2apic_mode(source) && dest == X2APIC_BROADCAST)
+			return -EINVAL;
+		if (!apic_x2apic_mode(source) && dest == APIC_BROADCAST)
+			return -EINVAL;
+
+		l1_physical_id = dest;
+
+		if (WARN_ON_ONCE(l1_physical_id != index))
+			return -EINVAL;
+
+	} else {
+		u32 bitmap, cluster;
+		int logid_index;
+
+		if (apic_x2apic_mode(source)) {
+			/* 16 bit dest mask, 16 bit cluster id */
+			bitmap = dest & 0xFFFF0000;
+			cluster = (dest >> 16) << 4;
+		} else if (kvm_lapic_get_reg(source, APIC_DFR) == APIC_DFR_FLAT) {
+			/* 8 bit dest mask*/
+			bitmap = dest;
+			cluster = 0;
+		} else {
+			/* 4 bit desk mask, 4 bit cluster id */
+			bitmap = dest & 0xF;
+			cluster = (dest >> 4) << 2;
+		}
+
+		if (unlikely(!bitmap))
+			/* guest bug: nobody to send the logical interrupt to */
+			return 0;
+
+		if (!is_power_of_2(bitmap))
+			/* multiple logical destinations, use slow path */
+			return -EINVAL;
+
+		logid_index = cluster + __ffs(bitmap);
+
+		if (!apic_x2apic_mode(source)) {
+			u32 *avic_logical_id_table =
+				page_address(kvm_svm->avic_logical_id_table_page);
+
+			u32 logid_entry = avic_logical_id_table[logid_index];
+
+			if (WARN_ON_ONCE(index != logid_index))
+				return -EINVAL;
+
+			/* guest bug: non existing/reserved logical destination */
+			if (unlikely(!(logid_entry & AVIC_LOGICAL_ID_ENTRY_VALID_MASK)))
+				return 0;
+
+			l1_physical_id = logid_entry &
+					 AVIC_LOGICAL_ID_ENTRY_GUEST_PHYSICAL_ID_MASK;
+		} else {
+			/*
+			 * For x2APIC logical mode, cannot leverage the index.
+			 * Instead, calculate physical ID from logical ID in ICRH.
+			 */
+			int cluster = (icrh & 0xffff0000) >> 16;
+			int apic = ffs(icrh & 0xffff) - 1;
+
+			/*
+			 * If the x2APIC logical ID sub-field (i.e. icrh[15:0])
+			 * contains anything but a single bit, we cannot use the
+			 * fast path, because it is limited to a single vCPU.
+			 */
+			if (apic < 0 || icrh != (1 << apic))
+				return -EINVAL;
+
+			l1_physical_id = (cluster << 4) + apic;
+		}
+	}
+
+	target_vcpu = kvm_get_vcpu_by_id(kvm, l1_physical_id);
+	if (unlikely(!target_vcpu))
+		/* guest bug: non existing vCPU is a target of this IPI*/
+		return 0;
+
+	target_vcpu->arch.apic->irr_pending = true;
+	svm_complete_interrupt_delivery(target_vcpu,
+					icrl & APIC_MODE_MASK,
+					icrl & APIC_INT_LEVELTRIG,
+					icrl & APIC_VECTOR_MASK);
+	return 0;
+}
+
+static void avic_kick_target_vcpus(struct kvm *kvm, struct kvm_lapic *source,
+				   u32 icrl, u32 icrh, u32 index)
+{
+	unsigned long i;
+	struct kvm_vcpu *vcpu;
+
+	if (!avic_kick_target_vcpus_fast(kvm, source, icrl, icrh, index))
+		return;
+
+	trace_kvm_avic_kick_vcpu_slowpath(icrh, icrl, index);
+
+	/*
+	 * Wake any target vCPUs that are blocking, i.e. waiting for a wake
+	 * event.  There's no need to signal doorbells, as hardware has handled
+	 * vCPUs that were in guest at the time of the IPI, and vCPUs that have
+	 * since entered the guest will have processed pending IRQs at VMRUN.
