irq_comm.c

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// SPDX-License-Identifier: GPL-2.0-only
/*
 * irq_comm.c: Common API for in kernel interrupt controller
 * Copyright (c) 2007, Intel Corporation.
 *
 * Authors:
 *   Yaozu (Eddie) Dong <Eddie.dong@intel.com>
 *
 * Copyright 2010 Red Hat, Inc. and/or its affiliates.
 */
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
#include <linux/kvm_host.h>
#include <linux/slab.h>
#include <linux/export.h>
#include <linux/rculist.h>
 
#include <trace/events/kvm.h>
 
#include "irq.h"
 
#include "ioapic.h"
 
#include "lapic.h"
 
#include "hyperv.h"
#include "x86.h"
#include "xen.h"
 
static int kvm_set_pic_irq(struct kvm_kernel_irq_routing_entry *e,
               struct kvm *kvm, int irq_source_id, int level,
               bool line_status)
{
    struct kvm_pic *pic = kvm->arch.vpic;
    return kvm_pic_set_irq(pic, e->irqchip.pin, irq_source_id, level);
}
 
static int kvm_set_ioapic_irq(struct kvm_kernel_irq_routing_entry *e,
                  struct kvm *kvm, int irq_source_id, int level,
                  bool line_status)
{
    struct kvm_ioapic *ioapic = kvm->arch.vioapic;
    return kvm_ioapic_set_irq(ioapic, e->irqchip.pin, irq_source_id, level,
                line_status);
}
 
int kvm_irq_delivery_to_apic(struct kvm *kvm, struct kvm_lapic *src,
        struct kvm_lapic_irq *irq, struct dest_map *dest_map)
{
    int r = -1;
    struct kvm_vcpu *vcpu, *lowest = NULL;
    unsigned long i, dest_vcpu_bitmap[BITS_TO_LONGS(KVM_MAX_VCPUS)];
    unsigned int dest_vcpus = 0;
 
    if (kvm_irq_delivery_to_apic_fast(kvm, src, irq, &r, dest_map))
        return r;
 
    if (irq->dest_mode == APIC_DEST_PHYSICAL &&
        irq->dest_id == 0xff && kvm_lowest_prio_delivery(irq)) {
        pr_info("apic: phys broadcast and lowest prio\n");
        irq->delivery_mode = APIC_DM_FIXED;
    }
 
    memset(dest_vcpu_bitmap, 0, sizeof(dest_vcpu_bitmap));
 
    kvm_for_each_vcpu(i, vcpu, kvm) {
        if (!kvm_apic_present(vcpu))
            continue;
 
        if (!kvm_apic_match_dest(vcpu, src, irq->shorthand,
                    irq->dest_id, irq->dest_mode))
            continue;
 
        if (!kvm_lowest_prio_delivery(irq)) {
            if (r < 0)
                r = 0;
            r += kvm_apic_set_irq(vcpu, irq, dest_map);
        } else if (kvm_apic_sw_enabled(vcpu->arch.apic)) {
            if (!kvm_vector_hashing_enabled()) {
                if (!lowest)
                    lowest = vcpu;
                else if (kvm_apic_compare_prio(vcpu, lowest) < 0)
                    lowest = vcpu;
            } else {
                __set_bit(i, dest_vcpu_bitmap);
                dest_vcpus++;
            }
        }
    }
 
    if (dest_vcpus != 0) {
        int idx = kvm_vector_to_index(irq->vector, dest_vcpus,
                    dest_vcpu_bitmap, KVM_MAX_VCPUS);
 
        lowest = kvm_get_vcpu(kvm, idx);
    }
 
    if (lowest)
        r = kvm_apic_set_irq(lowest, irq, dest_map);
 
    return r;
}
 
void kvm_set_msi_irq(struct kvm *kvm, struct kvm_kernel_irq_routing_entry *e,
             struct kvm_lapic_irq *irq)
{
    struct msi_msg msg = { .address_lo = e->msi.address_lo,
                   .address_hi = e->msi.address_hi,
                   .data = e->msi.data };
 
    trace_kvm_msi_set_irq(msg.address_lo | (kvm->arch.x2apic_format ?
                  (u64)msg.address_hi << 32 : 0), msg.data);
 
