Re: [PATCH v2 4/6] python/machine: use socketpair() for console connections

[Daniel P . Berrangé]

On Thu, Jul 27, 2023 at 11:22:35AM +0530, Ani Sinha wrote:
> 
> 
> > On 26-Jul-2023, at 10:51 PM, John Snow <jsnow@redhat.com> wrote:
> > 
> > 
> > 
> > On Wed, Jul 26, 2023, 6:50 AM Ani Sinha <anisinha@redhat.com> wrote:
> > 
> > 
> > > On 25-Jul-2023, at 11:33 PM, John Snow <jsnow@redhat.com> wrote:
> > > 
> > > Create a socketpair for the console output. This should help eliminate
> > > race conditions around console text early in the boot process that might
> > > otherwise have been dropped on the floor before being able to connect to
> > > QEMU under "server,nowait".
> > > 
> > > Signed-off-by: John Snow <jsnow@redhat.com>
> > 
> > Thanks for doing this. I recall we spoke about this late last year in the 
> > context of fixing my bios-bits avocado test and adding a console output 
> > there.
> > 
> > Yep! I think you need a few more changes to do what you wanted. IIRC, you 
> > also want to be able to drain the console log while waiting for the vm to 
> > terminate of its own accord, which I don't support yet.
> > 
> > (If you use console socket's self draining mode, it should be possible to 
> > forego the early termination of the console socket and allow this behavior. 
> > Maybe I can work that in now...)
> 
> yeah we want to collect all the console logs while the VM is running until it 
> self terminates. Maybe you can add a flag for this behavior to not early 
> terminate the socket. I think we need to add mathods to keep reading the 
> socket and write to a file until the socket is closed. Maybe QemuMachine 
> needs to be enhanced.


There's no special code required for that - any -chardev backend can
have logfile=/some/path added to it.


With regards,
Daniel
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