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 #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_stw_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     ThreadPool *pool = aio_get_thread_pool(qemu_get_aio_context());
  74
  75     trace_virtio_pmem_flush_request();
  76     req_data = virtqueue_pop(vq, sizeof(VirtIODeviceRequest));
  77     if (!req_data) {
  78         virtio_error(vdev, "virtio-pmem missing request data");
  79         return;
  80     }
  81
  82     if (req_data->elem.out_num < 1 || req_data->elem.in_num < 1) {
  83         virtio_error(vdev, "virtio-pmem request not proper");
  84         virtqueue_detach_element(vq, (VirtQueueElement *)req_data, 0);
  85         g_free(req_data);
  86         return;
  87     }
  88     req_data->fd   = memory_region_get_fd(&backend->mr);
  89     req_data->pmem = pmem;
  90     req_data->vdev = vdev;
  91     thread_pool_submit_aio(pool, worker_cb, req_data, done_cb, req_data);
  92 }
  93
  94 static void virtio_pmem_get_config(VirtIODevice *vdev, uint8_t *config)
  95 {
  96     VirtIOPMEM *pmem = VIRTIO_PMEM(vdev);
  97     struct virtio_pmem_config *pmemcfg = (struct virtio_pmem_config *) config;
  98
  99     virtio_stq_p(vdev, &pmemcfg->start, pmem->start);
 100     virtio_stq_p(vdev, &pmemcfg->size, memory_region_size(&pmem->memdev->mr));
 101 }
 102
 103 static uint64_t virtio_pmem_get_features(VirtIODevice *vdev, uint64_t features,
 104                                         Error **errp)
 105 {
 106     return features;
 107 }
 108
 109 static void virtio_pmem_realize(DeviceState *dev, Error **errp)
 110 {
 111     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 112     VirtIOPMEM *pmem = VIRTIO_PMEM(dev);
 113
 114     if (!pmem->memdev) {
 115         error_setg(errp, "virtio-pmem memdev not set");
 116         return;
 117     }
 118
 119     if (host_memory_backend_is_mapped(pmem->memdev)) {
 120         error_setg(errp, "can't use already busy memdev: %s",
 121                    object_get_canonical_path_component(OBJECT(pmem->memdev)));
 122         return;
 123     }
 124
 125     host_memory_backend_set_mapped(pmem->memdev, true);
 126     virtio_init(vdev, TYPE_VIRTIO_PMEM, VIRTIO_ID_PMEM,
 127                 sizeof(struct virtio_pmem_config));
 128     pmem->rq_vq = virtio_add_queue(vdev, 128, virtio_pmem_flush);
 129 }
 130
 131 static void virtio_pmem_unrealize(DeviceState *dev)
 132 {
 133     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 134     VirtIOPMEM *pmem = VIRTIO_PMEM(dev);
 135
 136     host_memory_backend_set_mapped(pmem->memdev, false);
 137     virtio_delete_queue(pmem->rq_vq);
 138     virtio_cleanup(vdev);
 139 }
 140
 141 static void virtio_pmem_fill_device_info(const VirtIOPMEM *pmem,
 142                                          VirtioPMEMDeviceInfo *vi)
 143 {
 144     vi->memaddr = pmem->start;
 145     vi->size    = memory_region_size(&pmem->memdev->mr);
 146     vi->memdev  = object_get_canonical_path(OBJECT(pmem->memdev));
 147 }
 148
 149 static MemoryRegion *virtio_pmem_get_memory_region(VirtIOPMEM *pmem,
 150                                                    Error **errp)
 151 {
 152     if (!pmem->memdev) {
 153         error_setg(errp, "'%s' property must be set", VIRTIO_PMEM_MEMDEV_PROP);
 154         return NULL;
 155     }
 156
 157     return &pmem->memdev->mr;
 158 }
 159
 160 static Property virtio_pmem_properties[] = {
 161     DEFINE_PROP_UINT64(VIRTIO_PMEM_ADDR_PROP, VirtIOPMEM, start, 0),
 162     DEFINE_PROP_LINK(VIRTIO_PMEM_MEMDEV_PROP, VirtIOPMEM, memdev,
 163                      TYPE_MEMORY_BACKEND, HostMemoryBackend *),
 164     DEFINE_PROP_END_OF_LIST(),
 165 };
 166
 167 static void virtio_pmem_class_init(ObjectClass *klass, void *data)
 168 {
 169     DeviceClass *dc = DEVICE_CLASS(klass);
 170     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
 171     VirtIOPMEMClass *vpc = VIRTIO_PMEM_CLASS(klass);
 172
 173     device_class_set_props(dc, virtio_pmem_properties);
 174
 175     vdc->realize = virtio_pmem_realize;
 176     vdc->unrealize = virtio_pmem_unrealize;
 177     vdc->get_config = virtio_pmem_get_config;
 178     vdc->get_features = virtio_pmem_get_features;
 179
 180     vpc->fill_device_info = virtio_pmem_fill_device_info;
 181     vpc->get_memory_region = virtio_pmem_get_memory_region;
 182 }
 183
 184 static TypeInfo virtio_pmem_info = {
 185     .name          = TYPE_VIRTIO_PMEM,
 186     .parent        = TYPE_VIRTIO_DEVICE,
 187     .class_size    = sizeof(VirtIOPMEMClass),
 188     .class_init    = virtio_pmem_class_init,
 189     .instance_size = sizeof(VirtIOPMEM),
 190 };
 191
 192 static void virtio_register_types(void)
 193 {
 194     type_register_static(&virtio_pmem_info);
 195 }
 196
 197 type_init(virtio_register_types)