/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (c) 2008-2009 Silicon Graphics, Inc.  All Rights Reserved.
 */

/*
 * Cross Partition Communication (XPC) uv-based functions.
 *
 *     Architecture specific implementation of common functions.
 *
 */

#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/cpu.h>
#include <linux/module.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/numa.h>
#include <asm/uv/uv_hub.h>
#include <asm/uv/bios.h>
#include <asm/uv/uv_irq.h>
#include "../sgi-gru/gru.h"
#include "../sgi-gru/grukservices.h"
#include "xpc.h"

static struct xpc_heartbeat_uv *xpc_heartbeat_uv;

#define XPC_ACTIVATE_MSG_SIZE_UV        (1 * GRU_CACHE_LINE_BYTES)
#define XPC_ACTIVATE_MQ_SIZE_UV         (4 * XP_MAX_NPARTITIONS_UV * \
                                         XPC_ACTIVATE_MSG_SIZE_UV)
#define XPC_ACTIVATE_IRQ_NAME           "xpc_activate"

#define XPC_NOTIFY_MSG_SIZE_UV          (2 * GRU_CACHE_LINE_BYTES)
#define XPC_NOTIFY_MQ_SIZE_UV           (4 * XP_MAX_NPARTITIONS_UV * \
                                         XPC_NOTIFY_MSG_SIZE_UV)
#define XPC_NOTIFY_IRQ_NAME             "xpc_notify"

static int xpc_mq_node = NUMA_NO_NODE;

static struct xpc_gru_mq_uv *xpc_activate_mq_uv;
static struct xpc_gru_mq_uv *xpc_notify_mq_uv;

static int
xpc_setup_partitions_uv(void)
{
        short partid;
        struct xpc_partition_uv *part_uv;

        for (partid = 0; partid < XP_MAX_NPARTITIONS_UV; partid++) {
                part_uv = &xpc_partitions[partid].sn.uv;

                mutex_init(&part_uv->cached_activate_gru_mq_desc_mutex);
                spin_lock_init(&part_uv->flags_lock);
                part_uv->remote_act_state = XPC_P_AS_INACTIVE;
        }
        return 0;
}

static void
xpc_teardown_partitions_uv(void)
{
        short partid;
        struct xpc_partition_uv *part_uv;
        unsigned long irq_flags;

        for (partid = 0; partid < XP_MAX_NPARTITIONS_UV; partid++) {
                part_uv = &xpc_partitions[partid].sn.uv;

                if (part_uv->cached_activate_gru_mq_desc != NULL) {
                        mutex_lock(&part_uv->cached_activate_gru_mq_desc_mutex);
                        spin_lock_irqsave(&part_uv->flags_lock, irq_flags);
                        part_uv->flags &= ~XPC_P_CACHED_ACTIVATE_GRU_MQ_DESC_UV;
                        spin_unlock_irqrestore(&part_uv->flags_lock, irq_flags);
                        kfree(part_uv->cached_activate_gru_mq_desc);
                        part_uv->cached_activate_gru_mq_desc = NULL;
                        mutex_unlock(&part_uv->
                                     cached_activate_gru_mq_desc_mutex);
                }
        }
}

static int
xpc_get_gru_mq_irq_uv(struct xpc_gru_mq_uv *mq, int cpu, char *irq_name)
{
        int mmr_pnode = uv_blade_to_pnode(mq->mmr_blade);

        mq->irq = uv_setup_irq(irq_name, cpu, mq->mmr_blade, mq->mmr_offset,
                        UV_AFFINITY_CPU);
        if (mq->irq < 0)
                return mq->irq;

        mq->mmr_value = uv_read_global_mmr64(mmr_pnode, mq->mmr_offset);

        return 0;
}

static void
xpc_release_gru_mq_irq_uv(struct xpc_gru_mq_uv *mq)
{
        uv_teardown_irq(mq->irq);
}

static int
xpc_gru_mq_watchlist_alloc_uv(struct xpc_gru_mq_uv *mq)
{
        int ret;

        ret = uv_bios_mq_watchlist_alloc(uv_gpa(mq->address),
                                         mq->order, &mq->mmr_offset);
        if (ret < 0) {
                dev_err(xpc_part, "uv_bios_mq_watchlist_alloc() failed, "
                        "ret=%d\n", ret);
                return ret;
        }

        mq->watchlist_num = ret;
        return 0;
}

static void
xpc_gru_mq_watchlist_free_uv(struct xpc_gru_mq_uv *mq)
{
        int ret;
        int mmr_pnode = uv_blade_to_pnode(mq->mmr_blade);

        ret = uv_bios_mq_watchlist_free(mmr_pnode, mq->watchlist_num);
        BUG_ON(ret != BIOS_STATUS_SUCCESS);
}

static struct xpc_gru_mq_uv *
xpc_create_gru_mq_uv(unsigned int mq_size, int cpu, char *irq_name,
                     irq_handler_t irq_handler)
{
        enum xp_retval xp_ret;
        int ret;
        int nid;
        int nasid;
        int pg_order;
        struct page *page;
        struct xpc_gru_mq_uv *mq;
        struct uv_IO_APIC_route_entry *mmr_value;

        mq = kmalloc_obj(struct xpc_gru_mq_uv);
        if (mq == NULL) {
                dev_err(xpc_part, "xpc_create_gru_mq_uv() failed to kmalloc() "
                        "a xpc_gru_mq_uv structure\n");
                ret = -ENOMEM;
                goto out_0;
        }

        mq->gru_mq_desc = kzalloc_obj(struct gru_message_queue_desc);
        if (mq->gru_mq_desc == NULL) {
                dev_err(xpc_part, "xpc_create_gru_mq_uv() failed to kmalloc() "
                        "a gru_message_queue_desc structure\n");
                ret = -ENOMEM;
                goto out_1;
        }

        pg_order = get_order(mq_size);
        mq->order = pg_order + PAGE_SHIFT;
        mq_size = 1UL << mq->order;

        mq->mmr_blade = uv_cpu_to_blade_id(cpu);

        nid = cpu_to_node(cpu);
        page = __alloc_pages_node(nid,
                                      GFP_KERNEL | __GFP_ZERO | __GFP_THISNODE,
                                      pg_order);
        if (page == NULL) {
                dev_err(xpc_part, "xpc_create_gru_mq_uv() failed to alloc %d "
                        "bytes of memory on nid=%d for GRU mq\n", mq_size, nid);
                ret = -ENOMEM;
                goto out_2;
        }
        mq->address = page_address(page);

        /* enable generation of irq when GRU mq operation occurs to this mq */
        ret = xpc_gru_mq_watchlist_alloc_uv(mq);
        if (ret != 0)
                goto out_3;

        ret = xpc_get_gru_mq_irq_uv(mq, cpu, irq_name);
        if (ret != 0)
                goto out_4;

        ret = request_irq(mq->irq, irq_handler, 0, irq_name, NULL);
        if (ret != 0) {
                dev_err(xpc_part, "request_irq(irq=%d) returned error=%d\n",
                        mq->irq, -ret);
                goto out_5;
        }

        nasid = UV_PNODE_TO_NASID(uv_cpu_to_pnode(cpu));

        mmr_value = (struct uv_IO_APIC_route_entry *)&mq->mmr_value;
        ret = gru_create_message_queue(mq->gru_mq_desc, mq->address, mq_size,
                                     nasid, mmr_value->vector, mmr_value->dest);
        if (ret != 0) {
                dev_err(xpc_part, "gru_create_message_queue() returned "
                        "error=%d\n", ret);
                ret = -EINVAL;
                goto out_6;
        }

        /* allow other partitions to access this GRU mq */
        xp_ret = xp_expand_memprotect(xp_pa(mq->address), mq_size);
        if (xp_ret != xpSuccess) {
                ret = -EACCES;
                goto out_6;
        }

        return mq;

