Archipelago » qemu

/*

 * Virtio PCI Bindings

 *

 * Copyright IBM, Corp. 2007

 * Copyright (c) 2009 CodeSourcery

 *

 * Authors:

 *  Anthony Liguori   <aliguori@us.ibm.com>

 *  Paul Brook        <paul@codesourcery.com>

 *

 * This work is licensed under the terms of the GNU GPL, version 2.  See

 * the COPYING file in the top-level directory.

 *

 * Contributions after 2012-01-13 are licensed under the terms of the

 * GNU GPL, version 2 or (at your option) any later version.

 */

#include <inttypes.h>

#include "virtio.h"

#include "virtio-blk.h"

#include "virtio-net.h"

#include "virtio-serial.h"

#include "virtio-scsi.h"

#include "pci.h"

#include "qemu-error.h"

#include "msi.h"

#include "msix.h"

#include "net.h"

#include "loader.h"

#include "kvm.h"

#include "blockdev.h"

#include "virtio-pci.h"

#include "range.h"

/* from Linux's linux/virtio_pci.h */

/* A 32-bit r/o bitmask of the features supported by the host */

#define VIRTIO_PCI_HOST_FEATURES        0

/* A 32-bit r/w bitmask of features activated by the guest */

#define VIRTIO_PCI_GUEST_FEATURES       4

/* A 32-bit r/w PFN for the currently selected queue */

#define VIRTIO_PCI_QUEUE_PFN            8

/* A 16-bit r/o queue size for the currently selected queue */

#define VIRTIO_PCI_QUEUE_NUM            12

/* A 16-bit r/w queue selector */

#define VIRTIO_PCI_QUEUE_SEL            14

/* A 16-bit r/w queue notifier */

#define VIRTIO_PCI_QUEUE_NOTIFY         16

/* An 8-bit device status register.  */

#define VIRTIO_PCI_STATUS               18

/* An 8-bit r/o interrupt status register.  Reading the value will return the

 * current contents of the ISR and will also clear it.  This is effectively

 * a read-and-acknowledge. */

#define VIRTIO_PCI_ISR                  19

/* MSI-X registers: only enabled if MSI-X is enabled. */

/* A 16-bit vector for configuration changes. */

#define VIRTIO_MSI_CONFIG_VECTOR        20

/* A 16-bit vector for selected queue notifications. */

#define VIRTIO_MSI_QUEUE_VECTOR         22

/* Config space size */

#define VIRTIO_PCI_CONFIG_NOMSI         20

#define VIRTIO_PCI_CONFIG_MSI           24

#define VIRTIO_PCI_REGION_SIZE(dev)     (msix_present(dev) ? \

                                         VIRTIO_PCI_CONFIG_MSI : \

                                         VIRTIO_PCI_CONFIG_NOMSI)

/* The remaining space is defined by each driver as the per-driver

 * configuration space */

#define VIRTIO_PCI_CONFIG(dev)          (msix_enabled(dev) ? \

                                         VIRTIO_PCI_CONFIG_MSI : \

                                         VIRTIO_PCI_CONFIG_NOMSI)

/* How many bits to shift physical queue address written to QUEUE_PFN.

 * 12 is historical, and due to x86 page size. */

#define VIRTIO_PCI_QUEUE_ADDR_SHIFT    12

/* Flags track per-device state like workarounds for quirks in older guests. */

#define VIRTIO_PCI_FLAG_BUS_MASTER_BUG  (1 << 0)

/* QEMU doesn't strictly need write barriers since everything runs in

 * lock-step.  We'll leave the calls to wmb() in though to make it obvious for

 * KVM or if kqemu gets SMP support.

 */

#define wmb() do { } while (0)

/* HACK for virtio to determine if it's running a big endian guest */

bool virtio_is_big_endian(void);

/* virtio device */

static void virtio_pci_notify(void *opaque, uint16_t vector)

{

    VirtIOPCIProxy *proxy = opaque;

    if (msix_enabled(&proxy->pci_dev))

        msix_notify(&proxy->pci_dev, vector);

    else

        qemu_set_irq(proxy->pci_dev.irq[0], proxy->vdev->isr & 1);

}

static void virtio_pci_save_config(void * opaque, QEMUFile *f)

{

    VirtIOPCIProxy *proxy = opaque;

    pci_device_save(&proxy->pci_dev, f);

    msix_save(&proxy->pci_dev, f);

    if (msix_present(&proxy->pci_dev))

        qemu_put_be16(f, proxy->vdev->config_vector);