+	 */
+	kvm_for_each_vcpu(i, vcpu, kvm) {
+		u32 dest;
+
+		if (apic_x2apic_mode(vcpu->arch.apic))
+			dest = icrh;
+		else
+			dest = GET_XAPIC_DEST_FIELD(icrh);
+
+		if (kvm_apic_match_dest(vcpu, source, icrl & APIC_SHORT_MASK,
+					dest, icrl & APIC_DEST_MASK)) {
+			vcpu->arch.apic->irr_pending = true;
+			svm_complete_interrupt_delivery(vcpu,
+							icrl & APIC_MODE_MASK,
+							icrl & APIC_INT_LEVELTRIG,
+							icrl & APIC_VECTOR_MASK);
+		}
+	}
+}
+
+int avic_incomplete_ipi_interception(struct kvm_vcpu *vcpu)
+{
+	struct vcpu_svm *svm = to_svm(vcpu);
+	u32 icrh = svm->vmcb->control.exit_info_1 >> 32;
+	u32 icrl = svm->vmcb->control.exit_info_1;
+	u32 id = svm->vmcb->control.exit_info_2 >> 32;
+	u32 index = svm->vmcb->control.exit_info_2 & 0x1FF;
+	struct kvm_lapic *apic = vcpu->arch.apic;
+
+	trace_kvm_avic_incomplete_ipi(vcpu->vcpu_id, icrh, icrl, id, index);
+
+	switch (id) {
+	case AVIC_IPI_FAILURE_INVALID_TARGET:
+	case AVIC_IPI_FAILURE_INVALID_INT_TYPE:
+		/*
+		 * Emulate IPIs that are not handled by AVIC hardware, which
+		 * only virtualizes Fixed, Edge-Triggered INTRs, and falls over
+		 * if _any_ targets are invalid, e.g. if the logical mode mask
+		 * is a superset of running vCPUs.
+		 *
+		 * The exit is a trap, e.g. ICR holds the correct value and RIP
+		 * has been advanced, KVM is responsible only for emulating the
+		 * IPI.  Sadly, hardware may sometimes leave the BUSY flag set,
+		 * in which case KVM needs to emulate the ICR write as well in
+		 * order to clear the BUSY flag.
+		 */
+		if (icrl & APIC_ICR_BUSY)
+			kvm_apic_write_nodecode(vcpu, APIC_ICR);
+		else
+			kvm_apic_send_ipi(apic, icrl, icrh);
+		break;
+	case AVIC_IPI_FAILURE_TARGET_NOT_RUNNING:
+		/*
+		 * At this point, we expect that the AVIC HW has already
+		 * set the appropriate IRR bits on the valid target
+		 * vcpus. So, we just need to kick the appropriate vcpu.
+		 */
+		avic_kick_target_vcpus(vcpu->kvm, apic, icrl, icrh, index);
+		break;
+	case AVIC_IPI_FAILURE_INVALID_BACKING_PAGE:
+		WARN_ONCE(1, "Invalid backing page\n");
+		break;
+	case AVIC_IPI_FAILURE_INVALID_IPI_VECTOR:
+		/* Invalid IPI with vector < 16 */
+		break;
+	default:
+		vcpu_unimpl(vcpu, "Unknown avic incomplete IPI interception\n");
+	}
+
+	return 1;
+}
+
+unsigned long avic_vcpu_get_apicv_inhibit_reasons(struct kvm_vcpu *vcpu)
+{
+	if (is_guest_mode(vcpu))
+		return APICV_INHIBIT_REASON_NESTED;
+	return 0;
+}
+
+static u32 *avic_get_logical_id_entry(struct kvm_vcpu *vcpu, u32 ldr, bool flat)
+{
+	struct kvm_svm *kvm_svm = to_kvm_svm(vcpu->kvm);
+	int index;
+	u32 *logical_apic_id_table;
+	int dlid = GET_APIC_LOGICAL_ID(ldr);
+
+	if (!dlid)
+		return NULL;
+
+	if (flat) { /* flat */
+		index = ffs(dlid) - 1;
+		if (index > 7)
+			return NULL;
+	} else { /* cluster */
+		int cluster = (dlid & 0xf0) >> 4;
+		int apic = ffs(dlid & 0x0f) - 1;
+
+		if ((apic < 0) || (apic > 7) ||
+		    (cluster >= 0xf))
+			return NULL;
+		index = (cluster << 2) + apic;
+	}
+
