qemu/hw/virtio/virtio-pmem.c
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   1/*
   2 * Virtio PMEM device
   3 *
   4 * Copyright (C) 2018-2019 Red Hat, Inc.
   5 *
   6 * Authors:
   7 *  Pankaj Gupta <pagupta@redhat.com>
   8 *  David Hildenbrand <david@redhat.com>
   9 *
  10 * This work is licensed under the terms of the GNU GPL, version 2.
  11 * See the COPYING file in the top-level directory.
  12 */
  13
  14#include "qemu/osdep.h"
  15#include "qapi/error.h"
  16#include "qemu-common.h"
  17#include "qemu/error-report.h"
  18#include "qemu/main-loop.h"
  19#include "hw/virtio/virtio-pmem.h"
  20#include "hw/qdev-properties.h"
  21#include "hw/virtio/virtio-access.h"
  22#include "standard-headers/linux/virtio_ids.h"
  23#include "standard-headers/linux/virtio_pmem.h"
  24#include "sysemu/hostmem.h"
  25#include "block/aio.h"
  26#include "block/thread-pool.h"
  27
  28typedef struct VirtIODeviceRequest {
  29    VirtQueueElement elem;
  30    int fd;
  31    VirtIOPMEM *pmem;
  32    VirtIODevice *vdev;
  33    struct virtio_pmem_req req;
  34    struct virtio_pmem_resp resp;
  35} VirtIODeviceRequest;
  36
  37static int worker_cb(void *opaque)
  38{
  39    VirtIODeviceRequest *req_data = opaque;
  40    int err = 0;
  41
  42    /* flush raw backing image */
  43    err = fsync(req_data->fd);
  44    if (err != 0) {
  45        err = 1;
  46    }
  47
  48    virtio_stw_p(req_data->vdev, &req_data->resp.ret, err);
  49
  50    return 0;
  51}
  52
  53static void done_cb(void *opaque, int ret)
  54{
  55    VirtIODeviceRequest *req_data = opaque;
  56    int len = iov_from_buf(req_data->elem.in_sg, req_data->elem.in_num, 0,
  57                              &req_data->resp, sizeof(struct virtio_pmem_resp));
  58
  59    /* Callbacks are serialized, so no need to use atomic ops. */
  60    virtqueue_push(req_data->pmem->rq_vq, &req_data->elem, len);
  61    virtio_notify((VirtIODevice *)req_data->pmem, req_data->pmem->rq_vq);
  62    g_free(req_data);
  63}
  64
  65static void virtio_pmem_flush(VirtIODevice *vdev, VirtQueue *vq)
  66{
  67    VirtIODeviceRequest *req_data;
  68    VirtIOPMEM *pmem = VIRTIO_PMEM(vdev);
  69    HostMemoryBackend *backend = MEMORY_BACKEND(pmem->memdev);
  70    ThreadPool *pool = aio_get_thread_pool(qemu_get_aio_context());
  71
  72    req_data = virtqueue_pop(vq, sizeof(VirtIODeviceRequest));
  73    if (!req_data) {
  74        virtio_error(vdev, "virtio-pmem missing request data");
  75        return;
  76    }
  77
  78    if (req_data->elem.out_num < 1 || req_data->elem.in_num < 1) {
  79        virtio_error(vdev, "virtio-pmem request not proper");
  80        g_free(req_data);
  81        return;
  82    }
  83    req_data->fd   = memory_region_get_fd(&backend->mr);
  84    req_data->pmem = pmem;
  85    req_data->vdev = vdev;
  86    thread_pool_submit_aio(pool, worker_cb, req_data, done_cb, req_data);
  87}
  88
  89static void virtio_pmem_get_config(VirtIODevice *vdev, uint8_t *config)
  90{
  91    VirtIOPMEM *pmem = VIRTIO_PMEM(vdev);
  92    struct virtio_pmem_config *pmemcfg = (struct virtio_pmem_config *) config;
  93
  94    virtio_stq_p(vdev, &pmemcfg->start, pmem->start);
  95    virtio_stq_p(vdev, &pmemcfg->size, memory_region_size(&pmem->memdev->mr));
  96}
  97
