// 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"

#define SVM_AVIC_DOORBELL       0xc001011b

#define AVIC_HPA_MASK   ~((0xFFFULL << 52) | 0xFFF)

/*
 * 0xff is broadcast, so the max index allowed for physical APIC ID
 * table is 0xfe.  APIC IDs above 0xff are reserved.
 */
#define AVIC_MAX_PHYSICAL_ID_COUNT      255

#define AVIC_UNACCEL_ACCESS_WRITE_MASK          1
#define AVIC_UNACCEL_ACCESS_OFFSET_MASK         0xFF0
#define AVIC_UNACCEL_ACCESS_VECTOR_MASK         0xFFFFFFFF

/* AVIC GATAG is encoded using VM and VCPU IDs */
#define AVIC_VCPU_ID_BITS               8
#define AVIC_VCPU_ID_MASK               ((1 << AVIC_VCPU_ID_BITS) - 1)

#define AVIC_VM_ID_BITS                 24
#define AVIC_VM_ID_NR                   (1 << AVIC_VM_ID_BITS)
#define AVIC_VM_ID_MASK                 ((1 << AVIC_VM_ID_BITS) - 1)

#define AVIC_GATAG(x, y)                (((x & AVIC_VM_ID_MASK) << AVIC_VCPU_ID_BITS) | \
                                                (y & AVIC_VCPU_ID_MASK))
#define AVIC_GATAG_TO_VMID(x)           ((x >> AVIC_VCPU_ID_BITS) & AVIC_VM_ID_MASK)
#define AVIC_GATAG_TO_VCPUID(x)         (x & AVIC_VCPU_ID_MASK)

/* 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);

/*
 * 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 */
};

enum avic_ipi_failure_cause {
        AVIC_IPI_FAILURE_INVALID_INT_TYPE,
        AVIC_IPI_FAILURE_TARGET_NOT_RUNNING,
        AVIC_IPI_FAILURE_INVALID_TARGET,
        AVIC_IPI_FAILURE_INVALID_BACKING_PAGE,
};

/* 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 = svm->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_physical_id |= AVIC_MAX_PHYSICAL_ID_COUNT;
        vmcb->control.avic_vapic_bar = APIC_DEFAULT_PHYS_BASE & VMCB_AVIC_APIC_BAR_MASK;

        if (kvm_apicv_activated(svm->vcpu.kvm))
                vmcb->control.int_ctl |= AVIC_ENABLE_MASK;
        else
                vmcb->control.int_ctl &= ~AVIC_ENABLE_MASK;
}

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 (index >= AVIC_MAX_PHYSICAL_ID_COUNT)
                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 (id >= AVIC_MAX_PHYSICAL_ID_COUNT)
                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;
}

static void avic_kick_target_vcpus(struct kvm *kvm, struct kvm_lapic *source,
                                   u32 icrl, u32 icrh)
{
        struct kvm_vcpu *vcpu;
        int i;

        kvm_for_each_vcpu(i, vcpu, kvm) {
                bool m = kvm_apic_match_dest(vcpu, source,
                                             icrl & APIC_SHORT_MASK,
                                             GET_APIC_DEST_FIELD(icrh),
                                             icrl & APIC_DEST_MASK);

                if (m && !avic_vcpu_is_running(vcpu))
                        kvm_vcpu_wake_up(vcpu);
        }
}