+	logical_apic_id_table = (u32 *) page_address(kvm_svm->avic_logical_id_table_page);
+
+	return &logical_apic_id_table[index];
+}
+
+static int avic_ldr_write(struct kvm_vcpu *vcpu, u8 g_physical_id, u32 ldr)
+{
+	bool flat;
+	u32 *entry, new_entry;
+
+	flat = kvm_lapic_get_reg(vcpu->arch.apic, APIC_DFR) == APIC_DFR_FLAT;
+	entry = avic_get_logical_id_entry(vcpu, ldr, flat);
+	if (!entry)
+		return -EINVAL;
+
+	new_entry = READ_ONCE(*entry);
+	new_entry &= ~AVIC_LOGICAL_ID_ENTRY_GUEST_PHYSICAL_ID_MASK;
+	new_entry |= (g_physical_id & AVIC_LOGICAL_ID_ENTRY_GUEST_PHYSICAL_ID_MASK);
+	new_entry |= AVIC_LOGICAL_ID_ENTRY_VALID_MASK;
+	WRITE_ONCE(*entry, new_entry);
+
+	return 0;
+}
+
+static void avic_invalidate_logical_id_entry(struct kvm_vcpu *vcpu)
+{
+	struct vcpu_svm *svm = to_svm(vcpu);
+	bool flat = svm->dfr_reg == APIC_DFR_FLAT;
+	u32 *entry;
+
+	/* Note: x2AVIC does not use logical APIC ID table */
+	if (apic_x2apic_mode(vcpu->arch.apic))
+		return;
+
+	entry = avic_get_logical_id_entry(vcpu, svm->ldr_reg, flat);
+	if (entry)
+		clear_bit(AVIC_LOGICAL_ID_ENTRY_VALID_BIT, (unsigned long *)entry);
+}
+
+static int avic_handle_ldr_update(struct kvm_vcpu *vcpu)
+{
+	int ret = 0;
+	struct vcpu_svm *svm = to_svm(vcpu);
+	u32 ldr = kvm_lapic_get_reg(vcpu->arch.apic, APIC_LDR);
+	u32 id = kvm_xapic_id(vcpu->arch.apic);
+
+	/* AVIC does not support LDR update for x2APIC */
+	if (apic_x2apic_mode(vcpu->arch.apic))
+		return 0;
+
+	if (ldr == svm->ldr_reg)
+		return 0;
+
+	avic_invalidate_logical_id_entry(vcpu);
+
+	if (ldr)
+		ret = avic_ldr_write(vcpu, id, ldr);
+
+	if (!ret)
+		svm->ldr_reg = ldr;
+
+	return ret;
+}
+
+static void avic_handle_dfr_update(struct kvm_vcpu *vcpu)
+{
+	struct vcpu_svm *svm = to_svm(vcpu);
+	u32 dfr = kvm_lapic_get_reg(vcpu->arch.apic, APIC_DFR);
+
+	if (svm->dfr_reg == dfr)
+		return;
+
+	avic_invalidate_logical_id_entry(vcpu);
+	svm->dfr_reg = dfr;
+}
+
+static int avic_unaccel_trap_write(struct kvm_vcpu *vcpu)
+{
+	u32 offset = to_svm(vcpu)->vmcb->control.exit_info_1 &
+				AVIC_UNACCEL_ACCESS_OFFSET_MASK;
+
+	switch (offset) {
+	case APIC_LDR:
+		if (avic_handle_ldr_update(vcpu))
+			return 0;
+		break;
+	case APIC_DFR:
+		avic_handle_dfr_update(vcpu);
+		break;
+	default:
+		break;
+	}
+
+	kvm_apic_write_nodecode(vcpu, offset);
+	return 1;
+}
+
+static bool is_avic_unaccelerated_access_trap(u32 offset)
+{
+	bool ret = false;
+
+	switch (offset) {
+	case APIC_ID:
+	case APIC_EOI:
+	case APIC_RRR:
+	case APIC_LDR:
+	case APIC_DFR:
+	case APIC_SPIV:
+	case APIC_ESR:
+	case APIC_ICR:
+	case APIC_LVTT:
+	case APIC_LVTTHMR:
+	case APIC_LVTPC:
+	case APIC_LVT0:
+	case APIC_LVT1:
+	case APIC_LVTERR:
+	case APIC_TMICT:
+	case APIC_TDCR:
+		ret = true;
+		break;
+	default:
+		break;
+	}
+	return ret;
+}
+
+int avic_unaccelerated_access_interception(struct kvm_vcpu *vcpu)
+{
+	struct vcpu_svm *svm = to_svm(vcpu);
+	int ret = 0;
+	u32 offset = svm->vmcb->control.exit_info_1 &
+		     AVIC_UNACCEL_ACCESS_OFFSET_MASK;
