RE: [PATCH v7] x86/mce: retrieve poison range from hardware

Luck, Tony
2022-08-23T18:35:55Z

> What I'm missing from this text here is, what *is* the mce->misc LSB
> field in human speak? What does that field denote?

The SDM says:

Recoverable Address LSB (bits 5:0): The lowest valid recoverable address bit. Indicates the position of the least
significant bit (LSB) of the recoverable error address. For example, if the processor logs bits [43:9] of the
address, the LSB sub-field in IA32_MCi_MISC is 01001b (9 decimal). For this example, bits [8:0] of the
recoverable error address in IA32_MCi_ADDR should be ignored.

So in human speak "how much data did you lose". "6" is a common value saying a cache line (2<<6 == 64)
was lost. Sometimes you see "12' (2<<12 == 4096) for a whole page lost.

-Tony