root/arch/riscv/kvm/aia_aplic.c
// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2021 Western Digital Corporation or its affiliates.
 * Copyright (C) 2022 Ventana Micro Systems Inc.
 *
 * Authors:
 *      Anup Patel <apatel@ventanamicro.com>
 */

#include <linux/irqchip/riscv-aplic.h>
#include <linux/kvm_host.h>
#include <linux/math.h>
#include <linux/nospec.h>
#include <linux/spinlock.h>
#include <linux/swab.h>
#include <kvm/iodev.h>

struct aplic_irq {
        raw_spinlock_t lock;
        u32 sourcecfg;
        u32 state;
#define APLIC_IRQ_STATE_PENDING         BIT(0)
#define APLIC_IRQ_STATE_ENABLED         BIT(1)
#define APLIC_IRQ_STATE_ENPEND          (APLIC_IRQ_STATE_PENDING | \
                                         APLIC_IRQ_STATE_ENABLED)
#define APLIC_IRQ_STATE_INPUT           BIT(8)
        u32 target;
};

struct aplic {
        struct kvm_io_device iodev;

        u32 domaincfg;
        u32 genmsi;

        u32 nr_irqs;
        u32 nr_words;
        struct aplic_irq *irqs;
};

static u32 aplic_read_sourcecfg(struct aplic *aplic, u32 irq)
{
        u32 ret;
        unsigned long flags;
        struct aplic_irq *irqd;

        if (!irq || aplic->nr_irqs <= irq)
                return 0;
        irqd = &aplic->irqs[array_index_nospec(irq, aplic->nr_irqs)];

        raw_spin_lock_irqsave(&irqd->lock, flags);
        ret = irqd->sourcecfg;
        raw_spin_unlock_irqrestore(&irqd->lock, flags);

        return ret;
}

static void aplic_write_sourcecfg(struct aplic *aplic, u32 irq, u32 val)
{
        unsigned long flags;
        struct aplic_irq *irqd;

        if (!irq || aplic->nr_irqs <= irq)
                return;
        irqd = &aplic->irqs[array_index_nospec(irq, aplic->nr_irqs)];

        if (val & APLIC_SOURCECFG_D)
                val = 0;
        else
                val &= APLIC_SOURCECFG_SM_MASK;

        raw_spin_lock_irqsave(&irqd->lock, flags);
        irqd->sourcecfg = val;
        raw_spin_unlock_irqrestore(&irqd->lock, flags);
}

static u32 aplic_read_target(struct aplic *aplic, u32 irq)
{
        u32 ret;
        unsigned long flags;
        struct aplic_irq *irqd;

        if (!irq || aplic->nr_irqs <= irq)
                return 0;
        irqd = &aplic->irqs[array_index_nospec(irq, aplic->nr_irqs)];

        raw_spin_lock_irqsave(&irqd->lock, flags);
        ret = irqd->target;
        raw_spin_unlock_irqrestore(&irqd->lock, flags);

        return ret;
}

static void aplic_write_target(struct aplic *aplic, u32 irq, u32 val)
{
        unsigned long flags;
        struct aplic_irq *irqd;

        if (!irq || aplic->nr_irqs <= irq)
                return;
        irqd = &aplic->irqs[array_index_nospec(irq, aplic->nr_irqs)];

        val &= APLIC_TARGET_EIID_MASK |
               (APLIC_TARGET_HART_IDX_MASK << APLIC_TARGET_HART_IDX_SHIFT) |
               (APLIC_TARGET_GUEST_IDX_MASK << APLIC_TARGET_GUEST_IDX_SHIFT);

        raw_spin_lock_irqsave(&irqd->lock, flags);
        irqd->target = val;
        raw_spin_unlock_irqrestore(&irqd->lock, flags);
}

static bool aplic_read_pending(struct aplic *aplic, u32 irq)
{
        bool ret;
        unsigned long flags;
        struct aplic_irq *irqd;

        if (!irq || aplic->nr_irqs <= irq)
                return false;
        irqd = &aplic->irqs[array_index_nospec(irq, aplic->nr_irqs)];