+	u32 vector = svm->vmcb->control.exit_info_2 &
+		     AVIC_UNACCEL_ACCESS_VECTOR_MASK;
+	bool write = (svm->vmcb->control.exit_info_1 >> 32) &
+		     AVIC_UNACCEL_ACCESS_WRITE_MASK;
+	bool trap = is_avic_unaccelerated_access_trap(offset);
+
+	trace_kvm_avic_unaccelerated_access(vcpu->vcpu_id, offset,
+					    trap, write, vector);
+	if (trap) {
+		/* Handling Trap */
+		WARN_ONCE(!write, "svm: Handling trap read.\n");
+		ret = avic_unaccel_trap_write(vcpu);
+	} else {
+		/* Handling Fault */
+		ret = kvm_emulate_instruction(vcpu, 0);
+	}
+
+	return ret;
+}
+
+int avic_init_vcpu(struct vcpu_svm *svm)
+{
+	int ret;
+	struct kvm_vcpu *vcpu = &svm->vcpu;
+
+	if (!enable_apicv || !irqchip_in_kernel(vcpu->kvm))
+		return 0;
+
+	ret = avic_init_backing_page(vcpu);
+	if (ret)
+		return ret;
+
+	INIT_LIST_HEAD(&svm->ir_list);
+	spin_lock_init(&svm->ir_list_lock);
+	svm->dfr_reg = APIC_DFR_FLAT;
+
+	return ret;
+}
+
+void avic_apicv_post_state_restore(struct kvm_vcpu *vcpu)
+{
+	avic_handle_dfr_update(vcpu);
+	avic_handle_ldr_update(vcpu);
+}
+
+static int avic_set_pi_irte_mode(struct kvm_vcpu *vcpu, bool activate)
+{
+	int ret = 0;
+	unsigned long flags;
+	struct amd_svm_iommu_ir *ir;
+	struct vcpu_svm *svm = to_svm(vcpu);
+
+	if (!kvm_arch_has_assigned_device(vcpu->kvm))
+		return 0;
+
+	/*
+	 * Here, we go through the per-vcpu ir_list to update all existing
+	 * interrupt remapping table entry targeting this vcpu.
+	 */
+	spin_lock_irqsave(&svm->ir_list_lock, flags);
+
+	if (list_empty(&svm->ir_list))
+		goto out;
+
+	list_for_each_entry(ir, &svm->ir_list, node) {
+		if (activate)
+			ret = amd_iommu_activate_guest_mode(ir->data);
+		else
+			ret = amd_iommu_deactivate_guest_mode(ir->data);
+		if (ret)
+			break;
+	}
+out:
+	spin_unlock_irqrestore(&svm->ir_list_lock, flags);
+	return ret;
+}
+
+static void svm_ir_list_del(struct vcpu_svm *svm, struct amd_iommu_pi_data *pi)
+{
+	unsigned long flags;
+	struct amd_svm_iommu_ir *cur;
+
+	spin_lock_irqsave(&svm->ir_list_lock, flags);
+	list_for_each_entry(cur, &svm->ir_list, node) {
+		if (cur->data != pi->ir_data)
+			continue;
+		list_del(&cur->node);
+		kfree(cur);
+		break;
+	}
+	spin_unlock_irqrestore(&svm->ir_list_lock, flags);
+}
+
+static int svm_ir_list_add(struct vcpu_svm *svm, struct amd_iommu_pi_data *pi)
+{
+	int ret = 0;
+	unsigned long flags;
+	struct amd_svm_iommu_ir *ir;
+	u64 entry;
+
+	/**
+	 * In some cases, the existing irte is updated and re-set,
+	 * so we need to check here if it's already been * added
+	 * to the ir_list.
+	 */
+	if (pi->ir_data && (pi->prev_ga_tag != 0)) {
+		struct kvm *kvm = svm->vcpu.kvm;
+		u32 vcpu_id = AVIC_GATAG_TO_VCPUID(pi->prev_ga_tag);
+		struct kvm_vcpu *prev_vcpu = kvm_get_vcpu_by_id(kvm, vcpu_id);
+		struct vcpu_svm *prev_svm;
+
+		if (!prev_vcpu) {
+			ret = -EINVAL;
+			goto out;
+		}
+
+		prev_svm = to_svm(prev_vcpu);
+		svm_ir_list_del(prev_svm, pi);
+	}
+
+	/**
+	 * Allocating new amd_iommu_pi_data, which will get
+	 * add to the per-vcpu ir_list.