    irq->dest_id = x86_msi_msg_get_destid(&msg, kvm->arch.x2apic_format);
    irq->vector = msg.arch_data.vector;
    irq->dest_mode = kvm_lapic_irq_dest_mode(msg.arch_addr_lo.dest_mode_logical);
    irq->trig_mode = msg.arch_data.is_level;
    irq->delivery_mode = msg.arch_data.delivery_mode << 8;
    irq->msi_redir_hint = msg.arch_addr_lo.redirect_hint;
    irq->level = 1;
    irq->shorthand = APIC_DEST_NOSHORT;
}
EXPORT_SYMBOL_GPL(kvm_set_msi_irq);
 
static inline bool kvm_msi_route_invalid(struct kvm *kvm,
        struct kvm_kernel_irq_routing_entry *e)
{
    return kvm->arch.x2apic_format && (e->msi.address_hi & 0xff);
}
 
int kvm_set_msi(struct kvm_kernel_irq_routing_entry *e,
        struct kvm *kvm, int irq_source_id, int level, bool line_status)
{
    struct kvm_lapic_irq irq;
 
    if (kvm_msi_route_invalid(kvm, e))
        return -EINVAL;
 
    if (!level)
        return -1;
 
    kvm_set_msi_irq(kvm, e, &irq);
 
    return kvm_irq_delivery_to_apic(kvm, NULL, &irq, NULL);
}
 
#ifdef CONFIG_KVM_HYPERV
static int kvm_hv_set_sint(struct kvm_kernel_irq_routing_entry *e,
            struct kvm *kvm, int irq_source_id, int level,
            bool line_status)
{
    if (!level)
        return -1;
 
    return kvm_hv_synic_set_irq(kvm, e->hv_sint.vcpu, e->hv_sint.sint);
}
#endif
 
int kvm_arch_set_irq_inatomic(struct kvm_kernel_irq_routing_entry *e,
                  struct kvm *kvm, int irq_source_id, int level,
                  bool line_status)
{
    struct kvm_lapic_irq irq;
    int r;
 
    switch (e->type) {
#ifdef CONFIG_KVM_HYPERV
    case KVM_IRQ_ROUTING_HV_SINT:
        return kvm_hv_set_sint(e, kvm, irq_source_id, level,
                       line_status);
#endif
 
    case KVM_IRQ_ROUTING_MSI:
        if (kvm_msi_route_invalid(kvm, e))
            return -EINVAL;
 
        kvm_set_msi_irq(kvm, e, &irq);
 
        if (kvm_irq_delivery_to_apic_fast(kvm, NULL, &irq, &r, NULL))
            return r;
        break;
 
#ifdef CONFIG_KVM_XEN
    case KVM_IRQ_ROUTING_XEN_EVTCHN:
        if (!level)
            return -1;
 
        return kvm_xen_set_evtchn_fast(&e->xen_evtchn, kvm);
#endif
    default:
        break;
    }
 
    return -EWOULDBLOCK;
}
 
int kvm_request_irq_source_id(struct kvm *kvm)
{
    unsigned long *bitmap = &kvm->arch.irq_sources_bitmap;
    int irq_source_id;
 
    mutex_lock(&kvm->irq_lock);
    irq_source_id = find_first_zero_bit(bitmap, BITS_PER_LONG);
 
    if (irq_source_id >= BITS_PER_LONG) {
        pr_warn("exhausted allocatable IRQ sources!\n");
        irq_source_id = -EFAULT;
        goto unlock;
    }
 
    ASSERT(irq_source_id != KVM_USERSPACE_IRQ_SOURCE_ID);
    ASSERT(irq_source_id != KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID);
    set_bit(irq_source_id, bitmap);
unlock:
    mutex_unlock(&kvm->irq_lock);
 
    return irq_source_id;
}
 
void kvm_free_irq_source_id(struct kvm *kvm, int irq_source_id)
{
    ASSERT(irq_source_id != KVM_USERSPACE_IRQ_SOURCE_ID);
    ASSERT(irq_source_id != KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID);
 
    mutex_lock(&kvm->irq_lock);
    if (irq_source_id < 0 ||
        irq_source_id >= BITS_PER_LONG) {
        pr_err("IRQ source ID out of range!\n");
        goto unlock;
    }
    clear_bit(irq_source_id, &kvm->arch.irq_sources_bitmap);
    if (!irqchip_kernel(kvm))
        goto unlock;
 
    kvm_ioapic_clear_all(kvm->arch.vioapic, irq_source_id);
    kvm_pic_clear_all(kvm->arch.vpic, irq_source_id);
unlock:
    mutex_unlock(&kvm->irq_lock);
}
 