        /* something went wrong */
out_6:
        free_irq(mq->irq, NULL);
out_5:
        xpc_release_gru_mq_irq_uv(mq);
out_4:
        xpc_gru_mq_watchlist_free_uv(mq);
out_3:
        free_pages((unsigned long)mq->address, pg_order);
out_2:
        kfree(mq->gru_mq_desc);
out_1:
        kfree(mq);
out_0:
        return ERR_PTR(ret);
}

static void
xpc_destroy_gru_mq_uv(struct xpc_gru_mq_uv *mq)
{
        unsigned int mq_size;
        int pg_order;
        int ret;

        /* disallow other partitions to access GRU mq */
        mq_size = 1UL << mq->order;
        ret = xp_restrict_memprotect(xp_pa(mq->address), mq_size);
        BUG_ON(ret != xpSuccess);

        /* unregister irq handler and release mq irq/vector mapping */
        free_irq(mq->irq, NULL);
        xpc_release_gru_mq_irq_uv(mq);

        /* disable generation of irq when GRU mq op occurs to this mq */
        xpc_gru_mq_watchlist_free_uv(mq);

        pg_order = mq->order - PAGE_SHIFT;
        free_pages((unsigned long)mq->address, pg_order);

        kfree(mq);
}

static enum xp_retval
xpc_send_gru_msg(struct gru_message_queue_desc *gru_mq_desc, void *msg,
                 size_t msg_size)
{
        enum xp_retval xp_ret;
        int ret;

        while (1) {
                ret = gru_send_message_gpa(gru_mq_desc, msg, msg_size);
                if (ret == MQE_OK) {
                        xp_ret = xpSuccess;
                        break;
                }

                if (ret == MQE_QUEUE_FULL) {
                        dev_dbg(xpc_chan, "gru_send_message_gpa() returned "
                                "error=MQE_QUEUE_FULL\n");
                        /* !!! handle QLimit reached; delay & try again */
                        /* ??? Do we add a limit to the number of retries? */
                        (void)msleep_interruptible(10);
                } else if (ret == MQE_CONGESTION) {
                        dev_dbg(xpc_chan, "gru_send_message_gpa() returned "
                                "error=MQE_CONGESTION\n");
                        /* !!! handle LB Overflow; simply try again */
                        /* ??? Do we add a limit to the number of retries? */
                } else {
                        /* !!! Currently this is MQE_UNEXPECTED_CB_ERR */
                        dev_err(xpc_chan, "gru_send_message_gpa() returned "
                                "error=%d\n", ret);
                        xp_ret = xpGruSendMqError;
                        break;
                }
        }
        return xp_ret;
}

static void
xpc_process_activate_IRQ_rcvd_uv(void)
{
        unsigned long irq_flags;
        short partid;
        struct xpc_partition *part;
        u8 act_state_req;

        DBUG_ON(xpc_activate_IRQ_rcvd == 0);

        spin_lock_irqsave(&xpc_activate_IRQ_rcvd_lock, irq_flags);
        for (partid = 0; partid < XP_MAX_NPARTITIONS_UV; partid++) {
                part = &xpc_partitions[partid];

                if (part->sn.uv.act_state_req == 0)
                        continue;

                xpc_activate_IRQ_rcvd--;
                BUG_ON(xpc_activate_IRQ_rcvd < 0);

                act_state_req = part->sn.uv.act_state_req;
                part->sn.uv.act_state_req = 0;
                spin_unlock_irqrestore(&xpc_activate_IRQ_rcvd_lock, irq_flags);

                if (act_state_req == XPC_P_ASR_ACTIVATE_UV) {
                        if (part->act_state == XPC_P_AS_INACTIVE)
                                xpc_activate_partition(part);
                        else if (part->act_state == XPC_P_AS_DEACTIVATING)
                                XPC_DEACTIVATE_PARTITION(part, xpReactivating);

                } else if (act_state_req == XPC_P_ASR_REACTIVATE_UV) {
                        if (part->act_state == XPC_P_AS_INACTIVE)
                                xpc_activate_partition(part);
                        else
                                XPC_DEACTIVATE_PARTITION(part, xpReactivating);

                } else if (act_state_req == XPC_P_ASR_DEACTIVATE_UV) {
                        XPC_DEACTIVATE_PARTITION(part, part->sn.uv.reason);

                } else {
                        BUG();
                }

                spin_lock_irqsave(&xpc_activate_IRQ_rcvd_lock, irq_flags);
                if (xpc_activate_IRQ_rcvd == 0)
                        break;
        }
        spin_unlock_irqrestore(&xpc_activate_IRQ_rcvd_lock, irq_flags);

}

static void
xpc_handle_activate_mq_msg_uv(struct xpc_partition *part,
                              struct xpc_activate_mq_msghdr_uv *msg_hdr,
                              int part_setup,
                              int *wakeup_hb_checker)
{
        unsigned long irq_flags;
        struct xpc_partition_uv *part_uv = &part->sn.uv;
        struct xpc_openclose_args *args;

        part_uv->remote_act_state = msg_hdr->act_state;

        switch (msg_hdr->type) {
        case XPC_ACTIVATE_MQ_MSG_SYNC_ACT_STATE_UV:
                /* syncing of remote_act_state was just done above */
                break;

        case XPC_ACTIVATE_MQ_MSG_ACTIVATE_REQ_UV: {
                struct xpc_activate_mq_msg_activate_req_uv *msg;

                /*
                 * ??? Do we deal here with ts_jiffies being different
                 * ??? if act_state != XPC_P_AS_INACTIVE instead of
                 * ??? below?
                 */
                msg = container_of(msg_hdr, struct
                                   xpc_activate_mq_msg_activate_req_uv, hdr);

                spin_lock_irqsave(&xpc_activate_IRQ_rcvd_lock, irq_flags);
                if (part_uv->act_state_req == 0)
                        xpc_activate_IRQ_rcvd++;
                part_uv->act_state_req = XPC_P_ASR_ACTIVATE_UV;
                part->remote_rp_pa = msg->rp_gpa; /* !!! _pa is _gpa */
                part->remote_rp_ts_jiffies = msg_hdr->rp_ts_jiffies;
                part_uv->heartbeat_gpa = msg->heartbeat_gpa;

                if (msg->activate_gru_mq_desc_gpa !=
                    part_uv->activate_gru_mq_desc_gpa) {
                        spin_lock(&part_uv->flags_lock);
                        part_uv->flags &= ~XPC_P_CACHED_ACTIVATE_GRU_MQ_DESC_UV;
                        spin_unlock(&part_uv->flags_lock);
                        part_uv->activate_gru_mq_desc_gpa =
                            msg->activate_gru_mq_desc_gpa;
                }
                spin_unlock_irqrestore(&xpc_activate_IRQ_rcvd_lock, irq_flags);

                (*wakeup_hb_checker)++;
                break;
        }
        case XPC_ACTIVATE_MQ_MSG_DEACTIVATE_REQ_UV: {
                struct xpc_activate_mq_msg_deactivate_req_uv *msg;

                msg = container_of(msg_hdr, struct
                                   xpc_activate_mq_msg_deactivate_req_uv, hdr);

                spin_lock_irqsave(&xpc_activate_IRQ_rcvd_lock, irq_flags);
                if (part_uv->act_state_req == 0)
                        xpc_activate_IRQ_rcvd++;
                part_uv->act_state_req = XPC_P_ASR_DEACTIVATE_UV;
                part_uv->reason = msg->reason;
                spin_unlock_irqrestore(&xpc_activate_IRQ_rcvd_lock, irq_flags);

