From: Dan Williams dan.j.williams@intel.com
commit b93dfa6bda4d4e88e5386490f2b277a26958f9d3 upstream.
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 jacek.zloch@intel.com Cc: Lukasz Sobieraj lukasz.sobieraj@intel.com Cc: "Lee, Chun-Yi" jlee@suse.com Cc: stable@vger.kernel.org Fixes: c2f32acdf848 ("acpi, nfit: treat virtual ramdisk SPA as pmem region") Reported-by: Krzysztof Rusocki krzysztof.rusocki@intel.com Reported-by: Damian Bassa damian.bassa@intel.com Reviewed-by: Jeff Moyer jmoyer@redhat.com Link: https://lore.kernel.org/r/162870796589.2521182.1240403310175570220.stgit@dwi... Signed-off-by: Dan Williams dan.j.williams@intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/acpi/nfit/core.c | 3 +++ 1 file changed, 3 insertions(+)
--- a/drivers/acpi/nfit/core.c +++ b/drivers/acpi/nfit/core.c @@ -3021,6 +3021,9 @@ static int acpi_nfit_register_region(str 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) {