void kvm_register_irq_mask_notifier(struct kvm *kvm, int irq,
                    struct kvm_irq_mask_notifier *kimn)
{
    mutex_lock(&kvm->irq_lock);
    kimn->irq = irq;
    hlist_add_head_rcu(&kimn->link, &kvm->arch.mask_notifier_list);
    mutex_unlock(&kvm->irq_lock);
}
 
void kvm_unregister_irq_mask_notifier(struct kvm *kvm, int irq,
                      struct kvm_irq_mask_notifier *kimn)
{
    mutex_lock(&kvm->irq_lock);
    hlist_del_rcu(&kimn->link);
    mutex_unlock(&kvm->irq_lock);
    synchronize_srcu(&kvm->irq_srcu);
}
 
void kvm_fire_mask_notifiers(struct kvm *kvm, unsigned irqchip, unsigned pin,
                 bool mask)
{
    struct kvm_irq_mask_notifier *kimn;
    int idx, gsi;
 
    idx = srcu_read_lock(&kvm->irq_srcu);
    gsi = kvm_irq_map_chip_pin(kvm, irqchip, pin);
    if (gsi != -1)
        hlist_for_each_entry_rcu(kimn, &kvm->arch.mask_notifier_list, link)
            if (kimn->irq == gsi)
                kimn->func(kimn, mask);
    srcu_read_unlock(&kvm->irq_srcu, idx);
}
 
bool kvm_arch_can_set_irq_routing(struct kvm *kvm)
{
    return irqchip_in_kernel(kvm);
}
 
int kvm_set_routing_entry(struct kvm *kvm,
              struct kvm_kernel_irq_routing_entry *e,
              const struct kvm_irq_routing_entry *ue)
{
    /* We can't check irqchip_in_kernel() here as some callers are
     * currently initializing the irqchip. Other callers should therefore
     * check kvm_arch_can_set_irq_routing() before calling this function.
     */
    switch (ue->type) {
    case KVM_IRQ_ROUTING_IRQCHIP:
        if (irqchip_split(kvm))
            return -EINVAL;
        e->irqchip.pin = ue->u.irqchip.pin;
        switch (ue->u.irqchip.irqchip) {
        case KVM_IRQCHIP_PIC_SLAVE:
            e->irqchip.pin += PIC_NUM_PINS / 2;
            fallthrough;
        case KVM_IRQCHIP_PIC_MASTER:
            if (ue->u.irqchip.pin >= PIC_NUM_PINS / 2)
                return -EINVAL;
            e->set = kvm_set_pic_irq;
            break;
        case KVM_IRQCHIP_IOAPIC:
            if (ue->u.irqchip.pin >= KVM_IOAPIC_NUM_PINS)
                return -EINVAL;
            e->set = kvm_set_ioapic_irq;
            break;
        default:
            return -EINVAL;
        }
        e->irqchip.irqchip = ue->u.irqchip.irqchip;
        break;
    case KVM_IRQ_ROUTING_MSI:
        e->set = kvm_set_msi;
        e->msi.address_lo = ue->u.msi.address_lo;
        e->msi.address_hi = ue->u.msi.address_hi;
        e->msi.data = ue->u.msi.data;
 
        if (kvm_msi_route_invalid(kvm, e))
            return -EINVAL;
        break;
#ifdef CONFIG_KVM_HYPERV
    case KVM_IRQ_ROUTING_HV_SINT:
        e->set = kvm_hv_set_sint;
        e->hv_sint.vcpu = ue->u.hv_sint.vcpu;
        e->hv_sint.sint = ue->u.hv_sint.sint;
        break;
#endif
#ifdef CONFIG_KVM_XEN
    case KVM_IRQ_ROUTING_XEN_EVTCHN:
        return kvm_xen_setup_evtchn(kvm, e, ue);
#endif
    default:
        return -EINVAL;
    }
 
    return 0;
}
 
bool kvm_intr_is_single_vcpu(struct kvm *kvm, struct kvm_lapic_irq *irq,
                 struct kvm_vcpu **dest_vcpu)
{
    int r = 0;
    unsigned long i;
    struct kvm_vcpu *vcpu;
 
    if (kvm_intr_is_single_vcpu_fast(kvm, irq, dest_vcpu))
        return true;
 
    kvm_for_each_vcpu(i, vcpu, kvm) {
        if (!kvm_apic_present(vcpu))
            continue;
 
        if (!kvm_apic_match_dest(vcpu, NULL, irq->shorthand,
                    irq->dest_id, irq->dest_mode))
            continue;
 
        if (++r == 2)
            return false;
 
