bwlp/qemu.git - Experimental fork of QEMU with video encoding patches

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/*
 * Inter-VM Shared Memory PCI device.
 *
 * Author:
 *      Cam Macdonell <cam@cs.ualberta.ca>
 *
 * Based On: cirrus_vga.c
 *          Copyright (c) 2004 Fabrice Bellard
 *          Copyright (c) 2004 Makoto Suzuki (suzu)
 *
 *      and rtl8139.c
 *          Copyright (c) 2006 Igor Kovalenko
 *
 * This code is licensed under the GNU GPL v2.
 *
 * Contributions after 2012-01-13 are licensed under the terms of the
 * GNU GPL, version 2 or (at your option) any later version.
 */
#include "qemu/osdep.h"
#include "hw/hw.h"
#include "hw/i386/pc.h"
#include "hw/pci/pci.h"
#include "hw/pci/msi.h"
#include "hw/pci/msix.h"
#include "sysemu/kvm.h"
#include "migration/migration.h"
#include "qemu/error-report.h"
#include "qemu/event_notifier.h"
#include "qemu/fifo8.h"
#include "sysemu/char.h"
#include "sysemu/hostmem.h"
#include "qapi/visitor.h"
#include "exec/ram_addr.h"

#include "hw/misc/ivshmem.h"

#include <sys/mman.h>

#define PCI_VENDOR_ID_IVSHMEM   PCI_VENDOR_ID_REDHAT_QUMRANET
#define PCI_DEVICE_ID_IVSHMEM   0x1110

#define IVSHMEM_MAX_PEERS G_MAXUINT16
#define IVSHMEM_IOEVENTFD   0
#define IVSHMEM_MSI     1

#define IVSHMEM_PEER    0
#define IVSHMEM_MASTER  1

#define IVSHMEM_REG_BAR_SIZE 0x100

#define IVSHMEM_DEBUG 0
#define IVSHMEM_DPRINTF(fmt, ...)                       \
    do {                                                \
        if (IVSHMEM_DEBUG) {                            \
            printf("IVSHMEM: " fmt, ## __VA_ARGS__);    \
        }                                               \
    } while (0)

#define TYPE_IVSHMEM "ivshmem"
#define IVSHMEM(obj) \
    OBJECT_CHECK(IVShmemState, (obj), TYPE_IVSHMEM)

typedef struct Peer {
    int nb_eventfds;
    EventNotifier *eventfds;
} Peer;

typedef struct MSIVector {
    PCIDevice *pdev;
    int virq;
} MSIVector;

typedef struct IVShmemState {
    /*< private >*/
    PCIDevice parent_obj;
    /*< public >*/

    HostMemoryBackend *hostmem;
    uint32_t intrmask;
    uint32_t intrstatus;

    CharDriverState **eventfd_chr;
    CharDriverState *server_chr;
    Fifo8 incoming_fifo;
    MemoryRegion ivshmem_mmio;

    /* We might need to register the BAR before we actually have the memory.
     * So prepare a container MemoryRegion for the BAR immediately and
     * add a subregion when we have the memory.
     */
    MemoryRegion bar;
    MemoryRegion ivshmem;
    uint64_t ivshmem_size; /* size of shared memory region */
    uint32_t ivshmem_64bit;

    Peer *peers;
    int nb_peers; /* how many peers we have space for */

    int vm_id;
    uint32_t vectors;
    uint32_t features;
    MSIVector *msi_vectors;

    Error *migration_blocker;

    char * shmobj;
    char * sizearg;
    char * role;
    int role_val;   /* scalar to avoid multiple string comparisons */
} IVShmemState;

/* registers for the Inter-VM shared memory device */
enum ivshmem_registers {
    INTRMASK = 0,
    INTRSTATUS = 4,
    IVPOSITION = 8,
    DOORBELL = 12,
};

static inline uint32_t ivshmem_has_feature(IVShmemState *ivs,
                                                    unsigned int feature) {
    return (ivs->features & (1 << feature));
}

/* accessing registers - based on rtl8139 */
static void ivshmem_update_irq(IVShmemState *s)
{
    PCIDevice *d = PCI_DEVICE(s);
    int isr;
    isr = (s->intrstatus & s->intrmask) & 0xffffffff;