}

static void virtio_pci_save_queue(void * opaque, int n, QEMUFile *f)

{

    VirtIOPCIProxy *proxy = opaque;

    if (msix_present(&proxy->pci_dev))

        qemu_put_be16(f, virtio_queue_vector(proxy->vdev, n));

}

static int virtio_pci_load_config(void * opaque, QEMUFile *f)

{

    VirtIOPCIProxy *proxy = opaque;

    int ret;

    ret = pci_device_load(&proxy->pci_dev, f);

    if (ret) {

        return ret;

    }

    msix_load(&proxy->pci_dev, f);

    if (msix_present(&proxy->pci_dev)) {

        qemu_get_be16s(f, &proxy->vdev->config_vector);

    } else {

        proxy->vdev->config_vector = VIRTIO_NO_VECTOR;

    }

    if (proxy->vdev->config_vector != VIRTIO_NO_VECTOR) {

        return msix_vector_use(&proxy->pci_dev, proxy->vdev->config_vector);

    }

    return 0;

}

static int virtio_pci_load_queue(void * opaque, int n, QEMUFile *f)

{

    VirtIOPCIProxy *proxy = opaque;

    uint16_t vector;

    if (msix_present(&proxy->pci_dev)) {

        qemu_get_be16s(f, &vector);

    } else {

        vector = VIRTIO_NO_VECTOR;

    }

    virtio_queue_set_vector(proxy->vdev, n, vector);

    if (vector != VIRTIO_NO_VECTOR) {

        return msix_vector_use(&proxy->pci_dev, vector);

    }

    return 0;

}

static int virtio_pci_set_host_notifier_internal(VirtIOPCIProxy *proxy,

                                                 int n, bool assign)

{

    VirtQueue *vq = virtio_get_queue(proxy->vdev, n);

    EventNotifier *notifier = virtio_queue_get_host_notifier(vq);

    int r = 0;

    if (assign) {

        r = event_notifier_init(notifier, 1);

        if (r < 0) {

            error_report("%s: unable to init event notifier: %d",

                         __func__, r);

            return r;

        }

        memory_region_add_eventfd(&proxy->bar, VIRTIO_PCI_QUEUE_NOTIFY, 2,

                                  true, n, event_notifier_get_fd(notifier));

    } else {

        memory_region_del_eventfd(&proxy->bar, VIRTIO_PCI_QUEUE_NOTIFY, 2,

                                  true, n, event_notifier_get_fd(notifier));

        /* Handle the race condition where the guest kicked and we deassigned

         * before we got around to handling the kick.

         */

        if (event_notifier_test_and_clear(notifier)) {

            virtio_queue_notify_vq(vq);

        }

        event_notifier_cleanup(notifier);

    }

    return r;

}

static void virtio_pci_host_notifier_read(void *opaque)

{

    VirtQueue *vq = opaque;

    EventNotifier *n = virtio_queue_get_host_notifier(vq);

    if (event_notifier_test_and_clear(n)) {

        virtio_queue_notify_vq(vq);

    }

}

static void virtio_pci_set_host_notifier_fd_handler(VirtIOPCIProxy *proxy,

                                                    int n, bool assign)

{

    VirtQueue *vq = virtio_get_queue(proxy->vdev, n);

    EventNotifier *notifier = virtio_queue_get_host_notifier(vq);

    if (assign) {

        qemu_set_fd_handler(event_notifier_get_fd(notifier),

                            virtio_pci_host_notifier_read, NULL, vq);

    } else {

        qemu_set_fd_handler(event_notifier_get_fd(notifier),

                            NULL, NULL, NULL);

    }

}

static void virtio_pci_start_ioeventfd(VirtIOPCIProxy *proxy)

{

    int n, r;

    if (!(proxy->flags & VIRTIO_PCI_FLAG_USE_IOEVENTFD) ||

        proxy->ioeventfd_disabled ||

        proxy->ioeventfd_started) {

        return;

    }

    for (n = 0; n < VIRTIO_PCI_QUEUE_MAX; n++) {

        if (!virtio_queue_get_num(proxy->vdev, n)) {

            continue;

        }

        r = virtio_pci_set_host_notifier_internal(proxy, n, true);

        if (r < 0) {

            goto assign_error;

