Documentation/acronyms: Add several acronyms

Change-Id: I3d925516e48231b15d9aa78c5ef05b6de1ef42ca
Signed-off-by: Maximilian Brune <maximilian.brune@9elements.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/71665
Reviewed-by: Felix Singer <felixsinger@posteo.net>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>
diff --git a/Documentation/acronyms.md b/Documentation/acronyms.md
index 6b88b4c..d5616bb 100644
--- a/Documentation/acronyms.md
+++ b/Documentation/acronyms.md
@@ -247,6 +247,7 @@
   Graphics Card, Sound Card. DMA is an essential feature of all modern
   computers, as it allows devices of different speeds to communicate
   without subjecting the CPU to a massive interrupt load.
+* DMI - Direct Media Interface is a link/bus between CPU and PCH.
 * DMI - [**Desktop Management Interface**](Desktop_Management_Interface)
 * DMIC - Digital Microphone
 * DMTF - [**Distributed Management Task Force**](https://en.wikipedia.org/wiki/Distributed_Management_Task_Force)
@@ -377,6 +378,7 @@
   Real Time Clock, and maybe a few other registers running.
 * GART - AMD: [**Graphics Address Remapping Table**](https://en.wikipedia.org/wiki/Graphics_address_remapping_table)
 * GATT - Graphics Aperture Translation Table
+* GDT - [Global Descriptor Table](https://wiki.osdev.org/Global_Descriptor_Table)
 * GLK - Intel: [**Gemini Lake**](https://en.wikichip.org/wiki/intel/cores/gemini_lake)
 * GMA - Intel: [**Graphics Media
   Accelerator**](https://en.wikipedia.org/wiki/Intel_GMA)
@@ -450,6 +452,7 @@
 * IDSEL/AD - Initialization Device SELect/Address and Data. Each PCI
   slot has a signal called IDSEL. It is used to differentiate between
   the different slots.
+* IDT - [Interrupt Descriptor Table](https://en.wikipedia.org/wiki/Interrupt_descriptor_table)
 * IF - AMD: [**Infinity
   Fabric**](https://en.wikipedia.org/wiki/HyperTransport#Infinity_Fabric)
   is a superset of AMD's earlier Hypertransport interconnect.
@@ -561,6 +564,7 @@
 * MCU - Memory Control Unit
 * MCU - [**MicroController
   Unit**](https://en.wikipedia.org/wiki/Microcontroller)
+* MCTP - [**Management Component Transport Protocol**](https://en.wikipedia.org/wiki/Management_Component_Transport_Protocol)
 * MDFIO - Intel: Multi-Die Fabric IO
 * MDN - AMD: Mendocino
 * ME - Intel: Management Engine
@@ -609,8 +613,13 @@
 * MT/s - MegaTransfers per second
 * MTL - Intel: Meteor Lake
 * MTL - ARM: MHU Transport Layer
-* MTRR - [**Memory Type and Range
-  Register**](http://en.wikipedia.org/wiki/MTRR)
+* MTRR - [**Memory Type and Range Register**](http://en.wikipedia.org/wiki/MTRR)
+  allows to set the cache behaviour on memory access in x86. Basically,
+  it tells the CPU how to cache certain ranges of memory
+  (e.g. write-through, write-combining, write-back...). Memory ranges
+  are specified over physical address ranges. In Linux, they are visible
+  over `/proc/mtrr` and they can be modified there. For further
+  information, see the [**Linux documentation**](https://www.kernel.org/doc/html/v5.19/x86/pat.html).
 
 
 ## N
@@ -664,7 +673,9 @@
 * PAT - [**Page Attribute
   Table**](https://en.wikipedia.org/wiki/Page_attribute_table) This can
   be used independently or in combination with MTRR to setup memory type
-  access ranges. Allows more finely-grained control than MTRR.
+  access ranges. Allows more finely-grained control than MTRR. Compared to MTRR,
+  which sets memory types by physical address ranges, PAT sets them at Page
+  level.
 * PAT - Intel: [**Performance Acceleration
   Technology**](https://en.wikipedia.org/wiki/Performance_acceleration_technology)
 * PATA - Parallel Advanced Technology Attachment - A renaming of ATA
@@ -858,6 +869,7 @@
 * SEEP - Serial EEPROM (Electrically Erasable Programmable Read-Only
   Memory)
 * SEV - AMD: Secure Encrypted Virtualization
+* SF - Snoop Filter
 * Shadow RAM - RAM which content is copied from ROM residing at the same
   address for speedup purposes.
 * Shim - A small piece of code whose only purpose is to act as an