| Message ID | 20250603221949.53272-8-Smita.KoralahalliChannabasappa@amd.com |
|---|---|
| State | New |
| Headers | show |
| Series | Add managed SOFT RESERVE resource handling | expand |
On Tue, 3 Jun 2025 22:19:49 +0000 Smita Koralahalli <Smita.KoralahalliChannabasappa@amd.com> wrote: > From: Nathan Fontenot <nathan.fontenot@amd.com> > > The DAX HMEM driver currently consumes all SOFT RESERVED iomem resources > during initialization. This interferes with the CXL driver’s ability to > create regions and trim overlapping SOFT RESERVED ranges before DAX uses > them. > > To resolve this, defer the DAX driver's resource consumption if the > cxl_acpi driver is enabled. The DAX HMEM initialization skips walking the > iomem resource tree in this case. After CXL region creation completes, > any remaining SOFT RESERVED resources are explicitly registered with the > DAX driver by the CXL driver. > > This sequencing ensures proper handling of overlaps and fixes hotplug > failures. > > Co-developed-by: Nathan Fontenot <Nathan.Fontenot@amd.com> > Signed-off-by: Nathan Fontenot <Nathan.Fontenot@amd.com> > Co-developed-by: Terry Bowman <terry.bowman@amd.com> > Signed-off-by: Terry Bowman <terry.bowman@amd.com> > Signed-off-by: Smita Koralahalli <Smita.KoralahalliChannabasappa@amd.com> > --- > drivers/cxl/core/region.c | 10 +++++++++ > drivers/dax/hmem/device.c | 43 ++++++++++++++++++++------------------- > drivers/dax/hmem/hmem.c | 3 ++- > include/linux/dax.h | 6 ++++++ > 4 files changed, 40 insertions(+), 22 deletions(-) > > diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c > index 3a5ca44d65f3..c6c0c7ba3b20 100644 > --- a/drivers/cxl/core/region.c > +++ b/drivers/cxl/core/region.c > @@ -10,6 +10,7 @@ > #include <linux/sort.h> > #include <linux/idr.h> > #include <linux/memory-tiers.h> > +#include <linux/dax.h> > #include <cxlmem.h> > #include <cxl.h> > #include "core.h" > @@ -3553,6 +3554,11 @@ static struct resource *normalize_resource(struct resource *res) > return NULL; > } > > +static int cxl_softreserv_mem_register(struct resource *res, void *unused) > +{ > + return hmem_register_device(phys_to_target_node(res->start), res); > +} > + > static int __cxl_region_softreserv_update(struct resource *soft, > void *_cxlr) > { > @@ -3590,6 +3596,10 @@ int cxl_region_softreserv_update(void) > __cxl_region_softreserv_update); > } > > + /* Now register any remaining SOFT RESERVES with DAX */ > + walk_iomem_res_desc(IORES_DESC_SOFT_RESERVED, IORESOURCE_MEM, > + 0, -1, NULL, cxl_softreserv_mem_register); > + > return 0; > } > EXPORT_SYMBOL_NS_GPL(cxl_region_softreserv_update, "CXL"); > diff --git a/drivers/dax/hmem/device.c b/drivers/dax/hmem/device.c > index 59ad44761191..cc1ed7bbdb1a 100644 > --- a/drivers/dax/hmem/device.c > +++ b/drivers/dax/hmem/device.c > @@ -8,7 +8,6 @@ > static bool nohmem; > module_param_named(disable, nohmem, bool, 0444); > > -static bool platform_initialized; > static DEFINE_MUTEX(hmem_resource_lock); > static struct resource hmem_active = { > .name = "HMEM devices", > @@ -35,9 +34,7 @@ EXPORT_SYMBOL_GPL(walk_hmem_resources); > > static void __hmem_register_resource(int target_nid, struct resource *res) > { > - struct platform_device *pdev; > struct resource *new; > - int rc; > > new = __request_region(&hmem_active, res->start, resource_size(res), "", > 0); > @@ -47,21 +44,6 @@ static void __hmem_register_resource(int target_nid, struct resource *res) > } > > new->desc = target_nid; > - > - if (platform_initialized) > - return; > - > - pdev = platform_device_alloc("hmem_platform", 0); > - if (!pdev) { > - pr_err_once("failed to register device-dax hmem_platform device\n"); > - return; > - } > - > - rc = platform_device_add(pdev); > - if (rc) > - platform_device_put(pdev); > - else > - platform_initialized = true; > } > > void hmem_register_resource(int target_nid, struct resource *res) > @@ -83,9 +65,28 @@ static __init int hmem_register_one(struct resource *res, void *data) > > static __init int hmem_init(void) > { > - walk_iomem_res_desc(IORES_DESC_SOFT_RESERVED, > - IORESOURCE_MEM, 0, -1, NULL, hmem_register_one); > - return 0; > + struct platform_device *pdev; > + int rc; > + > + if (!IS_ENABLED(CONFIG_CXL_ACPI)) { > + walk_iomem_res_desc(IORES_DESC_SOFT_RESERVED, > + IORESOURCE_MEM, 0, -1, NULL, > + hmem_register_one); > + } > + > + pdev = platform_device_alloc("hmem_platform", 0); > + if (!pdev) { > + pr_err("failed to register device-dax hmem_platform device\n"); > + return -1; > + } > + > + rc = platform_device_add(pdev); platform_device_register_simple("hmem_platform", -1, NULL, 0); or something like that? There are quite a few variants of platform_device_register to cover simple cases. > + if (rc) { > + pr_err("failed to add device-dax hmem_platform device\n"); > + platform_device_put(pdev); > + } > + > + return rc; > } > > /*
diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c index 3a5ca44d65f3..c6c0c7ba3b20 100644 --- a/drivers/cxl/core/region.c +++ b/drivers/cxl/core/region.c @@ -10,6 +10,7 @@ #include <linux/sort.h> #include <linux/idr.h> #include <linux/memory-tiers.h> +#include <linux/dax.h> #include <cxlmem.h> #include <cxl.h> #include "core.h" @@ -3553,6 +3554,11 @@ static struct resource *normalize_resource(struct resource *res) return NULL; } +static int cxl_softreserv_mem_register(struct resource *res, void *unused) +{ + return hmem_register_device(phys_to_target_node(res->start), res); +} + static int __cxl_region_softreserv_update(struct resource *soft, void *_cxlr) { @@ -3590,6 +3596,10 @@ int cxl_region_softreserv_update(void) __cxl_region_softreserv_update); } + /* Now register any remaining SOFT RESERVES with DAX */ + walk_iomem_res_desc(IORES_DESC_SOFT_RESERVED, IORESOURCE_MEM, + 0, -1, NULL, cxl_softreserv_mem_register); + return 0; } EXPORT_SYMBOL_NS_GPL(cxl_region_softreserv_update, "CXL"); diff --git a/drivers/dax/hmem/device.c b/drivers/dax/hmem/device.c index 59ad44761191..cc1ed7bbdb1a 100644 --- a/drivers/dax/hmem/device.c +++ b/drivers/dax/hmem/device.c @@ -8,7 +8,6 @@ static bool nohmem; module_param_named(disable, nohmem, bool, 0444); -static bool platform_initialized; static DEFINE_MUTEX(hmem_resource_lock); static struct resource hmem_active = { .name = "HMEM devices", @@ -35,9 +34,7 @@ EXPORT_SYMBOL_GPL(walk_hmem_resources); static void __hmem_register_resource(int target_nid, struct resource *res) { - struct platform_device *pdev; struct resource *new; - int rc; new = __request_region(&hmem_active, res->start, resource_size(res), "", 0); @@ -47,21 +44,6 @@ static void __hmem_register_resource(int target_nid, struct resource *res) } new->desc = target_nid; - - if (platform_initialized) - return; - - pdev = platform_device_alloc("hmem_platform", 0); - if (!pdev) { - pr_err_once("failed to register device-dax hmem_platform device\n"); - return; - } - - rc = platform_device_add(pdev); - if (rc) - platform_device_put(pdev); - else - platform_initialized = true; } void hmem_register_resource(int target_nid, struct resource *res) @@ -83,9 +65,28 @@ static __init int hmem_register_one(struct resource *res, void *data) static __init int hmem_init(void) { - walk_iomem_res_desc(IORES_DESC_SOFT_RESERVED, - IORESOURCE_MEM, 0, -1, NULL, hmem_register_one); - return 0; + struct platform_device *pdev; + int rc; + + if (!IS_ENABLED(CONFIG_CXL_ACPI)) { + walk_iomem_res_desc(IORES_DESC_SOFT_RESERVED, + IORESOURCE_MEM, 0, -1, NULL, + hmem_register_one); + } + + pdev = platform_device_alloc("hmem_platform", 0); + if (!pdev) { + pr_err("failed to register device-dax hmem_platform device\n"); + return -1; + } + + rc = platform_device_add(pdev); + if (rc) { + pr_err("failed to add device-dax hmem_platform device\n"); + platform_device_put(pdev); + } + + return rc; } /* diff --git a/drivers/dax/hmem/hmem.c b/drivers/dax/hmem/hmem.c index 3aedef5f1be1..a206b9b383e4 100644 --- a/drivers/dax/hmem/hmem.c +++ b/drivers/dax/hmem/hmem.c @@ -61,7 +61,7 @@ static void release_hmem(void *pdev) platform_device_unregister(pdev); } -static int hmem_register_device(int target_nid, const struct resource *res) +int hmem_register_device(int target_nid, const struct resource *res) { struct device *host = &dax_hmem_pdev->dev; struct platform_device *pdev; @@ -124,6 +124,7 @@ static int hmem_register_device(int target_nid, const struct resource *res) platform_device_put(pdev); return rc; } +EXPORT_SYMBOL_GPL(hmem_register_device); static int dax_hmem_platform_probe(struct platform_device *pdev) { diff --git a/include/linux/dax.h b/include/linux/dax.h index a4ad3708ea35..5052dca8b3bc 100644 --- a/include/linux/dax.h +++ b/include/linux/dax.h @@ -299,10 +299,16 @@ static inline int dax_mem2blk_err(int err) #ifdef CONFIG_DEV_DAX_HMEM_DEVICES void hmem_register_resource(int target_nid, struct resource *r); +int hmem_register_device(int target_nid, const struct resource *res); #else static inline void hmem_register_resource(int target_nid, struct resource *r) { } + +static inline int hmem_register_device(int target_nid, const struct resource *res) +{ + return 0; +} #endif typedef int (*walk_hmem_fn)(int target_nid, const struct resource *res);