    /* don't print ISR resets */
    if (isr) {
        IVSHMEM_DPRINTF("Set IRQ to %d (%04x %04x)\n",
                        isr ? 1 : 0, s->intrstatus, s->intrmask);
    }

    pci_set_irq(d, (isr != 0));
}

static void ivshmem_IntrMask_write(IVShmemState *s, uint32_t val)
{
    IVSHMEM_DPRINTF("IntrMask write(w) val = 0x%04x\n", val);

    s->intrmask = val;

    ivshmem_update_irq(s);
}

static uint32_t ivshmem_IntrMask_read(IVShmemState *s)
{
    uint32_t ret = s->intrmask;

    IVSHMEM_DPRINTF("intrmask read(w) val = 0x%04x\n", ret);

    return ret;
}

static void ivshmem_IntrStatus_write(IVShmemState *s, uint32_t val)
{
    IVSHMEM_DPRINTF("IntrStatus write(w) val = 0x%04x\n", val);

    s->intrstatus = val;

    ivshmem_update_irq(s);
}

static uint32_t ivshmem_IntrStatus_read(IVShmemState *s)
{
    uint32_t ret = s->intrstatus;

    /* reading ISR clears all interrupts */
    s->intrstatus = 0;

    ivshmem_update_irq(s);

    return ret;
}

static void ivshmem_io_write(void *opaque, hwaddr addr,
                             uint64_t val, unsigned size)
{
    IVShmemState *s = opaque;

    uint16_t dest = val >> 16;
    uint16_t vector = val & 0xff;

    addr &= 0xfc;

    IVSHMEM_DPRINTF("writing to addr " TARGET_FMT_plx "\n", addr);
    switch (addr)
    {
        case INTRMASK:
            ivshmem_IntrMask_write(s, val);
            break;

        case INTRSTATUS:
            ivshmem_IntrStatus_write(s, val);
            break;

        case DOORBELL:
            /* check that dest VM ID is reasonable */
            if (dest >= s->nb_peers) {
                IVSHMEM_DPRINTF("Invalid destination VM ID (%d)\n", dest);
                break;
            }

            /* check doorbell range */
            if (vector < s->peers[dest].nb_eventfds) {
                IVSHMEM_DPRINTF("Notifying VM %d on vector %d\n", dest, vector);
                event_notifier_set(&s->peers[dest].eventfds[vector]);
            } else {
                IVSHMEM_DPRINTF("Invalid destination vector %d on VM %d\n",
                                vector, dest);
            }
            break;
        default:
            IVSHMEM_DPRINTF("Unhandled write " TARGET_FMT_plx "\n", addr);
    }
}

static uint64_t ivshmem_io_read(void *opaque, hwaddr addr,
                                unsigned size)
{

    IVShmemState *s = opaque;
    uint32_t ret;

    switch (addr)
    {
        case INTRMASK:
            ret = ivshmem_IntrMask_read(s);
            break;

        case INTRSTATUS:
            ret = ivshmem_IntrStatus_read(s);
            break;

        case IVPOSITION:
            /* return my VM ID if the memory is mapped */
            if (memory_region_is_mapped(&s->ivshmem)) {
                ret = s->vm_id;
            } else {
                ret = -1;
            }
            break;

        default:
            IVSHMEM_DPRINTF("why are we reading " TARGET_FMT_plx "\n", addr);
            ret = 0;
    }

    return ret;
}

static const MemoryRegionOps ivshmem_mmio_ops = {
    .read = ivshmem_io_read,
    .write = ivshmem_io_write,
    .endianness = DEVICE_NATIVE_ENDIAN,
    .impl = {
        .min_access_size = 4,
        .max_access_size = 4,
    },
};

static int ivshmem_can_receive(void * opaque)
{
    return sizeof(int64_t);
}

static void ivshmem_event(void *opaque, int event)
{
    IVSHMEM_DPRINTF("ivshmem_event %d\n", event);
}

static void ivshmem_vector_notify(void *opaque)
{
    MSIVector *entry = opaque;
    PCIDevice *pdev = entry->pdev;
    IVShmemState *s = IVSHMEM(pdev);
    int vector = entry - s->msi_vectors;
    EventNotifier *n = &s->peers[s->vm_id].eventfds[vector];

    if (!event_notifier_test_and_clear(n)) {
        return;
    }

    IVSHMEM_DPRINTF("interrupt on vector %p %d\n", pdev, vector);
    if (ivshmem_has_feature(s, IVSHMEM_MSI)) {
        msix_notify(pdev, vector);
    } else {
        ivshmem_IntrStatus_write(s, 1);
    }
}

static int ivshmem_vector_unmask(PCIDevice *dev, unsigned vector,
                                 MSIMessage msg)
{
    IVShmemState *s = IVSHMEM(dev);
    EventNotifier *n = &s->peers[s->vm_id].eventfds[vector];
    MSIVector *v = &s->msi_vectors[vector];
    int ret;

