Re: [PATCH 04/14] hw/i386: Restrict fw_cfg to the PC machines

From: Paolo Bonzini <pbonzini@redhat.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: "Fam Zheng" <fam@euphon.net>,
	"Eduardo Habkost" <ehabkost@redhat.com>,
	"Sergio Lopez" <slp@redhat.com>,
	"Jason Wang" <jasowang@redhat.com>,
	"Mark Cave-Ayland" <mark.cave-ayland@ilande.co.uk>,
	qemu-devel@nongnu.org, "Artyom Tarasenko" <atar4qemu@gmail.com>,
	"Aleksandar Markovic" <amarkovic@wavecomp.com>,
	qemu-ppc@nongnu.org, "Gerd Hoffmann" <kraxel@redhat.com>,
	"Aleksandar Rikalo" <aleksandar.rikalo@rt-rk.com>,
	"David Gibson" <david@gibson.dropbear.id.au>,
	"Philippe Mathieu-Daudé" <philmd@redhat.com>,
	"Aurelien Jarno" <aurelien@aurel32.net>,
	"Richard Henderson" <rth@twiddle.net>
Subject: Re: [PATCH 04/14] hw/i386: Restrict fw_cfg to the PC machines
Date: Tue, 7 Jan 2020 13:22:12 +0100	[thread overview]
Message-ID: <21529c45-117d-ed7d-d518-e8073af86581@redhat.com> (raw)
In-Reply-To: <20200107050921-mutt-send-email-mst@kernel.org>

On 07/01/20 11:16, Michael S. Tsirkin wrote:
> On Tue, Jan 07, 2020 at 11:01:48AM +0100, Paolo Bonzini wrote:
>> On 31/12/19 19:32, Philippe Mathieu-Daudé wrote:
>>> Only the PC-based machines use the fw_cfg device. In particular,
>>> the MicroVM machine does not use it. Only compile/link it when
>>> machines require it.
>>>
>>> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
>>> ---
>>> Cc: Sergio Lopez <slp@redhat.com>
>>> ---
>>>  hw/i386/Makefile.objs | 2 +-
>>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/hw/i386/Makefile.objs b/hw/i386/Makefile.objs
>>> index 6ebb6d0cf0..48f2693546 100644
>>> --- a/hw/i386/Makefile.objs
>>> +++ b/hw/i386/Makefile.objs
>>> @@ -5,7 +5,7 @@ obj-$(CONFIG_PC) += pc.o pc_sysfw.o
>>>  obj-$(CONFIG_I440FX) += pc_piix.o
>>>  obj-$(CONFIG_Q35) += pc_q35.o
>>>  obj-$(CONFIG_MICROVM) += microvm.o
>>> -obj-y += fw_cfg.o
>>> +obj-$(CONFIG_PC) += fw_cfg.o
>>>  obj-$(CONFIG_X86_IOMMU) += x86-iommu.o
>>>  obj-$(CONFIG_VTD) += intel_iommu.o
>>>  obj-$(CONFIG_AMD_IOMMU) += amd_iommu.o
>>>
>>
>> Ah no, this is hw/i386/fw_cfg.c; of course hw/nvram/fw_cfg.c has its own
>> Kconfig symbol.
> 
> Sorry couldn't find it. Which symbol is that?

None. :)  fw_cfg has a bunch of uses in vl.c, it's not really going to
be easy to stub it out and probably pointless because it's an easy way
for firmware to get QEMU-specific information.

Paolo