Re: [PATCH kvmtool v2] virtio: 9p: Order used ring updates before notifications

On Mon, 03 Aug 2026 09:32:26 +0800, Xie Bo wrote:
> virtio_p9_do_io() signals the guest immediately after adding each
> request to the used ring. Unlike the block and net backends, it bypasses
> virtio_queue__should_signal(), which provides the full memory barrier
> needed between publishing used->idx and injecting the interrupt.
> 
> On weakly ordered architectures, the guest can therefore handle the
> interrupt before the updated used->idx becomes visible. If it observes
> the old index and goes back to sleep, the completed request can remain
> stuck indefinitely because no further interrupt is generated.
> 
> [...]

Applied to kvmtool (master), thanks!

[1/1] virtio: 9p: Order used ring updates before notifications
      https://git.kernel.org/will/kvmtool/c/59ccded8ade3

Cheers,
-- 
Will

https://fixes.arm64.dev
https://next.arm64.dev
https://will.arm64.dev