// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright 2017 Benjamin Herrenschmidt, IBM Corporation.
 */

#define pr_fmt(fmt) "xive-kvm: " fmt

#include <linux/kernel.h>
#include <linux/kvm_host.h>
#include <linux/err.h>
#include <linux/gfp.h>
#include <linux/spinlock.h>
#include <linux/delay.h>
#include <linux/percpu.h>
#include <linux/cpumask.h>
#include <linux/uaccess.h>
#include <asm/kvm_book3s.h>
#include <asm/kvm_ppc.h>
#include <asm/hvcall.h>
#include <asm/xics.h>
#include <asm/xive.h>
#include <asm/xive-regs.h>
#include <asm/debug.h>
#include <asm/debugfs.h>
#include <asm/time.h>
#include <asm/opal.h>

#include <linux/debugfs.h>
#include <linux/seq_file.h>

#include "book3s_xive.h"


/*
 * Virtual mode variants of the hcalls for use on radix/radix
 * with AIL. They require the VCPU's VP to be "pushed"
 *
 * We still instantiate them here because we use some of the
 * generated utility functions as well in this file.
 */
#define XIVE_RUNTIME_CHECKS
#define X_PFX xive_vm_
#define X_STATIC static
#define X_STAT_PFX stat_vm_
#define __x_tima                xive_tima
#define __x_eoi_page(xd)        ((void __iomem *)((xd)->eoi_mmio))
#define __x_trig_page(xd)       ((void __iomem *)((xd)->trig_mmio))
#define __x_writeb      __raw_writeb
#define __x_readw       __raw_readw
#define __x_readq       __raw_readq
#define __x_writeq      __raw_writeq

#include "book3s_xive_template.c"

/*
 * We leave a gap of a couple of interrupts in the queue to
 * account for the IPI and additional safety guard.
 */
#define XIVE_Q_GAP      2

/*
 * Push a vcpu's context to the XIVE on guest entry.
 * This assumes we are in virtual mode (MMU on)
 */
void kvmppc_xive_push_vcpu(struct kvm_vcpu *vcpu)
{
        void __iomem *tima = local_paca->kvm_hstate.xive_tima_virt;
        u64 pq;

        if (!tima)
                return;
        eieio();
        __raw_writeq(vcpu->arch.xive_saved_state.w01, tima + TM_QW1_OS);
        __raw_writel(vcpu->arch.xive_cam_word, tima + TM_QW1_OS + TM_WORD2);
        vcpu->arch.xive_pushed = 1;
        eieio();

        /*
         * We clear the irq_pending flag. There is a small chance of a
         * race vs. the escalation interrupt happening on another
         * processor setting it again, but the only consequence is to
         * cause a spurious wakeup on the next H_CEDE, which is not an
         * issue.
         */
        vcpu->arch.irq_pending = 0;

        /*
         * In single escalation mode, if the escalation interrupt is
         * on, we mask it.
         */
        if (vcpu->arch.xive_esc_on) {
                pq = __raw_readq((void __iomem *)(vcpu->arch.xive_esc_vaddr +
                                                  XIVE_ESB_SET_PQ_01));
                mb();

                /*
                 * We have a possible subtle race here: The escalation
                 * interrupt might have fired and be on its way to the
                 * host queue while we mask it, and if we unmask it
                 * early enough (re-cede right away), there is a
                 * theorical possibility that it fires again, thus
                 * landing in the target queue more than once which is
                 * a big no-no.
                 *
                 * Fortunately, solving this is rather easy. If the
                 * above load setting PQ to 01 returns a previous
                 * value where P is set, then we know the escalation
                 * interrupt is somewhere on its way to the host. In
                 * that case we simply don't clear the xive_esc_on
                 * flag below. It will be eventually cleared by the
                 * handler for the escalation interrupt.
                 *
                 * Then, when doing a cede, we check that flag again
                 * before re-enabling the escalation interrupt, and if
                 * set, we abort the cede.
                 */
                if (!(pq & XIVE_ESB_VAL_P))
                        /* Now P is 0, we can clear the flag */
                        vcpu->arch.xive_esc_on = 0;
        }
}
EXPORT_SYMBOL_GPL(kvmppc_xive_push_vcpu);

/*
 * This is a simple trigger for a generic XIVE IRQ. This must
 * only be called for interrupts that support a trigger page
 */
static bool xive_irq_trigger(struct xive_irq_data *xd)
{
        /* This should be only for MSIs */
        if (WARN_ON(xd->flags & XIVE_IRQ_FLAG_LSI))
                return false;

        /* Those interrupts should always have a trigger page */
        if (WARN_ON(!xd->trig_mmio))
                return false;

        out_be64(xd->trig_mmio, 0);

        return true;
}

static irqreturn_t xive_esc_irq(int irq, void *data)
{
        struct kvm_vcpu *vcpu = data;

        vcpu->arch.irq_pending = 1;
        smp_mb();
        if (vcpu->arch.ceded)
                kvmppc_fast_vcpu_kick(vcpu);

        /* Since we have the no-EOI flag, the interrupt is effectively
         * disabled now. Clearing xive_esc_on means we won't bother
         * doing so on the next entry.
         *
         * This also allows the entry code to know that if a PQ combination
         * of 10 is observed while xive_esc_on is true, it means the queue
         * contains an unprocessed escalation interrupt. We don't make use of
         * that knowledge today but might (see comment in book3s_hv_rmhandler.S)
         */
        vcpu->arch.xive_esc_on = false;

        return IRQ_HANDLED;
}

int kvmppc_xive_attach_escalation(struct kvm_vcpu *vcpu, u8 prio,
                                  bool single_escalation)
{
        struct kvmppc_xive_vcpu *xc = vcpu->arch.xive_vcpu;
        struct xive_q *q = &xc->queues[prio];
        char *name = NULL;
        int rc;

        /* Already there ? */
        if (xc->esc_virq[prio])
                return 0;

        /* Hook up the escalation interrupt */
        xc->esc_virq[prio] = irq_create_mapping(NULL, q->esc_irq);
        if (!xc->esc_virq[prio]) {
                pr_err("Failed to map escalation interrupt for queue %d of VCPU %d\n",
                       prio, xc->server_num);
                return -EIO;
        }

        if (single_escalation)
                name = kasprintf(GFP_KERNEL, "kvm-%d-%d",
                                 vcpu->kvm->arch.lpid, xc->server_num);
        else
                name = kasprintf(GFP_KERNEL, "kvm-%d-%d-%d",
                                 vcpu->kvm->arch.lpid, xc->server_num, prio);
        if (!name) {
                pr_err("Failed to allocate escalation irq name for queue %d of VCPU %d\n",
                       prio, xc->server_num);
                rc = -ENOMEM;
                goto error;
        }

        pr_devel("Escalation %s irq %d (prio %d)\n", name, xc->esc_virq[prio], prio);

        rc = request_irq(xc->esc_virq[prio], xive_esc_irq,
                         IRQF_NO_THREAD, name, vcpu);
        if (rc) {
                pr_err("Failed to request escalation interrupt for queue %d of VCPU %d\n",
                       prio, xc->server_num);
                goto error;
        }
        xc->esc_virq_names[prio] = name;

        /* In single escalation mode, we grab the ESB MMIO of the
         * interrupt and mask it. Also populate the VCPU v/raddr
         * of the ESB page for use by asm entry/exit code. Finally
         * set the XIVE_IRQ_NO_EOI flag which will prevent the
         * core code from performing an EOI on the escalation
         * interrupt, thus leaving it effectively masked after
         * it fires once.
         */
        if (single_escalation) {
                struct irq_data *d = irq_get_irq_data(xc->esc_virq[prio]);
                struct xive_irq_data *xd = irq_data_get_irq_handler_data(d);

                xive_vm_esb_load(xd, XIVE_ESB_SET_PQ_01);
                vcpu->arch.xive_esc_raddr = xd->eoi_page;
                vcpu->arch.xive_esc_vaddr = (__force u64)xd->eoi_mmio;
                xd->flags |= XIVE_IRQ_NO_EOI;
        }

        return 0;
error:
        irq_dispose_mapping(xc->esc_virq[prio]);
        xc->esc_virq[prio] = 0;
        kfree(name);
        return rc;
}

static int xive_provision_queue(struct kvm_vcpu *vcpu, u8 prio)
{
        struct kvmppc_xive_vcpu *xc = vcpu->arch.xive_vcpu;
        struct kvmppc_xive *xive = xc->xive;
        struct xive_q *q =  &xc->queues[prio];
        void *qpage;
        int rc;

        if (WARN_ON(q->qpage))
                return 0;

        /* Allocate the queue and retrieve infos on current node for now */
        qpage = (__be32 *)__get_free_pages(GFP_KERNEL, xive->q_page_order);
        if (!qpage) {
                pr_err("Failed to allocate queue %d for VCPU %d\n",
                       prio, xc->server_num);
                return -ENOMEM;
        }
        memset(qpage, 0, 1 << xive->q_order);

