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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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include/uapi/linux/virtio_pmem.h
+7
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;