    IVSHMEM_DPRINTF("vector unmask %p %d\n", dev, vector);

    ret = kvm_irqchip_update_msi_route(kvm_state, v->virq, msg, dev);
    if (ret < 0) {
        return ret;
    }

    return kvm_irqchip_add_irqfd_notifier_gsi(kvm_state, n, NULL, v->virq);
}

static void ivshmem_vector_mask(PCIDevice *dev, unsigned vector)
{
    IVShmemState *s = IVSHMEM(dev);
    EventNotifier *n = &s->peers[s->vm_id].eventfds[vector];
    int ret;

    IVSHMEM_DPRINTF("vector mask %p %d\n", dev, vector);

    ret = kvm_irqchip_remove_irqfd_notifier_gsi(kvm_state, n,
                                                s->msi_vectors[vector].virq);
    if (ret != 0) {
        error_report("remove_irqfd_notifier_gsi failed");
    }
}

static void ivshmem_vector_poll(PCIDevice *dev,
                                unsigned int vector_start,
                                unsigned int vector_end)
{
    IVShmemState *s = IVSHMEM(dev);
    unsigned int vector;

    IVSHMEM_DPRINTF("vector poll %p %d-%d\n", dev, vector_start, vector_end);

    vector_end = MIN(vector_end, s->vectors);

    for (vector = vector_start; vector < vector_end; vector++) {
        EventNotifier *notifier = &s->peers[s->vm_id].eventfds[vector];

        if (!msix_is_masked(dev, vector)) {
            continue;
        }

        if (event_notifier_test_and_clear(notifier)) {
            msix_set_pending(dev, vector);
        }
    }
}

static void watch_vector_notifier(IVShmemState *s, EventNotifier *n,
                                 int vector)
{
    int eventfd = event_notifier_get_fd(n);

    /* if MSI is supported we need multiple interrupts */
    s->msi_vectors[vector].pdev = PCI_DEVICE(s);

    qemu_set_fd_handler(eventfd, ivshmem_vector_notify,
                        NULL, &s->msi_vectors[vector]);
}

static int check_shm_size(IVShmemState *s, int fd, Error **errp)
{
    /* check that the guest isn't going to try and map more memory than the
     * the object has allocated return -1 to indicate error */

    struct stat buf;

    if (fstat(fd, &buf) < 0) {
        error_setg(errp, "exiting: fstat on fd %d failed: %s",
                   fd, strerror(errno));
        return -1;
    }

    if (s->ivshmem_size > buf.st_size) {
        error_setg(errp, "Requested memory size greater"
                   " than shared object size (%" PRIu64 " > %" PRIu64")",
                   s->ivshmem_size, (uint64_t)buf.st_size);
        return -1;
    } else {
        return 0;
    }
}

/* create the shared memory BAR when we are not using the server, so we can
 * create the BAR and map the memory immediately */
static int create_shared_memory_BAR(IVShmemState *s, int fd, uint8_t attr,
                                    Error **errp)
{
    void * ptr;

    ptr = mmap(0, s->ivshmem_size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
    if (ptr == MAP_FAILED) {
        error_setg_errno(errp, errno, "Failed to mmap shared memory");
        return -1;
    }

    memory_region_init_ram_ptr(&s->ivshmem, OBJECT(s), "ivshmem.bar2",
                               s->ivshmem_size, ptr);
    qemu_set_ram_fd(memory_region_get_ram_addr(&s->ivshmem), fd);
    vmstate_register_ram(&s->ivshmem, DEVICE(s));
    memory_region_add_subregion(&s->bar, 0, &s->ivshmem);

    /* region for shared memory */
    pci_register_bar(PCI_DEVICE(s), 2, attr, &s->bar);

    return 0;
}

static void ivshmem_add_eventfd(IVShmemState *s, int posn, int i)
{
    memory_region_add_eventfd(&s->ivshmem_mmio,
                              DOORBELL,
                              4,
                              true,
                              (posn << 16) | i,
                              &s->peers[posn].eventfds[i]);
}

static void ivshmem_del_eventfd(IVShmemState *s, int posn, int i)
{
    memory_region_del_eventfd(&s->ivshmem_mmio,
                              DOORBELL,
                              4,
                              true,
                              (posn << 16) | i,
                              &s->peers[posn].eventfds[i]);
}

static void close_peer_eventfds(IVShmemState *s, int posn)
{
    int i, n;

