Re: [PATCH v4 29/42] hw/cxl/host: Add support for CXL Fixed Memory Windows.

[Alex Bennée]

Jonathan Cameron <Jonathan.Cameron@Huawei.com> writes:

> On Tue, 25 Jan 2022 17:02:32 +0000
> Alex Bennée <alex.bennee@linaro.org> wrote:
>
>> Jonathan Cameron <Jonathan.Cameron@huawei.com> writes:
>> 
>> > From: Jonathan Cameron <jonathan.cameron@huawei.com>
>> >
>> > The concept of these is introduced in [1] in terms of the
>> > description the CEDT ACPI table. The principal is more general.
>> > Unlike once traffic hits the CXL root bridges, the host system
>> > memory address routing is implementation defined and effectively
>> > static once observable by standard / generic system software.
>> > Each CXL Fixed Memory Windows (CFMW) is a region of PA space
>> > which has fixed system dependent routing configured so that
>> > accesses can be routed to the CXL devices below a set of target
>> > root bridges. The accesses may be interleaved across multiple
>> > root bridges.  
>> 
>> This breaks the linux-user builds...
>> > diff --git a/hw/cxl/meson.build b/hw/cxl/meson.build
>> > index 0eca715d10..27dff3868b 100644
>> > --- a/hw/cxl/meson.build
>> > +++ b/hw/cxl/meson.build
>> > @@ -1,5 +1,9 @@
>> > -softmmu_ss.add(when: 'CONFIG_CXL', if_true: files(
>> > -  'cxl-component-utils.c',
>> > -  'cxl-device-utils.c',
>> > -  'cxl-mailbox-utils.c',
>> > +specific_ss.add(when: 'CONFIG_CXL', if_true: files(
>> > +      'cxl-component-utils.c',
>> > +      'cxl-device-utils.c',
>> > +      'cxl-mailbox-utils.c',
>> > +      'cxl-host.c',
>> > +))
>> > +specific_ss.add(when: 'CONFIG_CXL', if_false: files(
>> > +      'cxl-host-stubs.c',
>> >  ))  
>> 
>> I think you want this:
>> 
>>   softmmu_ss.add(when: 'CONFIG_CXL',
>>                  if_true: files(
>>                    'cxl-component-utils.c',
>>                    'cxl-device-utils.c',
>>                    'cxl-mailbox-utils.c',
>>                    'cxl-host.c'),
>>                  if_false: files(
>>                    'cxl-host-stubs.c',
>>                  ))
>> 
>>   # This is required as well:
>>   softmmu_ss.add(when: 'CONFIG_ALL', if_true: files('cxl-host-stubs.c'))
>
> Ah.  I'd started with the first block and got incomprehensible error
> message.  Second block fixes it.

  https://qemu.readthedocs.io/en/latest/devel/build-system.html#stage-2-meson

documents some of this although we could probably do a better job of
sign posting the bits in the root meson file.

>
> I'll not pretend to understand the 'why' :)
>
> Thanks,
>
> Jonathan
>
>> 
>> 


-- 
Alex Bennée