+	 */
+	ir = kzalloc(sizeof(struct amd_svm_iommu_ir), GFP_KERNEL_ACCOUNT);
+	if (!ir) {
+		ret = -ENOMEM;
+		goto out;
+	}
+	ir->data = pi->ir_data;
+
+	spin_lock_irqsave(&svm->ir_list_lock, flags);
+
+	/*
+	 * Update the target pCPU for IOMMU doorbells if the vCPU is running.
+	 * If the vCPU is NOT running, i.e. is blocking or scheduled out, KVM
+	 * will update the pCPU info when the vCPU awkened and/or scheduled in.
+	 * See also avic_vcpu_load().
+	 */
+	entry = READ_ONCE(*(svm->avic_physical_id_cache));
+	if (entry & AVIC_PHYSICAL_ID_ENTRY_IS_RUNNING_MASK)
+		amd_iommu_update_ga(entry & AVIC_PHYSICAL_ID_ENTRY_HOST_PHYSICAL_ID_MASK,
+				    true, pi->ir_data);
+
+	list_add(&ir->node, &svm->ir_list);
+	spin_unlock_irqrestore(&svm->ir_list_lock, flags);
+out:
+	return ret;
+}
+
+/*
+ * Note:
+ * The HW cannot support posting multicast/broadcast
+ * interrupts to a vCPU. So, we still use legacy interrupt
+ * remapping for these kind of interrupts.
+ *
+ * For lowest-priority interrupts, we only support
+ * those with single CPU as the destination, e.g. user
+ * configures the interrupts via /proc/irq or uses
+ * irqbalance to make the interrupts single-CPU.
+ */
+static int
+get_pi_vcpu_info(struct kvm *kvm, struct kvm_kernel_irq_routing_entry *e,
+		 struct vcpu_data *vcpu_info, struct vcpu_svm **svm)
+{
+	struct kvm_lapic_irq irq;
+	struct kvm_vcpu *vcpu = NULL;
+
+	kvm_set_msi_irq(kvm, e, &irq);
+
+	if (!kvm_intr_is_single_vcpu(kvm, &irq, &vcpu) ||
+	    !kvm_irq_is_postable(&irq)) {
+		pr_debug("SVM: %s: use legacy intr remap mode for irq %u\n",
+			 __func__, irq.vector);
+		return -1;
+	}
+
+	pr_debug("SVM: %s: use GA mode for irq %u\n", __func__,
+		 irq.vector);
+	*svm = to_svm(vcpu);
+	vcpu_info->pi_desc_addr = __sme_set(page_to_phys((*svm)->avic_backing_page));
+	vcpu_info->vector = irq.vector;
+
+	return 0;
+}
+
+/*
+ * avic_pi_update_irte - set IRTE for Posted-Interrupts
+ *
+ * @kvm: kvm
+ * @host_irq: host irq of the interrupt
+ * @guest_irq: gsi of the interrupt
+ * @set: set or unset PI
+ * returns 0 on success, < 0 on failure
+ */
+int avic_pi_update_irte(struct kvm *kvm, unsigned int host_irq,
+			uint32_t guest_irq, bool set)
+{
+	struct kvm_kernel_irq_routing_entry *e;
+	struct kvm_irq_routing_table *irq_rt;
+	int idx, ret = 0;
+
+	if (!kvm_arch_has_assigned_device(kvm) ||
+	    !irq_remapping_cap(IRQ_POSTING_CAP))
+		return 0;
+
+	pr_debug("SVM: %s: host_irq=%#x, guest_irq=%#x, set=%#x\n",
+		 __func__, host_irq, guest_irq, set);
+
+	idx = srcu_read_lock(&kvm->irq_srcu);
+	irq_rt = srcu_dereference(kvm->irq_routing, &kvm->irq_srcu);
+
+	if (guest_irq >= irq_rt->nr_rt_entries ||
+		hlist_empty(&irq_rt->map[guest_irq])) {
+		pr_warn_once("no route for guest_irq %u/%u (broken user space?)\n",
+			     guest_irq, irq_rt->nr_rt_entries);
+		goto out;
+	}
+
+	hlist_for_each_entry(e, &irq_rt->map[guest_irq], link) {
+		struct vcpu_data vcpu_info;
+		struct vcpu_svm *svm = NULL;
+
+		if (e->type != KVM_IRQ_ROUTING_MSI)
+			continue;
+
+		/**
+		 * Here, we setup with legacy mode in the following cases:
+		 * 1. When cannot target interrupt to a specific vcpu.
