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virtio_pmem: support feature SHMEM_REGION

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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>
This commit is contained in:
Changyuan Lyu 2023-12-20 12:49:06 -08:00 committed by Michael S. Tsirkin
parent b12fbc3f78
commit 35967bdcff
2 changed files with 39 additions and 4 deletions
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36
drivers/nvdimm/virtio_pmem.c
View File

@ -29,12 +29,27 @@ static int init_vq(struct virtio_pmem *vpmem)
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) {
@ -57,10 +72,16 @@ static int virtio_pmem_probe(struct virtio_device *vdev)
goto out_err;
}
virtio_cread_le(vpmem->vdev, struct virtio_pmem_config,
start, &vpmem->start);
virtio_cread_le(vpmem->vdev, struct virtio_pmem_config,
size, &vpmem->size);
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;
@ -122,10 +143,17 @@ static void virtio_pmem_remove(struct virtio_device *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,
};

7
include/uapi/linux/virtio_pmem.h
View File

@ -14,6 +14,13 @@
#include <linux/virtio_ids.h>
#include <linux/virtio_config.h>
/* Feature bits */
/* guest physical address range will be indicated as shared memory region 0 */
#define VIRTIO_PMEM_F_SHMEM_REGION 0
/* shmid of the shared memory region corresponding to the pmem */
#define VIRTIO_PMEM_SHMEM_REGION_ID 0
struct virtio_pmem_config {
__le64 start;
__le64 size;