        raw_spin_lock_irqsave(&irqd->lock, flags);
        ret = (irqd->state & APLIC_IRQ_STATE_PENDING) ? true : false;
        raw_spin_unlock_irqrestore(&irqd->lock, flags);

        return ret;
}

static void aplic_write_pending(struct aplic *aplic, u32 irq, bool pending)
{
        unsigned long flags, sm;
        struct aplic_irq *irqd;

        if (!irq || aplic->nr_irqs <= irq)
                return;
        irqd = &aplic->irqs[array_index_nospec(irq, aplic->nr_irqs)];

        raw_spin_lock_irqsave(&irqd->lock, flags);

        sm = irqd->sourcecfg & APLIC_SOURCECFG_SM_MASK;
        if (sm == APLIC_SOURCECFG_SM_INACTIVE)
                goto skip_write_pending;

        if (sm == APLIC_SOURCECFG_SM_LEVEL_HIGH ||
            sm == APLIC_SOURCECFG_SM_LEVEL_LOW) {
                if (!pending)
                        goto noskip_write_pending;
                if ((irqd->state & APLIC_IRQ_STATE_INPUT) &&
                    sm == APLIC_SOURCECFG_SM_LEVEL_LOW)
                        goto skip_write_pending;
                if (!(irqd->state & APLIC_IRQ_STATE_INPUT) &&
                    sm == APLIC_SOURCECFG_SM_LEVEL_HIGH)
                        goto skip_write_pending;
        }

noskip_write_pending:
        if (pending)
                irqd->state |= APLIC_IRQ_STATE_PENDING;
        else
                irqd->state &= ~APLIC_IRQ_STATE_PENDING;

skip_write_pending:
        raw_spin_unlock_irqrestore(&irqd->lock, flags);
}

static bool aplic_read_enabled(struct aplic *aplic, u32 irq)
{
        bool ret;
        unsigned long flags;
        struct aplic_irq *irqd;

        if (!irq || aplic->nr_irqs <= irq)
                return false;
        irqd = &aplic->irqs[array_index_nospec(irq, aplic->nr_irqs)];

        raw_spin_lock_irqsave(&irqd->lock, flags);
        ret = (irqd->state & APLIC_IRQ_STATE_ENABLED) ? true : false;
        raw_spin_unlock_irqrestore(&irqd->lock, flags);

        return ret;
}

static void aplic_write_enabled(struct aplic *aplic, u32 irq, bool enabled)
{
        unsigned long flags;
        struct aplic_irq *irqd;

        if (!irq || aplic->nr_irqs <= irq)
                return;
        irqd = &aplic->irqs[array_index_nospec(irq, aplic->nr_irqs)];

        raw_spin_lock_irqsave(&irqd->lock, flags);
        if (enabled)
                irqd->state |= APLIC_IRQ_STATE_ENABLED;
        else
                irqd->state &= ~APLIC_IRQ_STATE_ENABLED;
        raw_spin_unlock_irqrestore(&irqd->lock, flags);
}

static bool aplic_read_input(struct aplic *aplic, u32 irq)
{
        u32 sourcecfg, sm, raw_input, irq_inverted;
        struct aplic_irq *irqd;
        unsigned long flags;
        bool ret = false;

        if (!irq || aplic->nr_irqs <= irq)
                return false;
        irqd = &aplic->irqs[array_index_nospec(irq, aplic->nr_irqs)];

        raw_spin_lock_irqsave(&irqd->lock, flags);

        sourcecfg = irqd->sourcecfg;
        if (sourcecfg & APLIC_SOURCECFG_D)
                goto skip;

        sm = sourcecfg & APLIC_SOURCECFG_SM_MASK;
        if (sm == APLIC_SOURCECFG_SM_INACTIVE)
                goto skip;

        raw_input = (irqd->state & APLIC_IRQ_STATE_INPUT) ? 1 : 0;
        irq_inverted = (sm == APLIC_SOURCECFG_SM_LEVEL_LOW ||
                        sm == APLIC_SOURCECFG_SM_EDGE_FALL) ? 1 : 0;
        ret = !!(raw_input ^ irq_inverted);

skip:
        raw_spin_unlock_irqrestore(&irqd->lock, flags);