        /*
         * Reconfigure the queue. This will set q->qpage only once the
         * queue is fully configured. This is a requirement for prio 0
         * as we will stop doing EOIs for every IPI as soon as we observe
         * qpage being non-NULL, and instead will only EOI when we receive
         * corresponding queue 0 entries
         */
        rc = xive_native_configure_queue(xc->vp_id, q, prio, qpage,
                                         xive->q_order, true);
        if (rc)
                pr_err("Failed to configure queue %d for VCPU %d\n",
                       prio, xc->server_num);
        return rc;
}

/* Called with xive->lock held */
static int xive_check_provisioning(struct kvm *kvm, u8 prio)
{
        struct kvmppc_xive *xive = kvm->arch.xive;
        struct kvm_vcpu *vcpu;
        int i, rc;

        lockdep_assert_held(&xive->lock);

        /* Already provisioned ? */
        if (xive->qmap & (1 << prio))
                return 0;

        pr_devel("Provisioning prio... %d\n", prio);

        /* Provision each VCPU and enable escalations if needed */
        kvm_for_each_vcpu(i, vcpu, kvm) {
                if (!vcpu->arch.xive_vcpu)
                        continue;
                rc = xive_provision_queue(vcpu, prio);
                if (rc == 0 && !xive->single_escalation)
                        kvmppc_xive_attach_escalation(vcpu, prio,
                                                      xive->single_escalation);
                if (rc)
                        return rc;
        }

        /* Order previous stores and mark it as provisioned */
        mb();
        xive->qmap |= (1 << prio);
        return 0;
}

static void xive_inc_q_pending(struct kvm *kvm, u32 server, u8 prio)
{
        struct kvm_vcpu *vcpu;
        struct kvmppc_xive_vcpu *xc;
        struct xive_q *q;

        /* Locate target server */
        vcpu = kvmppc_xive_find_server(kvm, server);
        if (!vcpu) {
                pr_warn("%s: Can't find server %d\n", __func__, server);
                return;
        }
        xc = vcpu->arch.xive_vcpu;
        if (WARN_ON(!xc))
                return;

        q = &xc->queues[prio];
        atomic_inc(&q->pending_count);
}

static int xive_try_pick_queue(struct kvm_vcpu *vcpu, u8 prio)
{
        struct kvmppc_xive_vcpu *xc = vcpu->arch.xive_vcpu;
        struct xive_q *q;
        u32 max;

        if (WARN_ON(!xc))
                return -ENXIO;
        if (!xc->valid)
                return -ENXIO;

        q = &xc->queues[prio];
        if (WARN_ON(!q->qpage))
                return -ENXIO;

        /* Calculate max number of interrupts in that queue. */
        max = (q->msk + 1) - XIVE_Q_GAP;
        return atomic_add_unless(&q->count, 1, max) ? 0 : -EBUSY;
}

int kvmppc_xive_select_target(struct kvm *kvm, u32 *server, u8 prio)
{
        struct kvm_vcpu *vcpu;
        int i, rc;

        /* Locate target server */
        vcpu = kvmppc_xive_find_server(kvm, *server);
        if (!vcpu) {
                pr_devel("Can't find server %d\n", *server);
                return -EINVAL;
        }

        pr_devel("Finding irq target on 0x%x/%d...\n", *server, prio);

        /* Try pick it */
        rc = xive_try_pick_queue(vcpu, prio);
        if (rc == 0)
                return rc;

        pr_devel(" .. failed, looking up candidate...\n");

        /* Failed, pick another VCPU */
        kvm_for_each_vcpu(i, vcpu, kvm) {
                if (!vcpu->arch.xive_vcpu)
                        continue;
                rc = xive_try_pick_queue(vcpu, prio);
                if (rc == 0) {
                        *server = vcpu->arch.xive_vcpu->server_num;
                        pr_devel("  found on 0x%x/%d\n", *server, prio);
                        return rc;
                }
        }
        pr_devel("  no available target !\n");

        /* No available target ! */
        return -EBUSY;
}

static u8 xive_lock_and_mask(struct kvmppc_xive *xive,
                             struct kvmppc_xive_src_block *sb,
                             struct kvmppc_xive_irq_state *state)
{
        struct xive_irq_data *xd;
        u32 hw_num;
        u8 old_prio;
        u64 val;

        /*
         * Take the lock, set masked, try again if racing
         * with H_EOI
         */
        for (;;) {
                arch_spin_lock(&sb->lock);
                old_prio = state->guest_priority;
                state->guest_priority = MASKED;
                mb();
                if (!state->in_eoi)
                        break;
                state->guest_priority = old_prio;
                arch_spin_unlock(&sb->lock);
        }

        /* No change ? Bail */
        if (old_prio == MASKED)
                return old_prio;

        /* Get the right irq */
        kvmppc_xive_select_irq(state, &hw_num, &xd);

        /*
         * If the interrupt is marked as needing masking via
         * firmware, we do it here. Firmware masking however
         * is "lossy", it won't return the old p and q bits
         * and won't set the interrupt to a state where it will
         * record queued ones. If this is an issue we should do
         * lazy masking instead.
         *
         * For now, we work around this in unmask by forcing
         * an interrupt whenever we unmask a non-LSI via FW
         * (if ever).
         */
        if (xd->flags & OPAL_XIVE_IRQ_MASK_VIA_FW) {
                xive_native_configure_irq(hw_num,
                                kvmppc_xive_vp(xive, state->act_server),
                                MASKED, state->number);
                /* set old_p so we can track if an H_EOI was done */
                state->old_p = true;
                state->old_q = false;
        } else {
                /* Set PQ to 10, return old P and old Q and remember them */
                val = xive_vm_esb_load(xd, XIVE_ESB_SET_PQ_10);
                state->old_p = !!(val & 2);
                state->old_q = !!(val & 1);

                /*
                 * Synchronize hardware to sensure the queues are updated
                 * when masking
                 */
                xive_native_sync_source(hw_num);
        }

        return old_prio;
}

static void xive_lock_for_unmask(struct kvmppc_xive_src_block *sb,
                                 struct kvmppc_xive_irq_state *state)
{
        /*
         * Take the lock try again if racing with H_EOI
         */
        for (;;) {
                arch_spin_lock(&sb->lock);
                if (!state->in_eoi)
                        break;
                arch_spin_unlock(&sb->lock);
        }
}

static void xive_finish_unmask(struct kvmppc_xive *xive,
                               struct kvmppc_xive_src_block *sb,
                               struct kvmppc_xive_irq_state *state,
                               u8 prio)
{
        struct xive_irq_data *xd;
        u32 hw_num;

        /* If we aren't changing a thing, move on */
        if (state->guest_priority != MASKED)
                goto bail;

        /* Get the right irq */
        kvmppc_xive_select_irq(state, &hw_num, &xd);

        /*
         * See command in xive_lock_and_mask() concerning masking
         * via firmware.
         */
        if (xd->flags & OPAL_XIVE_IRQ_MASK_VIA_FW) {
                xive_native_configure_irq(hw_num,
                                kvmppc_xive_vp(xive, state->act_server),
                                state->act_priority, state->number);
                /* If an EOI is needed, do it here */
                if (!state->old_p)
                        xive_vm_source_eoi(hw_num, xd);
                /* If this is not an LSI, force a trigger */
                if (!(xd->flags & OPAL_XIVE_IRQ_LSI))
                        xive_irq_trigger(xd);
                goto bail;
        }

        /* Old Q set, set PQ to 11 */
        if (state->old_q)
                xive_vm_esb_load(xd, XIVE_ESB_SET_PQ_11);

        /*
         * If not old P, then perform an "effective" EOI,
         * on the source. This will handle the cases where
         * FW EOI is needed.
         */
        if (!state->old_p)
                xive_vm_source_eoi(hw_num, xd);

        /* Synchronize ordering and mark unmasked */
        mb();
bail:
        state->guest_priority = prio;
}

/*
 * Target an interrupt to a given server/prio, this will fallback
 * to another server if necessary and perform the HW targetting
 * updates as needed
 *
 * NOTE: Must be called with the state lock held
 */
static int xive_target_interrupt(struct kvm *kvm,
                                 struct kvmppc_xive_irq_state *state,
                                 u32 server, u8 prio)
{
        struct kvmppc_xive *xive = kvm->arch.xive;
        u32 hw_num;
        int rc;

        /*
         * This will return a tentative server and actual
         * priority. The count for that new target will have
         * already been incremented.
         */
        rc = kvmppc_xive_select_target(kvm, &server, prio);

        /*
         * We failed to find a target ? Not much we can do
         * at least until we support the GIQ.
         */
        if (rc)
                return rc;

        /*
         * Increment the old queue pending count if there
         * was one so that the old queue count gets adjusted later
         * when observed to be empty.
         */
        if (state->act_priority != MASKED)
                xive_inc_q_pending(kvm,
                                   state->act_server,
                                   state->act_priority);
        /*
         * Update state and HW
         */
        state->act_priority = prio;
        state->act_server = server;