                (*wakeup_hb_checker)++;
                return;
        }
        case XPC_ACTIVATE_MQ_MSG_CHCTL_CLOSEREQUEST_UV: {
                struct xpc_activate_mq_msg_chctl_closerequest_uv *msg;

                if (!part_setup)
                        break;

                msg = container_of(msg_hdr, struct
                                   xpc_activate_mq_msg_chctl_closerequest_uv,
                                   hdr);
                args = &part->remote_openclose_args[msg->ch_number];
                args->reason = msg->reason;

                spin_lock_irqsave(&part->chctl_lock, irq_flags);
                part->chctl.flags[msg->ch_number] |= XPC_CHCTL_CLOSEREQUEST;
                spin_unlock_irqrestore(&part->chctl_lock, irq_flags);

                xpc_wakeup_channel_mgr(part);
                break;
        }
        case XPC_ACTIVATE_MQ_MSG_CHCTL_CLOSEREPLY_UV: {
                struct xpc_activate_mq_msg_chctl_closereply_uv *msg;

                if (!part_setup)
                        break;

                msg = container_of(msg_hdr, struct
                                   xpc_activate_mq_msg_chctl_closereply_uv,
                                   hdr);

                spin_lock_irqsave(&part->chctl_lock, irq_flags);
                part->chctl.flags[msg->ch_number] |= XPC_CHCTL_CLOSEREPLY;
                spin_unlock_irqrestore(&part->chctl_lock, irq_flags);

                xpc_wakeup_channel_mgr(part);
                break;
        }
        case XPC_ACTIVATE_MQ_MSG_CHCTL_OPENREQUEST_UV: {
                struct xpc_activate_mq_msg_chctl_openrequest_uv *msg;

                if (!part_setup)
                        break;

                msg = container_of(msg_hdr, struct
                                   xpc_activate_mq_msg_chctl_openrequest_uv,
                                   hdr);
                args = &part->remote_openclose_args[msg->ch_number];
                args->entry_size = msg->entry_size;
                args->local_nentries = msg->local_nentries;

                spin_lock_irqsave(&part->chctl_lock, irq_flags);
                part->chctl.flags[msg->ch_number] |= XPC_CHCTL_OPENREQUEST;
                spin_unlock_irqrestore(&part->chctl_lock, irq_flags);

                xpc_wakeup_channel_mgr(part);
                break;
        }
        case XPC_ACTIVATE_MQ_MSG_CHCTL_OPENREPLY_UV: {
                struct xpc_activate_mq_msg_chctl_openreply_uv *msg;

                if (!part_setup)
                        break;

                msg = container_of(msg_hdr, struct
                                   xpc_activate_mq_msg_chctl_openreply_uv, hdr);
                args = &part->remote_openclose_args[msg->ch_number];
                args->remote_nentries = msg->remote_nentries;
                args->local_nentries = msg->local_nentries;
                args->local_msgqueue_pa = msg->notify_gru_mq_desc_gpa;

                spin_lock_irqsave(&part->chctl_lock, irq_flags);
                part->chctl.flags[msg->ch_number] |= XPC_CHCTL_OPENREPLY;
                spin_unlock_irqrestore(&part->chctl_lock, irq_flags);

                xpc_wakeup_channel_mgr(part);
                break;
        }
        case XPC_ACTIVATE_MQ_MSG_CHCTL_OPENCOMPLETE_UV: {
                struct xpc_activate_mq_msg_chctl_opencomplete_uv *msg;

                if (!part_setup)
                        break;

                msg = container_of(msg_hdr, struct
                                xpc_activate_mq_msg_chctl_opencomplete_uv, hdr);
                spin_lock_irqsave(&part->chctl_lock, irq_flags);
                part->chctl.flags[msg->ch_number] |= XPC_CHCTL_OPENCOMPLETE;
                spin_unlock_irqrestore(&part->chctl_lock, irq_flags);

                xpc_wakeup_channel_mgr(part);
        }
                fallthrough;
        case XPC_ACTIVATE_MQ_MSG_MARK_ENGAGED_UV:
                spin_lock_irqsave(&part_uv->flags_lock, irq_flags);
                part_uv->flags |= XPC_P_ENGAGED_UV;
                spin_unlock_irqrestore(&part_uv->flags_lock, irq_flags);
                break;

        case XPC_ACTIVATE_MQ_MSG_MARK_DISENGAGED_UV:
                spin_lock_irqsave(&part_uv->flags_lock, irq_flags);
                part_uv->flags &= ~XPC_P_ENGAGED_UV;
                spin_unlock_irqrestore(&part_uv->flags_lock, irq_flags);
                break;

        default:
                dev_err(xpc_part, "received unknown activate_mq msg type=%d "
                        "from partition=%d\n", msg_hdr->type, XPC_PARTID(part));

                /* get hb checker to deactivate from the remote partition */
                spin_lock_irqsave(&xpc_activate_IRQ_rcvd_lock, irq_flags);
                if (part_uv->act_state_req == 0)
                        xpc_activate_IRQ_rcvd++;
                part_uv->act_state_req = XPC_P_ASR_DEACTIVATE_UV;
                part_uv->reason = xpBadMsgType;
                spin_unlock_irqrestore(&xpc_activate_IRQ_rcvd_lock, irq_flags);

                (*wakeup_hb_checker)++;
                return;
        }

        if (msg_hdr->rp_ts_jiffies != part->remote_rp_ts_jiffies &&
            part->remote_rp_ts_jiffies != 0) {
                /*
                 * ??? Does what we do here need to be sensitive to
                 * ??? act_state or remote_act_state?
                 */
                spin_lock_irqsave(&xpc_activate_IRQ_rcvd_lock, irq_flags);
                if (part_uv->act_state_req == 0)
                        xpc_activate_IRQ_rcvd++;
                part_uv->act_state_req = XPC_P_ASR_REACTIVATE_UV;
                spin_unlock_irqrestore(&xpc_activate_IRQ_rcvd_lock, irq_flags);

                (*wakeup_hb_checker)++;
        }
}

static irqreturn_t
xpc_handle_activate_IRQ_uv(int irq, void *dev_id)
{
        struct xpc_activate_mq_msghdr_uv *msg_hdr;
        short partid;
        struct xpc_partition *part;
        int wakeup_hb_checker = 0;
        int part_referenced;

        while (1) {
                msg_hdr = gru_get_next_message(xpc_activate_mq_uv->gru_mq_desc);
                if (msg_hdr == NULL)
                        break;

                partid = msg_hdr->partid;
                if (partid < 0 || partid >= XP_MAX_NPARTITIONS_UV) {
                        dev_err(xpc_part, "xpc_handle_activate_IRQ_uv() "
                                "received invalid partid=0x%x in message\n",
                                partid);
                } else {
                        part = &xpc_partitions[partid];

                        part_referenced = xpc_part_ref(part);
                        xpc_handle_activate_mq_msg_uv(part, msg_hdr,
                                                      part_referenced,
                                                      &wakeup_hb_checker);
                        if (part_referenced)
                                xpc_part_deref(part);
                }

                gru_free_message(xpc_activate_mq_uv->gru_mq_desc, msg_hdr);
        }

        if (wakeup_hb_checker)
                wake_up_interruptible(&xpc_activate_IRQ_wq);

        return IRQ_HANDLED;
}

static enum xp_retval
xpc_cache_remote_gru_mq_desc_uv(struct gru_message_queue_desc *gru_mq_desc,
                                unsigned long gru_mq_desc_gpa)
{
        enum xp_retval ret;

        ret = xp_remote_memcpy(uv_gpa(gru_mq_desc), gru_mq_desc_gpa,
                               sizeof(struct gru_message_queue_desc));
        if (ret == xpSuccess)
                gru_mq_desc->mq = NULL;

        return ret;
}

static enum xp_retval
xpc_send_activate_IRQ_uv(struct xpc_partition *part, void *msg, size_t msg_size,
                         int msg_type)
{
        struct xpc_activate_mq_msghdr_uv *msg_hdr = msg;
        struct xpc_partition_uv *part_uv = &part->sn.uv;
        struct gru_message_queue_desc *gru_mq_desc;
        unsigned long irq_flags;
        enum xp_retval ret;

