Ubuntu
qemu package

Code review comment for ~rafaeldtinoco/ubuntu/+source/qemu:lp1805256-bionic-refix

  1. Git
  2. lp:~rafaeldtinoco/ubuntu/+source/qemu
  3. lp1805256-bionic-refix
  4. Merge into ubuntu/bionic-devel
Revision history for this message
Rafael David Tinoco (rafaeldtinoco) wrote :

Hello Christian,

This is a very clean backport of the commit:

commit 5710a3e09f
Author: Paolo Bonzini <email address hidden>
Date: Tue Apr 7 14:07:46 2020

    async: use explicit memory barriers

...

main responsible for fixing the Aarch64 race window we've seen.

After thinking a bit about the patches I had backported... I decided to "KISS" so I have kept current AIO logic intact - with existent, or not, BUGS - but did implement the stronger atomics, needed by Aarch64 and the extra barriers.

I've made some tests with and without i/o threads and it worked well.

Suggestion for next steps:

- Do a full battery of tests using your regression tests
  (including the io-threaded test this time)

- Try to reproduce the Aarch64 issue (from LP: #1805256) without this patch
  PROBLEM: I dont think we ever did reproduce this with Bionic's version.

- Decide (based on reproducer - or not) if you want to go on with this SRU.

Let me know your thoughts, please.

I'm uploading to the PPA now...

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