| commit | dfa4ed14de248cb87ed666a56a36a8757cfa4a31 | [log] [tgz] |
|---|---|---|
| author | Venkatesh Srinivas <venkateshs@google.com> | Tue Jan 29 15:30:23 2019 -0800 |
| committer | CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org> | Wed Jan 30 01:38:09 2019 +0000 |
| tree | 697c362d07b7e803f09a10293c4064bd56be40d5 | |
| parent | 63985c224d4f40572613479482d2dacdbfcdead9 [diff] |
[virtio] ring: Barriers before updating avail->idx/after reading used->idx virtio::ring needs to have a write memory barrier with the DMA domain after writing descriptor chains, before updating avail->idx, to ensure the device sees up-to-date descriptor chains. virtio::ring needs to have a read memory barrier with the DMA domain after reading used->idx and before reading completed descriptor chains from the device. virtio::ring needs a write barrier after updating avail->idx but before notifying the device, so that the device sees the newest avail->idx. This barrier could be fused into PIO/MMIO notification writes in the future - on some platforms UC stores may imply the required barrier. Tested: * Used virtio-net and virtio-blk on QEMU Change-Id: I0bd1529022625a1509b657c443b6259c0a061d5b
Zircon is the core platform that powers the Fuchsia OS. Zircon is composed of a microkernel (source in kernel/...) as well as a small set of userspace services, drivers, and libraries (source in system/...) necessary for the system to boot, talk to hardware, load userspace processes and run them, etc. Fuchsia builds a much larger OS on top of this foundation.
The canonical Zircon Git repository is located at: https://fuchsia.googlesource.com/zircon
The Zircon Kernel provides syscalls to manage processes, threads, virtual memory, inter-process communication, waiting on object state changes, and locking (via futexes).
Currently there are some temporary syscalls that have been used for early bringup work, which will be going away in the future as the long term syscall API/ABI surface is finalized. The expectation is that there will be about 100 syscalls.
Zircon syscalls are generally non-blocking. The wait_one, wait_many port_wait and thread sleep being the notable exceptions.
This page is a non-comprehensive index of the zircon documentation.