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