+		 * 2. Unsetting posted interrupt.
+		 * 3. APIC virtualization is disabled for the vcpu.
+		 * 4. IRQ has incompatible delivery mode (SMI, INIT, etc)
+		 */
+		if (!get_pi_vcpu_info(kvm, e, &vcpu_info, &svm) && set &&
+		    kvm_vcpu_apicv_active(&svm->vcpu)) {
+			struct amd_iommu_pi_data pi;
+
+			/* Try to enable guest_mode in IRTE */
+			pi.base = __sme_set(page_to_phys(svm->avic_backing_page) &
+					    AVIC_HPA_MASK);
+			pi.ga_tag = AVIC_GATAG(to_kvm_svm(kvm)->avic_vm_id,
+						     svm->vcpu.vcpu_id);
+			pi.is_guest_mode = true;
+			pi.vcpu_data = &vcpu_info;
+			ret = irq_set_vcpu_affinity(host_irq, &pi);
+
+			/**
+			 * Here, we successfully setting up vcpu affinity in
+			 * IOMMU guest mode. Now, we need to store the posted
+			 * interrupt information in a per-vcpu ir_list so that
+			 * we can reference to them directly when we update vcpu
+			 * scheduling information in IOMMU irte.
+			 */
+			if (!ret && pi.is_guest_mode)
+				svm_ir_list_add(svm, &pi);
+		} else {
+			/* Use legacy mode in IRTE */
+			struct amd_iommu_pi_data pi;
+
+			/**
+			 * Here, pi is used to:
+			 * - Tell IOMMU to use legacy mode for this interrupt.
+			 * - Retrieve ga_tag of prior interrupt remapping data.
+			 */
+			pi.prev_ga_tag = 0;
+			pi.is_guest_mode = false;
+			ret = irq_set_vcpu_affinity(host_irq, &pi);
+
+			/**
+			 * Check if the posted interrupt was previously
+			 * setup with the guest_mode by checking if the ga_tag
+			 * was cached. If so, we need to clean up the per-vcpu
+			 * ir_list.
+			 */
+			if (!ret && pi.prev_ga_tag) {
+				int id = AVIC_GATAG_TO_VCPUID(pi.prev_ga_tag);
+				struct kvm_vcpu *vcpu;
+
+				vcpu = kvm_get_vcpu_by_id(kvm, id);
+				if (vcpu)
+					svm_ir_list_del(to_svm(vcpu), &pi);
+			}
+		}
+
+		if (!ret && svm) {
+			trace_kvm_pi_irte_update(host_irq, svm->vcpu.vcpu_id,
+						 e->gsi, vcpu_info.vector,
+						 vcpu_info.pi_desc_addr, set);
+		}
+
+		if (ret < 0) {
+			pr_err("%s: failed to update PI IRTE\n", __func__);
+			goto out;
+		}
+	}
+
+	ret = 0;
+out:
+	srcu_read_unlock(&kvm->irq_srcu, idx);
+	return ret;
+}
+
+bool avic_check_apicv_inhibit_reasons(enum kvm_apicv_inhibit reason)
+{
+	ulong supported = BIT(APICV_INHIBIT_REASON_DISABLE) |
+			  BIT(APICV_INHIBIT_REASON_ABSENT) |
+			  BIT(APICV_INHIBIT_REASON_HYPERV) |
+			  BIT(APICV_INHIBIT_REASON_NESTED) |
+			  BIT(APICV_INHIBIT_REASON_IRQWIN) |
+			  BIT(APICV_INHIBIT_REASON_PIT_REINJ) |
+			  BIT(APICV_INHIBIT_REASON_BLOCKIRQ) |
+			  BIT(APICV_INHIBIT_REASON_SEV)      |
+			  BIT(APICV_INHIBIT_REASON_APIC_ID_MODIFIED) |
+			  BIT(APICV_INHIBIT_REASON_APIC_BASE_MODIFIED);
+
+	return supported & BIT(reason);
+}
+
+
+static inline int
+avic_update_iommu_vcpu_affinity(struct kvm_vcpu *vcpu, int cpu, bool r)
+{
+	int ret = 0;
+	struct amd_svm_iommu_ir *ir;
+	struct vcpu_svm *svm = to_svm(vcpu);
+
+	lockdep_assert_held(&svm->ir_list_lock);
+
+	if (!kvm_arch_has_assigned_device(vcpu->kvm))
+		return 0;
+
+	/*
+	 * Here, we go through the per-vcpu ir_list to update all existing
+	 * interrupt remapping table entry targeting this vcpu.
