External/cloud-hypervisor
1
0
Fork 0
mirror of https://github.com/cloud-hypervisor/cloud-hypervisor.git synced 2025-02-21 10:52:25 +00:00
Code Issues Packages Projects Releases Wiki Activity

docs: Fix broken link to intel 0x80 debug port

Browse Source 
Previous link to provide details of `0x80 debug port` is removed, which
could no longer be found on intel site [1]. Use snapshot found in web
archive [2] to fix this link.

Format `debug-port.md` using `mdformat` with GitHub Flavored Markdown
(GFM).

[1] https://www.intel.com/content/www/us/en/homepage.html
[2] https://web.archive.org

Signed-off-by: Ruoqing He <heruoqing@iscas.ac.cn>
This commit is contained in:
Ruoqing He 2025-02-08 15:59:29 +08:00
parent 1caa69d0cc
commit 730cf1e944
2 changed files with 16 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

29
docs/debug-port.md
View File

@ -1,8 +1,9 @@
# `cloud-hypervisor` debug IO ports
When running x86 guests, `cloud-hypervisor` provides different kinds of debug ports:
- [`0x80` debug port](https://www.intel.com/content/www/us/en/support/articles/000005500/boards-and-kits.html)
- Debug console (by default at `0xe9`).
- [`0x80` debug port](https://web.archive.org/web/20211028033025/https://www.intel.com/content/www/us/en/support/articles/000005500/boards-and-kits.html)
- Debug console (by default at `0xe9`).
- Firmware debug port at `0x402`.
All of them can be used to trace user-defined guest events and all of them can
@ -25,13 +26,13 @@ for debugging specific components of the guest software stack. When logging a
write of one of those codes to the debug port, `cloud-hypervisor` adds a
pre-defined string to the logs.
| Code Range | Component | Log string |
| ---------------- | ----------- | ------------ |
| `0x00` to `0x1f` | Firmware | `Firmware` |
| `0x20` to `0x3f` | Bootloader | `Bootloader` |
| `0x40` to `0x5f` | Kernel | `Kernel` |
| `0x60` to `0x7f` | Userspace | `Userspace` |
| `0x80` to `0xff` | Custom | `Custom` |
| Code Range | Component | Log string |
| ---------------- | ---------- | ------------ |
| `0x00` to `0x1f` | Firmware | `Firmware` |
| `0x20` to `0x3f` | Bootloader | `Bootloader` |
| `0x40` to `0x5f` | Kernel | `Kernel` |
| `0x60` to `0x7f` | Userspace | `Userspace` |
| `0x80` to `0xff` | Custom | `Custom` |
One typical use case is guest boot time measurement and tracing. By writing
different values to the debug I/O port at different boot process steps, the
@ -71,8 +72,8 @@ cloud-hypervisor: 403.499628ms: DEBUG:vmm/src/vm.rs:510 -- [Debug I/O port: Firm
### Debug console port
The debug console is inspired by QEMU and Bochs, which have a similar feature.
By default, the I/O port `0xe9` is used. This port can be configured like a
The debug console is inspired by QEMU and Bochs, which have a similar feature.
By default, the I/O port `0xe9` is used. This port can be configured like a
console. Thus, it can print to a tty, a file, or a pty, for example.
### Firmware debug port
@ -83,7 +84,7 @@ it. The firmware debug port only prints to stdout.
## When do I need these ports?
The ports are on the one hand interesting for firmware or kernel developers, as
they provide an easy way to print debug information from within a guest.
they provide an easy way to print debug information from within a guest.
Furthermore, you can patch "normal" software to measure certain events, such as
the boot time of a guest.
@ -91,6 +92,6 @@ the boot time of a guest.
The `0x80` debug port and the port of the firmware debug device are always
available. The debug console must be activated via the command line, but
provides more configuration options.
provides more configuration options.
You can use different ports for different aspect of your logging messages.
You can use different ports for different aspect of your logging messages.

2
release-notes.md
View File

@ -3216,7 +3216,7 @@ enabled by default.
Based on the Firecracker idea of using a dedicated I/O port to measure guest
boot times, we added support for logging guest events through the
[0x80](https://www.intel.com/content/www/us/en/support/articles/000005500/boards-and-kits.html)
[0x80](https://web.archive.org/web/20211028033025/https://www.intel.com/content/www/us/en/support/articles/000005500/boards-and-kits.html)
PC debug port. This allows, among other things, for granular guest boot time
measurements. See our [debug port documentation](docs/debug-port.md) for more
details.