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 "hw/virtio/virtio.h"

#include "hw/virtio/virtio-blk.h"

#include "hw/virtio/virtio-net.h"

#include "hw/virtio/virtio-serial.h"

#include "hw/virtio/virtio-scsi.h"

#include "hw/virtio/virtio-balloon.h"

#include "hw/pci/pci.h"

#include "qemu/error-report.h"

#include "hw/pci/msi.h"

#include "hw/pci/msix.h"

#include "hw/loader.h"

#include "sysemu/kvm.h"

#include "sysemu/blockdev.h"

#include "virtio-pci.h"

#include "qemu/range.h"

#include "hw/virtio/virtio-bus.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 */

/* DeviceState to VirtIOPCIProxy. For use off data-path. TODO: use QOM. */

static inline VirtIOPCIProxy *to_virtio_pci_proxy(DeviceState *d)

{

    return container_of(d, VirtIOPCIProxy, pci_dev.qdev);

}

/* DeviceState to VirtIOPCIProxy. Note: used on datapath,

 * be careful and test performance if you change this.

 */

static inline VirtIOPCIProxy *to_virtio_pci_proxy_fast(DeviceState *d)

{

    return container_of(d, VirtIOPCIProxy, pci_dev.qdev);

}

static void virtio_pci_notify(DeviceState *d, uint16_t vector)

{

    VirtIOPCIProxy *proxy = to_virtio_pci_proxy_fast(d);

    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(DeviceState *d, QEMUFile *f)

{

    VirtIOPCIProxy *proxy = to_virtio_pci_proxy(d);

    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(DeviceState *d, int n, QEMUFile *f)

{

    VirtIOPCIProxy *proxy = to_virtio_pci_proxy(d);

    if (msix_present(&proxy->pci_dev))

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

}

static int virtio_pci_load_config(DeviceState *d, QEMUFile *f)

{

    VirtIOPCIProxy *proxy = to_virtio_pci_proxy(d);

    int ret;

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

    if (ret) {

        return ret;

    }

    msix_unuse_all_vectors(&proxy->pci_dev);

    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(DeviceState *d, int n, QEMUFile *f)

{

    VirtIOPCIProxy *proxy = to_virtio_pci_proxy(d);

    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, bool set_handler)

{

    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;

        }

        virtio_queue_set_host_notifier_fd_handler(vq, true, set_handler);

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

                                  true, n, notifier);

    } else {

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

                                  true, n, notifier);

        virtio_queue_set_host_notifier_fd_handler(vq, false, false);

        event_notifier_cleanup(notifier);

    }

    return r;

}

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, true);

        if (r < 0) {

            goto assign_error;

        }

    }

    proxy->ioeventfd_started = true;

    return;

assign_error:

    while (--n >= 0) {

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

            continue;

        }

        r = virtio_pci_set_host_notifier_internal(proxy, n, false, 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;

        }

        r = virtio_pci_set_host_notifier_internal(proxy, n, false, false);

        assert(r >= 0);

    }

    proxy->ioeventfd_started = false;

}

static void virtio_pci_reset(DeviceState *d)

{

    VirtIOPCIProxy *proxy = to_virtio_pci_proxy(d);

    virtio_pci_stop_ioeventfd(proxy);

    virtio_reset(proxy->vdev);

    msix_unuse_all_vectors(&proxy->pci_dev);

    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;

    hwaddr 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 = (hwaddr)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 uint64_t virtio_pci_config_read(void *opaque, hwaddr addr,

                                       unsigned size)

{

    VirtIOPCIProxy *proxy = opaque;

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

    uint64_t val = 0;

    if (addr < config) {

        return virtio_ioport_read(proxy, addr);

    }

    addr -= config;

    switch (size) {

    case 1:

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

        break;

    case 2:

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

        if (virtio_is_big_endian()) {

            val = bswap16(val);

        }

        break;

    case 4:

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

        if (virtio_is_big_endian()) {

            val = bswap32(val);

        }

        break;

    }

    return val;

}

static void virtio_pci_config_write(void *opaque, hwaddr addr,

                                    uint64_t val, unsigned size)

{

    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-PCI is odd. Ioports are LE but config space is target native

     * endian.

