diff mbox series

[v13,19/22] cxl: add region flag for precluding a device memory to be used for dax

Message ID 20250414151336.3852990-20-alejandro.lucero-palau@amd.com (mailing list archive)
State Not Applicable
Headers show
Series Type2 device basic support | expand

Checks

Context Check Description
netdev/series_format fail Series longer than 15 patches
netdev/tree_selection success Guessed tree name to be net-next
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 3 this patch: 3
netdev/build_tools success Errors and warnings before: 26 (+2) this patch: 26 (+2)
netdev/cc_maintainers warning 4 maintainers not CCed: dave@stgolabs.net vishal.l.verma@intel.com ira.weiny@intel.com alison.schofield@intel.com
netdev/build_clang success Errors and warnings before: 4 this patch: 4
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 4 this patch: 4
netdev/checkpatch warning WARNING: line length of 82 exceeds 80 columns
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 5 this patch: 5
netdev/source_inline success Was 0 now: 0

Commit Message

Lucero Palau, Alejandro April 14, 2025, 3:13 p.m. UTC 
From: Alejandro Lucero <alucerop@amd.com>

By definition a type2 cxl device will use the host managed memory for
specific functionality, therefore it should not be available to other
uses. However, a dax interface could be just good enough in some cases.

Add a flag to a cxl region for specifically state to not create a dax
device. Allow a Type2 driver to set that flag at region creation time.

Signed-off-by: Alejandro Lucero <alucerop@amd.com>
Reviewed-by: Zhi Wang <zhiw@nvidia.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Ben Cheatham <benjamin.cheatham@amd.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
---
 drivers/cxl/core/region.c | 10 +++++++++-
 drivers/cxl/cxl.h         |  3 +++
 include/cxl/cxl.h         |  3 ++-
 3 files changed, 14 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
index f55fb253ecde..cec168a26efb 100644
--- a/drivers/cxl/core/region.c
+++ b/drivers/cxl/core/region.c
@@ -3649,12 +3649,14 @@  __construct_new_region(struct cxl_root_decoder *cxlrd,
  * @cxlrd: root decoder to allocate HPA
  * @cxled: endpoint decoder with reserved DPA capacity
  * @ways: interleave ways required
+ * @no_dax: if true no DAX device should be created
  *
  * Returns a fully formed region in the commit state and attached to the
  * cxl_region driver.
  */
 struct cxl_region *cxl_create_region(struct cxl_root_decoder *cxlrd,
-				     struct cxl_endpoint_decoder *cxled, int ways)
+				     struct cxl_endpoint_decoder *cxled, int ways,
+				     bool no_dax)
 {
 	struct cxl_region *cxlr;
 
@@ -3670,6 +3672,9 @@  struct cxl_region *cxl_create_region(struct cxl_root_decoder *cxlrd,
 		return ERR_PTR(-ENODEV);
 	}
 
+	if (no_dax)
+		set_bit(CXL_REGION_F_NO_DAX, &cxlr->flags);
+
 	return cxlr;
 }
 EXPORT_SYMBOL_NS_GPL(cxl_create_region, "CXL");
@@ -3833,6 +3838,9 @@  static int cxl_region_probe(struct device *dev)
 	if (rc)
 		return rc;
 
+	if (test_bit(CXL_REGION_F_NO_DAX, &cxlr->flags))
+		return 0;
+
 	switch (cxlr->mode) {
 	case CXL_PARTMODE_PMEM:
 		return devm_cxl_add_pmem_region(cxlr);
diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
index c35620c24c8f..2eb927c9229c 100644
--- a/drivers/cxl/cxl.h
+++ b/drivers/cxl/cxl.h
@@ -405,6 +405,9 @@  struct cxl_region_params {
  */
 #define CXL_REGION_F_NEEDS_RESET 1
 
+/* Allow Type2 drivers to specify if a dax region should not be created. */
+#define CXL_REGION_F_NO_DAX 2
+
 /**
  * struct cxl_region - CXL region
  * @dev: This region's device
diff --git a/include/cxl/cxl.h b/include/cxl/cxl.h
index 21cb39dcee9e..0a5d97d5a6bb 100644
--- a/include/cxl/cxl.h
+++ b/include/cxl/cxl.h
@@ -267,7 +267,8 @@  struct cxl_endpoint_decoder *cxl_request_dpa(struct cxl_memdev *cxlmd,
 					     resource_size_t alloc);
 int cxl_dpa_free(struct cxl_endpoint_decoder *cxled);
 struct cxl_region *cxl_create_region(struct cxl_root_decoder *cxlrd,
-				     struct cxl_endpoint_decoder *cxled, int ways);
+				     struct cxl_endpoint_decoder *cxled, int ways,
+				     bool no_dax);
 
 int cxl_accel_region_detach(struct cxl_endpoint_decoder *cxled);
 #endif /* __CXL_CXL_H__ */