        DBUG_ON(msg_size > XPC_ACTIVATE_MSG_SIZE_UV);

        msg_hdr->type = msg_type;
        msg_hdr->partid = xp_partition_id;
        msg_hdr->act_state = part->act_state;
        msg_hdr->rp_ts_jiffies = xpc_rsvd_page->ts_jiffies;

        mutex_lock(&part_uv->cached_activate_gru_mq_desc_mutex);
again:
        if (!(part_uv->flags & XPC_P_CACHED_ACTIVATE_GRU_MQ_DESC_UV)) {
                gru_mq_desc = part_uv->cached_activate_gru_mq_desc;
                if (gru_mq_desc == NULL) {
                        gru_mq_desc = kmalloc_obj(struct gru_message_queue_desc,
                                                  GFP_ATOMIC);
                        if (gru_mq_desc == NULL) {
                                ret = xpNoMemory;
                                goto done;
                        }
                        part_uv->cached_activate_gru_mq_desc = gru_mq_desc;
                }

                ret = xpc_cache_remote_gru_mq_desc_uv(gru_mq_desc,
                                                      part_uv->
                                                      activate_gru_mq_desc_gpa);
                if (ret != xpSuccess)
                        goto done;

                spin_lock_irqsave(&part_uv->flags_lock, irq_flags);
                part_uv->flags |= XPC_P_CACHED_ACTIVATE_GRU_MQ_DESC_UV;
                spin_unlock_irqrestore(&part_uv->flags_lock, irq_flags);
        }

        /* ??? Is holding a spin_lock (ch->lock) during this call a bad idea? */
        ret = xpc_send_gru_msg(part_uv->cached_activate_gru_mq_desc, msg,
                               msg_size);
        if (ret != xpSuccess) {
                smp_rmb();      /* ensure a fresh copy of part_uv->flags */
                if (!(part_uv->flags & XPC_P_CACHED_ACTIVATE_GRU_MQ_DESC_UV))
                        goto again;
        }
done:
        mutex_unlock(&part_uv->cached_activate_gru_mq_desc_mutex);
        return ret;
}

static void
xpc_send_activate_IRQ_part_uv(struct xpc_partition *part, void *msg,
                              size_t msg_size, int msg_type)
{
        enum xp_retval ret;

        ret = xpc_send_activate_IRQ_uv(part, msg, msg_size, msg_type);
        if (unlikely(ret != xpSuccess))
                XPC_DEACTIVATE_PARTITION(part, ret);
}

static void
xpc_send_activate_IRQ_ch_uv(struct xpc_channel *ch, unsigned long *irq_flags,
                         void *msg, size_t msg_size, int msg_type)
{
        struct xpc_partition *part = &xpc_partitions[ch->partid];
        enum xp_retval ret;

        ret = xpc_send_activate_IRQ_uv(part, msg, msg_size, msg_type);
        if (unlikely(ret != xpSuccess)) {
                if (irq_flags != NULL)
                        spin_unlock_irqrestore(&ch->lock, *irq_flags);

                XPC_DEACTIVATE_PARTITION(part, ret);

                if (irq_flags != NULL)
                        spin_lock_irqsave(&ch->lock, *irq_flags);
        }
}

static void
xpc_send_local_activate_IRQ_uv(struct xpc_partition *part, int act_state_req)
{
        unsigned long irq_flags;
        struct xpc_partition_uv *part_uv = &part->sn.uv;

        /*
         * !!! Make our side think that the remote partition sent an activate
         * !!! mq message our way by doing what the activate IRQ handler would
         * !!! do had one really been sent.
         */

        spin_lock_irqsave(&xpc_activate_IRQ_rcvd_lock, irq_flags);
        if (part_uv->act_state_req == 0)
                xpc_activate_IRQ_rcvd++;
        part_uv->act_state_req = act_state_req;
        spin_unlock_irqrestore(&xpc_activate_IRQ_rcvd_lock, irq_flags);

        wake_up_interruptible(&xpc_activate_IRQ_wq);
}

static enum xp_retval
xpc_get_partition_rsvd_page_pa_uv(void *buf, u64 *cookie, unsigned long *rp_pa,
                                  size_t *len)
{
        s64 status;
        enum xp_retval ret;

        status = uv_bios_reserved_page_pa((u64)buf, cookie, (u64 *)rp_pa,
                                          (u64 *)len);
        if (status == BIOS_STATUS_SUCCESS)
                ret = xpSuccess;
        else if (status == BIOS_STATUS_MORE_PASSES)
                ret = xpNeedMoreInfo;
        else
                ret = xpBiosError;

        return ret;
}

static int
xpc_setup_rsvd_page_uv(struct xpc_rsvd_page *rp)
{
        xpc_heartbeat_uv =
            &xpc_partitions[sn_partition_id].sn.uv.cached_heartbeat;
        rp->sn.uv.heartbeat_gpa = uv_gpa(xpc_heartbeat_uv);
        rp->sn.uv.activate_gru_mq_desc_gpa =
            uv_gpa(xpc_activate_mq_uv->gru_mq_desc);
        return 0;
}

static void
xpc_allow_hb_uv(short partid)
{
}

static void
xpc_disallow_hb_uv(short partid)
{
}

static void
xpc_disallow_all_hbs_uv(void)
{
}

static void
xpc_increment_heartbeat_uv(void)
{
        xpc_heartbeat_uv->value++;
}

static void
xpc_offline_heartbeat_uv(void)
{
        xpc_increment_heartbeat_uv();
        xpc_heartbeat_uv->offline = 1;
}

static void
xpc_online_heartbeat_uv(void)
{
        xpc_increment_heartbeat_uv();
        xpc_heartbeat_uv->offline = 0;
}

static void
xpc_heartbeat_init_uv(void)
{
        xpc_heartbeat_uv->value = 1;
        xpc_heartbeat_uv->offline = 0;
}

static void
xpc_heartbeat_exit_uv(void)
{
        xpc_offline_heartbeat_uv();
}

static enum xp_retval
xpc_get_remote_heartbeat_uv(struct xpc_partition *part)
{
        struct xpc_partition_uv *part_uv = &part->sn.uv;
        enum xp_retval ret;

        ret = xp_remote_memcpy(uv_gpa(&part_uv->cached_heartbeat),
                               part_uv->heartbeat_gpa,
                               sizeof(struct xpc_heartbeat_uv));
        if (ret != xpSuccess)
                return ret;

        if (part_uv->cached_heartbeat.value == part->last_heartbeat &&
            !part_uv->cached_heartbeat.offline) {

                ret = xpNoHeartbeat;
        } else {
                part->last_heartbeat = part_uv->cached_heartbeat.value;
        }
        return ret;
}

static void
xpc_request_partition_activation_uv(struct xpc_rsvd_page *remote_rp,
                                    unsigned long remote_rp_gpa, int nasid)
{
        short partid = remote_rp->SAL_partid;
        struct xpc_partition *part = &xpc_partitions[partid];
        struct xpc_activate_mq_msg_activate_req_uv msg;

        part->remote_rp_pa = remote_rp_gpa; /* !!! _pa here is really _gpa */
        part->remote_rp_ts_jiffies = remote_rp->ts_jiffies;
        part->sn.uv.heartbeat_gpa = remote_rp->sn.uv.heartbeat_gpa;
        part->sn.uv.activate_gru_mq_desc_gpa =
            remote_rp->sn.uv.activate_gru_mq_desc_gpa;

        /*
         * ??? Is it a good idea to make this conditional on what is
         * ??? potentially stale state information?
         */
        if (part->sn.uv.remote_act_state == XPC_P_AS_INACTIVE) {
                msg.rp_gpa = uv_gpa(xpc_rsvd_page);
                msg.heartbeat_gpa = xpc_rsvd_page->sn.uv.heartbeat_gpa;
                msg.activate_gru_mq_desc_gpa =
                    xpc_rsvd_page->sn.uv.activate_gru_mq_desc_gpa;
                xpc_send_activate_IRQ_part_uv(part, &msg, sizeof(msg),
                                           XPC_ACTIVATE_MQ_MSG_ACTIVATE_REQ_UV);
        }

        if (part->act_state == XPC_P_AS_INACTIVE)
                xpc_send_local_activate_IRQ_uv(part, XPC_P_ASR_ACTIVATE_UV);
}

static void
xpc_request_partition_reactivation_uv(struct xpc_partition *part)
{
        xpc_send_local_activate_IRQ_uv(part, XPC_P_ASR_ACTIVATE_UV);
}

static void
xpc_request_partition_deactivation_uv(struct xpc_partition *part)
{
        struct xpc_activate_mq_msg_deactivate_req_uv msg;

