On Tue, Dec 19, 2023 at 7:57 PM Jason Wang <jasow...@redhat.com> wrote:
>
> On Tue, Dec 19, 2023 at 3:19 PM Changyuan Lyu <changyu...@google.com> wrote:
> >
> > +/* shmid of the shared memory region corresponding to the pmem */
> > +#define VIRTIO_PMEM_SHMCAP_ID 0
>
> NIT: not a native speaker, but any reason for "CAP" here? Would it be
> better to use SHMMEM_REGION_ID?
I was following the name VIRTIO_FS_SHMCAP_ID_CACHE in
include/uapi/linux/virtio_fs.h, where I guess "CAP" was referring to
the shared memory capability when the device is on PCI bus. I agree
SHMMEM_REGION_ID is a better name.
On Tue, Dec 19, 2023 at 3:19 PM Changyuan Lyu <changyu...@google.com> wrote:
>
> + if (!have_shm) {
> + dev_err(&vdev->dev, "failed to get shared memory region
> %d\n",
> + VIRTIO_PMEM_SHMCAP_ID);
> + return -EINVAL;
> + }
I realized that it needs to jump to tag out_vq to clean up vqs
instead of simply returnning an error.
Thanks for reviewing the patch!
---8<---
As per virtio spec 1.2 section 5.19.5.2, if the feature
VIRTIO_PMEM_F_SHMEM_REGION has been negotiated, the driver MUST query
shared memory ID 0 for the physical address ranges.
Signed-off-by: Changyuan Lyu <changyu...@google.com>
---
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 | 30 ++++++++++++++++++++++++++----
include/uapi/linux/virtio_pmem.h | 8 ++++++++
2 files changed, 34 insertions(+), 4 deletions(-)
diff --git a/drivers/nvdimm/virtio_pmem.c b/drivers/nvdimm/virtio_pmem.c
index a92eb172f0e7..8e447c7558cb 100644
--- a/drivers/nvdimm/virtio_pmem.c
+++ b/drivers/nvdimm/virtio_pmem.c
@@ -35,6 +35,8 @@ static int virtio_pmem_probe(struct virtio_device *vdev)
struct nd_region *nd_region;
struct virtio_pmem *vpmem;
struct resource res;
+ struct virtio_shm_region shm_reg;
+ bool have_shm;
int err = 0;
if (!vdev->config->get) {
@@ -57,10 +59,24 @@ 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)) {
+ have_shm = virtio_get_shm_region(vdev, &shm_reg,
+ (u8)VIRTIO_PMEM_SHMEM_REGION_ID);
+ 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;
+ }
+ 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;
@@ -122,7 +138,13 @@ 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,
diff --git a/include/uapi/linux/virtio_pmem.h b/include/uapi/linux/virtio_pmem.h
index d676b3620383..c5e49b6e58b1 100644
--- a/include/uapi/linux/virtio_pmem.h
+++ b/include/uapi/linux/virtio_pmem.h
@@ -14,6 +14,14 @@
#include <linux/virtio_ids.h>
#include <linux/virtio_config.h>
+/* Feature bits */
+#define VIRTIO_PMEM_F_SHMEM_REGION 0 /* guest physical address range will be
+ * indicated as shared memory 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