        /* Get the right irq */
        kvmppc_xive_select_irq(state, &hw_num, NULL);

        return xive_native_configure_irq(hw_num,
                                         kvmppc_xive_vp(xive, server),
                                         prio, state->number);
}

/*
 * Targetting rules: In order to avoid losing track of
 * pending interrupts accross mask and unmask, which would
 * allow queue overflows, we implement the following rules:
 *
 *  - Unless it was never enabled (or we run out of capacity)
 *    an interrupt is always targetted at a valid server/queue
 *    pair even when "masked" by the guest. This pair tends to
 *    be the last one used but it can be changed under some
 *    circumstances. That allows us to separate targetting
 *    from masking, we only handle accounting during (re)targetting,
 *    this also allows us to let an interrupt drain into its target
 *    queue after masking, avoiding complex schemes to remove
 *    interrupts out of remote processor queues.
 *
 *  - When masking, we set PQ to 10 and save the previous value
 *    of P and Q.
 *
 *  - When unmasking, if saved Q was set, we set PQ to 11
 *    otherwise we leave PQ to the HW state which will be either
 *    10 if nothing happened or 11 if the interrupt fired while
 *    masked. Effectively we are OR'ing the previous Q into the
 *    HW Q.
 *
 *    Then if saved P is clear, we do an effective EOI (Q->P->Trigger)
 *    which will unmask the interrupt and shoot a new one if Q was
 *    set.
 *
 *    Otherwise (saved P is set) we leave PQ unchanged (so 10 or 11,
 *    effectively meaning an H_EOI from the guest is still expected
 *    for that interrupt).
 *
 *  - If H_EOI occurs while masked, we clear the saved P.
 *
 *  - When changing target, we account on the new target and
 *    increment a separate "pending" counter on the old one.
 *    This pending counter will be used to decrement the old
 *    target's count when its queue has been observed empty.
 */

int kvmppc_xive_set_xive(struct kvm *kvm, u32 irq, u32 server,
                         u32 priority)
{
        struct kvmppc_xive *xive = kvm->arch.xive;
        struct kvmppc_xive_src_block *sb;
        struct kvmppc_xive_irq_state *state;
        u8 new_act_prio;
        int rc = 0;
        u16 idx;

        if (!xive)
                return -ENODEV;

        pr_devel("set_xive ! irq 0x%x server 0x%x prio %d\n",
                 irq, server, priority);

        /* First, check provisioning of queues */
        if (priority != MASKED) {
                mutex_lock(&xive->lock);
                rc = xive_check_provisioning(xive->kvm,
                              xive_prio_from_guest(priority));
                mutex_unlock(&xive->lock);
        }
        if (rc) {
                pr_devel("  provisioning failure %d !\n", rc);
                return rc;
        }

        sb = kvmppc_xive_find_source(xive, irq, &idx);
        if (!sb)
                return -EINVAL;
        state = &sb->irq_state[idx];

        /*
         * We first handle masking/unmasking since the locking
         * might need to be retried due to EOIs, we'll handle
         * targetting changes later. These functions will return
         * with the SB lock held.
         *
         * xive_lock_and_mask() will also set state->guest_priority
         * but won't otherwise change other fields of the state.
         *
         * xive_lock_for_unmask will not actually unmask, this will
         * be done later by xive_finish_unmask() once the targetting
         * has been done, so we don't try to unmask an interrupt
         * that hasn't yet been targetted.
         */
        if (priority == MASKED)
                xive_lock_and_mask(xive, sb, state);
        else
                xive_lock_for_unmask(sb, state);


        /*
         * Then we handle targetting.
         *
         * First calculate a new "actual priority"
         */
        new_act_prio = state->act_priority;
        if (priority != MASKED)
                new_act_prio = xive_prio_from_guest(priority);

        pr_devel(" new_act_prio=%x act_server=%x act_prio=%x\n",
                 new_act_prio, state->act_server, state->act_priority);

        /*
         * Then check if we actually need to change anything,
         *
         * The condition for re-targetting the interrupt is that
         * we have a valid new priority (new_act_prio is not 0xff)
         * and either the server or the priority changed.
         *
         * Note: If act_priority was ff and the new priority is
         *       also ff, we don't do anything and leave the interrupt
         *       untargetted. An attempt of doing an int_on on an
         *       untargetted interrupt will fail. If that is a problem
         *       we could initialize interrupts with valid default
         */

        if (new_act_prio != MASKED &&
            (state->act_server != server ||
             state->act_priority != new_act_prio))
                rc = xive_target_interrupt(kvm, state, server, new_act_prio);

        /*
         * Perform the final unmasking of the interrupt source
         * if necessary
         */
        if (priority != MASKED)
                xive_finish_unmask(xive, sb, state, priority);

        /*
         * Finally Update saved_priority to match. Only int_on/off
         * set this field to a different value.
         */
        state->saved_priority = priority;

        arch_spin_unlock(&sb->lock);
        return rc;
}

int kvmppc_xive_get_xive(struct kvm *kvm, u32 irq, u32 *server,
                         u32 *priority)
{
        struct kvmppc_xive *xive = kvm->arch.xive;
        struct kvmppc_xive_src_block *sb;
        struct kvmppc_xive_irq_state *state;
        u16 idx;

        if (!xive)
                return -ENODEV;

        sb = kvmppc_xive_find_source(xive, irq, &idx);
        if (!sb)
                return -EINVAL;
        state = &sb->irq_state[idx];
        arch_spin_lock(&sb->lock);
        *server = state->act_server;
        *priority = state->guest_priority;
        arch_spin_unlock(&sb->lock);

        return 0;
}

int kvmppc_xive_int_on(struct kvm *kvm, u32 irq)
{
        struct kvmppc_xive *xive = kvm->arch.xive;
        struct kvmppc_xive_src_block *sb;
        struct kvmppc_xive_irq_state *state;
        u16 idx;

        if (!xive)
                return -ENODEV;

        sb = kvmppc_xive_find_source(xive, irq, &idx);
        if (!sb)
                return -EINVAL;
        state = &sb->irq_state[idx];

        pr_devel("int_on(irq=0x%x)\n", irq);

        /*
         * Check if interrupt was not targetted
         */
        if (state->act_priority == MASKED) {
                pr_devel("int_on on untargetted interrupt\n");
                return -EINVAL;
        }

        /* If saved_priority is 0xff, do nothing */
        if (state->saved_priority == MASKED)
                return 0;

        /*
         * Lock and unmask it.
         */
        xive_lock_for_unmask(sb, state);
        xive_finish_unmask(xive, sb, state, state->saved_priority);
        arch_spin_unlock(&sb->lock);

        return 0;
}

int kvmppc_xive_int_off(struct kvm *kvm, u32 irq)
{
        struct kvmppc_xive *xive = kvm->arch.xive;
        struct kvmppc_xive_src_block *sb;
        struct kvmppc_xive_irq_state *state;
        u16 idx;

        if (!xive)
                return -ENODEV;

        sb = kvmppc_xive_find_source(xive, irq, &idx);
        if (!sb)
                return -EINVAL;
        state = &sb->irq_state[idx];

        pr_devel("int_off(irq=0x%x)\n", irq);

        /*
         * Lock and mask
         */
        state->saved_priority = xive_lock_and_mask(xive, sb, state);
        arch_spin_unlock(&sb->lock);

        return 0;
}

static bool xive_restore_pending_irq(struct kvmppc_xive *xive, u32 irq)
{
        struct kvmppc_xive_src_block *sb;
        struct kvmppc_xive_irq_state *state;
        u16 idx;

        sb = kvmppc_xive_find_source(xive, irq, &idx);
        if (!sb)
                return false;
        state = &sb->irq_state[idx];
        if (!state->valid)
                return false;

        /*
         * Trigger the IPI. This assumes we never restore a pass-through
         * interrupt which should be safe enough
         */
        xive_irq_trigger(&state->ipi_data);

        return true;
}

u64 kvmppc_xive_get_icp(struct kvm_vcpu *vcpu)
{
        struct kvmppc_xive_vcpu *xc = vcpu->arch.xive_vcpu;

        if (!xc)
                return 0;

        /* Return the per-cpu state for state saving/migration */
        return (u64)xc->cppr << KVM_REG_PPC_ICP_CPPR_SHIFT |
               (u64)xc->mfrr << KVM_REG_PPC_ICP_MFRR_SHIFT |
               (u64)0xff << KVM_REG_PPC_ICP_PPRI_SHIFT;
}

int kvmppc_xive_set_icp(struct kvm_vcpu *vcpu, u64 icpval)
{
        struct kvmppc_xive_vcpu *xc = vcpu->arch.xive_vcpu;
        struct kvmppc_xive *xive = vcpu->kvm->arch.xive;
        u8 cppr, mfrr;
        u32 xisr;

        if (!xc || !xive)
                return -ENOENT;

        /* Grab individual state fields. We don't use pending_pri */
        cppr = icpval >> KVM_REG_PPC_ICP_CPPR_SHIFT;
        xisr = (icpval >> KVM_REG_PPC_ICP_XISR_SHIFT) &
                KVM_REG_PPC_ICP_XISR_MASK;
        mfrr = icpval >> KVM_REG_PPC_ICP_MFRR_SHIFT;

        pr_devel("set_icp vcpu %d cppr=0x%x mfrr=0x%x xisr=0x%x\n",
                 xc->server_num, cppr, mfrr, xisr);