  98static uint64_t virtio_pmem_get_features(VirtIODevice *vdev, uint64_t features,
  99                                        Error **errp)
 100{
 101    return features;
 102}
 103
 104static void virtio_pmem_realize(DeviceState *dev, Error **errp)
 105{
 106    VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 107    VirtIOPMEM *pmem = VIRTIO_PMEM(dev);
 108
 109    if (!pmem->memdev) {
 110        error_setg(errp, "virtio-pmem memdev not set");
 111        return;
 112    }
 113
 114    if (host_memory_backend_is_mapped(pmem->memdev)) {
 115        char *path = object_get_canonical_path_component(OBJECT(pmem->memdev));
 116        error_setg(errp, "can't use already busy memdev: %s", path);
 117        g_free(path);
 118        return;
 119    }
 120
 121    host_memory_backend_set_mapped(pmem->memdev, true);
 122    virtio_init(vdev, TYPE_VIRTIO_PMEM, VIRTIO_ID_PMEM,
 123                sizeof(struct virtio_pmem_config));
 124    pmem->rq_vq = virtio_add_queue(vdev, 128, virtio_pmem_flush);
 125}
 126
 127static void virtio_pmem_unrealize(DeviceState *dev, Error **errp)
 128{
 129    VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 130    VirtIOPMEM *pmem = VIRTIO_PMEM(dev);
 131
 132    host_memory_backend_set_mapped(pmem->memdev, false);
 133    virtio_cleanup(vdev);
 134}
 135
 136static void virtio_pmem_fill_device_info(const VirtIOPMEM *pmem,
 137                                         VirtioPMEMDeviceInfo *vi)
 138{
 139    vi->memaddr = pmem->start;
 140    vi->size    = memory_region_size(&pmem->memdev->mr);
 141    vi->memdev  = object_get_canonical_path(OBJECT(pmem->memdev));
 142}
 143
 144static MemoryRegion *virtio_pmem_get_memory_region(VirtIOPMEM *pmem,
 145                                                   Error **errp)
 146{
 147    if (!pmem->memdev) {
 148        error_setg(errp, "'%s' property must be set", VIRTIO_PMEM_MEMDEV_PROP);
 149        return NULL;
 150    }
 151
 152    return &pmem->memdev->mr;
 153}
 154
 155static Property virtio_pmem_properties[] = {
 156    DEFINE_PROP_UINT64(VIRTIO_PMEM_ADDR_PROP, VirtIOPMEM, start, 0),
 157    DEFINE_PROP_LINK(VIRTIO_PMEM_MEMDEV_PROP, VirtIOPMEM, memdev,
 158                     TYPE_MEMORY_BACKEND, HostMemoryBackend *),
 159    DEFINE_PROP_END_OF_LIST(),
 160};
 161
 162static void virtio_pmem_class_init(ObjectClass *klass, void *data)
 163{
 164    DeviceClass *dc = DEVICE_CLASS(klass);
 165    VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
 166    VirtIOPMEMClass *vpc = VIRTIO_PMEM_CLASS(klass);
 167
 168    dc->props = virtio_pmem_properties;
 169
 170    vdc->realize = virtio_pmem_realize;
 171    vdc->unrealize = virtio_pmem_unrealize;
 172    vdc->get_config = virtio_pmem_get_config;
 173    vdc->get_features = virtio_pmem_get_features;
 174
 175    vpc->fill_device_info = virtio_pmem_fill_device_info;
 176    vpc->get_memory_region = virtio_pmem_get_memory_region;
 177}
 178
 179static TypeInfo virtio_pmem_info = {
 180    .name          = TYPE_VIRTIO_PMEM,
 181    .parent        = TYPE_VIRTIO_DEVICE,
 182    .class_size    = sizeof(VirtIOPMEMClass),
 183    .class_init    = virtio_pmem_class_init,
 184    .instance_size = sizeof(VirtIOPMEM),
 185};
 186
 187static void virtio_register_types(void)
 188{
 189    type_register_static(&virtio_pmem_info);
 190}
 191
 192type_init(virtio_register_types)
 193