linux/drivers/nvdimm/virtio_pmem.c
Changyuan Lyu 35967bdcff virtio_pmem: support feature SHMEM_REGION
This patch adds the support for feature VIRTIO_PMEM_F_SHMEM_REGION
(virtio spec v1.2 section 5.19.5.2 [1]).

During feature negotiation, if VIRTIO_PMEM_F_SHMEM_REGION is offered
by the device, the driver looks for a shared memory region of id 0.
If it is found, this feature is understood. Otherwise, this feature
bit is cleared.

During probe, if VIRTIO_PMEM_F_SHMEM_REGION has been negotiated,
virtio pmem ignores the `start` and `size` fields in device config
and uses the physical address range of shared memory region 0.

[1] https://docs.oasis-open.org/virtio/virtio/v1.2/csd01/virtio-v1.2-csd01.html#x1-6480002

Signed-off-by: Changyuan Lyu <changyuanl@google.com>
Message-Id: <20231220204906.566922-1-changyuanl@google.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
2024-01-10 13:01:37 -05:00

165 lines
4.2 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* virtio_pmem.c: Virtio pmem Driver
*
* Discovers persistent memory range information
* from host and registers the virtual pmem device
* with libnvdimm core.
*/
#include "virtio_pmem.h"
#include "nd.h"
static struct virtio_device_id id_table[] = {
{ VIRTIO_ID_PMEM, VIRTIO_DEV_ANY_ID },
{ 0 },
};
/* Initialize virt queue */
static int init_vq(struct virtio_pmem *vpmem)
{
/* single vq */
vpmem->req_vq = virtio_find_single_vq(vpmem->vdev,
virtio_pmem_host_ack, "flush_queue");
if (IS_ERR(vpmem->req_vq))
return PTR_ERR(vpmem->req_vq);
spin_lock_init(&vpmem->pmem_lock);
INIT_LIST_HEAD(&vpmem->req_list);
return 0;
};
static int virtio_pmem_validate(struct virtio_device *vdev)
{
struct virtio_shm_region shm_reg;
if (virtio_has_feature(vdev, VIRTIO_PMEM_F_SHMEM_REGION) &&
!virtio_get_shm_region(vdev, &shm_reg, (u8)VIRTIO_PMEM_SHMEM_REGION_ID)
) {
dev_notice(&vdev->dev, "failed to get shared memory region %d\n",
VIRTIO_PMEM_SHMEM_REGION_ID);
__virtio_clear_bit(vdev, VIRTIO_PMEM_F_SHMEM_REGION);
}
return 0;
}
static int virtio_pmem_probe(struct virtio_device *vdev)
{
struct nd_region_desc ndr_desc = {};
struct nd_region *nd_region;
struct virtio_pmem *vpmem;
struct resource res;
struct virtio_shm_region shm_reg;
int err = 0;
if (!vdev->config->get) {
dev_err(&vdev->dev, "%s failure: config access disabled\n",
__func__);
return -EINVAL;
}
vpmem = devm_kzalloc(&vdev->dev, sizeof(*vpmem), GFP_KERNEL);
if (!vpmem) {
err = -ENOMEM;
goto out_err;
}
vpmem->vdev = vdev;
vdev->priv = vpmem;
err = init_vq(vpmem);
if (err) {
dev_err(&vdev->dev, "failed to initialize virtio pmem vq's\n");
goto out_err;
}
if (virtio_has_feature(vdev, VIRTIO_PMEM_F_SHMEM_REGION)) {
virtio_get_shm_region(vdev, &shm_reg, (u8)VIRTIO_PMEM_SHMEM_REGION_ID);
vpmem->start = shm_reg.addr;
vpmem->size = shm_reg.len;
} else {
virtio_cread_le(vpmem->vdev, struct virtio_pmem_config,
start, &vpmem->start);
virtio_cread_le(vpmem->vdev, struct virtio_pmem_config,
size, &vpmem->size);
}
res.start = vpmem->start;
res.end = vpmem->start + vpmem->size - 1;
vpmem->nd_desc.provider_name = "virtio-pmem";
vpmem->nd_desc.module = THIS_MODULE;
vpmem->nvdimm_bus = nvdimm_bus_register(&vdev->dev,
&vpmem->nd_desc);
if (!vpmem->nvdimm_bus) {
dev_err(&vdev->dev, "failed to register device with nvdimm_bus\n");
err = -ENXIO;
goto out_vq;
}
dev_set_drvdata(&vdev->dev, vpmem->nvdimm_bus);
ndr_desc.res = &res;
ndr_desc.numa_node = memory_add_physaddr_to_nid(res.start);
ndr_desc.target_node = phys_to_target_node(res.start);
if (ndr_desc.target_node == NUMA_NO_NODE) {
ndr_desc.target_node = ndr_desc.numa_node;
dev_dbg(&vdev->dev, "changing target node from %d to %d",
NUMA_NO_NODE, ndr_desc.target_node);
}
ndr_desc.flush = async_pmem_flush;
ndr_desc.provider_data = vdev;
set_bit(ND_REGION_PAGEMAP, &ndr_desc.flags);
set_bit(ND_REGION_ASYNC, &ndr_desc.flags);
/*
* The NVDIMM region could be available before the
* virtio_device_ready() that is called by
* virtio_dev_probe(), so we set device ready here.
*/
virtio_device_ready(vdev);
nd_region = nvdimm_pmem_region_create(vpmem->nvdimm_bus, &ndr_desc);
if (!nd_region) {
dev_err(&vdev->dev, "failed to create nvdimm region\n");
err = -ENXIO;
goto out_nd;
}
return 0;
out_nd:
virtio_reset_device(vdev);
nvdimm_bus_unregister(vpmem->nvdimm_bus);
out_vq:
vdev->config->del_vqs(vdev);
out_err:
return err;
}
static void virtio_pmem_remove(struct virtio_device *vdev)
{
struct nvdimm_bus *nvdimm_bus = dev_get_drvdata(&vdev->dev);
nvdimm_bus_unregister(nvdimm_bus);
vdev->config->del_vqs(vdev);
virtio_reset_device(vdev);
}
static unsigned int features[] = {
VIRTIO_PMEM_F_SHMEM_REGION,
};
static struct virtio_driver virtio_pmem_driver = {
.feature_table = features,
.feature_table_size = ARRAY_SIZE(features),
.driver.name = KBUILD_MODNAME,
.driver.owner = THIS_MODULE,
.id_table = id_table,
.validate = virtio_pmem_validate,
.probe = virtio_pmem_probe,
.remove = virtio_pmem_remove,
};
module_virtio_driver(virtio_pmem_driver);
MODULE_DEVICE_TABLE(virtio, id_table);
MODULE_DESCRIPTION("Virtio pmem driver");
MODULE_LICENSE("GPL");