From b93dfa6bda4d4e88e5386490f2b277a26958f9d3 Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Wed, 11 Aug 2021 11:53:37 -0700 Subject: [PATCH] ACPI: NFIT: Fix support for virtual SPA ranges Fix the NFIT parsing code to treat a 0 index in a SPA Range Structure as a special case and not match Region Mapping Structures that use 0 to indicate that they are not mapped. Without this fix some platform BIOS descriptions of "virtual disk" ranges do not result in the pmem driver attaching to the range. Details: In addition to typical persistent memory ranges, the ACPI NFIT may also convey "virtual" ranges. These ranges are indicated by a UUID in the SPA Range Structure of UUID_VOLATILE_VIRTUAL_DISK, UUID_VOLATILE_VIRTUAL_CD, UUID_PERSISTENT_VIRTUAL_DISK, or UUID_PERSISTENT_VIRTUAL_CD. The critical difference between virtual ranges and UUID_PERSISTENT_MEMORY, is that virtual do not support associations with Region Mapping Structures. For this reason the "index" value of virtual SPA Range Structures is allowed to be 0. If a platform BIOS decides to represent NVDIMMs with disconnected "Region Mapping Structures" (range-index == 0), the kernel may falsely associate them with standalone ranges where the "SPA Range Structure Index" is also zero. When this happens the driver may falsely require labels where "virtual disks" are expected to be label-less. I.e. "label-less" is where the namespace-range == region-range and the pmem driver attaches with no user action to create a namespace. Cc: Jacek Zloch Cc: Lukasz Sobieraj Cc: "Lee, Chun-Yi" Cc: Fixes: c2f32acdf848 ("acpi, nfit: treat virtual ramdisk SPA as pmem region") Reported-by: Krzysztof Rusocki Reported-by: Damian Bassa Reviewed-by: Jeff Moyer Link: https://lore.kernel.org/r/162870796589.2521182.1240403310175570220.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams --- drivers/acpi/nfit/core.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c index 23d9a09d7060..a3ef6cce644c 100644 --- a/drivers/acpi/nfit/core.c +++ b/drivers/acpi/nfit/core.c @@ -3021,6 +3021,9 @@ static int acpi_nfit_register_region(struct acpi_nfit_desc *acpi_desc, struct acpi_nfit_memory_map *memdev = nfit_memdev->memdev; struct nd_mapping_desc *mapping; + /* range index 0 == unmapped in SPA or invalid-SPA */ + if (memdev->range_index == 0 || spa->range_index == 0) + continue; if (memdev->range_index != spa->range_index) continue; if (count >= ND_MAX_MAPPINGS) { -- 2.11.0