Commit 09d09e04 authored by Dan Williams's avatar Dan Williams
Browse files

cxl/dax: Create dax devices for CXL RAM regions 



While platform firmware takes some responsibility for mapping the RAM
capacity of CXL devices present at boot, the OS is responsible for
mapping the remainder and hot-added devices. Platform firmware is also
responsible for identifying the platform general purpose memory pool,
typically DDR attached DRAM, and arranging for the remainder to be 'Soft
Reserved'. That reservation allows the CXL subsystem to route the memory
to core-mm via memory-hotplug (dax_kmem), or leave it for dedicated
access (device-dax).

The new 'struct cxl_dax_region' object allows for a CXL memory resource
(region) to be published, but also allow for udev and module policy to
act on that event. It also prevents cxl_core.ko from having a module
loading dependency on any drivers/dax/ modules.

Tested-by: default avatarFan Ni <fan.ni@samsung.com>
Reviewed-by: default avatarDave Jiang <dave.jiang@intel.com>
Reviewed-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/167602003896.1924368.10335442077318970468.stgit@dwillia2-xfh.jf.intel.com


Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent e9ee9fe3

MAINTAINERS

+1 −0
Original line number Diff line number Diff line
@@ -6035,6 +6035,7 @@ M: Dan Williams <dan.j.williams@intel.com> 
M:	Vishal Verma <vishal.l.verma@intel.com>

M:	Dave Jiang <dave.jiang@intel.com>

L:	nvdimm@lists.linux.dev

L:	linux-cxl@vger.kernel.org

S:	Supported

F:	drivers/dax/
































drivers/cxl/acpi.c



+2
−1






























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Diff line







@@ -731,7 +731,8 @@ static void __exit cxl_acpi_exit(void)







	cxl_bus_drain();









}



















module_init(cxl_acpi_init);









/* load before dax_hmem sees 'Soft Reserved' CXL ranges */









subsys_initcall(cxl_acpi_init);









module_exit(cxl_acpi_exit);









MODULE_LICENSE("GPL v2");









MODULE_IMPORT_NS(CXL);
































drivers/cxl/core/core.h



+3
−0






























Original line number
Diff line number
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@@ -15,12 +15,14 @@ extern struct device_attribute dev_attr_create_ram_region;







extern struct device_attribute dev_attr_delete_region;









extern struct device_attribute dev_attr_region;









extern const struct device_type cxl_pmem_region_type;









extern const struct device_type cxl_dax_region_type;









extern const struct device_type cxl_region_type;









void cxl_decoder_kill_region(struct cxl_endpoint_decoder *cxled);









#define CXL_REGION_ATTR(x) (&dev_attr_##x.attr)









#define CXL_REGION_TYPE(x) (&cxl_region_type)









#define SET_CXL_REGION_ATTR(x) (&dev_attr_##x.attr),









#define CXL_PMEM_REGION_TYPE(x) (&cxl_pmem_region_type)









#define CXL_DAX_REGION_TYPE(x) (&cxl_dax_region_type)









int cxl_region_init(void);









void cxl_region_exit(void);









#else








@@ -38,6 +40,7 @@ static inline void cxl_region_exit(void)







#define CXL_REGION_TYPE(x) NULL









#define SET_CXL_REGION_ATTR(x)









#define CXL_PMEM_REGION_TYPE(x) NULL









#define CXL_DAX_REGION_TYPE(x) NULL









#endif



















struct cxl_send_command;
































drivers/cxl/core/port.c



+3
−1






























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Diff line







@@ -46,6 +46,8 @@ static int cxl_device_id(struct device *dev)







		return CXL_DEVICE_NVDIMM;









	if (dev->type == CXL_PMEM_REGION_TYPE())









		return CXL_DEVICE_PMEM_REGION;









	if (dev->type == CXL_DAX_REGION_TYPE())









		return CXL_DEVICE_DAX_REGION;









	if (is_cxl_port(dev)) {









		if (is_cxl_root(to_cxl_port(dev)))









			return CXL_DEVICE_ROOT;








@@ -2015,6 +2017,6 @@ static void cxl_core_exit(void)







	debugfs_remove_recursive(cxl_debugfs);









}



















module_init(cxl_core_init);









subsys_initcall(cxl_core_init);









module_exit(cxl_core_exit);