        /*
         * We can't update the state of a "pushed" VCPU, but that
         * shouldn't happen because the vcpu->mutex makes running a
         * vcpu mutually exclusive with doing one_reg get/set on it.
         */
        if (WARN_ON(vcpu->arch.xive_pushed))
                return -EIO;

        /* Update VCPU HW saved state */
        vcpu->arch.xive_saved_state.cppr = cppr;
        xc->hw_cppr = xc->cppr = cppr;

        /*
         * Update MFRR state. If it's not 0xff, we mark the VCPU as
         * having a pending MFRR change, which will re-evaluate the
         * target. The VCPU will thus potentially get a spurious
         * interrupt but that's not a big deal.
         */
        xc->mfrr = mfrr;
        if (mfrr < cppr)
                xive_irq_trigger(&xc->vp_ipi_data);

        /*
         * Now saved XIRR is "interesting". It means there's something in
         * the legacy "1 element" queue... for an IPI we simply ignore it,
         * as the MFRR restore will handle that. For anything else we need
         * to force a resend of the source.
         * However the source may not have been setup yet. If that's the
         * case, we keep that info and increment a counter in the xive to
         * tell subsequent xive_set_source() to go look.
         */
        if (xisr > XICS_IPI && !xive_restore_pending_irq(xive, xisr)) {
                xc->delayed_irq = xisr;
                xive->delayed_irqs++;
                pr_devel("  xisr restore delayed\n");
        }

        return 0;
}

int kvmppc_xive_set_mapped(struct kvm *kvm, unsigned long guest_irq,
                           struct irq_desc *host_desc)
{
        struct kvmppc_xive *xive = kvm->arch.xive;
        struct kvmppc_xive_src_block *sb;
        struct kvmppc_xive_irq_state *state;
        struct irq_data *host_data = irq_desc_get_irq_data(host_desc);
        unsigned int host_irq = irq_desc_get_irq(host_desc);
        unsigned int hw_irq = (unsigned int)irqd_to_hwirq(host_data);
        u16 idx;
        u8 prio;
        int rc;

        if (!xive)
                return -ENODEV;

        pr_devel("set_mapped girq 0x%lx host HW irq 0x%x...\n",guest_irq, hw_irq);

        sb = kvmppc_xive_find_source(xive, guest_irq, &idx);
        if (!sb)
                return -EINVAL;
        state = &sb->irq_state[idx];

        /*
         * Mark the passed-through interrupt as going to a VCPU,
         * this will prevent further EOIs and similar operations
         * from the XIVE code. It will also mask the interrupt
         * to either PQ=10 or 11 state, the latter if the interrupt
         * is pending. This will allow us to unmask or retrigger it
         * after routing it to the guest with a simple EOI.
         *
         * The "state" argument is a "token", all it needs is to be
         * non-NULL to switch to passed-through or NULL for the
         * other way around. We may not yet have an actual VCPU
         * target here and we don't really care.
         */
        rc = irq_set_vcpu_affinity(host_irq, state);
        if (rc) {
                pr_err("Failed to set VCPU affinity for irq %d\n", host_irq);
                return rc;
        }

        /*
         * Mask and read state of IPI. We need to know if its P bit
         * is set as that means it's potentially already using a
         * queue entry in the target
         */
        prio = xive_lock_and_mask(xive, sb, state);
        pr_devel(" old IPI prio %02x P:%d Q:%d\n", prio,
                 state->old_p, state->old_q);

        /* Turn the IPI hard off */
        xive_vm_esb_load(&state->ipi_data, XIVE_ESB_SET_PQ_01);

        /*
         * Reset ESB guest mapping. Needed when ESB pages are exposed
         * to the guest in XIVE native mode
         */
        if (xive->ops && xive->ops->reset_mapped)
                xive->ops->reset_mapped(kvm, guest_irq);

        /* Grab info about irq */
        state->pt_number = hw_irq;
        state->pt_data = irq_data_get_irq_handler_data(host_data);

        /*
         * Configure the IRQ to match the existing configuration of
         * the IPI if it was already targetted. Otherwise this will
         * mask the interrupt in a lossy way (act_priority is 0xff)
         * which is fine for a never started interrupt.
         */
        xive_native_configure_irq(hw_irq,
                                  kvmppc_xive_vp(xive, state->act_server),
                                  state->act_priority, state->number);

        /*
         * We do an EOI to enable the interrupt (and retrigger if needed)
         * if the guest has the interrupt unmasked and the P bit was *not*
         * set in the IPI. If it was set, we know a slot may still be in
         * use in the target queue thus we have to wait for a guest
         * originated EOI
         */
        if (prio != MASKED && !state->old_p)
                xive_vm_source_eoi(hw_irq, state->pt_data);

        /* Clear old_p/old_q as they are no longer relevant */
        state->old_p = state->old_q = false;

        /* Restore guest prio (unlocks EOI) */
        mb();
        state->guest_priority = prio;
        arch_spin_unlock(&sb->lock);

        return 0;
}
EXPORT_SYMBOL_GPL(kvmppc_xive_set_mapped);

int kvmppc_xive_clr_mapped(struct kvm *kvm, unsigned long guest_irq,
                           struct irq_desc *host_desc)
{
        struct kvmppc_xive *xive = kvm->arch.xive;
        struct kvmppc_xive_src_block *sb;
        struct kvmppc_xive_irq_state *state;
        unsigned int host_irq = irq_desc_get_irq(host_desc);
        u16 idx;
        u8 prio;
        int rc;

        if (!xive)
                return -ENODEV;

        pr_devel("clr_mapped girq 0x%lx...\n", guest_irq);

        sb = kvmppc_xive_find_source(xive, guest_irq, &idx);

        if (!sb)
                return -EINVAL;
        state = &sb->irq_state[idx];

        /*
         * Mask and read state of IRQ. We need to know if its P bit
         * is set as that means it's potentially already using a
         * queue entry in the target
         */
        prio = xive_lock_and_mask(xive, sb, state);
        pr_devel(" old IRQ prio %02x P:%d Q:%d\n", prio,
                 state->old_p, state->old_q);

        /*
         * If old_p is set, the interrupt is pending, we switch it to
         * PQ=11. This will force a resend in the host so the interrupt
         * isn't lost to whatver host driver may pick it up
         */
        if (state->old_p)
                xive_vm_esb_load(state->pt_data, XIVE_ESB_SET_PQ_11);

        /* Release the passed-through interrupt to the host */
        rc = irq_set_vcpu_affinity(host_irq, NULL);
        if (rc) {
                pr_err("Failed to clr VCPU affinity for irq %d\n", host_irq);
                return rc;
        }

        /* Forget about the IRQ */
        state->pt_number = 0;
        state->pt_data = NULL;

        /*
         * Reset ESB guest mapping. Needed when ESB pages are exposed
         * to the guest in XIVE native mode
         */
        if (xive->ops && xive->ops->reset_mapped) {
                xive->ops->reset_mapped(kvm, guest_irq);
        }

        /* Reconfigure the IPI */
        xive_native_configure_irq(state->ipi_number,
                                  kvmppc_xive_vp(xive, state->act_server),
                                  state->act_priority, state->number);

        /*
         * If old_p is set (we have a queue entry potentially
         * occupied) or the interrupt is masked, we set the IPI
         * to PQ=10 state. Otherwise we just re-enable it (PQ=00).
         */
        if (prio == MASKED || state->old_p)
                xive_vm_esb_load(&state->ipi_data, XIVE_ESB_SET_PQ_10);
        else
                xive_vm_esb_load(&state->ipi_data, XIVE_ESB_SET_PQ_00);

        /* Restore guest prio (unlocks EOI) */
        mb();
        state->guest_priority = prio;
        arch_spin_unlock(&sb->lock);

        return 0;
}
EXPORT_SYMBOL_GPL(kvmppc_xive_clr_mapped);

void kvmppc_xive_disable_vcpu_interrupts(struct kvm_vcpu *vcpu)
{
        struct kvmppc_xive_vcpu *xc = vcpu->arch.xive_vcpu;
        struct kvm *kvm = vcpu->kvm;
        struct kvmppc_xive *xive = kvm->arch.xive;
        int i, j;

        for (i = 0; i <= xive->max_sbid; i++) {
                struct kvmppc_xive_src_block *sb = xive->src_blocks[i];

                if (!sb)
                        continue;
                for (j = 0; j < KVMPPC_XICS_IRQ_PER_ICS; j++) {
                        struct kvmppc_xive_irq_state *state = &sb->irq_state[j];

                        if (!state->valid)
                                continue;
                        if (state->act_priority == MASKED)
                                continue;
                        if (state->act_server != xc->server_num)
                                continue;

