hw/virtio/virtio-pmem.c

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