MODULE_LICENSE("GPL v2");
























drivers/cxl/core/region.c



+106
−2






























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Diff line number
Diff line







@@ -2278,6 +2278,75 @@ static struct cxl_pmem_region *cxl_pmem_region_alloc(struct cxl_region *cxlr)







	return cxlr_pmem;









}



















static void cxl_dax_region_release(struct device *dev)









{









	struct cxl_dax_region *cxlr_dax = to_cxl_dax_region(dev);



















	kfree(cxlr_dax);









}



















static const struct attribute_group *cxl_dax_region_attribute_groups[] = {









	&cxl_base_attribute_group,









	NULL,









};



















const struct device_type cxl_dax_region_type = {









	.name = "cxl_dax_region",









	.release = cxl_dax_region_release,









	.groups = cxl_dax_region_attribute_groups,









};



















static bool is_cxl_dax_region(struct device *dev)









{









	return dev->type == &cxl_dax_region_type;









}



















struct cxl_dax_region *to_cxl_dax_region(struct device *dev)









{









	if (dev_WARN_ONCE(dev, !is_cxl_dax_region(dev),









			  "not a cxl_dax_region device\n"))









		return NULL;









	return container_of(dev, struct cxl_dax_region, dev);









}









EXPORT_SYMBOL_NS_GPL(to_cxl_dax_region, CXL);



















static struct lock_class_key cxl_dax_region_key;



















static struct cxl_dax_region *cxl_dax_region_alloc(struct cxl_region *cxlr)









{









	struct cxl_region_params *p = &cxlr->params;









	struct cxl_dax_region *cxlr_dax;









	struct device *dev;



















	down_read(&cxl_region_rwsem);









	if (p->state != CXL_CONFIG_COMMIT) {









		cxlr_dax = ERR_PTR(-ENXIO);









		goto out;









	}



















	cxlr_dax = kzalloc(sizeof(*cxlr_dax), GFP_KERNEL);









	if (!cxlr_dax) {









		cxlr_dax = ERR_PTR(-ENOMEM);









		goto out;









	}



















	cxlr_dax->hpa_range.start = p->res->start;









	cxlr_dax->hpa_range.end = p->res->end;



















	dev = &cxlr_dax->dev;









	cxlr_dax->cxlr = cxlr;









	device_initialize(dev);









	lockdep_set_class(&dev->mutex, &cxl_dax_region_key);









	device_set_pm_not_required(dev);









	dev->parent = &cxlr->dev;









	dev->bus = &cxl_bus_type;









	dev->type = &cxl_dax_region_type;









out:









	up_read(&cxl_region_rwsem);



















	return cxlr_dax;









}



















static void cxlr_pmem_unregister(void *_cxlr_pmem)









{









	struct cxl_pmem_region *cxlr_pmem = _cxlr_pmem;








@@ -2362,6 +2431,42 @@ static int devm_cxl_add_pmem_region(struct cxl_region *cxlr)







	return rc;









}



















static void cxlr_dax_unregister(void *_cxlr_dax)









{









	struct cxl_dax_region *cxlr_dax = _cxlr_dax;



















	device_unregister(&cxlr_dax->dev);









}



















static int devm_cxl_add_dax_region(struct cxl_region *cxlr)









{









	struct cxl_dax_region *cxlr_dax;









	struct device *dev;









	int rc;



















	cxlr_dax = cxl_dax_region_alloc(cxlr);









	if (IS_ERR(cxlr_dax))









		return PTR_ERR(cxlr_dax);



















	dev = &cxlr_dax->dev;









	rc = dev_set_name(dev, "dax_region%d", cxlr->id);









	if (rc)









		goto err;



















	rc = device_add(dev);









	if (rc)









		goto err;



















	dev_dbg(&cxlr->dev, "%s: register %s\n", dev_name(dev->parent),









		dev_name(dev));



















	return devm_add_action_or_reset(&cxlr->dev, cxlr_dax_unregister,









					cxlr_dax);









err:









	put_device(dev);









	return rc;









}



















static int match_decoder_by_range(struct device *dev, void *data)









{









	struct range *r1, *r2 = data;








@@ -2624,8 +2729,7 @@ static int cxl_region_probe(struct device *dev)







					p->res->start, p->res->end, cxlr,









					is_system_ram) > 0)









			return 0;









		dev_dbg(dev, "TODO: hookup devdax\n");









		return 0;









		return devm_cxl_add_dax_region(cxlr);









	default:









		dev_dbg(&cxlr->dev, "unsupported region mode: %d\n",









			cxlr->mode);