                        /* Clean it up */
                        arch_spin_lock(&sb->lock);
                        state->act_priority = MASKED;
                        xive_vm_esb_load(&state->ipi_data, XIVE_ESB_SET_PQ_01);
                        xive_native_configure_irq(state->ipi_number, 0, MASKED, 0);
                        if (state->pt_number) {
                                xive_vm_esb_load(state->pt_data, XIVE_ESB_SET_PQ_01);
                                xive_native_configure_irq(state->pt_number, 0, MASKED, 0);
                        }
                        arch_spin_unlock(&sb->lock);
                }
        }

        /* Disable vcpu's escalation interrupt */
        if (vcpu->arch.xive_esc_on) {
                __raw_readq((void __iomem *)(vcpu->arch.xive_esc_vaddr +
                                             XIVE_ESB_SET_PQ_01));
                vcpu->arch.xive_esc_on = false;
        }

        /*
         * Clear pointers to escalation interrupt ESB.
         * This is safe because the vcpu->mutex is held, preventing
         * any other CPU from concurrently executing a KVM_RUN ioctl.
         */
        vcpu->arch.xive_esc_vaddr = 0;
        vcpu->arch.xive_esc_raddr = 0;
}

void kvmppc_xive_cleanup_vcpu(struct kvm_vcpu *vcpu)
{
        struct kvmppc_xive_vcpu *xc = vcpu->arch.xive_vcpu;
        struct kvmppc_xive *xive = vcpu->kvm->arch.xive;
        int i;

        if (!kvmppc_xics_enabled(vcpu))
                return;

        if (!xc)
                return;

        pr_devel("cleanup_vcpu(cpu=%d)\n", xc->server_num);

        /* Ensure no interrupt is still routed to that VP */
        xc->valid = false;
        kvmppc_xive_disable_vcpu_interrupts(vcpu);

        /* Mask the VP IPI */
        xive_vm_esb_load(&xc->vp_ipi_data, XIVE_ESB_SET_PQ_01);

        /* Disable the VP */
        xive_native_disable_vp(xc->vp_id);

        /* Free the queues & associated interrupts */
        for (i = 0; i < KVMPPC_XIVE_Q_COUNT; i++) {
                struct xive_q *q = &xc->queues[i];

                /* Free the escalation irq */
                if (xc->esc_virq[i]) {
                        free_irq(xc->esc_virq[i], vcpu);
                        irq_dispose_mapping(xc->esc_virq[i]);
                        kfree(xc->esc_virq_names[i]);
                }
                /* Free the queue */
                xive_native_disable_queue(xc->vp_id, q, i);
                if (q->qpage) {
                        free_pages((unsigned long)q->qpage,
                                   xive->q_page_order);
                        q->qpage = NULL;
                }
        }

        /* Free the IPI */
        if (xc->vp_ipi) {
                xive_cleanup_irq_data(&xc->vp_ipi_data);
                xive_native_free_irq(xc->vp_ipi);
        }
        /* Free the VP */
        kfree(xc);

        /* Cleanup the vcpu */
        vcpu->arch.irq_type = KVMPPC_IRQ_DEFAULT;
        vcpu->arch.xive_vcpu = NULL;
}

int kvmppc_xive_connect_vcpu(struct kvm_device *dev,
                             struct kvm_vcpu *vcpu, u32 cpu)
{
        struct kvmppc_xive *xive = dev->private;
        struct kvmppc_xive_vcpu *xc;
        int i, r = -EBUSY;

        pr_devel("connect_vcpu(cpu=%d)\n", cpu);

        if (dev->ops != &kvm_xive_ops) {
                pr_devel("Wrong ops !\n");
                return -EPERM;
        }
        if (xive->kvm != vcpu->kvm)
                return -EPERM;
        if (vcpu->arch.irq_type != KVMPPC_IRQ_DEFAULT)
                return -EBUSY;
        if (kvmppc_xive_find_server(vcpu->kvm, cpu)) {
                pr_devel("Duplicate !\n");
                return -EEXIST;
        }
        if (cpu >= (KVM_MAX_VCPUS * vcpu->kvm->arch.emul_smt_mode)) {
                pr_devel("Out of bounds !\n");
                return -EINVAL;
        }
        xc = kzalloc(sizeof(*xc), GFP_KERNEL);
        if (!xc)
                return -ENOMEM;

        /* We need to synchronize with queue provisioning */
        mutex_lock(&xive->lock);
        vcpu->arch.xive_vcpu = xc;
        xc->xive = xive;
        xc->vcpu = vcpu;
        xc->server_num = cpu;
        xc->vp_id = kvmppc_xive_vp(xive, cpu);
        xc->mfrr = 0xff;
        xc->valid = true;

        r = xive_native_get_vp_info(xc->vp_id, &xc->vp_cam, &xc->vp_chip_id);
        if (r)
                goto bail;

        /* Configure VCPU fields for use by assembly push/pull */
        vcpu->arch.xive_saved_state.w01 = cpu_to_be64(0xff000000);
        vcpu->arch.xive_cam_word = cpu_to_be32(xc->vp_cam | TM_QW1W2_VO);

        /* Allocate IPI */
        xc->vp_ipi = xive_native_alloc_irq();
        if (!xc->vp_ipi) {
                pr_err("Failed to allocate xive irq for VCPU IPI\n");
                r = -EIO;
                goto bail;
        }
        pr_devel(" IPI=0x%x\n", xc->vp_ipi);

        r = xive_native_populate_irq_data(xc->vp_ipi, &xc->vp_ipi_data);
        if (r)
                goto bail;

        /*
         * Enable the VP first as the single escalation mode will
         * affect escalation interrupts numbering
         */
        r = xive_native_enable_vp(xc->vp_id, xive->single_escalation);
        if (r) {
                pr_err("Failed to enable VP in OPAL, err %d\n", r);
                goto bail;
        }

        /*
         * Initialize queues. Initially we set them all for no queueing
         * and we enable escalation for queue 0 only which we'll use for
         * our mfrr change notifications. If the VCPU is hot-plugged, we
         * do handle provisioning however based on the existing "map"
         * of enabled queues.
         */
        for (i = 0; i < KVMPPC_XIVE_Q_COUNT; i++) {
                struct xive_q *q = &xc->queues[i];

                /* Single escalation, no queue 7 */
                if (i == 7 && xive->single_escalation)
                        break;

                /* Is queue already enabled ? Provision it */
                if (xive->qmap & (1 << i)) {
                        r = xive_provision_queue(vcpu, i);
                        if (r == 0 && !xive->single_escalation)
                                kvmppc_xive_attach_escalation(
                                        vcpu, i, xive->single_escalation);
                        if (r)
                                goto bail;
                } else {
                        r = xive_native_configure_queue(xc->vp_id,
                                                        q, i, NULL, 0, true);
                        if (r) {
                                pr_err("Failed to configure queue %d for VCPU %d\n",
                                       i, cpu);
                                goto bail;
                        }
                }
        }

        /* If not done above, attach priority 0 escalation */
        r = kvmppc_xive_attach_escalation(vcpu, 0, xive->single_escalation);
        if (r)
                goto bail;

        /* Route the IPI */
        r = xive_native_configure_irq(xc->vp_ipi, xc->vp_id, 0, XICS_IPI);
        if (!r)
                xive_vm_esb_load(&xc->vp_ipi_data, XIVE_ESB_SET_PQ_00);

bail:
        mutex_unlock(&xive->lock);
        if (r) {
                kvmppc_xive_cleanup_vcpu(vcpu);
                return r;
        }

        vcpu->arch.irq_type = KVMPPC_IRQ_XICS;
        return 0;
}

/*
 * Scanning of queues before/after migration save
 */
static void xive_pre_save_set_queued(struct kvmppc_xive *xive, u32 irq)
{
        struct kvmppc_xive_src_block *sb;
        struct kvmppc_xive_irq_state *state;
        u16 idx;

        sb = kvmppc_xive_find_source(xive, irq, &idx);
        if (!sb)
                return;

        state = &sb->irq_state[idx];

        /* Some sanity checking */
        if (!state->valid) {
                pr_err("invalid irq 0x%x in cpu queue!\n", irq);
                return;
        }

        /*
         * If the interrupt is in a queue it should have P set.
         * We warn so that gets reported. A backtrace isn't useful
         * so no need to use a WARN_ON.
         */
        if (!state->saved_p)
                pr_err("Interrupt 0x%x is marked in a queue but P not set !\n", irq);

        /* Set flag */
        state->in_queue = true;
}

static void xive_pre_save_mask_irq(struct kvmppc_xive *xive,
                                   struct kvmppc_xive_src_block *sb,
                                   u32 irq)
{
        struct kvmppc_xive_irq_state *state = &sb->irq_state[irq];

        if (!state->valid)
                return;

        /* Mask and save state, this will also sync HW queues */
        state->saved_scan_prio = xive_lock_and_mask(xive, sb, state);

        /* Transfer P and Q */
        state->saved_p = state->old_p;
        state->saved_q = state->old_q;