+	 */
+	if (list_empty(&svm->ir_list))
+		return 0;
+
+	list_for_each_entry(ir, &svm->ir_list, node) {
+		ret = amd_iommu_update_ga(cpu, r, ir->data);
+		if (ret)
+			return ret;
+	}
+	return 0;
+}
+
+void avic_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
+{
+	u64 entry;
+	int h_physical_id = kvm_cpu_get_apicid(cpu);
+	struct vcpu_svm *svm = to_svm(vcpu);
+	unsigned long flags;
+
+	lockdep_assert_preemption_disabled();
+
+	if (WARN_ON(h_physical_id & ~AVIC_PHYSICAL_ID_ENTRY_HOST_PHYSICAL_ID_MASK))
+		return;
+
+	/*
+	 * No need to update anything if the vCPU is blocking, i.e. if the vCPU
+	 * is being scheduled in after being preempted.  The CPU entries in the
+	 * Physical APIC table and IRTE are consumed iff IsRun{ning} is '1'.
+	 * If the vCPU was migrated, its new CPU value will be stuffed when the
+	 * vCPU unblocks.
+	 */
+	if (kvm_vcpu_is_blocking(vcpu))
+		return;
+
+	/*
+	 * Grab the per-vCPU interrupt remapping lock even if the VM doesn't
+	 * _currently_ have assigned devices, as that can change.  Holding
+	 * ir_list_lock ensures that either svm_ir_list_add() will consume
+	 * up-to-date entry information, or that this task will wait until
+	 * svm_ir_list_add() completes to set the new target pCPU.
+	 */
+	spin_lock_irqsave(&svm->ir_list_lock, flags);
+
+	entry = READ_ONCE(*(svm->avic_physical_id_cache));
+
+	entry &= ~AVIC_PHYSICAL_ID_ENTRY_HOST_PHYSICAL_ID_MASK;
+	entry |= (h_physical_id & AVIC_PHYSICAL_ID_ENTRY_HOST_PHYSICAL_ID_MASK);
+	entry |= AVIC_PHYSICAL_ID_ENTRY_IS_RUNNING_MASK;
+
+	WRITE_ONCE(*(svm->avic_physical_id_cache), entry);
+	avic_update_iommu_vcpu_affinity(vcpu, h_physical_id, true);
+
+	spin_unlock_irqrestore(&svm->ir_list_lock, flags);
+}
+
+void avic_vcpu_put(struct kvm_vcpu *vcpu)
+{
+	u64 entry;
+	struct vcpu_svm *svm = to_svm(vcpu);
+	unsigned long flags;
+
+	lockdep_assert_preemption_disabled();
+
+	/*
+	 * Note, reading the Physical ID entry outside of ir_list_lock is safe
+	 * as only the pCPU that has loaded (or is loading) the vCPU is allowed
+	 * to modify the entry, and preemption is disabled.  I.e. the vCPU
+	 * can't be scheduled out and thus avic_vcpu_{put,load}() can't run
+	 * recursively.
+	 */
+	entry = READ_ONCE(*(svm->avic_physical_id_cache));
+
+	/* Nothing to do if IsRunning == '0' due to vCPU blocking. */
+	if (!(entry & AVIC_PHYSICAL_ID_ENTRY_IS_RUNNING_MASK))
+		return;
+
+	/*
+	 * Take and hold the per-vCPU interrupt remapping lock while updating
+	 * the Physical ID entry even though the lock doesn't protect against
+	 * multiple writers (see above).  Holding ir_list_lock ensures that
+	 * either svm_ir_list_add() will consume up-to-date entry information,
+	 * or that this task will wait until svm_ir_list_add() completes to
+	 * mark the vCPU as not running.
