From e111de0752bea95f11963909aaaebf581a362833 Mon Sep 17 00:00:00 2001 From: Jonathan Zhang Date: Wed, 21 Apr 2021 10:40:31 -0700 Subject: lib: set up specific purpose memory as LB_MEM_SOFT_RESERVED CXL (Compute Express Link) [1] is a cache-coherent interconnect standard for processors, memory expansion and accelerators. CXL memory is provided through CXL device which is connected through CXL/PCIe link, while regular system memory is provided through DIMMs plugged into DIMM slots which are connected to memory controllers of processor. With CXL memory, the server's memory capacity is increased. CXL memory is in its own NUMA domain, with longer latency and added bandwidth, comparing to regular system memory. Host firmware may present CXL memory as specific purpose memory. Linux kernel dax driver provides direct access to such differentiated memory. In particular, hmem dax driver provides direct access to specific purpose memory. Specific purpose memory needs to be represented in e820 table as soft reserved, as described in [2]. Add IORESOURCE_SOFT_RESERVE resource property to indicate (memory) resource that needs to be soft reserved. Add soft_reserved_ram_resource macro to allow soc/mb code to add memory resource as soft reserved. [1] https://www.computeexpresslink.org/ [2] https://web.archive.org/web/20230130233752/https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=v5.10.32&id=262b45ae3ab4bf8e2caf1fcfd0d8307897519630 Signed-off-by: Jonathan Zhang Change-Id: Ie70795bcb8c97e9dd5fb772adc060e1606f9bab0 Reviewed-on: https://review.coreboot.org/c/coreboot/+/52585 Reviewed-by: Marc Jones Reviewed-by: David Hendricks Tested-by: build bot (Jenkins) Reviewed-by: Tim Wawrzynczak Reviewed-by: Lean Sheng Tan --- src/commonlib/include/commonlib/coreboot_tables.h | 1 + 1 file changed, 1 insertion(+) (limited to 'src/commonlib') diff --git a/src/commonlib/include/commonlib/coreboot_tables.h b/src/commonlib/include/commonlib/coreboot_tables.h index 86bf5438b7..e299e54a38 100644 --- a/src/commonlib/include/commonlib/coreboot_tables.h +++ b/src/commonlib/include/commonlib/coreboot_tables.h @@ -140,6 +140,7 @@ struct lb_memory_range { #define LB_MEM_UNUSABLE 5 /* Unusable address space */ #define LB_MEM_VENDOR_RSVD 6 /* Vendor Reserved */ #define LB_MEM_TABLE 16 /* Ram configuration tables are kept in */ +#define LB_MEM_SOFT_RESERVED 0xefffffff /* Specific purpose memory */ }; struct lb_memory { -- cgit v1.2.3