        /* Unlock */
        arch_spin_unlock(&sb->lock);
}

static void xive_pre_save_unmask_irq(struct kvmppc_xive *xive,
                                     struct kvmppc_xive_src_block *sb,
                                     u32 irq)
{
        struct kvmppc_xive_irq_state *state = &sb->irq_state[irq];

        if (!state->valid)
                return;

        /*
         * Lock / exclude EOI (not technically necessary if the
         * guest isn't running concurrently. If this becomes a
         * performance issue we can probably remove the lock.
         */
        xive_lock_for_unmask(sb, state);

        /* Restore mask/prio if it wasn't masked */
        if (state->saved_scan_prio != MASKED)
                xive_finish_unmask(xive, sb, state, state->saved_scan_prio);

        /* Unlock */
        arch_spin_unlock(&sb->lock);
}

static void xive_pre_save_queue(struct kvmppc_xive *xive, struct xive_q *q)
{
        u32 idx = q->idx;
        u32 toggle = q->toggle;
        u32 irq;

        do {
                irq = __xive_read_eq(q->qpage, q->msk, &idx, &toggle);
                if (irq > XICS_IPI)
                        xive_pre_save_set_queued(xive, irq);
        } while(irq);
}

static void xive_pre_save_scan(struct kvmppc_xive *xive)
{
        struct kvm_vcpu *vcpu = NULL;
        int i, j;

        /*
         * See comment in xive_get_source() about how this
         * work. Collect a stable state for all interrupts
         */
        for (i = 0; i <= xive->max_sbid; i++) {
                struct kvmppc_xive_src_block *sb = xive->src_blocks[i];
                if (!sb)
                        continue;
                for (j = 0;  j < KVMPPC_XICS_IRQ_PER_ICS; j++)
                        xive_pre_save_mask_irq(xive, sb, j);
        }

        /* Then scan the queues and update the "in_queue" flag */
        kvm_for_each_vcpu(i, vcpu, xive->kvm) {
                struct kvmppc_xive_vcpu *xc = vcpu->arch.xive_vcpu;
                if (!xc)
                        continue;
                for (j = 0; j < KVMPPC_XIVE_Q_COUNT; j++) {
                        if (xc->queues[j].qpage)
                                xive_pre_save_queue(xive, &xc->queues[j]);
                }
        }

        /* Finally restore interrupt states */
        for (i = 0; i <= xive->max_sbid; i++) {
                struct kvmppc_xive_src_block *sb = xive->src_blocks[i];
                if (!sb)
                        continue;
                for (j = 0;  j < KVMPPC_XICS_IRQ_PER_ICS; j++)
                        xive_pre_save_unmask_irq(xive, sb, j);
        }
}

static void xive_post_save_scan(struct kvmppc_xive *xive)
{
        u32 i, j;

        /* Clear all the in_queue flags */
        for (i = 0; i <= xive->max_sbid; i++) {
                struct kvmppc_xive_src_block *sb = xive->src_blocks[i];
                if (!sb)
                        continue;
                for (j = 0;  j < KVMPPC_XICS_IRQ_PER_ICS; j++)
                        sb->irq_state[j].in_queue = false;
        }

        /* Next get_source() will do a new scan */
        xive->saved_src_count = 0;
}

/*
 * This returns the source configuration and state to user space.
 */
static int xive_get_source(struct kvmppc_xive *xive, long irq, u64 addr)
{
        struct kvmppc_xive_src_block *sb;
        struct kvmppc_xive_irq_state *state;
        u64 __user *ubufp = (u64 __user *) addr;
        u64 val, prio;
        u16 idx;

        sb = kvmppc_xive_find_source(xive, irq, &idx);
        if (!sb)
                return -ENOENT;

        state = &sb->irq_state[idx];

        if (!state->valid)
                return -ENOENT;

        pr_devel("get_source(%ld)...\n", irq);

        /*
         * So to properly save the state into something that looks like a
         * XICS migration stream we cannot treat interrupts individually.
         *
         * We need, instead, mask them all (& save their previous PQ state)
         * to get a stable state in the HW, then sync them to ensure that
         * any interrupt that had already fired hits its queue, and finally
         * scan all the queues to collect which interrupts are still present
         * in the queues, so we can set the "pending" flag on them and
         * they can be resent on restore.
         *
         * So we do it all when the "first" interrupt gets saved, all the
         * state is collected at that point, the rest of xive_get_source()
         * will merely collect and convert that state to the expected
         * userspace bit mask.
         */
        if (xive->saved_src_count == 0)
                xive_pre_save_scan(xive);
        xive->saved_src_count++;

        /* Convert saved state into something compatible with xics */
        val = state->act_server;
        prio = state->saved_scan_prio;

        if (prio == MASKED) {
                val |= KVM_XICS_MASKED;
                prio = state->saved_priority;
        }
        val |= prio << KVM_XICS_PRIORITY_SHIFT;
        if (state->lsi) {
                val |= KVM_XICS_LEVEL_SENSITIVE;
                if (state->saved_p)
                        val |= KVM_XICS_PENDING;
        } else {
                if (state->saved_p)
                        val |= KVM_XICS_PRESENTED;

                if (state->saved_q)
                        val |= KVM_XICS_QUEUED;

                /*
                 * We mark it pending (which will attempt a re-delivery)
                 * if we are in a queue *or* we were masked and had
                 * Q set which is equivalent to the XICS "masked pending"
                 * state
                 */
                if (state->in_queue || (prio == MASKED && state->saved_q))
                        val |= KVM_XICS_PENDING;
        }

        /*
         * If that was the last interrupt saved, reset the
         * in_queue flags
         */
        if (xive->saved_src_count == xive->src_count)
                xive_post_save_scan(xive);

        /* Copy the result to userspace */
        if (put_user(val, ubufp))
                return -EFAULT;

        return 0;
}

struct kvmppc_xive_src_block *kvmppc_xive_create_src_block(
        struct kvmppc_xive *xive, int irq)
{
        struct kvmppc_xive_src_block *sb;
        int i, bid;

        bid = irq >> KVMPPC_XICS_ICS_SHIFT;

        mutex_lock(&xive->lock);

        /* block already exists - somebody else got here first */
        if (xive->src_blocks[bid])
                goto out;

        /* Create the ICS */
        sb = kzalloc(sizeof(*sb), GFP_KERNEL);
        if (!sb)
                goto out;

        sb->id = bid;

        for (i = 0; i < KVMPPC_XICS_IRQ_PER_ICS; i++) {
                sb->irq_state[i].number = (bid << KVMPPC_XICS_ICS_SHIFT) | i;
                sb->irq_state[i].eisn = 0;
                sb->irq_state[i].guest_priority = MASKED;
                sb->irq_state[i].saved_priority = MASKED;
                sb->irq_state[i].act_priority = MASKED;
        }
        smp_wmb();
        xive->src_blocks[bid] = sb;

        if (bid > xive->max_sbid)
                xive->max_sbid = bid;

out:
        mutex_unlock(&xive->lock);
        return xive->src_blocks[bid];
}

static bool xive_check_delayed_irq(struct kvmppc_xive *xive, u32 irq)
{
        struct kvm *kvm = xive->kvm;
        struct kvm_vcpu *vcpu = NULL;
        int i;

        kvm_for_each_vcpu(i, vcpu, kvm) {
                struct kvmppc_xive_vcpu *xc = vcpu->arch.xive_vcpu;

                if (!xc)
                        continue;

                if (xc->delayed_irq == irq) {
                        xc->delayed_irq = 0;
                        xive->delayed_irqs--;
                        return true;
                }
        }
        return false;
}

static int xive_set_source(struct kvmppc_xive *xive, long irq, u64 addr)
{
        struct kvmppc_xive_src_block *sb;
        struct kvmppc_xive_irq_state *state;
        u64 __user *ubufp = (u64 __user *) addr;
        u16 idx;
        u64 val;
        u8 act_prio, guest_prio;
        u32 server;
        int rc = 0;

        if (irq < KVMPPC_XICS_FIRST_IRQ || irq >= KVMPPC_XICS_NR_IRQS)
                return -ENOENT;

        pr_devel("set_source(irq=0x%lx)\n", irq);

        /* Find the source */
        sb = kvmppc_xive_find_source(xive, irq, &idx);
        if (!sb) {
                pr_devel("No source, creating source block...\n");
                sb = kvmppc_xive_create_src_block(xive, irq);
                if (!sb) {
                        pr_devel("Failed to create block...\n");
                        return -ENOMEM;
                }
        }
        state = &sb->irq_state[idx];

        /* Read user passed data */
        if (get_user(val, ubufp)) {
                pr_devel("fault getting user info !\n");
                return -EFAULT;
        }

        server = val & KVM_XICS_DESTINATION_MASK;
        guest_prio = val >> KVM_XICS_PRIORITY_SHIFT;

        pr_devel("  val=0x016%llx (server=0x%x, guest_prio=%d)\n",
                 val, server, guest_prio);

