[FEATURE]: detect mtrr default value
Bug #1322526 reported by
Alex Hung
This bug affects 1 person
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
Firmware Test Suite |
Fix Released
|
Undecided
|
Alex Hung |
Bug Description
mtrr tests show error messages as below:
mtrr: Memory range 0x1000 to 0x5efff (System RAM) has incorrect attribute Default (Most probably Uncached).
According to HP's BIOS engineer in UEFI Plugfest, HP's specifies default to "write-back", and therefore the error can be false positive. fwts should also detect whether default is specified in CPU.
Changed in fwts: | |
assignee: | nobody → Alex Hung (alexhung) |
summary: |
- [FEATURE]: detect mtrr default value + [FEATURE]: detect mtrr default value |
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According to Intel's 64-ia-32- architectures- software- developer- vol-3a- 3b-system- programming- manual, Section 11.5.1 defines CR0's two bits, NW and CD, that control system-wide catch behaviours, i.e. "If the NW and CD flags are clear, write-back is enabled for the whole of system memory". The definition of CR0 and these two bits can also be found in Section 2.5.