        /*
         * ??? Is it a good idea to make this conditional on what is
         * ??? potentially stale state information?
         */
        if (part->sn.uv.remote_act_state != XPC_P_AS_DEACTIVATING &&
            part->sn.uv.remote_act_state != XPC_P_AS_INACTIVE) {

                msg.reason = part->reason;
                xpc_send_activate_IRQ_part_uv(part, &msg, sizeof(msg),
                                         XPC_ACTIVATE_MQ_MSG_DEACTIVATE_REQ_UV);
        }
}

static void
xpc_cancel_partition_deactivation_request_uv(struct xpc_partition *part)
{
        /* nothing needs to be done */
        return;
}

static void
xpc_init_fifo_uv(struct xpc_fifo_head_uv *head)
{
        head->first = NULL;
        head->last = NULL;
        spin_lock_init(&head->lock);
        head->n_entries = 0;
}

static void *
xpc_get_fifo_entry_uv(struct xpc_fifo_head_uv *head)
{
        unsigned long irq_flags;
        struct xpc_fifo_entry_uv *first;

        spin_lock_irqsave(&head->lock, irq_flags);
        first = head->first;
        if (head->first != NULL) {
                head->first = first->next;
                if (head->first == NULL)
                        head->last = NULL;

                head->n_entries--;
                BUG_ON(head->n_entries < 0);

                first->next = NULL;
        }
        spin_unlock_irqrestore(&head->lock, irq_flags);
        return first;
}

static void
xpc_put_fifo_entry_uv(struct xpc_fifo_head_uv *head,
                      struct xpc_fifo_entry_uv *last)
{
        unsigned long irq_flags;

        last->next = NULL;
        spin_lock_irqsave(&head->lock, irq_flags);
        if (head->last != NULL)
                head->last->next = last;
        else
                head->first = last;
        head->last = last;
        head->n_entries++;
        spin_unlock_irqrestore(&head->lock, irq_flags);
}

static int
xpc_n_of_fifo_entries_uv(struct xpc_fifo_head_uv *head)
{
        return head->n_entries;
}

/*
 * Setup the channel structures that are uv specific.
 */
static enum xp_retval
xpc_setup_ch_structures_uv(struct xpc_partition *part)
{
        struct xpc_channel_uv *ch_uv;
        int ch_number;

        for (ch_number = 0; ch_number < part->nchannels; ch_number++) {
                ch_uv = &part->channels[ch_number].sn.uv;

                xpc_init_fifo_uv(&ch_uv->msg_slot_free_list);
                xpc_init_fifo_uv(&ch_uv->recv_msg_list);
        }

        return xpSuccess;
}

/*
 * Teardown the channel structures that are uv specific.
 */
static void
xpc_teardown_ch_structures_uv(struct xpc_partition *part)
{
        /* nothing needs to be done */
        return;
}

static enum xp_retval
xpc_make_first_contact_uv(struct xpc_partition *part)
{
        struct xpc_activate_mq_msg_uv msg;

        /*
         * We send a sync msg to get the remote partition's remote_act_state
         * updated to our current act_state which at this point should
         * be XPC_P_AS_ACTIVATING.
         */
        xpc_send_activate_IRQ_part_uv(part, &msg, sizeof(msg),
                                      XPC_ACTIVATE_MQ_MSG_SYNC_ACT_STATE_UV);

        while (!((part->sn.uv.remote_act_state == XPC_P_AS_ACTIVATING) ||
                 (part->sn.uv.remote_act_state == XPC_P_AS_ACTIVE))) {

                dev_dbg(xpc_part, "waiting to make first contact with "
                        "partition %d\n", XPC_PARTID(part));

                /* wait a 1/4 of a second or so */
                (void)msleep_interruptible(250);

                if (part->act_state == XPC_P_AS_DEACTIVATING)
                        return part->reason;
        }

        return xpSuccess;
}

static u64
xpc_get_chctl_all_flags_uv(struct xpc_partition *part)
{
        unsigned long irq_flags;
        union xpc_channel_ctl_flags chctl;

        spin_lock_irqsave(&part->chctl_lock, irq_flags);
        chctl = part->chctl;
        if (chctl.all_flags != 0)
                part->chctl.all_flags = 0;

        spin_unlock_irqrestore(&part->chctl_lock, irq_flags);
        return chctl.all_flags;
}

static enum xp_retval
xpc_allocate_send_msg_slot_uv(struct xpc_channel *ch)
{
        struct xpc_channel_uv *ch_uv = &ch->sn.uv;
        struct xpc_send_msg_slot_uv *msg_slot;
        unsigned long irq_flags;
        int nentries;
        int entry;
        size_t nbytes;

        for (nentries = ch->local_nentries; nentries > 0; nentries--) {
                nbytes = nentries * sizeof(struct xpc_send_msg_slot_uv);
                ch_uv->send_msg_slots = kzalloc(nbytes, GFP_KERNEL);
                if (ch_uv->send_msg_slots == NULL)
                        continue;

                for (entry = 0; entry < nentries; entry++) {
                        msg_slot = &ch_uv->send_msg_slots[entry];

                        msg_slot->msg_slot_number = entry;
                        xpc_put_fifo_entry_uv(&ch_uv->msg_slot_free_list,
                                              &msg_slot->next);
                }

                spin_lock_irqsave(&ch->lock, irq_flags);
                if (nentries < ch->local_nentries)
                        ch->local_nentries = nentries;
                spin_unlock_irqrestore(&ch->lock, irq_flags);
                return xpSuccess;
        }

        return xpNoMemory;
}

static enum xp_retval
xpc_allocate_recv_msg_slot_uv(struct xpc_channel *ch)
{
        struct xpc_channel_uv *ch_uv = &ch->sn.uv;
        struct xpc_notify_mq_msg_uv *msg_slot;
        unsigned long irq_flags;
        int nentries;
        int entry;
        size_t nbytes;

        for (nentries = ch->remote_nentries; nentries > 0; nentries--) {
                nbytes = nentries * ch->entry_size;
                ch_uv->recv_msg_slots = kzalloc(nbytes, GFP_KERNEL);
                if (ch_uv->recv_msg_slots == NULL)
                        continue;

                for (entry = 0; entry < nentries; entry++) {
                        msg_slot = ch_uv->recv_msg_slots +
                            entry * ch->entry_size;

                        msg_slot->hdr.msg_slot_number = entry;
                }

                spin_lock_irqsave(&ch->lock, irq_flags);
                if (nentries < ch->remote_nentries)
                        ch->remote_nentries = nentries;
                spin_unlock_irqrestore(&ch->lock, irq_flags);
                return xpSuccess;
        }

        return xpNoMemory;
}

/*
 * Allocate msg_slots associated with the channel.
 */
static enum xp_retval
xpc_setup_msg_structures_uv(struct xpc_channel *ch)
{
        static enum xp_retval ret;
        struct xpc_channel_uv *ch_uv = &ch->sn.uv;

        DBUG_ON(ch->flags & XPC_C_SETUP);

        ch_uv->cached_notify_gru_mq_desc = kmalloc_obj(struct gru_message_queue_desc);
        if (ch_uv->cached_notify_gru_mq_desc == NULL)
                return xpNoMemory;

        ret = xpc_allocate_send_msg_slot_uv(ch);
        if (ret == xpSuccess) {

                ret = xpc_allocate_recv_msg_slot_uv(ch);
                if (ret != xpSuccess) {
                        kfree(ch_uv->send_msg_slots);
                        xpc_init_fifo_uv(&ch_uv->msg_slot_free_list);
                }
        }
        return ret;
}