        /*
         * If the source doesn't already have an IPI, allocate
         * one and get the corresponding data
         */
        if (!state->ipi_number) {
                state->ipi_number = xive_native_alloc_irq();
                if (state->ipi_number == 0) {
                        pr_devel("Failed to allocate IPI !\n");
                        return -ENOMEM;
                }
                xive_native_populate_irq_data(state->ipi_number, &state->ipi_data);
                pr_devel(" src_ipi=0x%x\n", state->ipi_number);
        }

        /*
         * We use lock_and_mask() to set us in the right masked
         * state. We will override that state from the saved state
         * further down, but this will handle the cases of interrupts
         * that need FW masking. We set the initial guest_priority to
         * 0 before calling it to ensure it actually performs the masking.
         */
        state->guest_priority = 0;
        xive_lock_and_mask(xive, sb, state);

        /*
         * Now, we select a target if we have one. If we don't we
         * leave the interrupt untargetted. It means that an interrupt
         * can become "untargetted" accross migration if it was masked
         * by set_xive() but there is little we can do about it.
         */

        /* First convert prio and mark interrupt as untargetted */
        act_prio = xive_prio_from_guest(guest_prio);
        state->act_priority = MASKED;

        /*
         * We need to drop the lock due to the mutex below. Hopefully
         * nothing is touching that interrupt yet since it hasn't been
         * advertized to a running guest yet
         */
        arch_spin_unlock(&sb->lock);

        /* If we have a priority target the interrupt */
        if (act_prio != MASKED) {
                /* First, check provisioning of queues */
                mutex_lock(&xive->lock);
                rc = xive_check_provisioning(xive->kvm, act_prio);
                mutex_unlock(&xive->lock);

                /* Target interrupt */
                if (rc == 0)
                        rc = xive_target_interrupt(xive->kvm, state,
                                                   server, act_prio);
                /*
                 * If provisioning or targetting failed, leave it
                 * alone and masked. It will remain disabled until
                 * the guest re-targets it.
                 */
        }

        /*
         * Find out if this was a delayed irq stashed in an ICP,
         * in which case, treat it as pending
         */
        if (xive->delayed_irqs && xive_check_delayed_irq(xive, irq)) {
                val |= KVM_XICS_PENDING;
                pr_devel("  Found delayed ! forcing PENDING !\n");
        }

        /* Cleanup the SW state */
        state->old_p = false;
        state->old_q = false;
        state->lsi = false;
        state->asserted = false;

        /* Restore LSI state */
        if (val & KVM_XICS_LEVEL_SENSITIVE) {
                state->lsi = true;
                if (val & KVM_XICS_PENDING)
                        state->asserted = true;
                pr_devel("  LSI ! Asserted=%d\n", state->asserted);
        }

        /*
         * Restore P and Q. If the interrupt was pending, we
         * force Q and !P, which will trigger a resend.
         *
         * That means that a guest that had both an interrupt
         * pending (queued) and Q set will restore with only
         * one instance of that interrupt instead of 2, but that
         * is perfectly fine as coalescing interrupts that haven't
         * been presented yet is always allowed.
         */
        if (val & KVM_XICS_PRESENTED && !(val & KVM_XICS_PENDING))
                state->old_p = true;
        if (val & KVM_XICS_QUEUED || val & KVM_XICS_PENDING)
                state->old_q = true;

        pr_devel("  P=%d, Q=%d\n", state->old_p, state->old_q);

        /*
         * If the interrupt was unmasked, update guest priority and
         * perform the appropriate state transition and do a
         * re-trigger if necessary.
         */
        if (val & KVM_XICS_MASKED) {
                pr_devel("  masked, saving prio\n");
                state->guest_priority = MASKED;
                state->saved_priority = guest_prio;
        } else {
                pr_devel("  unmasked, restoring to prio %d\n", guest_prio);
                xive_finish_unmask(xive, sb, state, guest_prio);
                state->saved_priority = guest_prio;
        }

        /* Increment the number of valid sources and mark this one valid */
        if (!state->valid)
                xive->src_count++;
        state->valid = true;

        return 0;
}

int kvmppc_xive_set_irq(struct kvm *kvm, int irq_source_id, u32 irq, int level,
                        bool line_status)
{
        struct kvmppc_xive *xive = kvm->arch.xive;
        struct kvmppc_xive_src_block *sb;
        struct kvmppc_xive_irq_state *state;
        u16 idx;

        if (!xive)
                return -ENODEV;

        sb = kvmppc_xive_find_source(xive, irq, &idx);
        if (!sb)
                return -EINVAL;

        /* Perform locklessly .... (we need to do some RCUisms here...) */
        state = &sb->irq_state[idx];
        if (!state->valid)
                return -EINVAL;

        /* We don't allow a trigger on a passed-through interrupt */
        if (state->pt_number)
                return -EINVAL;

        if ((level == 1 && state->lsi) || level == KVM_INTERRUPT_SET_LEVEL)
                state->asserted = 1;
        else if (level == 0 || level == KVM_INTERRUPT_UNSET) {
                state->asserted = 0;
                return 0;
        }

        /* Trigger the IPI */
        xive_irq_trigger(&state->ipi_data);

        return 0;
}

static int xive_set_attr(struct kvm_device *dev, struct kvm_device_attr *attr)
{
        struct kvmppc_xive *xive = dev->private;

        /* We honor the existing XICS ioctl */
        switch (attr->group) {
        case KVM_DEV_XICS_GRP_SOURCES:
                return xive_set_source(xive, attr->attr, attr->addr);
        }
        return -ENXIO;
}

static int xive_get_attr(struct kvm_device *dev, struct kvm_device_attr *attr)
{
        struct kvmppc_xive *xive = dev->private;

        /* We honor the existing XICS ioctl */
        switch (attr->group) {
        case KVM_DEV_XICS_GRP_SOURCES:
                return xive_get_source(xive, attr->attr, attr->addr);
        }
        return -ENXIO;
}

static int xive_has_attr(struct kvm_device *dev, struct kvm_device_attr *attr)
{
        /* We honor the same limits as XICS, at least for now */
        switch (attr->group) {
        case KVM_DEV_XICS_GRP_SOURCES:
                if (attr->attr >= KVMPPC_XICS_FIRST_IRQ &&
                    attr->attr < KVMPPC_XICS_NR_IRQS)
                        return 0;
                break;
        }
        return -ENXIO;
}

static void kvmppc_xive_cleanup_irq(u32 hw_num, struct xive_irq_data *xd)
{
        xive_vm_esb_load(xd, XIVE_ESB_SET_PQ_01);
        xive_native_configure_irq(hw_num, 0, MASKED, 0);
}

void kvmppc_xive_free_sources(struct kvmppc_xive_src_block *sb)
{
        int i;

        for (i = 0; i < KVMPPC_XICS_IRQ_PER_ICS; i++) {
                struct kvmppc_xive_irq_state *state = &sb->irq_state[i];

                if (!state->valid)
                        continue;

                kvmppc_xive_cleanup_irq(state->ipi_number, &state->ipi_data);
                xive_cleanup_irq_data(&state->ipi_data);
                xive_native_free_irq(state->ipi_number);

                /* Pass-through, cleanup too but keep IRQ hw data */
                if (state->pt_number)
                        kvmppc_xive_cleanup_irq(state->pt_number, state->pt_data);

                state->valid = false;
        }
}

/*
 * Called when device fd is closed.  kvm->lock is held.
 */
static void kvmppc_xive_release(struct kvm_device *dev)
{
        struct kvmppc_xive *xive = dev->private;
        struct kvm *kvm = xive->kvm;
        struct kvm_vcpu *vcpu;
        int i;

        pr_devel("Releasing xive device\n");

        /*
         * Since this is the device release function, we know that
         * userspace does not have any open fd referring to the
         * device.  Therefore there can not be any of the device
         * attribute set/get functions being executed concurrently,
         * and similarly, the connect_vcpu and set/clr_mapped
         * functions also cannot be being executed.
         */

        debugfs_remove(xive->dentry);

        /*
         * We should clean up the vCPU interrupt presenters first.
         */
        kvm_for_each_vcpu(i, vcpu, kvm) {
                /*
                 * Take vcpu->mutex to ensure that no one_reg get/set ioctl
                 * (i.e. kvmppc_xive_[gs]et_icp) can be done concurrently.
                 * Holding the vcpu->mutex also means that the vcpu cannot
                 * be executing the KVM_RUN ioctl, and therefore it cannot
                 * be executing the XIVE push or pull code or accessing
                 * the XIVE MMIO regions.
                 */
                mutex_lock(&vcpu->mutex);
                kvmppc_xive_cleanup_vcpu(vcpu);
                mutex_unlock(&vcpu->mutex);
        }

        /*
         * Now that we have cleared vcpu->arch.xive_vcpu, vcpu->arch.irq_type
         * and vcpu->arch.xive_esc_[vr]addr on each vcpu, we are safe
         * against xive code getting called during vcpu execution or
         * set/get one_reg operations.
         */
        kvm->arch.xive = NULL;