        *dest_vcpu = vcpu;
    }
 
    return r == 1;
}
EXPORT_SYMBOL_GPL(kvm_intr_is_single_vcpu);
 
#define IOAPIC_ROUTING_ENTRY(irq) \
    { .gsi = irq, .type = KVM_IRQ_ROUTING_IRQCHIP,  \
      .u.irqchip = { .irqchip = KVM_IRQCHIP_IOAPIC, .pin = (irq) } }
#define ROUTING_ENTRY1(irq) IOAPIC_ROUTING_ENTRY(irq)
 
#define PIC_ROUTING_ENTRY(irq) \
    { .gsi = irq, .type = KVM_IRQ_ROUTING_IRQCHIP,  \
      .u.irqchip = { .irqchip = SELECT_PIC(irq), .pin = (irq) % 8 } }
#define ROUTING_ENTRY2(irq) \
    IOAPIC_ROUTING_ENTRY(irq), PIC_ROUTING_ENTRY(irq)
 
static const struct kvm_irq_routing_entry default_routing[] = {
    ROUTING_ENTRY2(0), ROUTING_ENTRY2(1),
    ROUTING_ENTRY2(2), ROUTING_ENTRY2(3),
    ROUTING_ENTRY2(4), ROUTING_ENTRY2(5),
    ROUTING_ENTRY2(6), ROUTING_ENTRY2(7),
    ROUTING_ENTRY2(8), ROUTING_ENTRY2(9),
    ROUTING_ENTRY2(10), ROUTING_ENTRY2(11),
    ROUTING_ENTRY2(12), ROUTING_ENTRY2(13),
    ROUTING_ENTRY2(14), ROUTING_ENTRY2(15),
    ROUTING_ENTRY1(16), ROUTING_ENTRY1(17),
    ROUTING_ENTRY1(18), ROUTING_ENTRY1(19),
    ROUTING_ENTRY1(20), ROUTING_ENTRY1(21),
    ROUTING_ENTRY1(22), ROUTING_ENTRY1(23),
};
 
int kvm_setup_default_irq_routing(struct kvm *kvm)
{
    return kvm_set_irq_routing(kvm, default_routing,
                   ARRAY_SIZE(default_routing), 0);
}
 
static const struct kvm_irq_routing_entry empty_routing[] = {};
 
int kvm_setup_empty_irq_routing(struct kvm *kvm)
{
    return kvm_set_irq_routing(kvm, empty_routing, 0, 0);
}
 
void kvm_arch_post_irq_routing_update(struct kvm *kvm)
{
    if (!irqchip_split(kvm))
        return;
    kvm_make_scan_ioapic_request(kvm);
}
 
void kvm_scan_ioapic_routes(struct kvm_vcpu *vcpu,
                ulong *ioapic_handled_vectors)
{
    struct kvm *kvm = vcpu->kvm;
    struct kvm_kernel_irq_routing_entry *entry;
    struct kvm_irq_routing_table *table;
    u32 i, nr_ioapic_pins;
    int idx;
 
    idx = srcu_read_lock(&kvm->irq_srcu);
    table = srcu_dereference(kvm->irq_routing, &kvm->irq_srcu);
    nr_ioapic_pins = min_t(u32, table->nr_rt_entries,
                   kvm->arch.nr_reserved_ioapic_pins);
    for (i = 0; i < nr_ioapic_pins; ++i) {
        hlist_for_each_entry(entry, &table->map[i], link) {
            struct kvm_lapic_irq irq;
 
            if (entry->type != KVM_IRQ_ROUTING_MSI)
                continue;
 
            kvm_set_msi_irq(vcpu->kvm, entry, &irq);
 
            if (irq.trig_mode &&
                (kvm_apic_match_dest(vcpu, NULL, APIC_DEST_NOSHORT,
                         irq.dest_id, irq.dest_mode) ||
                 kvm_apic_pending_eoi(vcpu, irq.vector)))
                __set_bit(irq.vector, ioapic_handled_vectors);
        }
    }
    srcu_read_unlock(&kvm->irq_srcu, idx);
}
 
void kvm_arch_irq_routing_update(struct kvm *kvm)
{
#ifdef CONFIG_KVM_HYPERV
    kvm_hv_irq_routing_update(kvm);
#endif
}