Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Add DMA passthrough section to manual #39

Merged
merged 1 commit into from
Mar 18, 2024
Merged

Add DMA passthrough section to manual #39

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
18 changes: 18 additions & 0 deletions docs/MANUAL.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -176,6 +176,24 @@ in the device tree. See device tree bindings documentation for the platform's
interrupt controller (e.g the GIC) or for the specific device you are trying to use.
Note that not all devices encode interrupts the same.

## Passing through DMA devices

Devices which communicate through DMA see the world through host physical
addresses, however virtual machines will give devices guest physical addresses
(i.e., host virtual addresses). In order for DMA passthrough to work, these two
addresses must be aligned. This can be done by setting the `phys_addr` of the
guest's RAM to be the same as its mapped virtual address.
```xml
<memory_region name="guest_ram" size="0x10_000_000" phys_addr="0x20000000" page_size="0x200_000" />
<protection_domain ...>
<virtual_machine ...>
<map mr="guest_ram" vaddr="0x20000000" perms="rwx" />
<!-- ... -->
</virtual_machine>
<!-- ... -->
</protection_domain>
```

# Adding platform support

This section will describe how to add support for a new platform to the `simple`
Expand Down
Loading