        }

        virtio_pci_set_host_notifier_fd_handler(proxy, n, true);

    }

    proxy->ioeventfd_started = true;

    return;

assign_error:

    while (--n >= 0) {

        if (!virtio_queue_get_num(proxy->vdev, n)) {

            continue;

        }

        virtio_pci_set_host_notifier_fd_handler(proxy, n, false);

        r = virtio_pci_set_host_notifier_internal(proxy, n, false);

        assert(r >= 0);

    }

    proxy->ioeventfd_started = false;

    error_report("%s: failed. Fallback to a userspace (slower).", __func__);

}

static void virtio_pci_stop_ioeventfd(VirtIOPCIProxy *proxy)

{

    int r;

    int n;

    if (!proxy->ioeventfd_started) {

        return;

    }

    for (n = 0; n < VIRTIO_PCI_QUEUE_MAX; n++) {

        if (!virtio_queue_get_num(proxy->vdev, n)) {

            continue;

        }

        virtio_pci_set_host_notifier_fd_handler(proxy, n, false);

        r = virtio_pci_set_host_notifier_internal(proxy, n, false);

        assert(r >= 0);

    }

    proxy->ioeventfd_started = false;

}

void virtio_pci_reset(DeviceState *d)

{

    VirtIOPCIProxy *proxy = container_of(d, VirtIOPCIProxy, pci_dev.qdev);

    virtio_pci_stop_ioeventfd(proxy);

    virtio_reset(proxy->vdev);

    proxy->flags &= ~VIRTIO_PCI_FLAG_BUS_MASTER_BUG;

}

static void virtio_ioport_write(void *opaque, uint32_t addr, uint32_t val)

{

    VirtIOPCIProxy *proxy = opaque;

    VirtIODevice *vdev = proxy->vdev;

    target_phys_addr_t pa;

    switch (addr) {

    case VIRTIO_PCI_GUEST_FEATURES:

        /* Guest does not negotiate properly?  We have to assume nothing. */

        if (val & (1 << VIRTIO_F_BAD_FEATURE)) {

            val = vdev->bad_features ? vdev->bad_features(vdev) : 0;

        }

        virtio_set_features(vdev, val);

        break;

    case VIRTIO_PCI_QUEUE_PFN:

        pa = (target_phys_addr_t)val << VIRTIO_PCI_QUEUE_ADDR_SHIFT;

        if (pa == 0) {

            virtio_pci_stop_ioeventfd(proxy);

            virtio_reset(proxy->vdev);

            msix_unuse_all_vectors(&proxy->pci_dev);

        }

        else

            virtio_queue_set_addr(vdev, vdev->queue_sel, pa);

        break;

    case VIRTIO_PCI_QUEUE_SEL:

        if (val < VIRTIO_PCI_QUEUE_MAX)

            vdev->queue_sel = val;

        break;

    case VIRTIO_PCI_QUEUE_NOTIFY:

        if (val < VIRTIO_PCI_QUEUE_MAX) {

            virtio_queue_notify(vdev, val);

        }

        break;

    case VIRTIO_PCI_STATUS:

        if (!(val & VIRTIO_CONFIG_S_DRIVER_OK)) {

            virtio_pci_stop_ioeventfd(proxy);

        }

        virtio_set_status(vdev, val & 0xFF);

        if (val & VIRTIO_CONFIG_S_DRIVER_OK) {

            virtio_pci_start_ioeventfd(proxy);

        }

        if (vdev->status == 0) {

            virtio_reset(proxy->vdev);

            msix_unuse_all_vectors(&proxy->pci_dev);

        }

        /* Linux before 2.6.34 sets the device as OK without enabling

           the PCI device bus master bit. In this case we need to disable

           some safety checks. */

        if ((val & VIRTIO_CONFIG_S_DRIVER_OK) &&

            !(proxy->pci_dev.config[PCI_COMMAND] & PCI_COMMAND_MASTER)) {

            proxy->flags |= VIRTIO_PCI_FLAG_BUS_MASTER_BUG;

        }

        break;

    case VIRTIO_MSI_CONFIG_VECTOR:

        msix_vector_unuse(&proxy->pci_dev, vdev->config_vector);

        /* Make it possible for guest to discover an error took place. */

        if (msix_vector_use(&proxy->pci_dev, val) < 0)

            val = VIRTIO_NO_VECTOR;

        vdev->config_vector = val;

        break;

    case VIRTIO_MSI_QUEUE_VECTOR:

        msix_vector_unuse(&proxy->pci_dev,

                          virtio_queue_vector(vdev, vdev->queue_sel));

