Re: [PATCH 1/2] system/vl.c: Fix handling of '-serial none -serial something'

[Daniel P . Berrangé]

On Mon, Jan 22, 2024 at 04:36:06PM +0000, Peter Maydell wrote:
> Currently if the user passes multiple -serial options on the command
> line, we mostly treat those as applying to the different serial
> devices in order, so that for example
>  -serial stdio -serial file:filename
> will connect the first serial port to stdio and the second to the
> named file.
> 
> The exception to this is the '-serial none' serial device type.  This
> means "don't allocate this serial device", but a bug means that
> following -serial options are not correctly handled, so that
>  -serial none -serial stdio
> has the unexpected effect that stdio is connected to the first serial
> port, not the second.
> 
> This is a very long-standing bug that dates back at least as far as
> commit 998bbd74b9d81 from 2009.
> 
> Make the 'none' serial type move forward in the indexing of serial
> devices like all the other serial types, so that any subsequent
> -serial options are correctly handled.
> 
> Note that if your commandline mistakenly had a '-serial none' that
> was being overridden by a following '-serial something' option, you
> should delete the unnecessary '-serial none'.  This will give you the
> same behaviour as before, on QEMU versions both with and without this
> bug fix.
> 
> Cc: qemu-stable@nongnu.org
> Reported-by: Bohdan Kostiv <bohdan.kostiv@tii.ae>
> Fixes: 998bbd74b9d81 ("default devices: core code & serial lines")
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---
> See the discussion of Bohdan's patch on the mailing list for
> further context:
> https://lore.kernel.org/qemu-devel/CAA3Sv1LQ8yDUNLCB5WqLVZjsHffrU0uSbL_YYJW_m+Db2PhEeQ@mail.gmail.com/
> ---
>  system/vl.c | 22 +++++++++++++---------
>  1 file changed, 13 insertions(+), 9 deletions(-)

Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>


With regards,
Daniel
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