/*
 * Free up msg_slots and clear other stuff that were setup for the specified
 * channel.
 */
static void
xpc_teardown_msg_structures_uv(struct xpc_channel *ch)
{
        struct xpc_channel_uv *ch_uv = &ch->sn.uv;

        lockdep_assert_held(&ch->lock);

        kfree(ch_uv->cached_notify_gru_mq_desc);
        ch_uv->cached_notify_gru_mq_desc = NULL;

        if (ch->flags & XPC_C_SETUP) {
                xpc_init_fifo_uv(&ch_uv->msg_slot_free_list);
                kfree(ch_uv->send_msg_slots);
                xpc_init_fifo_uv(&ch_uv->recv_msg_list);
                kfree(ch_uv->recv_msg_slots);
        }
}

static void
xpc_send_chctl_closerequest_uv(struct xpc_channel *ch, unsigned long *irq_flags)
{
        struct xpc_activate_mq_msg_chctl_closerequest_uv msg;

        msg.ch_number = ch->number;
        msg.reason = ch->reason;
        xpc_send_activate_IRQ_ch_uv(ch, irq_flags, &msg, sizeof(msg),
                                    XPC_ACTIVATE_MQ_MSG_CHCTL_CLOSEREQUEST_UV);
}

static void
xpc_send_chctl_closereply_uv(struct xpc_channel *ch, unsigned long *irq_flags)
{
        struct xpc_activate_mq_msg_chctl_closereply_uv msg;

        msg.ch_number = ch->number;
        xpc_send_activate_IRQ_ch_uv(ch, irq_flags, &msg, sizeof(msg),
                                    XPC_ACTIVATE_MQ_MSG_CHCTL_CLOSEREPLY_UV);
}

static void
xpc_send_chctl_openrequest_uv(struct xpc_channel *ch, unsigned long *irq_flags)
{
        struct xpc_activate_mq_msg_chctl_openrequest_uv msg;

        msg.ch_number = ch->number;
        msg.entry_size = ch->entry_size;
        msg.local_nentries = ch->local_nentries;
        xpc_send_activate_IRQ_ch_uv(ch, irq_flags, &msg, sizeof(msg),
                                    XPC_ACTIVATE_MQ_MSG_CHCTL_OPENREQUEST_UV);
}

static void
xpc_send_chctl_openreply_uv(struct xpc_channel *ch, unsigned long *irq_flags)
{
        struct xpc_activate_mq_msg_chctl_openreply_uv msg;

        msg.ch_number = ch->number;
        msg.local_nentries = ch->local_nentries;
        msg.remote_nentries = ch->remote_nentries;
        msg.notify_gru_mq_desc_gpa = uv_gpa(xpc_notify_mq_uv->gru_mq_desc);
        xpc_send_activate_IRQ_ch_uv(ch, irq_flags, &msg, sizeof(msg),
                                    XPC_ACTIVATE_MQ_MSG_CHCTL_OPENREPLY_UV);
}

static void
xpc_send_chctl_opencomplete_uv(struct xpc_channel *ch, unsigned long *irq_flags)
{
        struct xpc_activate_mq_msg_chctl_opencomplete_uv msg;

        msg.ch_number = ch->number;
        xpc_send_activate_IRQ_ch_uv(ch, irq_flags, &msg, sizeof(msg),
                                    XPC_ACTIVATE_MQ_MSG_CHCTL_OPENCOMPLETE_UV);
}

static void
xpc_send_chctl_local_msgrequest_uv(struct xpc_partition *part, int ch_number)
{
        unsigned long irq_flags;

        spin_lock_irqsave(&part->chctl_lock, irq_flags);
        part->chctl.flags[ch_number] |= XPC_CHCTL_MSGREQUEST;
        spin_unlock_irqrestore(&part->chctl_lock, irq_flags);

        xpc_wakeup_channel_mgr(part);
}

static enum xp_retval
xpc_save_remote_msgqueue_pa_uv(struct xpc_channel *ch,
                               unsigned long gru_mq_desc_gpa)
{
        struct xpc_channel_uv *ch_uv = &ch->sn.uv;

        DBUG_ON(ch_uv->cached_notify_gru_mq_desc == NULL);
        return xpc_cache_remote_gru_mq_desc_uv(ch_uv->cached_notify_gru_mq_desc,
                                               gru_mq_desc_gpa);
}

static void
xpc_indicate_partition_engaged_uv(struct xpc_partition *part)
{
        struct xpc_activate_mq_msg_uv msg;

        xpc_send_activate_IRQ_part_uv(part, &msg, sizeof(msg),
                                      XPC_ACTIVATE_MQ_MSG_MARK_ENGAGED_UV);
}

static void
xpc_indicate_partition_disengaged_uv(struct xpc_partition *part)
{
        struct xpc_activate_mq_msg_uv msg;

        xpc_send_activate_IRQ_part_uv(part, &msg, sizeof(msg),
                                      XPC_ACTIVATE_MQ_MSG_MARK_DISENGAGED_UV);
}

static void
xpc_assume_partition_disengaged_uv(short partid)
{
        struct xpc_partition_uv *part_uv = &xpc_partitions[partid].sn.uv;
        unsigned long irq_flags;

        spin_lock_irqsave(&part_uv->flags_lock, irq_flags);
        part_uv->flags &= ~XPC_P_ENGAGED_UV;
        spin_unlock_irqrestore(&part_uv->flags_lock, irq_flags);
}

static int
xpc_partition_engaged_uv(short partid)
{
        return (xpc_partitions[partid].sn.uv.flags & XPC_P_ENGAGED_UV) != 0;
}

static int
xpc_any_partition_engaged_uv(void)
{
        struct xpc_partition_uv *part_uv;
        short partid;

        for (partid = 0; partid < XP_MAX_NPARTITIONS_UV; partid++) {
                part_uv = &xpc_partitions[partid].sn.uv;
                if ((part_uv->flags & XPC_P_ENGAGED_UV) != 0)
                        return 1;
        }
        return 0;
}

static enum xp_retval
xpc_allocate_msg_slot_uv(struct xpc_channel *ch, u32 flags,
                         struct xpc_send_msg_slot_uv **address_of_msg_slot)
{
        enum xp_retval ret;
        struct xpc_send_msg_slot_uv *msg_slot;
        struct xpc_fifo_entry_uv *entry;

        while (1) {
                entry = xpc_get_fifo_entry_uv(&ch->sn.uv.msg_slot_free_list);
                if (entry != NULL)
                        break;

                if (flags & XPC_NOWAIT)
                        return xpNoWait;

                ret = xpc_allocate_msg_wait(ch);
                if (ret != xpInterrupted && ret != xpTimeout)
                        return ret;
        }

        msg_slot = container_of(entry, struct xpc_send_msg_slot_uv, next);
        *address_of_msg_slot = msg_slot;
        return xpSuccess;
}

static void
xpc_free_msg_slot_uv(struct xpc_channel *ch,
                     struct xpc_send_msg_slot_uv *msg_slot)
{
        xpc_put_fifo_entry_uv(&ch->sn.uv.msg_slot_free_list, &msg_slot->next);

        /* wakeup anyone waiting for a free msg slot */
        if (atomic_read(&ch->n_on_msg_allocate_wq) > 0)
                wake_up(&ch->msg_allocate_wq);
}

static void
xpc_notify_sender_uv(struct xpc_channel *ch,
                     struct xpc_send_msg_slot_uv *msg_slot,
                     enum xp_retval reason)
{
        xpc_notify_func func = msg_slot->func;

        if (func != NULL && cmpxchg(&msg_slot->func, func, NULL) == func) {

                atomic_dec(&ch->n_to_notify);

                dev_dbg(xpc_chan, "msg_slot->func() called, msg_slot=0x%p "
                        "msg_slot_number=%d partid=%d channel=%d\n", msg_slot,
                        msg_slot->msg_slot_number, ch->partid, ch->number);

                func(reason, ch->partid, ch->number, msg_slot->key);

                dev_dbg(xpc_chan, "msg_slot->func() returned, msg_slot=0x%p "
                        "msg_slot_number=%d partid=%d channel=%d\n", msg_slot,
                        msg_slot->msg_slot_number, ch->partid, ch->number);
        }
}

static void
xpc_handle_notify_mq_ack_uv(struct xpc_channel *ch,
                            struct xpc_notify_mq_msg_uv *msg)
{
        struct xpc_send_msg_slot_uv *msg_slot;
        int entry = msg->hdr.msg_slot_number % ch->local_nentries;

        msg_slot = &ch->sn.uv.send_msg_slots[entry];