     */

    switch (size) {

    case 1:

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

        break;

    case 2:

        if (virtio_is_big_endian()) {

            val = bswap16(val);

        }

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

        break;

    case 4:

        if (virtio_is_big_endian()) {

            val = bswap32(val);

        }

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

        break;

    }

}

static const MemoryRegionOps virtio_pci_config_ops = {

    .read = virtio_pci_config_read,

    .write = virtio_pci_config_write,

    .impl = {

        .min_access_size = 1,

        .max_access_size = 4,

    },

    .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(DeviceState *d)

{

    VirtIOPCIProxy *proxy = to_virtio_pci_proxy(d);

    return proxy->host_features;

}

static int kvm_virtio_pci_vq_vector_use(VirtIOPCIProxy *proxy,

                                        unsigned int queue_no,

                                        unsigned int vector,

                                        MSIMessage msg)

{

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

    int ret;

    if (irqfd->users == 0) {

        ret = kvm_irqchip_add_msi_route(kvm_state, msg);

        if (ret < 0) {

            return ret;

        }

        irqfd->virq = ret;

    }

    irqfd->users++;

    return 0;

}

static void kvm_virtio_pci_vq_vector_release(VirtIOPCIProxy *proxy,

                                             unsigned int vector)

{

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

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

        kvm_irqchip_release_virq(kvm_state, irqfd->virq);

    }

}

static int kvm_virtio_pci_irqfd_use(VirtIOPCIProxy *proxy,

                                 unsigned int queue_no,

                                 unsigned int vector)

{

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

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

    EventNotifier *n = virtio_queue_get_guest_notifier(vq);

    int ret;

    ret = kvm_irqchip_add_irqfd_notifier(kvm_state, n, irqfd->virq);

    return ret;

}

static void kvm_virtio_pci_irqfd_release(VirtIOPCIProxy *proxy,

                                      unsigned int queue_no,

                                      unsigned int vector)

{

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

    EventNotifier *n = virtio_queue_get_guest_notifier(vq);

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

    int ret;

    ret = kvm_irqchip_remove_irqfd_notifier(kvm_state, n, irqfd->virq);

    assert(ret == 0);

}

static int kvm_virtio_pci_vector_use(VirtIOPCIProxy *proxy, int nvqs)

{

    PCIDevice *dev = &proxy->pci_dev;

    VirtIODevice *vdev = proxy->vdev;

    unsigned int vector;

    int ret, queue_no;

    MSIMessage msg;

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

        if (!virtio_queue_get_num(vdev, queue_no)) {

            break;

        }

        vector = virtio_queue_vector(vdev, queue_no);

        if (vector >= msix_nr_vectors_allocated(dev)) {

            continue;

        }

        msg = msix_get_message(dev, vector);

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

        if (ret < 0) {

            goto undo;

        }

        /* If guest supports masking, set up irqfd now.

         * Otherwise, delay until unmasked in the frontend.

         */

        if (proxy->vdev->guest_notifier_mask) {

            ret = kvm_virtio_pci_irqfd_use(proxy, queue_no, vector);

            if (ret < 0) {

                kvm_virtio_pci_vq_vector_release(proxy, vector);

                goto undo;

            }

        }

    }

    return 0;

undo:

    while (--queue_no >= 0) {

        vector = virtio_queue_vector(vdev, queue_no);

        if (vector >= msix_nr_vectors_allocated(dev)) {

            continue;

        }

        if (proxy->vdev->guest_notifier_mask) {

            kvm_virtio_pci_irqfd_release(proxy, queue_no, vector);

        }

        kvm_virtio_pci_vq_vector_release(proxy, vector);

    }

    return ret;

}

static void kvm_virtio_pci_vector_release(VirtIOPCIProxy *proxy, int nvqs)

{

    PCIDevice *dev = &proxy->pci_dev;

    VirtIODevice *vdev = proxy->vdev;

    unsigned int vector;

    int queue_no;

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

        if (!virtio_queue_get_num(vdev, queue_no)) {

            break;

        }

        vector = virtio_queue_vector(vdev, queue_no);

        if (vector >= msix_nr_vectors_allocated(dev)) {

            continue;

        }

        /* If guest supports masking, clean up irqfd now.