+	 */
+	spin_lock_irqsave(&svm->ir_list_lock, flags);
+
+	avic_update_iommu_vcpu_affinity(vcpu, -1, 0);
+
+	entry &= ~AVIC_PHYSICAL_ID_ENTRY_IS_RUNNING_MASK;
+	WRITE_ONCE(*(svm->avic_physical_id_cache), entry);
+
+	spin_unlock_irqrestore(&svm->ir_list_lock, flags);
+
+}
+
+void avic_refresh_virtual_apic_mode(struct kvm_vcpu *vcpu)
+{
+	struct vcpu_svm *svm = to_svm(vcpu);
+	struct vmcb *vmcb = svm->vmcb01.ptr;
+
+	if (!lapic_in_kernel(vcpu) || avic_mode == AVIC_MODE_NONE)
+		return;
+
+	if (!enable_apicv)
+		return;
+
+	if (kvm_vcpu_apicv_active(vcpu)) {
+		/**
+		 * During AVIC temporary deactivation, guest could update
+		 * APIC ID, DFR and LDR registers, which would not be trapped
+		 * by avic_unaccelerated_access_interception(). In this case,
+		 * we need to check and update the AVIC logical APIC ID table
+		 * accordingly before re-activating.
+		 */
+		avic_apicv_post_state_restore(vcpu);
+		avic_activate_vmcb(svm);
+	} else {
+		avic_deactivate_vmcb(svm);
+	}
+	vmcb_mark_dirty(vmcb, VMCB_AVIC);
+}
+
+void avic_refresh_apicv_exec_ctrl(struct kvm_vcpu *vcpu)
+{
+	bool activated = kvm_vcpu_apicv_active(vcpu);
+
+	if (!enable_apicv)
+		return;
+
+	avic_refresh_virtual_apic_mode(vcpu);
+
+	if (activated)
+		avic_vcpu_load(vcpu, vcpu->cpu);
+	else
+		avic_vcpu_put(vcpu);
+
+	avic_set_pi_irte_mode(vcpu, activated);
+}
+
+void avic_vcpu_blocking(struct kvm_vcpu *vcpu)
+{
+	if (!kvm_vcpu_apicv_active(vcpu))
+		return;
+
+       /*
+        * Unload the AVIC when the vCPU is about to block, _before_
+        * the vCPU actually blocks.
+        *
+        * Any IRQs that arrive before IsRunning=0 will not cause an
+        * incomplete IPI vmexit on the source, therefore vIRR will also
+        * be checked by kvm_vcpu_check_block() before blocking.  The
+        * memory barrier implicit in set_current_state orders writing
+        * IsRunning=0 before reading the vIRR.  The processor needs a
+        * matching memory barrier on interrupt delivery between writing
+        * IRR and reading IsRunning; the lack of this barrier might be
+        * the cause of errata #1235).
+        */
+	avic_vcpu_put(vcpu);
+}
+
+void avic_vcpu_unblocking(struct kvm_vcpu *vcpu)
+{
+	if (!kvm_vcpu_apicv_active(vcpu))
+		return;
+
+	avic_vcpu_load(vcpu, vcpu->cpu);
+}
+
+/*
+ * Note:
+ * - The module param avic enable both xAPIC and x2APIC mode.
+ * - Hypervisor can support both xAVIC and x2AVIC in the same guest.
+ * - The mode can be switched at run-time.
+ */
+bool avic_hardware_setup(struct kvm_x86_ops *x86_ops)
+{
+	if (!npt_enabled)
+		return false;
+
+	if (boot_cpu_has(X86_FEATURE_AVIC)) {
+		avic_mode = AVIC_MODE_X1;
+		pr_info("AVIC enabled\n");
+	} else if (force_avic) {
+		/*
+		 * Some older systems does not advertise AVIC support.
+		 * See Revision Guide for specific AMD processor for more detail.
+		 */
+		avic_mode = AVIC_MODE_X1;
+		pr_warn("AVIC is not supported in CPUID but force enabled");
+		pr_warn("Your system might crash and burn");
+	}
+
+	/* AVIC is a prerequisite for x2AVIC. */
+	if (boot_cpu_has(X86_FEATURE_X2AVIC)) {
+		if (avic_mode == AVIC_MODE_X1) {
+			avic_mode = AVIC_MODE_X2;
+			pr_info("x2AVIC enabled\n");
+		} else {
+			pr_warn(FW_BUG "Cannot support x2AVIC due to AVIC is disabled");
+			pr_warn(FW_BUG "Try enable AVIC using force_avic option");
+		}
+	}
+
+	if (avic_mode != AVIC_MODE_NONE)
+		amd_iommu_register_ga_log_notifier(&avic_ga_log_notifier);
+
+	return !!avic_mode;
+}