Extend cxl_validate_extent() — the per-extent check of the add pipeline
to check partition membership.
Resolves an extent's DPA to its containing DC partition. Then based on
if the partition is shareable:
- Shareable: tag must be non-null and shared_extn_seq must be non-zero
— multiple hosts reading the same allocation rely on the device-
stamped 1..n sequence to assemble extents in agreed order.
- Non-sharable: shared_extn_seq must be zero — sequencing is
meaningless when only one host consumes the allocation; tag is
optional (null UUID permitted).
Any cross-mix is a device firmware bug; reject the extent.
Based on patches by John Groves.
Signed-off-by: Ira Weiny <[email protected]>
Signed-off-by: John Groves <[email protected]>
Signed-off-by: Anisa Su <[email protected]>
---
Changes:
[anisa: split out as a separate validation step]
---
drivers/cxl/core/core.h | 4 ++
drivers/cxl/core/extent.c | 78 +++++++++++++++++++++++++++++++++++++--
2 files changed, 79 insertions(+), 3 deletions(-)
diff --git a/drivers/cxl/core/core.h b/drivers/cxl/core/core.h
index 1bae80dbf991..30b6b05b155b 100644
--- a/drivers/cxl/core/core.h
+++ b/drivers/cxl/core/core.h
@@ -179,6 +179,10 @@ int cxl_pci_get_bandwidth(struct pci_dev *pdev, struct
access_coordinate *c);
int cxl_port_get_switch_dport_bandwidth(struct cxl_port *port,
struct access_coordinate *c);
void memdev_release_extent(struct cxl_memdev_state *mds, struct range *range);
+const struct cxl_dpa_partition *
+cxl_extent_dc_partition(struct cxl_memdev_state *mds,
+ struct cxl_extent *extent,
+ struct range *ext_range);
static inline struct device *port_to_host(struct cxl_port *port)
{
diff --git a/drivers/cxl/core/extent.c b/drivers/cxl/core/extent.c
index 94128d06f4ed..b01507022cff 100644
--- a/drivers/cxl/core/extent.c
+++ b/drivers/cxl/core/extent.c
@@ -63,11 +63,55 @@ alloc_tag_group(struct cxl_dax_region *cxlr_dax, uuid_t
*uuid)
return no_free_ptr(group);
}
+/*
+ * Find the DC (Dynamic Capacity) partition that fully contains @ext_range,
+ * or NULL if the extent falls outside every DC partition on this memdev.
+ * The returned pointer is owned by mds->cxlds.part[] and lives for the
+ * lifetime of the memdev.
+ */
+const struct cxl_dpa_partition *
+cxl_extent_dc_partition(struct cxl_memdev_state *mds,
+ struct cxl_extent *extent,
+ struct range *ext_range)
+{
+ struct cxl_dev_state *cxlds = &mds->cxlds;
+ struct device *dev = mds->cxlds.dev;
+
+ for (int i = 0; i < cxlds->nr_partitions; i++) {
+ struct cxl_dpa_partition *part = &cxlds->part[i];
+ struct range partition_range = {
+ .start = part->res.start,
+ .end = part->res.end,
+ };
+
+ if (part->mode != CXL_PARTMODE_DYNAMIC_RAM_A)
+ continue;
+
+ if (range_contains(&partition_range, ext_range)) {
+ dev_dbg(dev, "DC extent DPA %pra (DCR:%pra)(%pU)\n",
+ ext_range, &partition_range, extent->uuid);
+ return part;
+ }
+ }
+
+ dev_err_ratelimited(dev,
+ "DC extent DPA %pra (%pU) is not in a valid DC
partition\n",
+ ext_range, extent->uuid);
+ return NULL;
+}
+
/*
* Stage 1 of the add pipeline: pure, no allocation. Resolve the extent
- * to its region/endpoint decoder and ext_range, and verify the range
- * fits in the resolved endpoint decoder's DPA resource. Further
- * per-extent invariants layer into this function in subsequent commits.
+ * to its region/endpoint decoder and ext_range, and enforce every
+ * per-extent invariant the device must satisfy:
+ *
+ * - DPA falls inside a Dynamic Capacity partition (cxl_extent_dc_partition).
+ * - CDAT-sharability rules:
+ * sharable: tag must be non-null AND shared_extn_seq != 0
+ * non-sharable: shared_extn_seq must be 0 (tag is optional)
+ * Any cross-mixing is a device firmware bug.
+ * - DPA resolves to an endpoint decoder attached to a region.
+ * - The extent's range is fully contained in that ED's DPA resource.
*
* Caller must hold cxl_rwsem.region for read (cxl_dpa_to_region()).
* On success, @out_cxled / @out_cxlr_dax / @out_ext_range carry the
@@ -81,6 +125,10 @@ static int cxl_validate_extent(struct cxl_memdev_state *mds,
{
u64 start_dpa = le64_to_cpu(extent->start_dpa);
struct cxl_memdev *cxlmd = mds->cxlds.cxlmd;
+ struct device *dev = mds->cxlds.dev;
+ uuid_t *uuid = (uuid_t *)extent->uuid;
+ u16 seq = le16_to_cpu(extent->shared_extn_seq);
+ const struct cxl_dpa_partition *part;
struct cxl_endpoint_decoder *cxled;
struct cxl_region *cxlr;
struct range ext_range = (struct range) {
@@ -89,6 +137,30 @@ static int cxl_validate_extent(struct cxl_memdev_state *mds,
};
struct range ed_range;
+ part = cxl_extent_dc_partition(mds, extent, &ext_range);
+ if (!part)
+ return -ENXIO;
+
+ if (part->perf.shareable) {
+ if (uuid_is_null(uuid)) {
+ dev_err_ratelimited(dev,
+ "DC extent DPA %pra: sharable-partition extent
has null tag (firmware bug)\n",
+ &ext_range);
+ return -ENXIO;
+ }
+ if (seq == 0) {
+ dev_err_ratelimited(dev,
+ "DC extent DPA %pra (%pU): sharable-partition
extent missing shared_extn_seq (firmware bug)\n",
+ &ext_range, uuid);
+ return -ENXIO;
+ }
+ } else if (seq != 0) {
+ dev_err_ratelimited(dev,
+ "DC extent DPA %pra (%pU): non-sharable partition but
shared_extn_seq=%u (firmware bug)\n",
+ &ext_range, uuid, seq);
+ return -ENXIO;
+ }
+
cxlr = cxl_dpa_to_region(cxlmd, start_dpa, &cxled);
if (!cxlr)
return -ENXIO;
--
2.43.0