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 & 0xFF;
        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_INT_TYPE:
                /*
                 * AVIC hardware handles the generation of
                 * IPIs when the specified Message Type is Fixed
                 * (also known as fixed delivery mode) and
                 * the Trigger Mode is edge-triggered. The hardware
                 * also supports self and broadcast delivery modes
                 * specified via the Destination Shorthand(DSH)
                 * field of the ICRL. Logical and physical APIC ID
                 * formats are supported. All other IPI types cause
                 * a #VMEXIT, which needs to emulated.
                 */
                kvm_lapic_reg_write(apic, APIC_ICR2, icrh);
                kvm_lapic_reg_write(apic, APIC_ICR, icrl);
                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);
                break;
        case AVIC_IPI_FAILURE_INVALID_TARGET:
                WARN_ONCE(1, "Invalid IPI target: index=%u, vcpu=%d, icr=%#0x:%#0x\n",
                          index, vcpu->vcpu_id, icrh, icrl);
                break;
        case AVIC_IPI_FAILURE_INVALID_BACKING_PAGE:
                WARN_ONCE(1, "Invalid backing page\n");
                break;
        default:
                pr_err("Unknown IPI interception\n");
        }

        return 1;
}

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 = 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);

        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 int avic_handle_apic_id_update(struct kvm_vcpu *vcpu)
{
        u64 *old, *new;
        struct vcpu_svm *svm = to_svm(vcpu);
        u32 id = kvm_xapic_id(vcpu->arch.apic);

        if (vcpu->vcpu_id == id)
                return 0;

        old = avic_get_physical_id_entry(vcpu, vcpu->vcpu_id);
        new = avic_get_physical_id_entry(vcpu, id);
        if (!new || !old)
                return 1;

        /* We need to move physical_id_entry to new offset */
        *new = *old;
        *old = 0ULL;
        to_svm(vcpu)->avic_physical_id_cache = new;

        /*
         * Also update the guest physical APIC ID in the logical
         * APIC ID table entry if already setup the LDR.
         */
        if (svm->ldr_reg)
                avic_handle_ldr_update(vcpu);

        return 0;
}

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 vcpu_svm *svm)
{
        struct kvm_lapic *apic = svm->vcpu.arch.apic;
        u32 offset = svm->vmcb->control.exit_info_1 &
                                AVIC_UNACCEL_ACCESS_OFFSET_MASK;

        switch (offset) {
        case APIC_ID:
                if (avic_handle_apic_id_update(&svm->vcpu))
                        return 0;
                break;
        case APIC_LDR:
                if (avic_handle_ldr_update(&svm->vcpu))
                        return 0;
                break;
        case APIC_DFR:
                avic_handle_dfr_update(&svm->vcpu);
                break;
        default:
                break;
        }

        kvm_lapic_reg_write(apic, offset, kvm_lapic_get_reg(apic, 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(svm);
        } 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_post_state_restore(struct kvm_vcpu *vcpu)
{
        if (avic_handle_apic_id_update(vcpu) != 0)
                return;
        avic_handle_dfr_update(vcpu);
        avic_handle_ldr_update(vcpu);
}

void svm_set_virtual_apic_mode(struct kvm_vcpu *vcpu)
{
        return;
}

void svm_hwapic_irr_update(struct kvm_vcpu *vcpu, int max_irr)
{
}

void svm_hwapic_isr_update(struct kvm_vcpu *vcpu, int max_isr)
{
}

static int svm_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;
}

void svm_refresh_apicv_exec_ctrl(struct kvm_vcpu *vcpu)
{
        struct vcpu_svm *svm = to_svm(vcpu);
        struct vmcb *vmcb = svm->vmcb01.ptr;
        bool activated = kvm_vcpu_apicv_active(vcpu);

        if (!enable_apicv)
                return;

        if (activated) {
                /**
                 * 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_post_state_restore(vcpu);
                vmcb->control.int_ctl |= AVIC_ENABLE_MASK;
        } else {
                vmcb->control.int_ctl &= ~AVIC_ENABLE_MASK;
        }
        vmcb_mark_dirty(vmcb, VMCB_AVIC);

        if (activated)
                avic_vcpu_load(vcpu, vcpu->cpu);
        else
                avic_vcpu_put(vcpu);

        svm_set_pi_irte_mode(vcpu, activated);
}

void svm_load_eoi_exitmap(struct kvm_vcpu *vcpu, u64 *eoi_exit_bitmap)
{
        return;
}