    if (!ivshmem_has_feature(s, IVSHMEM_IOEVENTFD)) {
        return;
    }
    if (posn < 0 || posn >= s->nb_peers) {
        error_report("invalid peer %d", posn);
        return;
    }

    n = s->peers[posn].nb_eventfds;

    memory_region_transaction_begin();
    for (i = 0; i < n; i++) {
        ivshmem_del_eventfd(s, posn, i);
    }
    memory_region_transaction_commit();
    for (i = 0; i < n; i++) {
        event_notifier_cleanup(&s->peers[posn].eventfds[i]);
    }

    g_free(s->peers[posn].eventfds);
    s->peers[posn].nb_eventfds = 0;
}

/* this function increase the dynamic storage need to store data about other
 * peers */
static int resize_peers(IVShmemState *s, int new_min_size)
{

    int j, old_size;

    /* limit number of max peers */
    if (new_min_size <= 0 || new_min_size > IVSHMEM_MAX_PEERS) {
        return -1;
    }
    if (new_min_size <= s->nb_peers) {
        return 0;
    }

    old_size = s->nb_peers;
    s->nb_peers = new_min_size;

    IVSHMEM_DPRINTF("bumping storage to %d peers\n", s->nb_peers);

    s->peers = g_realloc(s->peers, s->nb_peers * sizeof(Peer));

    for (j = old_size; j < s->nb_peers; j++) {
        s->peers[j].eventfds = g_new0(EventNotifier, s->vectors);
        s->peers[j].nb_eventfds = 0;
    }

    return 0;
}

static bool fifo_update_and_get(IVShmemState *s, const uint8_t *buf, int size,
                                void *data, size_t len)
{
    const uint8_t *p;
    uint32_t num;

    assert(len <= sizeof(int64_t)); /* limitation of the fifo */
    if (fifo8_is_empty(&s->incoming_fifo) && size == len) {
        memcpy(data, buf, size);
        return true;
    }

    IVSHMEM_DPRINTF("short read of %d bytes\n", size);

    num = MIN(size, sizeof(int64_t) - fifo8_num_used(&s->incoming_fifo));
    fifo8_push_all(&s->incoming_fifo, buf, num);

    if (fifo8_num_used(&s->incoming_fifo) < len) {
        assert(num == 0);
        return false;
    }

    size -= num;
    buf += num;
    p = fifo8_pop_buf(&s->incoming_fifo, len, &num);
    assert(num == len);

    memcpy(data, p, len);

    if (size > 0) {
        fifo8_push_all(&s->incoming_fifo, buf, size);
    }

    return true;
}

static bool fifo_update_and_get_i64(IVShmemState *s,
                                    const uint8_t *buf, int size, int64_t *i64)
{
    if (fifo_update_and_get(s, buf, size, i64, sizeof(*i64))) {
        *i64 = GINT64_FROM_LE(*i64);
        return true;
    }

    return false;
}

static int ivshmem_add_kvm_msi_virq(IVShmemState *s, int vector)
{
    PCIDevice *pdev = PCI_DEVICE(s);
    MSIMessage msg = msix_get_message(pdev, vector);
    int ret;

    IVSHMEM_DPRINTF("ivshmem_add_kvm_msi_virq vector:%d\n", vector);

    if (s->msi_vectors[vector].pdev != NULL) {
        return 0;
    }

    ret = kvm_irqchip_add_msi_route(kvm_state, msg, pdev);
    if (ret < 0) {
        error_report("ivshmem: kvm_irqchip_add_msi_route failed");
        return -1;
    }

    s->msi_vectors[vector].virq = ret;
    s->msi_vectors[vector].pdev = pdev;

    return 0;
}

static void setup_interrupt(IVShmemState *s, int vector)
{
    EventNotifier *n = &s->peers[s->vm_id].eventfds[vector];
    bool with_irqfd = kvm_msi_via_irqfd_enabled() &&
        ivshmem_has_feature(s, IVSHMEM_MSI);
    PCIDevice *pdev = PCI_DEVICE(s);