        /* Make it possible for guest to discover an error took place. */

        if (msix_vector_use(&proxy->pci_dev, val) < 0)

            val = VIRTIO_NO_VECTOR;

        virtio_queue_set_vector(vdev, vdev->queue_sel, val);

        break;

    default:

        error_report("%s: unexpected address 0x%x value 0x%x",

                     __func__, addr, val);

        break;

    }

}

static uint32_t virtio_ioport_read(VirtIOPCIProxy *proxy, uint32_t addr)

{

    VirtIODevice *vdev = proxy->vdev;

    uint32_t ret = 0xFFFFFFFF;

    switch (addr) {

    case VIRTIO_PCI_HOST_FEATURES:

        ret = proxy->host_features;

        break;

    case VIRTIO_PCI_GUEST_FEATURES:

        ret = vdev->guest_features;

        break;

    case VIRTIO_PCI_QUEUE_PFN:

        ret = virtio_queue_get_addr(vdev, vdev->queue_sel)

              >> VIRTIO_PCI_QUEUE_ADDR_SHIFT;

        break;

    case VIRTIO_PCI_QUEUE_NUM:

        ret = virtio_queue_get_num(vdev, vdev->queue_sel);

        break;

    case VIRTIO_PCI_QUEUE_SEL:

        ret = vdev->queue_sel;

        break;

    case VIRTIO_PCI_STATUS:

        ret = vdev->status;

        break;

    case VIRTIO_PCI_ISR:

        /* reading from the ISR also clears it. */

        ret = vdev->isr;

        vdev->isr = 0;

        qemu_set_irq(proxy->pci_dev.irq[0], 0);

        break;

    case VIRTIO_MSI_CONFIG_VECTOR:

        ret = vdev->config_vector;

        break;

    case VIRTIO_MSI_QUEUE_VECTOR:

        ret = virtio_queue_vector(vdev, vdev->queue_sel);

        break;

    default:

        break;

    }

    return ret;

}

static uint32_t virtio_pci_config_readb(void *opaque, uint32_t addr)

{

    VirtIOPCIProxy *proxy = opaque;

    uint32_t config = VIRTIO_PCI_CONFIG(&proxy->pci_dev);

    if (addr < config)

        return virtio_ioport_read(proxy, addr);

    addr -= config;

    return virtio_config_readb(proxy->vdev, addr);

}

static uint32_t virtio_pci_config_readw(void *opaque, uint32_t addr)

{

    VirtIOPCIProxy *proxy = opaque;

    uint32_t config = VIRTIO_PCI_CONFIG(&proxy->pci_dev);

    uint16_t val;

    if (addr < config)

        return virtio_ioport_read(proxy, addr);

    addr -= config;

    val = virtio_config_readw(proxy->vdev, addr);

    if (virtio_is_big_endian()) {

        /*

         * virtio is odd, ioports are LE but config space is target native

         * endian. However, in qemu, all PIO is LE, so we need to re-swap

         * on BE targets

         */

        val = bswap16(val);

    }

    return val;

}

static uint32_t virtio_pci_config_readl(void *opaque, uint32_t addr)

{

    VirtIOPCIProxy *proxy = opaque;

    uint32_t config = VIRTIO_PCI_CONFIG(&proxy->pci_dev);

    uint32_t val;

    if (addr < config)

        return virtio_ioport_read(proxy, addr);

    addr -= config;

    val = virtio_config_readl(proxy->vdev, addr);

    if (virtio_is_big_endian()) {

        val = bswap32(val);

    }

    return val;

}

static void virtio_pci_config_writeb(void *opaque, uint32_t addr, uint32_t val)

{

    VirtIOPCIProxy *proxy = opaque;

    uint32_t config = VIRTIO_PCI_CONFIG(&proxy->pci_dev);

    if (addr < config) {

        virtio_ioport_write(proxy, addr, val);

        return;

    }

    addr -= config;

    virtio_config_writeb(proxy->vdev, addr, val);

}

static void virtio_pci_config_writew(void *opaque, uint32_t addr, uint32_t val)

{

    VirtIOPCIProxy *proxy = opaque;

    uint32_t config = VIRTIO_PCI_CONFIG(&proxy->pci_dev);

    if (addr < config) {

        virtio_ioport_write(proxy, addr, val);

        return;

