Thanks Michael for the feedback!
On Tue, Dec 19, 2023 at 11:44 PM Michael S. Tsirkin <mst@xxxxxxxxxx> wrote:
>
> > On Tue, Dec 19, 2023 at 11:32:27PM -0800, Changyuan Lyu wrote:
> >
> > + if (!have_shm) {
> > + dev_err(&vdev->dev, "failed to get shared memory region %d\n",
> > + VIRTIO_PMEM_SHMEM_REGION_ID);
> > + err = -ENXIO;
> > + goto out_vq;
> > + }
>
> Maybe additionally, add a validate callback and clear
> VIRTIO_PMEM_F_SHMEM_REGION if VIRTIO_PMEM_SHMEM_REGION_ID is not there.
Done.
> > +/* Feature bits */
> > +#define VIRTIO_PMEM_F_SHMEM_REGION 0 /* guest physical address range will be
> > + * indicated as shared memory region 0
> > + */
>
> Either make this comment shorter to fit in one line, or put the
> multi-line comment before the define.
Done.
---8<---
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@xxxxxxxxxx>
---
v4:
* added virtio_pmem_validate callback.
v3:
* updated the patch description.
V2:
* renamed VIRTIO_PMEM_SHMCAP_ID to VIRTIO_PMEM_SHMEM_REGION_ID
* fixed the error handling when region 0 does not exist
---
drivers/nvdimm/virtio_pmem.c | 36 ++++++++++++++++++++++++++++----
include/uapi/linux/virtio_pmem.h | 7 +++++++
2 files changed, 39 insertions(+), 4 deletions(-)
diff --git a/drivers/nvdimm/virtio_pmem.c b/drivers/nvdimm/virtio_pmem.c
index a92eb172f0e7..4ceced5cefcf 100644
--- a/drivers/nvdimm/virtio_pmem.c
+++ b/drivers/nvdimm/virtio_pmem.c
@@ -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,
};
diff --git a/include/uapi/linux/virtio_pmem.h b/include/uapi/linux/virtio_pmem.h
index d676b3620383..ede4f3564977 100644
--- a/include/uapi/linux/virtio_pmem.h
+++ b/include/uapi/linux/virtio_pmem.h
@@ -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;
--
2.43.0.472.g3155946c3a-goog
