Re: [PATCH] hw/ide: Fix crash when plugging a piix3-ide device into the x-remote machine

[Philippe Mathieu-Daudé]

On 7/6/21 10:24 AM, Thomas Huth wrote:
> On 16/04/2021 14.52, Thomas Huth wrote:
>> QEMU currently crashes when the user tries to do something like:
>>
>>   qemu-system-x86_64 -M x-remote -device piix3-ide
> 
> It's now several months later already, and this crash has still not been
> fixed yet. The next softfreeze is around the corner and the
> "device-crash-test" still stumbles accross this problem.
> If the other solutions are not mergable yet (what's the status here?),

See this big thread about ISA vs PCI IDE modelling / design:
https://www.mail-archive.com/qemu-devel@nongnu.org/msg809678.html

TL;DR: short term we are screwed. long term, not worth it.

Stefan, IIRC the multi-process conclusion was we have to reject
PCI devices briding another (non-PCI) bus, such ISA / I2C / USB
/ SD / ... because QEMU register the bus type globally and the
command line machinery resolves it to plug user-creatable devices,
so we can not share such buses. Is that correct?

> could we please include my patch for QEMU v6.1 instead, so that we get
> this silenced in the device-crash-test script?

Yes please.

Regards,

Phil.

>> This happens because the "isabus" variable is not initialized with
>> the x-remote machine yet. Add a proper check for this condition
>> and propagate the error to the caller, so we can fail there gracefully.
>>
>> Signed-off-by: Thomas Huth <thuth@redhat.com>
>> ---
>>   hw/ide/ioport.c           | 16 ++++++++++------
>>   hw/ide/piix.c             | 22 +++++++++++++++++-----
>>   hw/isa/isa-bus.c          | 14 ++++++++++----
>>   include/hw/ide/internal.h |  2 +-
>>   include/hw/isa/isa.h      | 13 ++++++++-----
>>   5 files changed, 46 insertions(+), 21 deletions(-)