int svm_deliver_avic_intr(struct kvm_vcpu *vcpu, int vec)
{
        if (!vcpu->arch.apicv_active)
                return -1;

        kvm_lapic_set_irr(vec, vcpu->arch.apic);
        smp_mb__after_atomic();

        if (avic_vcpu_is_running(vcpu)) {
                int cpuid = vcpu->cpu;

                if (cpuid != get_cpu())
                        wrmsrl(SVM_AVIC_DOORBELL, kvm_cpu_get_apicid(cpuid));
                put_cpu();
        } else
                kvm_vcpu_wake_up(vcpu);

        return 0;
}

bool svm_dy_apicv_has_pending_interrupt(struct kvm_vcpu *vcpu)
{
        return false;
}

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;

        /**
         * 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);
        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;
}

/*
 * svm_update_pi_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 svm_update_pi_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 = -EINVAL;

        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);
        WARN_ON(guest_irq >= irq_rt->nr_rt_entries);

        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 svm_check_apicv_inhibit_reasons(ulong bit)
{
        ulong supported = BIT(APICV_INHIBIT_REASON_DISABLE) |
                          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_X2APIC);

        return supported & BIT(bit);
}


static inline int
avic_update_iommu_vcpu_affinity(struct kvm_vcpu *vcpu, int cpu, bool r)
{
        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) {
                ret = amd_iommu_update_ga(cpu, r, ir->data);
                if (ret)
                        break;
        }
out:
        spin_unlock_irqrestore(&svm->ir_list_lock, flags);
        return ret;
}

void avic_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
{
        u64 entry;
        /* ID = 0xff (broadcast), ID > 0xff (reserved) */
        int h_physical_id = kvm_cpu_get_apicid(cpu);
        struct vcpu_svm *svm = to_svm(vcpu);

        /*
         * Since the host physical APIC id is 8 bits,
         * we can support host APIC ID upto 255.
         */
        if (WARN_ON(h_physical_id > AVIC_PHYSICAL_ID_ENTRY_HOST_PHYSICAL_ID_MASK))
                return;

        entry = READ_ONCE(*(svm->avic_physical_id_cache));
        WARN_ON(entry & AVIC_PHYSICAL_ID_ENTRY_IS_RUNNING_MASK);

        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;
        if (svm->avic_is_running)
                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,
                                        svm->avic_is_running);
}

void avic_vcpu_put(struct kvm_vcpu *vcpu)
{
        u64 entry;
        struct vcpu_svm *svm = to_svm(vcpu);

        entry = READ_ONCE(*(svm->avic_physical_id_cache));
        if (entry & AVIC_PHYSICAL_ID_ENTRY_IS_RUNNING_MASK)
                avic_update_iommu_vcpu_affinity(vcpu, -1, 0);

        entry &= ~AVIC_PHYSICAL_ID_ENTRY_IS_RUNNING_MASK;
        WRITE_ONCE(*(svm->avic_physical_id_cache), entry);
}

/*
 * This function is called during VCPU halt/unhalt.
 */
static void avic_set_running(struct kvm_vcpu *vcpu, bool is_run)
{
        struct vcpu_svm *svm = to_svm(vcpu);

        svm->avic_is_running = is_run;

        if (!kvm_vcpu_apicv_active(vcpu))
                return;

        if (is_run)
                avic_vcpu_load(vcpu, vcpu->cpu);
        else
                avic_vcpu_put(vcpu);

}

void svm_vcpu_blocking(struct kvm_vcpu *vcpu)
{
        avic_set_running(vcpu, false);
}

void svm_vcpu_unblocking(struct kvm_vcpu *vcpu)
{
        if (kvm_check_request(KVM_REQ_APICV_UPDATE, vcpu))
                kvm_vcpu_update_apicv(vcpu);
        avic_set_running(vcpu, true);
}