         * Otherwise, it was cleaned when masked in the frontend.

         */

        if (proxy->vdev->guest_notifier_mask) {

            kvm_virtio_pci_irqfd_release(proxy, queue_no, vector);

        }

        kvm_virtio_pci_vq_vector_release(proxy, vector);

    }

}

static int virtio_pci_vq_vector_unmask(VirtIOPCIProxy *proxy,

                                       unsigned int queue_no,

                                       unsigned int vector,

                                       MSIMessage msg)

{

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

    EventNotifier *n = virtio_queue_get_guest_notifier(vq);

    VirtIOIRQFD *irqfd;

    int ret = 0;

    if (proxy->vector_irqfd) {

        irqfd = &proxy->vector_irqfd[vector];

        if (irqfd->msg.data != msg.data || irqfd->msg.address != msg.address) {

            ret = kvm_irqchip_update_msi_route(kvm_state, irqfd->virq, msg);

            if (ret < 0) {

                return ret;

            }

        }

    }

    /* If guest supports masking, irqfd is already setup, unmask it.

     * Otherwise, set it up now.

     */

    if (proxy->vdev->guest_notifier_mask) {

        proxy->vdev->guest_notifier_mask(proxy->vdev, queue_no, false);

        /* Test after unmasking to avoid losing events. */

        if (proxy->vdev->guest_notifier_pending &&

            proxy->vdev->guest_notifier_pending(proxy->vdev, queue_no)) {

            event_notifier_set(n);

        }

    } else {

        ret = kvm_virtio_pci_irqfd_use(proxy, queue_no, vector);

    }

    return ret;

}

static void virtio_pci_vq_vector_mask(VirtIOPCIProxy *proxy,

                                             unsigned int queue_no,

                                             unsigned int vector)

{

    /* If guest supports masking, keep irqfd but mask it.

     * Otherwise, clean it up now.

     */ 

    if (proxy->vdev->guest_notifier_mask) {

        proxy->vdev->guest_notifier_mask(proxy->vdev, queue_no, true);

    } else {

        kvm_virtio_pci_irqfd_release(proxy, queue_no, vector);

    }

}

static int virtio_pci_vector_unmask(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 < proxy->nvqs_with_notifiers; queue_no++) {

        if (!virtio_queue_get_num(vdev, queue_no)) {

            break;

        }

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

            continue;

        }

        ret = virtio_pci_vq_vector_unmask(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;

        }

        virtio_pci_vq_vector_mask(proxy, queue_no, vector);

    }

    return ret;

}

static void virtio_pci_vector_mask(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 < proxy->nvqs_with_notifiers; queue_no++) {

        if (!virtio_queue_get_num(vdev, queue_no)) {

            break;

        }

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

            continue;

        }

        virtio_pci_vq_vector_mask(proxy, queue_no, vector);

    }

}

static void virtio_pci_vector_poll(PCIDevice *dev,

                                   unsigned int vector_start,

                                   unsigned int vector_end)

{

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

    VirtIODevice *vdev = proxy->vdev;

    int queue_no;

    unsigned int vector;

    EventNotifier *notifier;

    VirtQueue *vq;

    for (queue_no = 0; queue_no < proxy->nvqs_with_notifiers; queue_no++) {

        if (!virtio_queue_get_num(vdev, queue_no)) {

            break;

        }

        vector = virtio_queue_vector(vdev, queue_no);

        if (vector < vector_start || vector >= vector_end ||

            !msix_is_masked(dev, vector)) {

            continue;

