irq_comm.c

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/*
 * irq_comm.c: Common API for in kernel interrupt controller
 * Copyright (c) 2007, Intel Corporation.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
 * Place - Suite 330, Boston, MA 02111-1307 USA.
 * Authors:
 *   Yaozu (Eddie) Dong <[email protected]>
 *
 * Copyright 2010 Red Hat, Inc. and/or its affiliates.
 */

#include <linux/kvm_host.h>
#include <linux/slab.h>
#include <trace/events/kvm.h>

#include <asm/msidef.h>
#ifdef CONFIG_IA64
#include <asm/iosapic.h>
#endif

#include "irq.h"

#include "ioapic.h"

static int kvm_set_pic_irq(struct kvm_kernel_irq_routing_entry *e,
               struct kvm *kvm, int irq_source_id, int level)
{
#ifdef CONFIG_X86
    struct kvm_pic *pic = pic_irqchip(kvm);
    return kvm_pic_set_irq(pic, e->irqchip.pin, irq_source_id, level);
#else
    return -1;
#endif
}

static int kvm_set_ioapic_irq(struct kvm_kernel_irq_routing_entry *e,
                  struct kvm *kvm, int irq_source_id, int level)
{
    struct kvm_ioapic *ioapic = kvm->arch.vioapic;
    return kvm_ioapic_set_irq(ioapic, e->irqchip.pin, irq_source_id, level);
}

inline static bool kvm_is_dm_lowest_prio(struct kvm_lapic_irq *irq)
{
#ifdef CONFIG_IA64
    return irq->delivery_mode ==
        (IOSAPIC_LOWEST_PRIORITY << IOSAPIC_DELIVERY_SHIFT);
#else
    return irq->delivery_mode == APIC_DM_LOWEST;
#endif
}

int kvm_irq_delivery_to_apic(struct kvm *kvm, struct kvm_lapic *src,
        struct kvm_lapic_irq *irq)
{
    int i, r = -1;
    struct kvm_vcpu *vcpu, *lowest = NULL;

    if (irq->dest_mode == 0 && irq->dest_id == 0xff &&
            kvm_is_dm_lowest_prio(irq)) {
        printk(KERN_INFO "kvm: apic: phys broadcast and lowest prio\n");
        irq->delivery_mode = APIC_DM_FIXED;
    }

    if (kvm_irq_delivery_to_apic_fast(kvm, src, irq, &r))
        return r;

    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_is_dm_lowest_prio(irq)) {
            if (r < 0)
                r = 0;
            r += kvm_apic_set_irq(vcpu, irq);
        } else if (kvm_lapic_enabled(vcpu)) {
            if (!lowest)
                lowest = vcpu;
            else if (kvm_apic_compare_prio(vcpu, lowest) < 0)
                lowest = vcpu;
        }
    }

    if (lowest)
        r = kvm_apic_set_irq(lowest, irq);

    return r;
}

int kvm_set_msi(struct kvm_kernel_irq_routing_entry *e,
        struct kvm *kvm, int irq_source_id, int level)
{
    struct kvm_lapic_irq irq;

    if (!level)
        return -1;

    trace_kvm_msi_set_irq(e->msi.address_lo, e->msi.data);

    irq.dest_id = (e->msi.address_lo &
            MSI_ADDR_DEST_ID_MASK) >> MSI_ADDR_DEST_ID_SHIFT;
    irq.vector = (e->msi.data &
            MSI_DATA_VECTOR_MASK) >> MSI_DATA_VECTOR_SHIFT;
    irq.dest_mode = (1 << MSI_ADDR_DEST_MODE_SHIFT) & e->msi.address_lo;
    irq.trig_mode = (1 << MSI_DATA_TRIGGER_SHIFT) & e->msi.data;
    irq.delivery_mode = e->msi.data & 0x700;
    irq.level = 1;
    irq.shorthand = 0;

    /* TODO Deal with RH bit of MSI message address */
    return kvm_irq_delivery_to_apic(kvm, NULL, &irq);
}

int kvm_send_userspace_msi(struct kvm *kvm, struct kvm_msi *msi)
{
    struct kvm_kernel_irq_routing_entry route;

    if (!irqchip_in_kernel(kvm) || msi->flags != 0)
        return -EINVAL;

    route.msi.address_lo = msi->address_lo;
    route.msi.address_hi = msi->address_hi;
    route.msi.data = msi->data;

    return kvm_set_msi(&route, kvm, KVM_USERSPACE_IRQ_SOURCE_ID, 1);
}

/*
 * Return value:
 *  < 0   Interrupt was ignored (masked or not delivered for other reasons)
 *  = 0   Interrupt was coalesced (previous irq is still pending)
 *  > 0   Number of CPUs interrupt was delivered to
 */
int kvm_set_irq(struct kvm *kvm, int irq_source_id, u32 irq, int level)
{
    struct kvm_kernel_irq_routing_entry *e, irq_set[KVM_NR_IRQCHIPS];
    int ret = -1, i = 0;
    struct kvm_irq_routing_table *irq_rt;
    struct hlist_node *n;

    trace_kvm_set_irq(irq, level, irq_source_id);