        return ret;
}

static void aplic_inject_msi(struct kvm *kvm, u32 irq, u32 target)
{
        u32 hart_idx, guest_idx, eiid;

        hart_idx = target >> APLIC_TARGET_HART_IDX_SHIFT;
        hart_idx &= APLIC_TARGET_HART_IDX_MASK;
        guest_idx = target >> APLIC_TARGET_GUEST_IDX_SHIFT;
        guest_idx &= APLIC_TARGET_GUEST_IDX_MASK;
        eiid = target & APLIC_TARGET_EIID_MASK;
        kvm_riscv_aia_inject_msi_by_id(kvm, hart_idx, guest_idx, eiid);
}

static void aplic_update_irq_range(struct kvm *kvm, u32 first, u32 last)
{
        bool inject;
        u32 irq, target;
        unsigned long flags;
        struct aplic_irq *irqd;
        struct aplic *aplic = kvm->arch.aia.aplic_state;

        if (!(aplic->domaincfg & APLIC_DOMAINCFG_IE))
                return;

        for (irq = first; irq <= last; irq++) {
                if (!irq || aplic->nr_irqs <= irq)
                        continue;
                irqd = &aplic->irqs[array_index_nospec(irq, aplic->nr_irqs)];

                raw_spin_lock_irqsave(&irqd->lock, flags);

                inject = false;
                target = irqd->target;
                if ((irqd->state & APLIC_IRQ_STATE_ENPEND) ==
                    APLIC_IRQ_STATE_ENPEND) {
                        irqd->state &= ~APLIC_IRQ_STATE_PENDING;
                        inject = true;
                }

                raw_spin_unlock_irqrestore(&irqd->lock, flags);

                if (inject)
                        aplic_inject_msi(kvm, irq, target);
        }
}

int kvm_riscv_aia_aplic_inject(struct kvm *kvm, u32 source, bool level)
{
        u32 target;
        bool inject = false, ie;
        unsigned long flags;
        struct aplic_irq *irqd;
        struct aplic *aplic = kvm->arch.aia.aplic_state;

        if (!aplic || !source || (aplic->nr_irqs <= source))
                return -ENODEV;
        irqd = &aplic->irqs[array_index_nospec(source, aplic->nr_irqs)];
        ie = (aplic->domaincfg & APLIC_DOMAINCFG_IE) ? true : false;

        raw_spin_lock_irqsave(&irqd->lock, flags);

        if (irqd->sourcecfg & APLIC_SOURCECFG_D)
                goto skip_unlock;

        switch (irqd->sourcecfg & APLIC_SOURCECFG_SM_MASK) {
        case APLIC_SOURCECFG_SM_EDGE_RISE:
                if (level && !(irqd->state & APLIC_IRQ_STATE_INPUT) &&
                    !(irqd->state & APLIC_IRQ_STATE_PENDING))
                        irqd->state |= APLIC_IRQ_STATE_PENDING;
                break;
        case APLIC_SOURCECFG_SM_EDGE_FALL:
                if (!level && (irqd->state & APLIC_IRQ_STATE_INPUT) &&
                    !(irqd->state & APLIC_IRQ_STATE_PENDING))
                        irqd->state |= APLIC_IRQ_STATE_PENDING;
                break;
        case APLIC_SOURCECFG_SM_LEVEL_HIGH:
                if (level && !(irqd->state & APLIC_IRQ_STATE_PENDING))
                        irqd->state |= APLIC_IRQ_STATE_PENDING;
                break;
        case APLIC_SOURCECFG_SM_LEVEL_LOW:
                if (!level && !(irqd->state & APLIC_IRQ_STATE_PENDING))
                        irqd->state |= APLIC_IRQ_STATE_PENDING;
                break;
        }

        if (level)
                irqd->state |= APLIC_IRQ_STATE_INPUT;
        else
                irqd->state &= ~APLIC_IRQ_STATE_INPUT;

        target = irqd->target;
        if (ie && ((irqd->state & APLIC_IRQ_STATE_ENPEND) ==
                   APLIC_IRQ_STATE_ENPEND)) {
                irqd->state &= ~APLIC_IRQ_STATE_PENDING;
                inject = true;
        }