        BUG_ON(msg_slot->msg_slot_number != msg->hdr.msg_slot_number);
        msg_slot->msg_slot_number += ch->local_nentries;

        if (msg_slot->func != NULL)
                xpc_notify_sender_uv(ch, msg_slot, xpMsgDelivered);

        xpc_free_msg_slot_uv(ch, msg_slot);
}

static void
xpc_handle_notify_mq_msg_uv(struct xpc_partition *part,
                            struct xpc_notify_mq_msg_uv *msg)
{
        struct xpc_partition_uv *part_uv = &part->sn.uv;
        struct xpc_channel *ch;
        struct xpc_channel_uv *ch_uv;
        struct xpc_notify_mq_msg_uv *msg_slot;
        unsigned long irq_flags;
        int ch_number = msg->hdr.ch_number;

        if (unlikely(ch_number >= part->nchannels)) {
                dev_err(xpc_part, "xpc_handle_notify_IRQ_uv() received invalid "
                        "channel number=0x%x in message from partid=%d\n",
                        ch_number, XPC_PARTID(part));

                /* get hb checker to deactivate from the remote partition */
                spin_lock_irqsave(&xpc_activate_IRQ_rcvd_lock, irq_flags);
                if (part_uv->act_state_req == 0)
                        xpc_activate_IRQ_rcvd++;
                part_uv->act_state_req = XPC_P_ASR_DEACTIVATE_UV;
                part_uv->reason = xpBadChannelNumber;
                spin_unlock_irqrestore(&xpc_activate_IRQ_rcvd_lock, irq_flags);

                wake_up_interruptible(&xpc_activate_IRQ_wq);
                return;
        }

        ch = &part->channels[ch_number];
        xpc_msgqueue_ref(ch);

        if (!(ch->flags & XPC_C_CONNECTED)) {
                xpc_msgqueue_deref(ch);
                return;
        }

        /* see if we're really dealing with an ACK for a previously sent msg */
        if (msg->hdr.size == 0) {
                xpc_handle_notify_mq_ack_uv(ch, msg);
                xpc_msgqueue_deref(ch);
                return;
        }

        /* we're dealing with a normal message sent via the notify_mq */
        ch_uv = &ch->sn.uv;

        msg_slot = ch_uv->recv_msg_slots +
            (msg->hdr.msg_slot_number % ch->remote_nentries) * ch->entry_size;

        BUG_ON(msg_slot->hdr.size != 0);

        memcpy(msg_slot, msg, msg->hdr.size);

        xpc_put_fifo_entry_uv(&ch_uv->recv_msg_list, &msg_slot->hdr.u.next);

        if (ch->flags & XPC_C_CONNECTEDCALLOUT_MADE) {
                /*
                 * If there is an existing idle kthread get it to deliver
                 * the payload, otherwise we'll have to get the channel mgr
                 * for this partition to create a kthread to do the delivery.
                 */
                if (atomic_read(&ch->kthreads_idle) > 0)
                        wake_up_nr(&ch->idle_wq, 1);
                else
                        xpc_send_chctl_local_msgrequest_uv(part, ch->number);
        }
        xpc_msgqueue_deref(ch);
}

static irqreturn_t
xpc_handle_notify_IRQ_uv(int irq, void *dev_id)
{
        struct xpc_notify_mq_msg_uv *msg;
        short partid;
        struct xpc_partition *part;

        while ((msg = gru_get_next_message(xpc_notify_mq_uv->gru_mq_desc)) !=
               NULL) {

                partid = msg->hdr.partid;
                if (partid < 0 || partid >= XP_MAX_NPARTITIONS_UV) {
                        dev_err(xpc_part, "xpc_handle_notify_IRQ_uv() received "
                                "invalid partid=0x%x in message\n", partid);
                } else {
                        part = &xpc_partitions[partid];

                        if (xpc_part_ref(part)) {
                                xpc_handle_notify_mq_msg_uv(part, msg);
                                xpc_part_deref(part);
                        }
                }

                gru_free_message(xpc_notify_mq_uv->gru_mq_desc, msg);
        }

        return IRQ_HANDLED;
}

static int
xpc_n_of_deliverable_payloads_uv(struct xpc_channel *ch)
{
        return xpc_n_of_fifo_entries_uv(&ch->sn.uv.recv_msg_list);
}

static void
xpc_process_msg_chctl_flags_uv(struct xpc_partition *part, int ch_number)
{
        struct xpc_channel *ch = &part->channels[ch_number];
        int ndeliverable_payloads;

        xpc_msgqueue_ref(ch);

        ndeliverable_payloads = xpc_n_of_deliverable_payloads_uv(ch);

        if (ndeliverable_payloads > 0 &&
            (ch->flags & XPC_C_CONNECTED) &&
            (ch->flags & XPC_C_CONNECTEDCALLOUT_MADE)) {

                xpc_activate_kthreads(ch, ndeliverable_payloads);
        }

        xpc_msgqueue_deref(ch);
}

static enum xp_retval
xpc_send_payload_uv(struct xpc_channel *ch, u32 flags, void *payload,
                    u16 payload_size, u8 notify_type, xpc_notify_func func,
                    void *key)
{
        enum xp_retval ret = xpSuccess;
        struct xpc_send_msg_slot_uv *msg_slot = NULL;
        struct xpc_notify_mq_msg_uv *msg;
        u8 msg_buffer[XPC_NOTIFY_MSG_SIZE_UV];
        size_t msg_size;

        DBUG_ON(notify_type != XPC_N_CALL);

        msg_size = sizeof(struct xpc_notify_mq_msghdr_uv) + payload_size;
        if (msg_size > ch->entry_size)
                return xpPayloadTooBig;

        xpc_msgqueue_ref(ch);

        if (ch->flags & XPC_C_DISCONNECTING) {
                ret = ch->reason;
                goto out_1;
        }
        if (!(ch->flags & XPC_C_CONNECTED)) {
                ret = xpNotConnected;
                goto out_1;
        }

        ret = xpc_allocate_msg_slot_uv(ch, flags, &msg_slot);
        if (ret != xpSuccess)
                goto out_1;

        if (func != NULL) {
                atomic_inc(&ch->n_to_notify);

                msg_slot->key = key;
                smp_wmb(); /* a non-NULL func must hit memory after the key */
                msg_slot->func = func;

                if (ch->flags & XPC_C_DISCONNECTING) {
                        ret = ch->reason;
                        goto out_2;
                }
        }

        msg = (struct xpc_notify_mq_msg_uv *)&msg_buffer;
        msg->hdr.partid = xp_partition_id;
        msg->hdr.ch_number = ch->number;
        msg->hdr.size = msg_size;
        msg->hdr.msg_slot_number = msg_slot->msg_slot_number;
        memcpy(&msg->payload, payload, payload_size);

        ret = xpc_send_gru_msg(ch->sn.uv.cached_notify_gru_mq_desc, msg,
                               msg_size);
        if (ret == xpSuccess)
                goto out_1;

        XPC_DEACTIVATE_PARTITION(&xpc_partitions[ch->partid], ret);
out_2:
        if (func != NULL) {
                /*
                 * Try to NULL the msg_slot's func field. If we fail, then
                 * xpc_notify_senders_of_disconnect_uv() beat us to it, in which
                 * case we need to pretend we succeeded to send the message
                 * since the user will get a callout for the disconnect error
                 * by xpc_notify_senders_of_disconnect_uv(), and to also get an
                 * error returned here will confuse them. Additionally, since
                 * in this case the channel is being disconnected we don't need
                 * to put the msg_slot back on the free list.
                 */
                if (cmpxchg(&msg_slot->func, func, NULL) != func) {
                        ret = xpSuccess;
                        goto out_1;
                }

                msg_slot->key = NULL;
                atomic_dec(&ch->n_to_notify);
        }
        xpc_free_msg_slot_uv(ch, msg_slot);
out_1:
        xpc_msgqueue_deref(ch);
        return ret;
}