    IVSHMEM_DPRINTF("setting up interrupt for vector: %d\n", vector);

    if (!with_irqfd) {
        IVSHMEM_DPRINTF("with eventfd\n");
        watch_vector_notifier(s, n, vector);
    } else if (msix_enabled(pdev)) {
        IVSHMEM_DPRINTF("with irqfd\n");
        if (ivshmem_add_kvm_msi_virq(s, vector) < 0) {
            return;
        }

        if (!msix_is_masked(pdev, vector)) {
            kvm_irqchip_add_irqfd_notifier_gsi(kvm_state, n, NULL,
                                               s->msi_vectors[vector].virq);
        }
    } else {
        /* it will be delayed until msix is enabled, in write_config */
        IVSHMEM_DPRINTF("with irqfd, delayed until msix enabled\n");
    }
}

static void ivshmem_read(void *opaque, const uint8_t *buf, int size)
{
    IVShmemState *s = opaque;
    int incoming_fd;
    int new_eventfd;
    int64_t incoming_posn;
    Error *err = NULL;
    Peer *peer;

    if (!fifo_update_and_get_i64(s, buf, size, &incoming_posn)) {
        return;
    }

    if (incoming_posn < -1) {
        IVSHMEM_DPRINTF("invalid incoming_posn %" PRId64 "\n", incoming_posn);
        return;
    }

    /* pick off s->server_chr->msgfd and store it, posn should accompany msg */
    incoming_fd = qemu_chr_fe_get_msgfd(s->server_chr);
    IVSHMEM_DPRINTF("posn is %" PRId64 ", fd is %d\n",
                    incoming_posn, incoming_fd);

    /* make sure we have enough space for this peer */
    if (incoming_posn >= s->nb_peers) {
        if (resize_peers(s, incoming_posn + 1) < 0) {
            error_report("failed to resize peers array");
            if (incoming_fd != -1) {
                close(incoming_fd);
            }
            return;
        }
    }

    peer = &s->peers[incoming_posn];

    if (incoming_fd == -1) {
        /* if posn is positive and unseen before then this is our posn*/
        if (incoming_posn >= 0 && s->vm_id == -1) {
            /* receive our posn */
            s->vm_id = incoming_posn;
        } else {
            /* otherwise an fd == -1 means an existing peer has gone away */
            IVSHMEM_DPRINTF("posn %" PRId64 " has gone away\n", incoming_posn);
            close_peer_eventfds(s, incoming_posn);
        }
        return;
    }

    /* if the position is -1, then it's shared memory region fd */
    if (incoming_posn == -1) {
        void * map_ptr;

        if (memory_region_is_mapped(&s->ivshmem)) {
            error_report("shm already initialized");
            close(incoming_fd);
            return;
        }

        if (check_shm_size(s, incoming_fd, &err) == -1) {
            error_report_err(err);
            close(incoming_fd);
            return;
        }

        /* mmap the region and map into the BAR2 */
        map_ptr = mmap(0, s->ivshmem_size, PROT_READ|PROT_WRITE, MAP_SHARED,
                                                            incoming_fd, 0);
        if (map_ptr == MAP_FAILED) {
            error_report("Failed to mmap shared memory %s", strerror(errno));
            close(incoming_fd);
            return;
        }
        memory_region_init_ram_ptr(&s->ivshmem, OBJECT(s),
                                   "ivshmem.bar2", s->ivshmem_size, map_ptr);
        qemu_set_ram_fd(memory_region_get_ram_addr(&s->ivshmem),
                        incoming_fd);
        vmstate_register_ram(&s->ivshmem, DEVICE(s));

        IVSHMEM_DPRINTF("guest h/w addr = %p, size = %" PRIu64 "\n",
                        map_ptr, s->ivshmem_size);

        memory_region_add_subregion(&s->bar, 0, &s->ivshmem);

        return;
    }

    /* each peer has an associated array of eventfds, and we keep
     * track of how many eventfds received so far */
    /* get a new eventfd: */
    if (peer->nb_eventfds >= s->vectors) {
        error_report("Too many eventfd received, device has %d vectors",
                     s->vectors);
        close(incoming_fd);
        return;
    }

    new_eventfd = peer->nb_eventfds++;

    /* this is an eventfd for a particular peer VM */
    IVSHMEM_DPRINTF("eventfds[%" PRId64 "][%d] = %d\n", incoming_posn,
                    new_eventfd, incoming_fd);
    event_notifier_init_fd(&peer->eventfds[new_eventfd], incoming_fd);
    fcntl_setfl(incoming_fd, O_NONBLOCK); /* msix/irqfd poll non block */

    if (incoming_posn == s->vm_id) {
        setup_interrupt(s, new_eventfd);
    }

    if (ivshmem_has_feature(s, IVSHMEM_IOEVENTFD)) {
        ivshmem_add_eventfd(s, incoming_posn, new_eventfd);
    }
}

static void ivshmem_check_version(void *opaque, const uint8_t * buf, int size)


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