skip_unlock:
        raw_spin_unlock_irqrestore(&irqd->lock, flags);

        if (inject)
                aplic_inject_msi(kvm, source, target);

        return 0;
}

static u32 aplic_read_input_word(struct aplic *aplic, u32 word)
{
        u32 i, ret = 0;

        for (i = 0; i < 32; i++)
                ret |= aplic_read_input(aplic, word * 32 + i) ? BIT(i) : 0;

        return ret;
}

static u32 aplic_read_pending_word(struct aplic *aplic, u32 word)
{
        u32 i, ret = 0;

        for (i = 0; i < 32; i++)
                ret |= aplic_read_pending(aplic, word * 32 + i) ? BIT(i) : 0;

        return ret;
}

static void aplic_write_pending_word(struct aplic *aplic, u32 word,
                                     u32 val, bool pending)
{
        u32 i;

        for (i = 0; i < 32; i++) {
                if (val & BIT(i))
                        aplic_write_pending(aplic, word * 32 + i, pending);
        }
}

static u32 aplic_read_enabled_word(struct aplic *aplic, u32 word)
{
        u32 i, ret = 0;

        for (i = 0; i < 32; i++)
                ret |= aplic_read_enabled(aplic, word * 32 + i) ? BIT(i) : 0;

        return ret;
}

static void aplic_write_enabled_word(struct aplic *aplic, u32 word,
                                     u32 val, bool enabled)
{
        u32 i;

        for (i = 0; i < 32; i++) {
                if (val & BIT(i))
                        aplic_write_enabled(aplic, word * 32 + i, enabled);
        }
}

static int aplic_mmio_read_offset(struct kvm *kvm, gpa_t off, u32 *val32)
{
        u32 i;
        struct aplic *aplic = kvm->arch.aia.aplic_state;

        if ((off & 0x3) != 0)
                return -EOPNOTSUPP;

        if (off == APLIC_DOMAINCFG) {
                *val32 = APLIC_DOMAINCFG_RDONLY |
                         aplic->domaincfg | APLIC_DOMAINCFG_DM;
        } else if ((off >= APLIC_SOURCECFG_BASE) &&
                 (off < (APLIC_SOURCECFG_BASE + (aplic->nr_irqs - 1) * 4))) {
                i = ((off - APLIC_SOURCECFG_BASE) >> 2) + 1;
                *val32 = aplic_read_sourcecfg(aplic, i);
        } else if ((off >= APLIC_SETIP_BASE) &&
                   (off < (APLIC_SETIP_BASE + aplic->nr_words * 4))) {
                i = (off - APLIC_SETIP_BASE) >> 2;
                *val32 = aplic_read_pending_word(aplic, i);
        } else if (off == APLIC_SETIPNUM) {
                *val32 = 0;
        } else if ((off >= APLIC_CLRIP_BASE) &&
                   (off < (APLIC_CLRIP_BASE + aplic->nr_words * 4))) {
                i = (off - APLIC_CLRIP_BASE) >> 2;
                *val32 = aplic_read_input_word(aplic, i);
        } else if (off == APLIC_CLRIPNUM) {
                *val32 = 0;
        } else if ((off >= APLIC_SETIE_BASE) &&
                   (off < (APLIC_SETIE_BASE + aplic->nr_words * 4))) {
                i = (off - APLIC_SETIE_BASE) >> 2;
                *val32 = aplic_read_enabled_word(aplic, i);
        } else if (off == APLIC_SETIENUM) {
                *val32 = 0;
        } else if ((off >= APLIC_CLRIE_BASE) &&
                   (off < (APLIC_CLRIE_BASE + aplic->nr_words * 4))) {
                *val32 = 0;
        } else if (off == APLIC_CLRIENUM) {
                *val32 = 0;
        } else if (off == APLIC_SETIPNUM_LE) {
                *val32 = 0;
        } else if (off == APLIC_SETIPNUM_BE) {
                *val32 = 0;
        } else if (off == APLIC_GENMSI) {
                *val32 = aplic->genmsi;
        } else if ((off >= APLIC_TARGET_BASE) &&
                   (off < (APLIC_TARGET_BASE + (aplic->nr_irqs - 1) * 4))) {
                i = ((off - APLIC_TARGET_BASE) >> 2) + 1;
                *val32 = aplic_read_target(aplic, i);
        } else
                return -ENODEV;

