> > Example CEDT Entries (truncated) > Subtable Type : 00 [CXL Host Bridge Structure] > Reserved : 00 > Length : 0020 > Associated host bridge : 00000005 > > Subtable Type : 01 [CXL Fixed Memory Window Structure] > Reserved : 00 > Length : 002C > Reserved : 00000000 > Window base address : 000000C050000000 > Window size : 0000003CA0000000 > > If this memory is NOT marked "Special Purpose" by BIOS (next section), Specific purpose. You don't want to know how long that term took to agree on... > you should find a matching entry EFI Memory Map and /proc/iomem > > BIOS-e820: [mem 0x000000c050000000-0x000000fcefffffff] usable Trivial but that's not the EFI memory map, that's the e820. On some architectures this really will be coming from the EFI memory map. > /proc/iomem: c050000000-fcefffffff : System RAM > > > --------------------------------------------------------------- > Step 3: EFI_MEMORY_SP - Deferring Management to the CXL Driver. > --------------------------------------------------------------- > > Assuming you DON'T want CXL memory to default to SystemRAM and prefer > NOT to have your kernel allocate arbitrary resources on CXL, you > probably want to defer managing these memory regions to the CXL driver. > > The mechanism for is setting EFI_MEMORY_SP bit on CXL memory in BIOS. > This will mark the memory "Special Purpose". Specific purpose if we are keeping the UEFI naming.
