Update Readme

README.md

@@ -1,5 +1,295 @@
 # snphost
-Management CLI for SEV-SNP host system administrators
 
-Please consult `docs/snphost.1.adoc` for an overview of `snphost` and
-descriptions of each `snphost` subcommand.
+`snphost` is a Command Line Interface (CLI) utility designed for administrators managing AMD SEV-SNP enabled host systems. This tool facilitates interaction with the AMD SEV-SNP firmware device, enabling various operations such as certificate management and attestation processes.
+
+- [Usage](#usage)
+  - [1. help](#1-help)
+  - [2. export](#2-export)
+  - [3. import](#3-import)
+  - [4. ok](#4-ok)
+  - [5. fetch](#5-fetch)
+  - [6. show](#6-show)
+  - [7. commit](#7-commit)
+  - [8. config](#8-config)
+  - [9. verify](#9-verify)
+- [Building](#building)
+  - [Ubuntu Dependencies](#ubuntu-dependencies)
+  - [RHEL and Compatible Distributions Dependencies](#rhel-and-compatible-distributions-dependencies)
+  - [openSUSE and Compatible Distributions Dependencies](#opensuse-and-compatible-distributions-dependencies)
+- [Reporting Bugs](#reporting-bugs)
+
+## Usage
+
+### 1. `help`
+
+Every `snphost` command and subcommand comes with a `--help` option that provides a description of its usage.
+
+**Usage:**
+
+```bash
+snphost --help
+```
+
+or for a specific subcommand:
+
+```bash
+snphost <subcommand> --help
+```
+
+### 2. `export`
+
+Deserializes a GHCB formatted cert chain file into individual certificates. The user must specify the desired encoding format (`der` or `pem`) for the certificates,  the file where the `GHCB` cert chain is stored in, and the target directory path where to store the deserialized certs. This command is useful for looking at the individual certs that will be used for an extended attestation.
+
+**Usage:**
+
+```bash
+snphost export [der|pem] CERT-FILE DIR-PATH
+```
+
+**Example:**
+
+```bash
+snphost export pem ghcb-certs.bin ./certs
+```
+
+### 3. `import`
+
+Converts a certificate chain into a GHCB formatted file for extended attestation. This formatted file can then be provided to QEMU to perform extended attestation on guests. Currently, only the `ASK`, `ASVK`, `ARK`, `VCEK`, and `VLEK` certificates are supported for serialization.
+
+**Usage:**
+
+```bash
+snphost import DIR-PATH CERT-FILE
+```
+
+**Example:**
+
+```bash
+snphost import ./certs ghcb-certs.bin
+```
+### 4. `ok`
+
+Verifies if the `snpost` service is operational.
+
+**Usage:**
+
+```sh
+snphost ok
+```
+
+**Example:**
+
+```
+```
+
+### 5. `fetch`
+
+Command to request certificates from the KDS.
+
+**Usage:**
+
+```bash
+snphost fetch <subcommand>
+```
+
+**Subcommands:**
+
+#### 1. `ca` 
+
+Fetches the host system's Certificate Authority (CA) certificate chain and writes the encoded certificates to the specified directory. Users must specify the desired encoding format (`der` or `pem`).
+
+**Usage:**
+
+```bash
+snphost fetch ca [der|pem] DIR-PATH
+```
+
+**Example:**
+
+```bash
+snphost fetch ca pem ./certs
+```
+
+#### 2. `vcek`
+
+Fetches the host system's Versioned Chip Endorsement Key (VCEK) and writes the encoded certificate to the specified directory. Users must specify the desired encoding format (`der` or `pem`).
+
+**Usage:**
+
+```bash
+snphost fetch vcek [der|pem] DIR-PATH
+```
+
+**Example:**
+
+```bash
+snphost fetch vcek pem ./certs
+```
+
+#### 3. `crl`
+Fetches the latest Certificate Revocation List (CRL) from the configured source.
+
+```sh
+snphost fetch crl
+```
+
+**Example:**
+
+```bash
+snphost fetch crl
+```
+
+### 6. `show`
+Displays various SNP-related information.
+
+**Usage:**
+```sh
+snphost show <subcommands>
+```
+
+**Subcommands:**
+
+#### 1. `guests`
+Lists all active guests.
+
+**Usage:**
+```sh
+snphost show guests
+```
+
+#### 2. `identifier`
+Displays the SNP identifier.
+
+**Usage:**
+```sh
+snphost show identifier
+```
+
+#### 3. `tcb`
+Shows the current Trusted Computing Base (TCB) version.
+
+**Usage:**
+```sh
+snphost show tcb
+```
+
+#### 4. `vcek-url`
+Displays the URL for fetching the VCEK certificate.
+
+**Usage:**
+```sh
+snphost show vcek-url
+```
+
+#### 5. `version`
+
+Prints the current version of `snphost`.
+
+**Usage:**
+```sh
+snphost show version
+```
+
+### 7. `commit`
+Commits pending configuration changes.
+
+**Usage:**
+```sh
+snphost commit
+```
+
+### 8. `config`
+Manages `snphost` configuration.
+
+**Usage:**
+```sh
+snphost config <subcommand>
+```
+
+**Subcommands**
+
+#### 1. `set`
+Sets a configuration parameter.
+
+**Usage:**
+```sh
+snphost config set BOOTLOADER TEE SNP-FW MICROCODE MASK-CHIP
+```
+
+**Example:**
+```sh
+snphost config set
+```
+
+#### 2.`reset`
+Resets a configuration parameter to its default value.
+
+**Usage:**
+```sh
+snphost config reset 
+```
+
+**Example:**
+```sh
+snphost config reset
+```
+
+### 9. `verify`
+
+Reads the certificates in a directory and verifies the certificate chain, ensuring its integrity and authenticity. This command is essential for validating the trustworthiness of the certificates that can be then passed to complete attestation.
+
+**Usage:**
+```bash
+snphost verify DIR-PATH
+```
+
+**Example:**
+```bash
+snphost verify ./certs
+```
+
+## Building
+
+Some packages may need to be installed on the host system in order to build snpguest.
+
+```bash
+#Rust Installation
+curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
+source "$HOME/.cargo/env"
+```
+
+### Ubuntu Dependencies
+
+```bash
+sudo apt install build-essential
+```
+
+### RHEL and its compatible distributions Dependencies
+
+```bash
+sudo dnf groupinstall "Development Tools" "Development Libraries"
+```
+
+### openSUSE and its compatible distributions Dependencies
+
+```bash
+sudo zypper in -t pattern "devel_basis"
+```
+
+After installing the necessary dependencies, clone the `snphost` repository and build the project:
+
+```bash
+git clone https://github.com/virtee/snphost.git
+cargo build --release
+cd snphost/target/release
+```
+
+The compiled binary will be located in the `target/release` directory.
+
+## Reporting Bugs
+
+If you encounter any issues or bugs while using `snphost`, please report them by opening an issue by clicking [here](https://github.com/virtee/snphost/issues). Provide a detailed description of the problem, including steps to reproduce the issue and any relevant system information. This will help the maintainers address the problem more effectively.
+
+---
+
+*Note: This README is structured similarly to the [snpguest README](https://github.com/virtee/snpguest/blob/main/README.md) to maintain consistency across related projects.*