        return 0;
}

static int aplic_mmio_read(struct kvm_vcpu *vcpu, struct kvm_io_device *dev,
                           gpa_t addr, int len, void *val)
{
        if (len != 4)
                return -EOPNOTSUPP;

        return aplic_mmio_read_offset(vcpu->kvm,
                                      addr - vcpu->kvm->arch.aia.aplic_addr,
                                      val);
}

static int aplic_mmio_write_offset(struct kvm *kvm, gpa_t off, u32 val32)
{
        u32 i;
        struct aplic *aplic = kvm->arch.aia.aplic_state;

        if ((off & 0x3) != 0)
                return -EOPNOTSUPP;

        if (off == APLIC_DOMAINCFG) {
                /* Only IE bit writeable */
                aplic->domaincfg = val32 & APLIC_DOMAINCFG_IE;
        } else if ((off >= APLIC_SOURCECFG_BASE) &&
                 (off < (APLIC_SOURCECFG_BASE + (aplic->nr_irqs - 1) * 4))) {
                i = ((off - APLIC_SOURCECFG_BASE) >> 2) + 1;
                aplic_write_sourcecfg(aplic, i, val32);
        } else if ((off >= APLIC_SETIP_BASE) &&
                   (off < (APLIC_SETIP_BASE + aplic->nr_words * 4))) {
                i = (off - APLIC_SETIP_BASE) >> 2;
                aplic_write_pending_word(aplic, i, val32, true);
        } else if (off == APLIC_SETIPNUM) {
                aplic_write_pending(aplic, val32, true);
        } else if ((off >= APLIC_CLRIP_BASE) &&
                   (off < (APLIC_CLRIP_BASE + aplic->nr_words * 4))) {
                i = (off - APLIC_CLRIP_BASE) >> 2;
                aplic_write_pending_word(aplic, i, val32, false);
        } else if (off == APLIC_CLRIPNUM) {
                aplic_write_pending(aplic, val32, false);
        } else if ((off >= APLIC_SETIE_BASE) &&
                   (off < (APLIC_SETIE_BASE + aplic->nr_words * 4))) {
                i = (off - APLIC_SETIE_BASE) >> 2;
                aplic_write_enabled_word(aplic, i, val32, true);
        } else if (off == APLIC_SETIENUM) {
                aplic_write_enabled(aplic, val32, true);
        } else if ((off >= APLIC_CLRIE_BASE) &&
                   (off < (APLIC_CLRIE_BASE + aplic->nr_words * 4))) {
                i = (off - APLIC_CLRIE_BASE) >> 2;
                aplic_write_enabled_word(aplic, i, val32, false);
        } else if (off == APLIC_CLRIENUM) {
                aplic_write_enabled(aplic, val32, false);
        } else if (off == APLIC_SETIPNUM_LE) {
                aplic_write_pending(aplic, val32, true);
        } else if (off == APLIC_SETIPNUM_BE) {
                aplic_write_pending(aplic, __swab32(val32), true);
        } else if (off == APLIC_GENMSI) {
                aplic->genmsi = val32 & ~(APLIC_TARGET_GUEST_IDX_MASK <<
                                          APLIC_TARGET_GUEST_IDX_SHIFT);
                kvm_riscv_aia_inject_msi_by_id(kvm,
                                val32 >> APLIC_TARGET_HART_IDX_SHIFT, 0,
                                val32 & APLIC_TARGET_EIID_MASK);
        } else if ((off >= APLIC_TARGET_BASE) &&
                   (off < (APLIC_TARGET_BASE + (aplic->nr_irqs - 1) * 4))) {
                i = ((off - APLIC_TARGET_BASE) >> 2) + 1;
                aplic_write_target(aplic, i, val32);
        } else
                return -ENODEV;

        aplic_update_irq_range(kvm, 1, aplic->nr_irqs - 1);

