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From: Dan Williams <dan.j.williams@intel.com>
To: nvdimm@lists.linux.dev
Cc: Jacek Zloch <jacek.zloch@intel.com>,
	Lukasz Sobieraj <lukasz.sobieraj@intel.com>,
	"Lee, Chun-Yi" <jlee@suse.com>,
	stable@vger.kernel.org,
	Krzysztof Rusocki <krzysztof.rusocki@intel.com>,
	Damian Bassa <damian.bassa@intel.com>,
	vishal.l.verma@intel.com
Subject: [PATCH] ACPI: NFIT: Fix support for virtual SPA ranges
Date: Fri, 30 Jul 2021 09:45:58 -0700	[thread overview]
Message-ID: <162766355874.3223041.9582643895337437921.stgit@dwillia2-desk3.amr.corp.intel.com> (raw)

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 unmapped
NVDIMMs with a 0 index in their "SPA Range Structure Index" the driver
falsely matches them and 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>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 drivers/acpi/nfit/core.c |    2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c
index 23d9a09d7060..6f15e56ef955 100644
--- a/drivers/acpi/nfit/core.c
+++ b/drivers/acpi/nfit/core.c
@@ -3021,6 +3021,8 @@ 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;
 
+		if (memdev->range_index == 0 || spa->range_index == 0)
+			continue;
 		if (memdev->range_index != spa->range_index)
 			continue;
 		if (count >= ND_MAX_MAPPINGS) {


             reply	other threads:[~2021-07-30 16:46 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-30 16:45 Dan Williams [this message]
2021-08-04 16:54 ` Jeff Moyer
2021-08-11 18:53 ` [PATCH v2] " Dan Williams

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