    }

    addr -= config;

    if (virtio_is_big_endian()) {

        val = bswap16(val);

    }

    virtio_config_writew(proxy->vdev, addr, val);

}

static void virtio_pci_config_writel(void *opaque, uint32_t addr, uint32_t val)

{

    VirtIOPCIProxy *proxy = opaque;

    uint32_t config = VIRTIO_PCI_CONFIG(&proxy->pci_dev);

    if (addr < config) {

        virtio_ioport_write(proxy, addr, val);

        return;

    }

    addr -= config;

    if (virtio_is_big_endian()) {

        val = bswap32(val);

    }

    virtio_config_writel(proxy->vdev, addr, val);

}

static const MemoryRegionPortio virtio_portio[] = {

    { 0, 0x10000, 1, .write = virtio_pci_config_writeb, },

    { 0, 0x10000, 2, .write = virtio_pci_config_writew, },

    { 0, 0x10000, 4, .write = virtio_pci_config_writel, },

    { 0, 0x10000, 1, .read = virtio_pci_config_readb, },

    { 0, 0x10000, 2, .read = virtio_pci_config_readw, },

    { 0, 0x10000, 4, .read = virtio_pci_config_readl, },

    PORTIO_END_OF_LIST()

};

static const MemoryRegionOps virtio_pci_config_ops = {

    .old_portio = virtio_portio,

    .endianness = DEVICE_LITTLE_ENDIAN,

};

static void virtio_write_config(PCIDevice *pci_dev, uint32_t address,

                                uint32_t val, int len)

{

    VirtIOPCIProxy *proxy = DO_UPCAST(VirtIOPCIProxy, pci_dev, pci_dev);

    pci_default_write_config(pci_dev, address, val, len);

    if (range_covers_byte(address, len, PCI_COMMAND) &&

        !(pci_dev->config[PCI_COMMAND] & PCI_COMMAND_MASTER) &&

        !(proxy->flags & VIRTIO_PCI_FLAG_BUS_MASTER_BUG)) {

        virtio_pci_stop_ioeventfd(proxy);

        virtio_set_status(proxy->vdev,

                          proxy->vdev->status & ~VIRTIO_CONFIG_S_DRIVER_OK);

    }

}

static unsigned virtio_pci_get_features(void *opaque)

{

    VirtIOPCIProxy *proxy = opaque;

    return proxy->host_features;

}

static void virtio_pci_guest_notifier_read(void *opaque)

{

    VirtQueue *vq = opaque;

    EventNotifier *n = virtio_queue_get_guest_notifier(vq);

    if (event_notifier_test_and_clear(n)) {

        virtio_irq(vq);

    }

}

static int kvm_virtio_pci_vq_vector_use(VirtIOPCIProxy *proxy,

                                        unsigned int queue_no,

                                        unsigned int vector,

                                        MSIMessage msg)

{

    VirtQueue *vq = virtio_get_queue(proxy->vdev, queue_no);

    VirtIOIRQFD *irqfd = &proxy->vector_irqfd[vector];

    int fd, ret;

    fd = event_notifier_get_fd(virtio_queue_get_guest_notifier(vq));

    if (irqfd->users == 0) {

        ret = kvm_irqchip_add_msi_route(kvm_state, msg);

        if (ret < 0) {

            return ret;

        }

        irqfd->virq = ret;

    }

    irqfd->users++;

    ret = kvm_irqchip_add_irqfd(kvm_state, fd, irqfd->virq);

    if (ret < 0) {

        if (--irqfd->users == 0) {

            kvm_irqchip_release_virq(kvm_state, irqfd->virq);

        }

        return ret;

    }

    qemu_set_fd_handler(fd, NULL, NULL, NULL);

    return 0;

}

static void kvm_virtio_pci_vq_vector_release(VirtIOPCIProxy *proxy,

                                             unsigned int queue_no,

                                             unsigned int vector)

{

    VirtQueue *vq = virtio_get_queue(proxy->vdev, queue_no);

    VirtIOIRQFD *irqfd = &proxy->vector_irqfd[vector];

    int fd, ret;

    fd = event_notifier_get_fd(virtio_queue_get_guest_notifier(vq));

    ret = kvm_irqchip_remove_irqfd(kvm_state, fd, irqfd->virq);

    assert(ret == 0);

    if (--irqfd->users == 0) {

        kvm_irqchip_release_virq(kvm_state, irqfd->virq);