/*
 * Tell the callers of xpc_send_notify() that the status of their payloads
 * is unknown because the channel is now disconnecting.
 *
 * We don't worry about putting these msg_slots on the free list since the
 * msg_slots themselves are about to be kfree'd.
 */
static void
xpc_notify_senders_of_disconnect_uv(struct xpc_channel *ch)
{
        struct xpc_send_msg_slot_uv *msg_slot;
        int entry;

        DBUG_ON(!(ch->flags & XPC_C_DISCONNECTING));

        for (entry = 0; entry < ch->local_nentries; entry++) {

                if (atomic_read(&ch->n_to_notify) == 0)
                        break;

                msg_slot = &ch->sn.uv.send_msg_slots[entry];
                if (msg_slot->func != NULL)
                        xpc_notify_sender_uv(ch, msg_slot, ch->reason);
        }
}

/*
 * Get the next deliverable message's payload.
 */
static void *
xpc_get_deliverable_payload_uv(struct xpc_channel *ch)
{
        struct xpc_fifo_entry_uv *entry;
        struct xpc_notify_mq_msg_uv *msg;
        void *payload = NULL;

        if (!(ch->flags & XPC_C_DISCONNECTING)) {
                entry = xpc_get_fifo_entry_uv(&ch->sn.uv.recv_msg_list);
                if (entry != NULL) {
                        msg = container_of(entry, struct xpc_notify_mq_msg_uv,
                                           hdr.u.next);
                        payload = &msg->payload;
                }
        }
        return payload;
}

static void
xpc_received_payload_uv(struct xpc_channel *ch, void *payload)
{
        struct xpc_notify_mq_msg_uv *msg;
        enum xp_retval ret;

        msg = container_of(payload, struct xpc_notify_mq_msg_uv, payload);

        /* return an ACK to the sender of this message */

        msg->hdr.partid = xp_partition_id;
        msg->hdr.size = 0;      /* size of zero indicates this is an ACK */

        ret = xpc_send_gru_msg(ch->sn.uv.cached_notify_gru_mq_desc, msg,
                               sizeof(struct xpc_notify_mq_msghdr_uv));
        if (ret != xpSuccess)
                XPC_DEACTIVATE_PARTITION(&xpc_partitions[ch->partid], ret);
}

static const struct xpc_arch_operations xpc_arch_ops_uv = {
        .setup_partitions = xpc_setup_partitions_uv,
        .teardown_partitions = xpc_teardown_partitions_uv,
        .process_activate_IRQ_rcvd = xpc_process_activate_IRQ_rcvd_uv,
        .get_partition_rsvd_page_pa = xpc_get_partition_rsvd_page_pa_uv,
        .setup_rsvd_page = xpc_setup_rsvd_page_uv,

        .allow_hb = xpc_allow_hb_uv,
        .disallow_hb = xpc_disallow_hb_uv,
        .disallow_all_hbs = xpc_disallow_all_hbs_uv,
        .increment_heartbeat = xpc_increment_heartbeat_uv,
        .offline_heartbeat = xpc_offline_heartbeat_uv,
        .online_heartbeat = xpc_online_heartbeat_uv,
        .heartbeat_init = xpc_heartbeat_init_uv,
        .heartbeat_exit = xpc_heartbeat_exit_uv,
        .get_remote_heartbeat = xpc_get_remote_heartbeat_uv,

        .request_partition_activation =
                xpc_request_partition_activation_uv,
        .request_partition_reactivation =
                xpc_request_partition_reactivation_uv,
        .request_partition_deactivation =
                xpc_request_partition_deactivation_uv,
        .cancel_partition_deactivation_request =
                xpc_cancel_partition_deactivation_request_uv,

        .setup_ch_structures = xpc_setup_ch_structures_uv,
        .teardown_ch_structures = xpc_teardown_ch_structures_uv,

        .make_first_contact = xpc_make_first_contact_uv,

        .get_chctl_all_flags = xpc_get_chctl_all_flags_uv,
        .send_chctl_closerequest = xpc_send_chctl_closerequest_uv,
        .send_chctl_closereply = xpc_send_chctl_closereply_uv,
        .send_chctl_openrequest = xpc_send_chctl_openrequest_uv,
        .send_chctl_openreply = xpc_send_chctl_openreply_uv,
        .send_chctl_opencomplete = xpc_send_chctl_opencomplete_uv,
        .process_msg_chctl_flags = xpc_process_msg_chctl_flags_uv,

        .save_remote_msgqueue_pa = xpc_save_remote_msgqueue_pa_uv,

        .setup_msg_structures = xpc_setup_msg_structures_uv,
        .teardown_msg_structures = xpc_teardown_msg_structures_uv,

        .indicate_partition_engaged = xpc_indicate_partition_engaged_uv,
        .indicate_partition_disengaged = xpc_indicate_partition_disengaged_uv,
        .assume_partition_disengaged = xpc_assume_partition_disengaged_uv,
        .partition_engaged = xpc_partition_engaged_uv,
        .any_partition_engaged = xpc_any_partition_engaged_uv,

        .n_of_deliverable_payloads = xpc_n_of_deliverable_payloads_uv,
        .send_payload = xpc_send_payload_uv,
        .get_deliverable_payload = xpc_get_deliverable_payload_uv,
        .received_payload = xpc_received_payload_uv,
        .notify_senders_of_disconnect = xpc_notify_senders_of_disconnect_uv,
};

static int
xpc_init_mq_node(int nid)
{
        int cpu;

        cpus_read_lock();

        for_each_cpu(cpu, cpumask_of_node(nid)) {
                xpc_activate_mq_uv =
                        xpc_create_gru_mq_uv(XPC_ACTIVATE_MQ_SIZE_UV, nid,
                                             XPC_ACTIVATE_IRQ_NAME,
                                             xpc_handle_activate_IRQ_uv);
                if (!IS_ERR(xpc_activate_mq_uv))
                        break;
        }
        if (IS_ERR(xpc_activate_mq_uv)) {
                cpus_read_unlock();
                return PTR_ERR(xpc_activate_mq_uv);
        }

        for_each_cpu(cpu, cpumask_of_node(nid)) {
                xpc_notify_mq_uv =
                        xpc_create_gru_mq_uv(XPC_NOTIFY_MQ_SIZE_UV, nid,
                                             XPC_NOTIFY_IRQ_NAME,
                                             xpc_handle_notify_IRQ_uv);
                if (!IS_ERR(xpc_notify_mq_uv))
                        break;
        }
        if (IS_ERR(xpc_notify_mq_uv)) {
                xpc_destroy_gru_mq_uv(xpc_activate_mq_uv);
                cpus_read_unlock();
                return PTR_ERR(xpc_notify_mq_uv);
        }

        cpus_read_unlock();
        return 0;
}

int
xpc_init_uv(void)
{
        int nid;
        int ret = 0;

        xpc_arch_ops = xpc_arch_ops_uv;

        if (sizeof(struct xpc_notify_mq_msghdr_uv) > XPC_MSG_HDR_MAX_SIZE) {
                dev_err(xpc_part, "xpc_notify_mq_msghdr_uv is larger than %d\n",
                        XPC_MSG_HDR_MAX_SIZE);
                return -E2BIG;
        }

        if (xpc_mq_node < 0)
                for_each_online_node(nid) {
                        ret = xpc_init_mq_node(nid);

                        if (!ret)
                                break;
                }
        else
                ret = xpc_init_mq_node(xpc_mq_node);

        if (ret < 0)
                dev_err(xpc_part, "xpc_init_mq_node() returned error=%d\n",
                        -ret);

        return ret;
}

void
xpc_exit_uv(void)
{
        xpc_destroy_gru_mq_uv(xpc_notify_mq_uv);
        xpc_destroy_gru_mq_uv(xpc_activate_mq_uv);
}

module_param(xpc_mq_node, int, 0);
MODULE_PARM_DESC(xpc_mq_node, "Node number on which to allocate message queues.");