| Message ID | 162766355874.3223041.9582643895337437921.stgit@dwillia2-desk3.amr.corp.intel.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | ACPI: NFIT: Fix support for virtual SPA ranges | expand |
Dan Williams <dan.j.williams@intel.com> writes: > 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 ^^^^^^^ That language confused me. I thought you were talking about a separate issue, whereby NVDIMMs which are not mapped (probably due to some errors with the dimms themselves) would get an index of 0. But upon re-reading, I think you just meant that the virtual media is not mapped via a region mapping structure. > 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) { The change looks good, but can you add a comment to the code? With that, you can add my: Reviewed-by: Jeff Moyer <jmoyer@redhat.com> Thanks! Jeff
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) {
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(+)