        return 0;
}

static int aplic_mmio_write(struct kvm_vcpu *vcpu, struct kvm_io_device *dev,
                            gpa_t addr, int len, const void *val)
{
        if (len != 4)
                return -EOPNOTSUPP;

        return aplic_mmio_write_offset(vcpu->kvm,
                                       addr - vcpu->kvm->arch.aia.aplic_addr,
                                       *((const u32 *)val));
}

static struct kvm_io_device_ops aplic_iodoev_ops = {
        .read = aplic_mmio_read,
        .write = aplic_mmio_write,
};

int kvm_riscv_aia_aplic_set_attr(struct kvm *kvm, unsigned long type, u32 v)
{
        int rc;

        if (!kvm->arch.aia.aplic_state)
                return -ENODEV;

        rc = aplic_mmio_write_offset(kvm, type, v);
        if (rc)
                return rc;

        return 0;
}

int kvm_riscv_aia_aplic_get_attr(struct kvm *kvm, unsigned long type, u32 *v)
{
        int rc;

        if (!kvm->arch.aia.aplic_state)
                return -ENODEV;

        rc = aplic_mmio_read_offset(kvm, type, v);
        if (rc)
                return rc;

        return 0;
}

int kvm_riscv_aia_aplic_has_attr(struct kvm *kvm, unsigned long type)
{
        int rc;
        u32 val;

        if (!kvm->arch.aia.aplic_state)
                return -ENODEV;

        rc = aplic_mmio_read_offset(kvm, type, &val);
        if (rc)
                return rc;

        return 0;
}

int kvm_riscv_aia_aplic_init(struct kvm *kvm)
{
        int i, ret = 0;
        struct aplic *aplic;

        /* Do nothing if we have zero sources */
        if (!kvm->arch.aia.nr_sources)
                return 0;

        /* Allocate APLIC global state */
        aplic = kzalloc_obj(*aplic);
        if (!aplic)
                return -ENOMEM;
        kvm->arch.aia.aplic_state = aplic;

        /* Setup APLIC IRQs */
        aplic->nr_irqs = kvm->arch.aia.nr_sources + 1;
        aplic->nr_words = DIV_ROUND_UP(aplic->nr_irqs, 32);
        aplic->irqs = kzalloc_objs(*aplic->irqs, aplic->nr_irqs);
        if (!aplic->irqs) {
                ret = -ENOMEM;
                goto fail_free_aplic;
        }
        for (i = 0; i < aplic->nr_irqs; i++)
                raw_spin_lock_init(&aplic->irqs[i].lock);

        /* Setup IO device */
        kvm_iodevice_init(&aplic->iodev, &aplic_iodoev_ops);
        mutex_lock(&kvm->slots_lock);
        ret = kvm_io_bus_register_dev(kvm, KVM_MMIO_BUS,
                                      kvm->arch.aia.aplic_addr,
                                      KVM_DEV_RISCV_APLIC_SIZE,
                                      &aplic->iodev);
        mutex_unlock(&kvm->slots_lock);
        if (ret)
                goto fail_free_aplic_irqs;

        /* Setup default IRQ routing */
        ret = kvm_riscv_setup_default_irq_routing(kvm, aplic->nr_irqs);
        if (ret)
                goto fail_unreg_iodev;

        return 0;

fail_unreg_iodev:
        mutex_lock(&kvm->slots_lock);
        kvm_io_bus_unregister_dev(kvm, KVM_MMIO_BUS, &aplic->iodev);
        mutex_unlock(&kvm->slots_lock);
fail_free_aplic_irqs:
        kfree(aplic->irqs);
fail_free_aplic:
        kvm->arch.aia.aplic_state = NULL;
        kfree(aplic);
        return ret;
}

void kvm_riscv_aia_aplic_cleanup(struct kvm *kvm)
{
        struct aplic *aplic = kvm->arch.aia.aplic_state;

        if (!aplic)
                return;

        mutex_lock(&kvm->slots_lock);
        kvm_io_bus_unregister_dev(kvm, KVM_MMIO_BUS, &aplic->iodev);
        mutex_unlock(&kvm->slots_lock);

        kfree(aplic->irqs);

        kvm->arch.aia.aplic_state = NULL;
        kfree(aplic);
}