ACPI: HMAT: attach a device for each soft-reserved range

The hmem enabling in commit b7f0a1ddc45b ("ACPI: NUMA: HMAT: Register
"soft reserved" memory as an "hmem" device") only registered ranges to the
hmem driver for each soft-reservation that also appeared in the HMAT.
While this is meant to encourage platform firmware to "do the right thing"
and publish an HMAT, the corollary is that platforms that fail to publish
an accurate HMAT will strand memory from Linux usage.  Additionally, the
"efi_fake_mem" kernel command line option enabling will strand memory by
default without an HMAT.

Arrange for "soft reserved" memory that goes unclaimed by HMAT entries to
be published as raw resource ranges for the hmem driver to consume.

Include a module parameter to disable either this fallback behavior, or
the hmat enabling from creating hmem devices.  The module parameter
requires the hmem device enabling to have unique name in the module
namespace: "device_hmem".

The driver depends on the architecture providing phys_to_target_node()
which is only x86 via numa_meminfo() and arm64 via a generic memblock
implementation.

[joao.m.martins@oracle.com: require NUMA_KEEP_MEMINFO for phys_to_target_node()]
Link: https://lkml.kernel.org/r/aaae71a7-4846-f5cc-5acf-cf05fdb1f2dc@oracle.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Joao Martins <joao.m.martins@oracle.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Brice Goglin <Brice.Goglin@inria.fr>
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: David Airlie <airlied@linux.ie>
Cc: David Hildenbrand <david@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jason Gunthorpe <jgg@mellanox.com>
Cc: Jia He <justin.he@arm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Wei Yang <richard.weiyang@linux.alibaba.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Hulk Robot <hulkci@huawei.com>
Cc: Jason Yan <yanaijie@huawei.com>
Cc: "Jérôme Glisse" <jglisse@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: kernel test robot <lkp@intel.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Link: https://lkml.kernel.org/r/159643098298.4062302.17587338161136144730.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/dax/Kconfig b/drivers/dax/Kconfig
index a66dff78f298b4e6d549c901650854b3a6b98d3e..567428e10b7b1fe06ba4aed46858a1104448d41a 100644 (file)
--- a/drivers/dax/Kconfig
+++ b/drivers/dax/Kconfig
@@ -35,6 +35,7 @@ config DEV_DAX_PMEM
 config DEV_DAX_HMEM
        tristate "HMEM DAX: direct access to 'specific purpose' memory"
        depends on EFI_SOFT_RESERVE
+       select NUMA_KEEP_MEMINFO if (NUMA && X86)
        default DEV_DAX
        help
          EFI 2.8 platforms, and others, may advertise 'specific purpose'
@@ -49,6 +50,7 @@ config DEV_DAX_HMEM
          Say M if unsure.
 
 config DEV_DAX_HMEM_DEVICES
+       depends on NUMA_KEEP_MEMINFO # for phys_to_target_node()
        depends on DEV_DAX_HMEM && DAX=y
        def_bool y
 

diff --git a/drivers/dax/hmem/Makefile b/drivers/dax/hmem/Makefile
index a9d353d0c9edd0f282d418c3779390ca00f5d205..57377b4c3d47d92abee7746eca55a28476c51ff9 100644 (file)
--- a/drivers/dax/hmem/Makefile
+++ b/drivers/dax/hmem/Makefile
@@ -1,5 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0
 obj-$(CONFIG_DEV_DAX_HMEM) += dax_hmem.o
-obj-$(CONFIG_DEV_DAX_HMEM_DEVICES) += device.o
+obj-$(CONFIG_DEV_DAX_HMEM_DEVICES) += device_hmem.o
 
+device_hmem-y := device.o
 dax_hmem-y := hmem.o

diff --git a/drivers/dax/hmem/device.c b/drivers/dax/hmem/device.c
index b9dd6b27745c783628f9fd5f69c8f84375de57e9..cb6401c9e9a4fcb69c501bdfd90cb82d79bba71d 100644 (file)
--- a/drivers/dax/hmem/device.c
+++ b/drivers/dax/hmem/device.c
@@ -5,6 +5,9 @@
 #include <linux/dax.h>
 #include <linux/mm.h>
 
+static bool nohmem;
+module_param_named(disable, nohmem, bool, 0444);
+
 void hmem_register_device(int target_nid, struct resource *r)
 {
        /* define a clean / non-busy resource for the platform device */
@@ -17,6 +20,9 @@ void hmem_register_device(int target_nid, struct resource *r)
        struct memregion_info info;
        int rc, id;
 
+       if (nohmem)
+               return;
+
        rc = region_intersects(res.start, resource_size(&res), IORESOURCE_MEM,
                        IORES_DESC_SOFT_RESERVED);
        if (rc != REGION_INTERSECTS)
@@ -63,3 +69,32 @@ out_resource:
 out_pdev:
        memregion_free(id);
 }
+
+static __init int hmem_register_one(struct resource *res, void *data)
+{
+       /*
+        * If the resource is not a top-level resource it was already
+        * assigned to a device by the HMAT parsing.
+        */
+       if (res->parent != &iomem_resource) {
+               pr_info("HMEM: skip %pr, already claimed\n", res);
+               return 0;
+       }
+
+       hmem_register_device(phys_to_target_node(res->start), res);
+
+       return 0;
+}
+
+static __init int hmem_init(void)
+{
+       walk_iomem_res_desc(IORES_DESC_SOFT_RESERVED,
+                       IORESOURCE_MEM, 0, -1, NULL, hmem_register_one);
+       return 0;
+}
+
+/*
+ * As this is a fallback for address ranges unclaimed by the ACPI HMAT
+ * parsing it must be at an initcall level greater than hmat_init().
+ */
+late_initcall(hmem_init);