5566e68d82
arch_rmrr_sanity_check() warns if the RMRR is not covered by an ACPI
Reserved region, but it seems like it should accept an NVS region as
well. The ACPI spec
https://uefi.org/specs/ACPI/6.5/15_System_Address_Map_Interfaces.html
uses similar wording for "Reserved" and "NVS" region types; for NVS
regions it says "This range of addresses is in use or reserved by the
system and must not be used by the operating system."
There is an old comment on this mailing list that also suggests NVS
regions should pass the arch_rmrr_sanity_check() test:
The warnings come from arch_rmrr_sanity_check() since it checks whether
the region is E820_TYPE_RESERVED. However, if the purpose of the check
is to detect RMRR has regions that may be used by OS as free memory,
isn't E820_TYPE_NVS safe, too?
This patch overlaps with another proposed patch that would add the region
type to the log since sometimes the bug reporter sees this log on the
console but doesn't know to include the kernel log:
https://lore.kernel.org/lkml/20220611204859.234975-3-atomlin@redhat.com/
Here's an example of the "Firmware Bug" apparent false positive (wrapped
for line length):
DMAR: [Firmware Bug]: No firmware reserved region can cover this RMRR
[0x000000006f760000-0x000000006f762fff], contact BIOS vendor for
fixes
DMAR: [Firmware Bug]: Your BIOS is broken; bad RMRR
[0x000000006f760000-0x000000006f762fff]
This is the snippet from the e820 table:
BIOS-e820: [mem 0x0000000068bff000-0x000000006ebfefff] reserved
BIOS-e820: [mem 0x000000006ebff000-0x000000006f9fefff] ACPI NVS
BIOS-e820: [mem 0x000000006f9ff000-0x000000006fffefff] ACPI data
Fixes:
|
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.