        /* Mask and free interrupts */
        for (i = 0; i <= xive->max_sbid; i++) {
                if (xive->src_blocks[i])
                        kvmppc_xive_free_sources(xive->src_blocks[i]);
                kfree(xive->src_blocks[i]);
                xive->src_blocks[i] = NULL;
        }

        if (xive->vp_base != XIVE_INVALID_VP)
                xive_native_free_vp_block(xive->vp_base);

        /*
         * A reference of the kvmppc_xive pointer is now kept under
         * the xive_devices struct of the machine for reuse. It is
         * freed when the VM is destroyed for now until we fix all the
         * execution paths.
         */

        kfree(dev);
}

/*
 * When the guest chooses the interrupt mode (XICS legacy or XIVE
 * native), the VM will switch of KVM device. The previous device will
 * be "released" before the new one is created.
 *
 * Until we are sure all execution paths are well protected, provide a
 * fail safe (transitional) method for device destruction, in which
 * the XIVE device pointer is recycled and not directly freed.
 */
struct kvmppc_xive *kvmppc_xive_get_device(struct kvm *kvm, u32 type)
{
        struct kvmppc_xive **kvm_xive_device = type == KVM_DEV_TYPE_XIVE ?
                &kvm->arch.xive_devices.native :
                &kvm->arch.xive_devices.xics_on_xive;
        struct kvmppc_xive *xive = *kvm_xive_device;

        if (!xive) {
                xive = kzalloc(sizeof(*xive), GFP_KERNEL);
                *kvm_xive_device = xive;
        } else {
                memset(xive, 0, sizeof(*xive));
        }

        return xive;
}

/*
 * Create a XICS device with XIVE backend.  kvm->lock is held.
 */
static int kvmppc_xive_create(struct kvm_device *dev, u32 type)
{
        struct kvmppc_xive *xive;
        struct kvm *kvm = dev->kvm;
        int ret = 0;

        pr_devel("Creating xive for partition\n");

        xive = kvmppc_xive_get_device(kvm, type);
        if (!xive)
                return -ENOMEM;

        dev->private = xive;
        xive->dev = dev;
        xive->kvm = kvm;
        mutex_init(&xive->lock);

        /* Already there ? */
        if (kvm->arch.xive)
                ret = -EEXIST;
        else
                kvm->arch.xive = xive;

        /* We use the default queue size set by the host */
        xive->q_order = xive_native_default_eq_shift();
        if (xive->q_order < PAGE_SHIFT)
                xive->q_page_order = 0;
        else
                xive->q_page_order = xive->q_order - PAGE_SHIFT;

        /* Allocate a bunch of VPs */
        xive->vp_base = xive_native_alloc_vp_block(KVM_MAX_VCPUS);
        pr_devel("VP_Base=%x\n", xive->vp_base);

        if (xive->vp_base == XIVE_INVALID_VP)
                ret = -ENOMEM;

        xive->single_escalation = xive_native_has_single_escalation();

        if (ret)
                return ret;

        return 0;
}

int kvmppc_xive_debug_show_queues(struct seq_file *m, struct kvm_vcpu *vcpu)
{
        struct kvmppc_xive_vcpu *xc = vcpu->arch.xive_vcpu;
        unsigned int i;

        for (i = 0; i < KVMPPC_XIVE_Q_COUNT; i++) {

                struct xive_q *q = &xc->queues[i];
                u32 i0, i1, idx;

                if (!q->qpage && !xc->esc_virq[i])
                        continue;

                seq_printf(m, " [q%d]: ", i);

                if (q->qpage) {
                        idx = q->idx;
                        i0 = be32_to_cpup(q->qpage + idx);
                        idx = (idx + 1) & q->msk;
                        i1 = be32_to_cpup(q->qpage + idx);
                        seq_printf(m, "T=%d %08x %08x...\n", q->toggle,
                                   i0, i1);
                }
                if (xc->esc_virq[i]) {
                        struct irq_data *d = irq_get_irq_data(xc->esc_virq[i]);
                        struct xive_irq_data *xd =
                                irq_data_get_irq_handler_data(d);
                        u64 pq = xive_vm_esb_load(xd, XIVE_ESB_GET);

                        seq_printf(m, "E:%c%c I(%d:%llx:%llx)",
                                   (pq & XIVE_ESB_VAL_P) ? 'P' : 'p',
                                   (pq & XIVE_ESB_VAL_Q) ? 'Q' : 'q',
                                   xc->esc_virq[i], pq, xd->eoi_page);
                        seq_puts(m, "\n");
                }
        }
        return 0;
}

static int xive_debug_show(struct seq_file *m, void *private)
{
        struct kvmppc_xive *xive = m->private;
        struct kvm *kvm = xive->kvm;
        struct kvm_vcpu *vcpu;
        u64 t_rm_h_xirr = 0;
        u64 t_rm_h_ipoll = 0;
        u64 t_rm_h_cppr = 0;
        u64 t_rm_h_eoi = 0;
        u64 t_rm_h_ipi = 0;
        u64 t_vm_h_xirr = 0;
        u64 t_vm_h_ipoll = 0;
        u64 t_vm_h_cppr = 0;
        u64 t_vm_h_eoi = 0;
        u64 t_vm_h_ipi = 0;
        unsigned int i;

        if (!kvm)
                return 0;

        seq_printf(m, "=========\nVCPU state\n=========\n");

        kvm_for_each_vcpu(i, vcpu, kvm) {
                struct kvmppc_xive_vcpu *xc = vcpu->arch.xive_vcpu;

                if (!xc)
                        continue;

                seq_printf(m, "cpu server %#x CPPR:%#x HWCPPR:%#x"
                           " MFRR:%#x PEND:%#x h_xirr: R=%lld V=%lld\n",
                           xc->server_num, xc->cppr, xc->hw_cppr,
                           xc->mfrr, xc->pending,
                           xc->stat_rm_h_xirr, xc->stat_vm_h_xirr);

                kvmppc_xive_debug_show_queues(m, vcpu);

                t_rm_h_xirr += xc->stat_rm_h_xirr;
                t_rm_h_ipoll += xc->stat_rm_h_ipoll;
                t_rm_h_cppr += xc->stat_rm_h_cppr;
                t_rm_h_eoi += xc->stat_rm_h_eoi;
                t_rm_h_ipi += xc->stat_rm_h_ipi;
                t_vm_h_xirr += xc->stat_vm_h_xirr;
                t_vm_h_ipoll += xc->stat_vm_h_ipoll;
                t_vm_h_cppr += xc->stat_vm_h_cppr;
                t_vm_h_eoi += xc->stat_vm_h_eoi;
                t_vm_h_ipi += xc->stat_vm_h_ipi;
        }

        seq_printf(m, "Hcalls totals\n");
        seq_printf(m, " H_XIRR  R=%10lld V=%10lld\n", t_rm_h_xirr, t_vm_h_xirr);
        seq_printf(m, " H_IPOLL R=%10lld V=%10lld\n", t_rm_h_ipoll, t_vm_h_ipoll);
        seq_printf(m, " H_CPPR  R=%10lld V=%10lld\n", t_rm_h_cppr, t_vm_h_cppr);
        seq_printf(m, " H_EOI   R=%10lld V=%10lld\n", t_rm_h_eoi, t_vm_h_eoi);
        seq_printf(m, " H_IPI   R=%10lld V=%10lld\n", t_rm_h_ipi, t_vm_h_ipi);

        return 0;
}

DEFINE_SHOW_ATTRIBUTE(xive_debug);

static void xive_debugfs_init(struct kvmppc_xive *xive)
{
        char *name;

        name = kasprintf(GFP_KERNEL, "kvm-xive-%p", xive);
        if (!name) {
                pr_err("%s: no memory for name\n", __func__);
                return;
        }

        xive->dentry = debugfs_create_file(name, S_IRUGO, powerpc_debugfs_root,
                                           xive, &xive_debug_fops);

        pr_debug("%s: created %s\n", __func__, name);
        kfree(name);
}

static void kvmppc_xive_init(struct kvm_device *dev)
{
        struct kvmppc_xive *xive = (struct kvmppc_xive *)dev->private;

        /* Register some debug interfaces */
        xive_debugfs_init(xive);
}

struct kvm_device_ops kvm_xive_ops = {
        .name = "kvm-xive",
        .create = kvmppc_xive_create,
        .init = kvmppc_xive_init,
        .release = kvmppc_xive_release,
        .set_attr = xive_set_attr,
        .get_attr = xive_get_attr,
        .has_attr = xive_has_attr,
};

void kvmppc_xive_init_module(void)
{
        __xive_vm_h_xirr = xive_vm_h_xirr;
        __xive_vm_h_ipoll = xive_vm_h_ipoll;
        __xive_vm_h_ipi = xive_vm_h_ipi;
        __xive_vm_h_cppr = xive_vm_h_cppr;
        __xive_vm_h_eoi = xive_vm_h_eoi;
}

void kvmppc_xive_exit_module(void)
{
        __xive_vm_h_xirr = NULL;
        __xive_vm_h_ipoll = NULL;
        __xive_vm_h_ipi = NULL;
        __xive_vm_h_cppr = NULL;
        __xive_vm_h_eoi = NULL;
}