    /* Not possible to detect if the guest uses the PIC or the
     * IOAPIC.  So set the bit in both. The guest will ignore
     * writes to the unused one.
     */
    rcu_read_lock();
    irq_rt = rcu_dereference(kvm->irq_routing);
    if (irq < irq_rt->nr_rt_entries)
        hlist_for_each_entry(e, n, &irq_rt->map[irq], link)
            irq_set[i++] = *e;
    rcu_read_unlock();

    while(i--) {
        int r;
        r = irq_set[i].set(&irq_set[i], kvm, irq_source_id, level);
        if (r < 0)
            continue;

        ret = r + ((ret < 0) ? 0 : ret);
    }

    return ret;
}

void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned pin)
{
    struct kvm_irq_ack_notifier *kian;
    struct hlist_node *n;
    int gsi;

    trace_kvm_ack_irq(irqchip, pin);

    rcu_read_lock();
    gsi = rcu_dereference(kvm->irq_routing)->chip[irqchip][pin];
    if (gsi != -1)
        hlist_for_each_entry_rcu(kian, n, &kvm->irq_ack_notifier_list,
                     link)
            if (kian->gsi == gsi)
                kian->irq_acked(kian);
    rcu_read_unlock();
}

void kvm_register_irq_ack_notifier(struct kvm *kvm,
                   struct kvm_irq_ack_notifier *kian)
{
    mutex_lock(&kvm->irq_lock);
    hlist_add_head_rcu(&kian->link, &kvm->irq_ack_notifier_list);
    mutex_unlock(&kvm->irq_lock);
}

void kvm_unregister_irq_ack_notifier(struct kvm *kvm,
                    struct kvm_irq_ack_notifier *kian)
{
    mutex_lock(&kvm->irq_lock);
    hlist_del_init_rcu(&kian->link);
    mutex_unlock(&kvm->irq_lock);
    synchronize_rcu();
}

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) {
        printk(KERN_WARNING "kvm: exhaust allocatable IRQ sources!\n");
        irq_source_id = -EFAULT;
        goto unlock;
    }

    ASSERT(irq_source_id != KVM_USERSPACE_IRQ_SOURCE_ID);
#ifdef CONFIG_X86
    ASSERT(irq_source_id != KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID);
#endif
    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);
#ifdef CONFIG_X86
    ASSERT(irq_source_id != KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID);
#endif

    mutex_lock(&kvm->irq_lock);
    if (irq_source_id < 0 ||
        irq_source_id >= BITS_PER_LONG) {
        printk(KERN_ERR "kvm: IRQ source ID out of range!\n");
        goto unlock;
    }
    clear_bit(irq_source_id, &kvm->arch.irq_sources_bitmap);
    if (!irqchip_in_kernel(kvm))
        goto unlock;

    kvm_ioapic_clear_all(kvm->arch.vioapic, irq_source_id);
#ifdef CONFIG_X86
    kvm_pic_clear_all(pic_irqchip(kvm), irq_source_id);
#endif
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->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_rcu();
}

void kvm_fire_mask_notifiers(struct kvm *kvm, unsigned irqchip, unsigned pin,
                 bool mask)
{
    struct kvm_irq_mask_notifier *kimn;
    struct hlist_node *n;
    int gsi;

    rcu_read_lock();
    gsi = rcu_dereference(kvm->irq_routing)->chip[irqchip][pin];
    if (gsi != -1)
        hlist_for_each_entry_rcu(kimn, n, &kvm->mask_notifier_list, link)
            if (kimn->irq == gsi)
                kimn->func(kimn, mask);
    rcu_read_unlock();
}

void kvm_free_irq_routing(struct kvm *kvm)
{
    /* Called only during vm destruction. Nobody can use the pointer
       at this stage */
    kfree(kvm->irq_routing);
}

static int setup_routing_entry(struct kvm_irq_routing_table *rt,
                   struct kvm_kernel_irq_routing_entry *e,
                   const struct kvm_irq_routing_entry *ue)
{
    int r = -EINVAL;
    int delta;
    unsigned max_pin;
    struct kvm_kernel_irq_routing_entry *ei;
    struct hlist_node *n;