    }

    qemu_set_fd_handler(fd, virtio_pci_guest_notifier_read, NULL, vq);

}

static int kvm_virtio_pci_vector_use(PCIDevice *dev, unsigned vector,

                                     MSIMessage msg)

{

    VirtIOPCIProxy *proxy = container_of(dev, VirtIOPCIProxy, pci_dev);

    VirtIODevice *vdev = proxy->vdev;

    int ret, queue_no;

    for (queue_no = 0; queue_no < VIRTIO_PCI_QUEUE_MAX; queue_no++) {

        if (!virtio_queue_get_num(vdev, queue_no)) {

            break;

        }

        if (virtio_queue_vector(vdev, queue_no) != vector) {

            continue;

        }

        ret = kvm_virtio_pci_vq_vector_use(proxy, queue_no, vector, msg);

        if (ret < 0) {

            goto undo;

        }

    }

    return 0;

undo:

    while (--queue_no >= 0) {

        if (virtio_queue_vector(vdev, queue_no) != vector) {

            continue;

        }

        kvm_virtio_pci_vq_vector_release(proxy, queue_no, vector);

    }

    return ret;

}

static void kvm_virtio_pci_vector_release(PCIDevice *dev, unsigned vector)

{

    VirtIOPCIProxy *proxy = container_of(dev, VirtIOPCIProxy, pci_dev);

    VirtIODevice *vdev = proxy->vdev;

    int queue_no;

    for (queue_no = 0; queue_no < VIRTIO_PCI_QUEUE_MAX; queue_no++) {

        if (!virtio_queue_get_num(vdev, queue_no)) {

            break;

        }

        if (virtio_queue_vector(vdev, queue_no) != vector) {

            continue;

        }

        kvm_virtio_pci_vq_vector_release(proxy, queue_no, vector);

    }

}

static int virtio_pci_set_guest_notifier(void *opaque, int n, bool assign)

{

    VirtIOPCIProxy *proxy = opaque;

    VirtQueue *vq = virtio_get_queue(proxy->vdev, n);

    EventNotifier *notifier = virtio_queue_get_guest_notifier(vq);

    if (assign) {

        int r = event_notifier_init(notifier, 0);

        if (r < 0) {

            return r;

        }

        qemu_set_fd_handler(event_notifier_get_fd(notifier),

                            virtio_pci_guest_notifier_read, NULL, vq);

    } else {

        qemu_set_fd_handler(event_notifier_get_fd(notifier),

                            NULL, NULL, NULL);

        /* Test and clear notifier before closing it,

         * in case poll callback didn't have time to run. */

        virtio_pci_guest_notifier_read(vq);

        event_notifier_cleanup(notifier);

    }

    return 0;

}

static bool virtio_pci_query_guest_notifiers(void *opaque)

{

    VirtIOPCIProxy *proxy = opaque;

    return msix_enabled(&proxy->pci_dev);

}

static int virtio_pci_set_guest_notifiers(void *opaque, bool assign)

{

    VirtIOPCIProxy *proxy = opaque;

    VirtIODevice *vdev = proxy->vdev;

    int r, n;

    /* Must unset vector notifier while guest notifier is still assigned */

    if (kvm_irqchip_in_kernel() && !assign) {

        msix_unset_vector_notifiers(&proxy->pci_dev);

        g_free(proxy->vector_irqfd);

        proxy->vector_irqfd = NULL;

    }

    for (n = 0; n < VIRTIO_PCI_QUEUE_MAX; n++) {

        if (!virtio_queue_get_num(vdev, n)) {

            break;

        }

        r = virtio_pci_set_guest_notifier(opaque, n, assign);

        if (r < 0) {

            goto assign_error;

        }

    }

    /* Must set vector notifier after guest notifier has been assigned */

    if (kvm_irqchip_in_kernel() && assign) {

        proxy->vector_irqfd =

            g_malloc0(sizeof(*proxy->vector_irqfd) *

                      msix_nr_vectors_allocated(&proxy->pci_dev));

        r = msix_set_vector_notifiers(&proxy->pci_dev,

                                      kvm_virtio_pci_vector_use,

                                      kvm_virtio_pci_vector_release);

        if (r < 0) {

            goto assign_error;

        }

    }

    return 0;

assign_error:

    /* We get here on assignment failure. Recover by undoing for VQs 0 .. n. */

    assert(assign);

    while (--n >= 0) {

        virtio_pci_set_guest_notifier(opaque, n, !assign);

    }

    return r;

}

static int virtio_pci_set_host_notifier(void *opaque, int n, bool assign)

{

    VirtIOPCIProxy *proxy = opaque;

    /* Stop using ioeventfd for virtqueue kick if the device starts using host

     * notifiers.  This makes it easy to avoid stepping on each others' toes.

