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/error-report.h"
  17 #include "qemu/iov.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 #include "trace.h"
  28
  29 typedef struct VirtIODeviceRequest {
  30     VirtQueueElement elem;
  31     int fd;
  32     VirtIOPMEM *pmem;
  33     VirtIODevice *vdev;
  34     struct virtio_pmem_req req;
  35     struct virtio_pmem_resp resp;
  36 } VirtIODeviceRequest;
  37
  38 static int worker_cb(void *opaque)
  39 {
  40     VirtIODeviceRequest *req_data = opaque;
  41     int err = 0;
  42
  43     /* flush raw backing image */
  44     err = fsync(req_data->fd);
  45     trace_virtio_pmem_flush_done(err);
  46     if (err != 0) {
  47         err = 1;
  48     }
  49
  50     virtio_stl_p(req_data->vdev, &req_data->resp.ret, err);
  51
  52     return 0;
  53 }
  54
  55 static void done_cb(void *opaque, int ret)
  56 {
  57     VirtIODeviceRequest *req_data = opaque;
  58     int len = iov_from_buf(req_data->elem.in_sg, req_data->elem.in_num, 0,
  59                               &req_data->resp, sizeof(struct virtio_pmem_resp));
  60
  61     /* Callbacks are serialized, so no need to use atomic ops. */
  62     virtqueue_push(req_data->pmem->rq_vq, &req_data->elem, len);
  63     virtio_notify((VirtIODevice *)req_data->pmem, req_data->pmem->rq_vq);
  64     trace_virtio_pmem_response();
  65     g_free(req_data);
  66 }
  67
  68 static void virtio_pmem_flush(VirtIODevice *vdev, VirtQueue *vq)
  69 {
  70     VirtIODeviceRequest *req_data;
  71     VirtIOPMEM *pmem = VIRTIO_PMEM(vdev);
  72     HostMemoryBackend *backend = MEMORY_BACKEND(pmem->memdev);
  73
  74     trace_virtio_pmem_flush_request();
  75     req_data = virtqueue_pop(vq, sizeof(VirtIODeviceRequest));
  76     if (!req_data) {
  77         virtio_error(vdev, "virtio-pmem missing request data");
  78         return;
  79     }
  80
  81     if (req_data->elem.out_num < 1 || req_data->elem.in_num < 1) {
  82         virtio_error(vdev, "virtio-pmem request not proper");
  83         virtqueue_detach_element(vq, (VirtQueueElement *)req_data, 0);
  84         g_free(req_data);
  85         return;
  86     }
  87     req_data->fd   = memory_region_get_fd(&backend->mr);
  88     req_data->pmem = pmem;
  89     req_data->vdev = vdev;
  90     thread_pool_submit_aio(worker_cb, req_data, done_cb, req_data);
  91 }
  92
  93 static void virtio_pmem_get_config(VirtIODevice *vdev, uint8_t *config)
  94 {
  95     VirtIOPMEM *pmem = VIRTIO_PMEM(vdev);
  96     struct virtio_pmem_config *pmemcfg = (struct virtio_pmem_config *) config;
  97
  98     virtio_stq_p(vdev, &pmemcfg->start, pmem->start);
  99     virtio_stq_p(vdev, &pmemcfg->size, memory_region_size(&pmem->memdev->mr));
 100 }
 101
 102 static uint64_t virtio_pmem_get_features(VirtIODevice *vdev, uint64_t features,
 103                                         Error **errp)
 104 {
 105     return features;
 106 }
 107
 108 static void virtio_pmem_realize(DeviceState *dev, Error **errp)
 109 {
 110     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 111     VirtIOPMEM *pmem = VIRTIO_PMEM(dev);
 112
 113     if (!pmem->memdev) {
 114         error_setg(errp, "virtio-pmem memdev not set");
 115         return;
 116     }
 117
 118     if (host_memory_backend_is_mapped(pmem->memdev)) {
 119         error_setg(errp, "can't use already busy memdev: %s",
 120                    object_get_canonical_path_component(OBJECT(pmem->memdev)));
 121         return;
 122     }
 123
 124     host_memory_backend_set_mapped(pmem->memdev, true);
 125     virtio_init(vdev, VIRTIO_ID_PMEM, sizeof(struct virtio_pmem_config));
 126     pmem->rq_vq = virtio_add_queue(vdev, 128, virtio_pmem_flush);
 127 }
 128
 129 static void virtio_pmem_unrealize(DeviceState *dev)
 130 {
 131     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 132     VirtIOPMEM *pmem = VIRTIO_PMEM(dev);
 133
 134     host_memory_backend_set_mapped(pmem->memdev, false);
 135     virtio_delete_queue(pmem->rq_vq);
 136     virtio_cleanup(vdev);
 137 }
 138
 139 static void virtio_pmem_fill_device_info(const VirtIOPMEM *pmem,
 140                                          VirtioPMEMDeviceInfo *vi)
 141 {
 142     vi->memaddr = pmem->start;
 143     vi->size    = memory_region_size(&pmem->memdev->mr);
 144     vi->memdev  = object_get_canonical_path(OBJECT(pmem->memdev));
 145 }
 146
 147 static MemoryRegion *virtio_pmem_get_memory_region(VirtIOPMEM *pmem,
 148                                                    Error **errp)
 149 {
 150     if (!pmem->memdev) {
 151         error_setg(errp, "'%s' property must be set", VIRTIO_PMEM_MEMDEV_PROP);
 152         return NULL;
 153     }
 154
 155     return &pmem->memdev->mr;
 156 }
 157
 158 static Property virtio_pmem_properties[] = {
 159     DEFINE_PROP_UINT64(VIRTIO_PMEM_ADDR_PROP, VirtIOPMEM, start, 0),
 160     DEFINE_PROP_LINK(VIRTIO_PMEM_MEMDEV_PROP, VirtIOPMEM, memdev,
 161                      TYPE_MEMORY_BACKEND, HostMemoryBackend *),
 162     DEFINE_PROP_END_OF_LIST(),
 163 };
 164
 165 static void virtio_pmem_class_init(ObjectClass *klass, void *data)
 166 {
 167     DeviceClass *dc = DEVICE_CLASS(klass);
 168     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
 169     VirtIOPMEMClass *vpc = VIRTIO_PMEM_CLASS(klass);
 170
 171     device_class_set_props(dc, virtio_pmem_properties);
 172
 173     vdc->realize = virtio_pmem_realize;
 174     vdc->unrealize = virtio_pmem_unrealize;
 175     vdc->get_config = virtio_pmem_get_config;
 176     vdc->get_features = virtio_pmem_get_features;
 177
 178     vpc->fill_device_info = virtio_pmem_fill_device_info;
 179     vpc->get_memory_region = virtio_pmem_get_memory_region;
 180     set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
 181 }
 182
 183 static const TypeInfo virtio_pmem_info = {
 184     .name          = TYPE_VIRTIO_PMEM,
 185     .parent        = TYPE_VIRTIO_DEVICE,
 186     .class_size    = sizeof(VirtIOPMEMClass),
 187     .class_init    = virtio_pmem_class_init,
 188     .instance_size = sizeof(VirtIOPMEM),
 189 };
 190
 191 static void virtio_register_types(void)
 192 {
 193     type_register_static(&virtio_pmem_info);
 194 }
 195
 196 type_init(virtio_register_types)