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/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
  28 typedef 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
  37 static 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
  53 static 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
  65 static 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         virtqueue_detach_element(vq, (VirtQueueElement *)req_data, 0);
  81         g_free(req_data);
  82         return;
  83     }
  84     req_data->fd   = memory_region_get_fd(&backend->mr);
  85     req_data->pmem = pmem;
  86     req_data->vdev = vdev;
  87     thread_pool_submit_aio(pool, worker_cb, req_data, done_cb, req_data);
  88 }
  89
  90 static void virtio_pmem_get_config(VirtIODevice *vdev, uint8_t *config)
  91 {
  92     VirtIOPMEM *pmem = VIRTIO_PMEM(vdev);
  93     struct virtio_pmem_config *pmemcfg = (struct virtio_pmem_config *) config;
  94
  95     virtio_stq_p(vdev, &pmemcfg->start, pmem->start);
  96     virtio_stq_p(vdev, &pmemcfg->size, memory_region_size(&pmem->memdev->mr));
  97 }
  98
  99 static uint64_t virtio_pmem_get_features(VirtIODevice *vdev, uint64_t features,
 100                                         Error **errp)
 101 {
 102     return features;
 103 }
 104
 105 static void virtio_pmem_realize(DeviceState *dev, Error **errp)
 106 {
 107     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 108     VirtIOPMEM *pmem = VIRTIO_PMEM(dev);
 109
 110     if (!pmem->memdev) {
 111         error_setg(errp, "virtio-pmem memdev not set");
 112         return;
 113     }
 114
 115     if (host_memory_backend_is_mapped(pmem->memdev)) {
 116         error_setg(errp, "can't use already busy memdev: %s",
 117                    object_get_canonical_path_component(OBJECT(pmem->memdev)));
 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
 127 static void virtio_pmem_unrealize(DeviceState *dev)
 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_delete_queue(pmem->rq_vq);
 134     virtio_cleanup(vdev);
 135 }
 136
 137 static void virtio_pmem_fill_device_info(const VirtIOPMEM *pmem,
 138                                          VirtioPMEMDeviceInfo *vi)
 139 {
 140     vi->memaddr = pmem->start;
 141     vi->size    = memory_region_size(&pmem->memdev->mr);
 142     vi->memdev  = object_get_canonical_path(OBJECT(pmem->memdev));
 143 }
 144
 145 static MemoryRegion *virtio_pmem_get_memory_region(VirtIOPMEM *pmem,
 146                                                    Error **errp)
 147 {
 148     if (!pmem->memdev) {
 149         error_setg(errp, "'%s' property must be set", VIRTIO_PMEM_MEMDEV_PROP);
 150         return NULL;
 151     }
 152
 153     return &pmem->memdev->mr;
 154 }
 155
 156 static Property virtio_pmem_properties[] = {
 157     DEFINE_PROP_UINT64(VIRTIO_PMEM_ADDR_PROP, VirtIOPMEM, start, 0),
 158     DEFINE_PROP_LINK(VIRTIO_PMEM_MEMDEV_PROP, VirtIOPMEM, memdev,
 159                      TYPE_MEMORY_BACKEND, HostMemoryBackend *),
 160     DEFINE_PROP_END_OF_LIST(),
 161 };
 162
 163 static void virtio_pmem_class_init(ObjectClass *klass, void *data)
 164 {
 165     DeviceClass *dc = DEVICE_CLASS(klass);
 166     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
 167     VirtIOPMEMClass *vpc = VIRTIO_PMEM_CLASS(klass);
 168
 169     device_class_set_props(dc, virtio_pmem_properties);
 170
 171     vdc->realize = virtio_pmem_realize;
 172     vdc->unrealize = virtio_pmem_unrealize;
 173     vdc->get_config = virtio_pmem_get_config;
 174     vdc->get_features = virtio_pmem_get_features;
 175
 176     vpc->fill_device_info = virtio_pmem_fill_device_info;
 177     vpc->get_memory_region = virtio_pmem_get_memory_region;
 178 }
 179
 180 static TypeInfo virtio_pmem_info = {
 181     .name          = TYPE_VIRTIO_PMEM,
 182     .parent        = TYPE_VIRTIO_DEVICE,
 183     .class_size    = sizeof(VirtIOPMEMClass),
 184     .class_init    = virtio_pmem_class_init,
 185     .instance_size = sizeof(VirtIOPMEM),
 186 };
 187
 188 static void virtio_register_types(void)
 189 {
 190     type_register_static(&virtio_pmem_info);
 191 }
 192
 193 type_init(virtio_register_types)