        }

        vq = virtio_get_queue(vdev, queue_no);

        notifier = virtio_queue_get_guest_notifier(vq);

        if (vdev->guest_notifier_pending) {

            if (vdev->guest_notifier_pending(vdev, queue_no)) {

                msix_set_pending(dev, vector);

            }

        } else if (event_notifier_test_and_clear(notifier)) {

            msix_set_pending(dev, vector);

        }

    }

}

static int virtio_pci_set_guest_notifier(DeviceState *d, int n, bool assign,

                                         bool with_irqfd)

{

    VirtIOPCIProxy *proxy = to_virtio_pci_proxy(d);

    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;

        }

        virtio_queue_set_guest_notifier_fd_handler(vq, true, with_irqfd);

    } else {

        virtio_queue_set_guest_notifier_fd_handler(vq, false, with_irqfd);

        event_notifier_cleanup(notifier);

    }

    return 0;

}

static bool virtio_pci_query_guest_notifiers(DeviceState *d)

{

    VirtIOPCIProxy *proxy = to_virtio_pci_proxy(d);

    return msix_enabled(&proxy->pci_dev);

}

static int virtio_pci_set_guest_notifiers(DeviceState *d, int nvqs, bool assign)

{

    VirtIOPCIProxy *proxy = to_virtio_pci_proxy(d);

    VirtIODevice *vdev = proxy->vdev;

    int r, n;

    bool with_irqfd = msix_enabled(&proxy->pci_dev) &&

        kvm_msi_via_irqfd_enabled();

    nvqs = MIN(nvqs, VIRTIO_PCI_QUEUE_MAX);

    /* When deassigning, pass a consistent nvqs value

     * to avoid leaking notifiers.

     */

    assert(assign || nvqs == proxy->nvqs_with_notifiers);

    proxy->nvqs_with_notifiers = nvqs;

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

    if ((proxy->vector_irqfd || vdev->guest_notifier_mask) && !assign) {

        msix_unset_vector_notifiers(&proxy->pci_dev);

        if (proxy->vector_irqfd) {

            kvm_virtio_pci_vector_release(proxy, nvqs);

            g_free(proxy->vector_irqfd);

            proxy->vector_irqfd = NULL;

        }

    }

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

        if (!virtio_queue_get_num(vdev, n)) {

            break;

        }

        r = virtio_pci_set_guest_notifier(d, n, assign,

                                          kvm_msi_via_irqfd_enabled());

        if (r < 0) {

            goto assign_error;

        }

    }

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

    if ((with_irqfd || vdev->guest_notifier_mask) && assign) {

        if (with_irqfd) {

            proxy->vector_irqfd =

                g_malloc0(sizeof(*proxy->vector_irqfd) *

                          msix_nr_vectors_allocated(&proxy->pci_dev));

            r = kvm_virtio_pci_vector_use(proxy, nvqs);

            if (r < 0) {

                goto assign_error;

            }

        }

        r = msix_set_vector_notifiers(&proxy->pci_dev,

                                      virtio_pci_vector_unmask,

                                      virtio_pci_vector_mask,

                                      virtio_pci_vector_poll);

        if (r < 0) {

            goto notifiers_error;

        }

    }

    return 0;

notifiers_error:

    if (with_irqfd) {

        assert(assign);

        kvm_virtio_pci_vector_release(proxy, nvqs);

    }

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(d, n, !assign, with_irqfd);

    }

    return r;

}

static int virtio_pci_set_host_notifier(DeviceState *d, int n, bool assign)

{

    VirtIOPCIProxy *proxy = to_virtio_pci_proxy(d);

    /* 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, false);

}

static void virtio_pci_vmstate_change(DeviceState *d, bool running)

{

    VirtIOPCIProxy *proxy = to_virtio_pci_proxy(d);

    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;

    if (vdev->nvectors &&

        msix_init_exclusive_bar(&proxy->pci_dev, vdev->nvectors, 1)) {

        vdev->nvectors = 0;

    }