     */

    proxy->ioeventfd_disabled = assign;

    if (assign) {

        virtio_pci_stop_ioeventfd(proxy);

    }

    /* We don't need to start here: it's not needed because backend

     * currently only stops on status change away from ok,

     * reset, vmstop and such. If we do add code to start here,

     * need to check vmstate, device state etc. */

    return virtio_pci_set_host_notifier_internal(proxy, n, assign);

}

static void virtio_pci_vmstate_change(void *opaque, bool running)

{

    VirtIOPCIProxy *proxy = opaque;

    if (running) {

        /* Try to find out if the guest has bus master disabled, but is

           in ready state. Then we have a buggy guest OS. */

        if ((proxy->vdev->status & VIRTIO_CONFIG_S_DRIVER_OK) &&

            !(proxy->pci_dev.config[PCI_COMMAND] & PCI_COMMAND_MASTER)) {

            proxy->flags |= VIRTIO_PCI_FLAG_BUS_MASTER_BUG;

        }

        virtio_pci_start_ioeventfd(proxy);

    } else {

        virtio_pci_stop_ioeventfd(proxy);

    }

}

static const VirtIOBindings virtio_pci_bindings = {

    .notify = virtio_pci_notify,

    .save_config = virtio_pci_save_config,

    .load_config = virtio_pci_load_config,

    .save_queue = virtio_pci_save_queue,

    .load_queue = virtio_pci_load_queue,

    .get_features = virtio_pci_get_features,

    .query_guest_notifiers = virtio_pci_query_guest_notifiers,

    .set_host_notifier = virtio_pci_set_host_notifier,

    .set_guest_notifiers = virtio_pci_set_guest_notifiers,

    .vmstate_change = virtio_pci_vmstate_change,

};

void virtio_init_pci(VirtIOPCIProxy *proxy, VirtIODevice *vdev)

{

    uint8_t *config;

    uint32_t size;

    proxy->vdev = vdev;

    config = proxy->pci_dev.config;

    if (proxy->class_code) {

        pci_config_set_class(config, proxy->class_code);

    }

    pci_set_word(config + PCI_SUBSYSTEM_VENDOR_ID,

                 pci_get_word(config + PCI_VENDOR_ID));

    pci_set_word(config + PCI_SUBSYSTEM_ID, vdev->device_id);

    config[PCI_INTERRUPT_PIN] = 1;

    memory_region_init(&proxy->msix_bar, "virtio-msix", 4096);

    if (vdev->nvectors && !msix_init(&proxy->pci_dev, vdev->nvectors,

                                     &proxy->msix_bar, 1, 0)) {

        pci_register_bar(&proxy->pci_dev, 1, PCI_BASE_ADDRESS_SPACE_MEMORY,

                         &proxy->msix_bar);

    } else

        vdev->nvectors = 0;

    proxy->pci_dev.config_write = virtio_write_config;

    size = VIRTIO_PCI_REGION_SIZE(&proxy->pci_dev) + vdev->config_len;

    if (size & (size-1))

        size = 1 << qemu_fls(size);

    memory_region_init_io(&proxy->bar, &virtio_pci_config_ops, proxy,

                          "virtio-pci", size);

    pci_register_bar(&proxy->pci_dev, 0, PCI_BASE_ADDRESS_SPACE_IO,

                     &proxy->bar);

    if (!kvm_has_many_ioeventfds()) {

        proxy->flags &= ~VIRTIO_PCI_FLAG_USE_IOEVENTFD;

    }

    virtio_bind_device(vdev, &virtio_pci_bindings, proxy);

    proxy->host_features |= 0x1 << VIRTIO_F_NOTIFY_ON_EMPTY;

    proxy->host_features |= 0x1 << VIRTIO_F_BAD_FEATURE;

    proxy->host_features = vdev->get_features(vdev, proxy->host_features);

