12th Generation Intel® Core™ Processors Datasheet Volume 2 of 2
ID | Date | Version | Classification |
---|---|---|---|
767625 | 07/13/2023 | Public |
Top of Upper Usable DRAM (TOUUD_0_0_0_PCI) – Offset A8
This 64 bit register defines the Top of Upper Usable DRAM.
Configuration software must set this value to TOM minus all ME stolen memory if reclaim is disabled. If reclaim is enabled, this value must be set to reclaim limit + 1byte, 1MB aligned, since reclaim limit is 1MB aligned. Address bits 19:0 are assumed to be 000_0000h for the purposes of address comparison. The Host interface positively decodes an address towards DRAM if the incoming address is less than the value programmed in this register and greater than or equal to 4GB.
BIOS Restriction: Minimum value for TOUUD is 4GB.
These bits are Intel TXT lockable.
Bit Range | Default | Access | Field Name and Description |
---|---|---|---|
63:42 | 0h | RO | Reserved |
41:20 | 0x0 | RW/L | (TOUUD) This register contains bits 41 to 20 of an address one byte above the maximum DRAM memory above 4G that is usable by the operating system. Configuration software must set this value to TOM minus all ME stolen memory if reclaim is disabled. If reclaim is enabled, this value must be set to reclaim limit 1MB aligned since reclaim limit + 1byte is 1MB aligned. Address bits 19:0 are assumed to be 000_0000h for the purposes of address comparison. The Host interface positively decodes an address towards DRAM if the incoming address is less than the value programmed in this register and greater than 4GB. |
19:1 | 0h | RO | Reserved |
0 | 0x0 | RW/L | (LOCK) This bit will lock all writable settings in this register, including itself. |