Updating README to add snp functionality

Signed-off-by: Diego Gonzalez Villalobos <Diego.GonzalezVillalobos@amd.com>

README.md

@@ -5,16 +5,42 @@
 
 # sev
 
-The `sev` crate provides an implementation of [AMD Secure Encrypted
-Virtualization (SEV)](https://developer.amd.com/sev/) APIs.
+The `sev` crate provides an implementation of the [AMD Secure Encrypted
+Virtualization (SEV)](https://www.amd.com/content/dam/amd/en/documents/epyc-technical-docs/programmer-references/55766_SEV-KM_API_Specification.pdf) APIs and the [SEV Secure Nested Paging
+Firmware (SNP)] (https://www.amd.com/content/dam/amd/en/documents/epyc-technical-docs/specifications/56860.pdf) ABIs.
+
+### SEV APIs
 
 The Linux kernel exposes two technically distinct AMD SEV APIs:
 
 1. An API for managing the SEV platform itself
 2. An API for managing SEV-enabled KVM virtual machines
 
-This crate implements both of those APIs and offers them to client
-code through a flexible and type-safe high level interface.
+This crate implements both of those APIs and offers them to client.
+code through a flexible and type-safe high-level interface.
+
+### SNP ABIs
+
+Like SEV, the Linux kernel exposes another two different AMD SEV-SNP ABIs:
+
+1. An ABI for managing the SEV-SNP platform itself
+2. An ABI for managing SEV-SNP enabled KVM virtual machines
+
+These new ABIs work only for **SEV-SNP** enabled hosts and guests.
+
+This crate implements APIs for both SEV and SEV-SNP management.
+
+### SEV and SEV-SNP enablement
+
+By default, both the SEV and SEV-SNP libraries are compiled.
+Because many modules provide support to both legacy SEV and SEV-SNP, they have been split into individual sub-modules `sev.rs` and `snp.rs`, isolating generation specific behavior.
+If desired, you may opt to exclude either of the sub-modules by disabling its feature in your project's `Cargo.toml`
+
+For example, to include the SEV APIs only:
+`sev = { version = "1.2.1", default-features = false, features = ["sev"] }`
+
+To include the SEV-SNP APIs only:
+`sev = { version = "1.2.1", default-features = false, features = ["snp"] }`
 
 ### Platform Management
 

src/lib.rs

@@ -1,15 +1,41 @@
 // SPDX-License-Identifier: Apache-2.0
 
-//! The `sev` crate provides an implementation of [AMD Secure Encrypted
-//! Virtualization (SEV)](https://developer.amd.com/sev/) APIs.
+//! The `sev` crate provides an implementation of the [AMD Secure Encrypted
+//! Virtualization (SEV)](https://www.amd.com/content/dam/amd/en/documents/epyc-technical-docs/programmer-references/55766_SEV-KM_API_Specification.pdf) APIs and the [SEV Secure Nested Paging
+//! Firmware (SNP)] (https://www.amd.com/content/dam/amd/en/documents/epyc-technical-docs/specifications/56860.pdf) ABIs.
+//!
+//! ## SEV APIs
 //!
 //! The Linux kernel exposes two technically distinct AMD SEV APIs:
 //!
 //! 1. An API for managing the SEV platform itself
 //! 2. An API for managing SEV-enabled KVM virtual machines
 //!
-//! This crate implements both of those APIs and offers them to client
-//! code through a flexible and type-safe high level interface.
+//! This crate implements both of those APIs and offers them to client.
+//! code through a flexible and type-safe high-level interface.
+//!
+//! ## SNP ABIs
+//!
+//! Like SEV, the Linux kernel exposes another two different AMD SEV-SNP ABIs:
+//!
+//! 1. An ABI for managing the SEV-SNP platform itself
+//! 2. An ABI for managing SEV-SNP enabled KVM virtual machines
+//!
+//! These new ABIs work only for **SEV-SNP** enabled hosts and guests.
+//!
+//! This crate implements APIs for both SEV and SEV-SNP management.
+//!
+//! ## SEV and SEV-SNP enablement
+//!
+//! By default, both the SEV and SEV-SNP libraries are compiled.
+//! Because many modules provide support to both legacy SEV and SEV-SNP, they have been split into individual sub-modules `sev.rs` and `snp.rs`, isolating generation specific behavior.
+//! If desired, you may opt to exclude either of the sub-modules by disabling its feature in your project's `Cargo.toml`  
+//!
+//! For example, to include the SEV APIs only:  
+//! `sev = { version = "1.2.1", default-features = false, features = ["sev"] }`  
+//!  
+//! To include the SEV-SNP APIs only:  
+//! `sev = { version = "1.2.1", default-features = false, features = ["snp"] }`  
 //!
 //! ## Platform Management
 //!