}

static int virtio_blk_init_pci(PCIDevice *pci_dev)

{

    VirtIOPCIProxy *proxy = DO_UPCAST(VirtIOPCIProxy, pci_dev, pci_dev);

    VirtIODevice *vdev;

    if (proxy->class_code != PCI_CLASS_STORAGE_SCSI &&

        proxy->class_code != PCI_CLASS_STORAGE_OTHER)

        proxy->class_code = PCI_CLASS_STORAGE_SCSI;

    vdev = virtio_blk_init(&pci_dev->qdev, &proxy->blk);

    if (!vdev) {

        return -1;

    }

    vdev->nvectors = proxy->nvectors;

    virtio_init_pci(proxy, vdev);

    /* make the actual value visible */

    proxy->nvectors = vdev->nvectors;

    return 0;

}

static int virtio_exit_pci(PCIDevice *pci_dev)

{

    VirtIOPCIProxy *proxy = DO_UPCAST(VirtIOPCIProxy, pci_dev, pci_dev);

    int r;

    memory_region_destroy(&proxy->bar);

    r = msix_uninit(pci_dev, &proxy->msix_bar);

    memory_region_destroy(&proxy->msix_bar);

    return r;

}

static int virtio_blk_exit_pci(PCIDevice *pci_dev)

{

    VirtIOPCIProxy *proxy = DO_UPCAST(VirtIOPCIProxy, pci_dev, pci_dev);

    virtio_pci_stop_ioeventfd(proxy);

    virtio_blk_exit(proxy->vdev);

    return virtio_exit_pci(pci_dev);

}

static int virtio_serial_init_pci(PCIDevice *pci_dev)

{

    VirtIOPCIProxy *proxy = DO_UPCAST(VirtIOPCIProxy, pci_dev, pci_dev);

    VirtIODevice *vdev;

    if (proxy->class_code != PCI_CLASS_COMMUNICATION_OTHER &&

        proxy->class_code != PCI_CLASS_DISPLAY_OTHER && /* qemu 0.10 */

        proxy->class_code != PCI_CLASS_OTHERS)          /* qemu-kvm  */

        proxy->class_code = PCI_CLASS_COMMUNICATION_OTHER;

    vdev = virtio_serial_init(&pci_dev->qdev, &proxy->serial);

    if (!vdev) {

        return -1;

    }

    vdev->nvectors = proxy->nvectors == DEV_NVECTORS_UNSPECIFIED

                                        ? proxy->serial.max_virtserial_ports + 1

                                        : proxy->nvectors;

    virtio_init_pci(proxy, vdev);

    proxy->nvectors = vdev->nvectors;

    return 0;

}

static int virtio_serial_exit_pci(PCIDevice *pci_dev)

{

    VirtIOPCIProxy *proxy = DO_UPCAST(VirtIOPCIProxy, pci_dev, pci_dev);

    virtio_pci_stop_ioeventfd(proxy);

    virtio_serial_exit(proxy->vdev);

    return virtio_exit_pci(pci_dev);

}

static int virtio_net_init_pci(PCIDevice *pci_dev)

{

    VirtIOPCIProxy *proxy = DO_UPCAST(VirtIOPCIProxy, pci_dev, pci_dev);

    VirtIODevice *vdev;

    vdev = virtio_net_init(&pci_dev->qdev, &proxy->nic, &proxy->net);

    vdev->nvectors = proxy->nvectors;

    virtio_init_pci(proxy, vdev);

    /* make the actual value visible */

    proxy->nvectors = vdev->nvectors;

    return 0;

}

static int virtio_net_exit_pci(PCIDevice *pci_dev)

{

    VirtIOPCIProxy *proxy = DO_UPCAST(VirtIOPCIProxy, pci_dev, pci_dev);

    virtio_pci_stop_ioeventfd(proxy);

    virtio_net_exit(proxy->vdev);

    return virtio_exit_pci(pci_dev);

}

static int virtio_balloon_init_pci(PCIDevice *pci_dev)

{

    VirtIOPCIProxy *proxy = DO_UPCAST(VirtIOPCIProxy, pci_dev, pci_dev);

    VirtIODevice *vdev;

    if (proxy->class_code != PCI_CLASS_OTHERS &&

        proxy->class_code != PCI_CLASS_MEMORY_RAM) { /* qemu < 1.1 */

        proxy->class_code = PCI_CLASS_OTHERS;

    }