Re: [Qemu-devel] [PATCH 2/2] pc: remove DEBUG_BIOS define and QEMU exit I/O ports

[Anthony Liguori <aliguori@us.ibm.com>]

Hervé Poussineau <hpoussin@reactos.org> writes:

> Anthony Liguori a écrit :
>> On 07/06/2012 04:53 PM, Hervé Poussineau wrote:
>>> Debug output ports (enabled by DEBUG_BIOS define) can be replaced by:
>>> -chardev stdio,id=debugcon,mux=on
>>> -device isa-debugcon,iobase=0x402,chardev=debugcon
>>> -device isa-debugcon,iobase=0x403,chardev=debugcon
>>> -device isa-debugcon,iobase=0x500,chardev=debugcon
>>> -device isa-debugcon,iobase=0x503,chardev=debugcon
>>>
>>> QEMU exit (which can be guest triggered) can be replaced by:
>>> -device isa-debugexit,iobase=0x501
>>> -device isa-debugexit,iobase=0x501,access-size=2
>>> -device isa-debugexit,iobase=0x502,access-size=2
>>>
>>> Signed-off-by: Hervé Poussineau<hpoussin@reactos.org>
>>> ---
>>>
>>> Anthony, this patch is a follow-up of a patch I sent in March 2012:
>>> http://lists.gnu.org/archive/html/qemu-devel/2012-03/msg00031.html
>>>
>>> Will you accept this approach, where your regression suite will require
>>> a new parameter "-device isa-debugexit,iobase=0x501" ?
>>>
>
> [...]
>
>>>
>>> @@ -602,18 +577,8 @@ static void *bochs_bios_init(void)
>>>       uint64_t *numa_fw_cfg;
>>>       int i, j;
>>>
>>> -    register_ioport_write(0x400, 1, 2, bochs_bios_write, NULL);
>>> -    register_ioport_write(0x401, 1, 2, bochs_bios_write, NULL);
>>> -    register_ioport_write(0x402, 1, 1, bochs_bios_write, NULL);
>>> -    register_ioport_write(0x403, 1, 1, bochs_bios_write, NULL);
>>>       register_ioport_write(0x8900, 1, 1, bochs_bios_write, NULL);
>>>
>>> -    register_ioport_write(0x501, 1, 1, bochs_bios_write, NULL);
>>> -    register_ioport_write(0x501, 1, 2, bochs_bios_write, NULL);
>>> -    register_ioport_write(0x502, 1, 2, bochs_bios_write, NULL);
>>> -    register_ioport_write(0x500, 1, 1, bochs_bios_write, NULL);
>>> -    register_ioport_write(0x503, 1, 1, bochs_bios_write, NULL);
>>> -
>>>       fw_cfg = fw_cfg_init(BIOS_CFG_IOPORT, BIOS_CFG_IOPORT + 1, 0, 0);
>>>
>>>       fw_cfg_add_i32(fw_cfg, FW_CFG_ID, 1);
>> 
>> Removing this from the default PC breaks compatibility.  I don't mind 
>> having a way to disable it but it needs to be there by default.
>> 
>> Among other things, my test suite depends on these ports.
>> 
>
> OK for keeping them on compat PC machines.
> However, for current ones (1.2 or later), I don't want to have them by 
> default as it is an QEMU exit which is guest triggerable.
> Will you accept this approach, where your regression suite will require
> a new parameter "-device isa-debugexit,iobase=0x501" ?

Yes although I'd prefer the iobase not be required to be explicitly
specified.

Regards,

Anthony Liguori

>
> Regards,
>
> Hervé