    /*
     * Do not allow GSI to be mapped to the same irqchip more than once.
     * Allow only one to one mapping between GSI and MSI.
     */
    hlist_for_each_entry(ei, n, &rt->map[ue->gsi], link)
        if (ei->type == KVM_IRQ_ROUTING_MSI ||
            ue->type == KVM_IRQ_ROUTING_MSI ||
            ue->u.irqchip.irqchip == ei->irqchip.irqchip)
            return r;

    e->gsi = ue->gsi;
    e->type = ue->type;
    switch (ue->type) {
    case KVM_IRQ_ROUTING_IRQCHIP:
        delta = 0;
        switch (ue->u.irqchip.irqchip) {
        case KVM_IRQCHIP_PIC_MASTER:
            e->set = kvm_set_pic_irq;
            max_pin = PIC_NUM_PINS;
            break;
        case KVM_IRQCHIP_PIC_SLAVE:
            e->set = kvm_set_pic_irq;
            max_pin = PIC_NUM_PINS;
            delta = 8;
            break;
        case KVM_IRQCHIP_IOAPIC:
            max_pin = KVM_IOAPIC_NUM_PINS;
            e->set = kvm_set_ioapic_irq;
            break;
        default:
            goto out;
        }
        e->irqchip.irqchip = ue->u.irqchip.irqchip;
        e->irqchip.pin = ue->u.irqchip.pin + delta;
        if (e->irqchip.pin >= max_pin)
            goto out;
        rt->chip[ue->u.irqchip.irqchip][e->irqchip.pin] = ue->gsi;
        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;
        break;
    default:
        goto out;
    }

    hlist_add_head(&e->link, &rt->map[e->gsi]);
    r = 0;
out:
    return r;
}


int kvm_set_irq_routing(struct kvm *kvm,
            const struct kvm_irq_routing_entry *ue,
            unsigned nr,
            unsigned flags)
{
    struct kvm_irq_routing_table *new, *old;
    u32 i, j, nr_rt_entries = 0;
    int r;

    for (i = 0; i < nr; ++i) {
        if (ue[i].gsi >= KVM_MAX_IRQ_ROUTES)
            return -EINVAL;
        nr_rt_entries = max(nr_rt_entries, ue[i].gsi);
    }

    nr_rt_entries += 1;

    new = kzalloc(sizeof(*new) + (nr_rt_entries * sizeof(struct hlist_head))
              + (nr * sizeof(struct kvm_kernel_irq_routing_entry)),
              GFP_KERNEL);

    if (!new)
        return -ENOMEM;

    new->rt_entries = (void *)&new->map[nr_rt_entries];

    new->nr_rt_entries = nr_rt_entries;
    for (i = 0; i < 3; i++)
        for (j = 0; j < KVM_IOAPIC_NUM_PINS; j++)
            new->chip[i][j] = -1;

    for (i = 0; i < nr; ++i) {
        r = -EINVAL;
        if (ue->flags)
            goto out;
        r = setup_routing_entry(new, &new->rt_entries[i], ue);
        if (r)
            goto out;
        ++ue;
    }

    mutex_lock(&kvm->irq_lock);
    old = kvm->irq_routing;
    kvm_irq_routing_update(kvm, new);
    mutex_unlock(&kvm->irq_lock);

    synchronize_rcu();

    new = old;
    r = 0;

out:
    kfree(new);
    return r;
}

#define IOAPIC_ROUTING_ENTRY(irq) \
    { .gsi = irq, .type = KVM_IRQ_ROUTING_IRQCHIP,  \
      .u.irqchip.irqchip = KVM_IRQCHIP_IOAPIC, .u.irqchip.pin = (irq) }
#define ROUTING_ENTRY1(irq) IOAPIC_ROUTING_ENTRY(irq)

#ifdef CONFIG_X86
#  define PIC_ROUTING_ENTRY(irq) \
    { .gsi = irq, .type = KVM_IRQ_ROUTING_IRQCHIP,  \
      .u.irqchip.irqchip = SELECT_PIC(irq), .u.irqchip.pin = (irq) % 8 }
#  define ROUTING_ENTRY2(irq) \
    IOAPIC_ROUTING_ENTRY(irq), PIC_ROUTING_ENTRY(irq)
#else
#  define ROUTING_ENTRY2(irq) \
    IOAPIC_ROUTING_ENTRY(irq)
#endif

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),
#ifdef CONFIG_IA64
    ROUTING_ENTRY1(24), ROUTING_ENTRY1(25),
    ROUTING_ENTRY1(26), ROUTING_ENTRY1(27),
    ROUTING_ENTRY1(28), ROUTING_ENTRY1(29),
    ROUTING_ENTRY1(30), ROUTING_ENTRY1(31),
    ROUTING_ENTRY1(32), ROUTING_ENTRY1(33),
    ROUTING_ENTRY1(34), ROUTING_ENTRY1(35),
    ROUTING_ENTRY1(36), ROUTING_ENTRY1(37),
    ROUTING_ENTRY1(38), ROUTING_ENTRY1(39),
    ROUTING_ENTRY1(40), ROUTING_ENTRY1(41),
    ROUTING_ENTRY1(42), ROUTING_ENTRY1(43),
    ROUTING_ENTRY1(44), ROUTING_ENTRY1(45),
    ROUTING_ENTRY1(46), ROUTING_ENTRY1(47),
#endif
};

int kvm_setup_default_irq_routing(struct kvm *kvm)
{
    return kvm_set_irq_routing(kvm, default_routing,
                   ARRAY_SIZE(default_routing), 0);
}