On Thu, 23 Feb 2023 08:37:46 +0100
Markus Armbruster <armbru@redhat.com> wrote:
Thomas Huth <thuth@redhat.com> writes:
On 22/02/2023 19.16, Philippe Mathieu-Daudé wrote:
+Thomas (meson) & Marc-André (conditional QAPI)
+ Markus
On 22/2/23 17:49, Jonathan Cameron wrote:
[...]
Doesn't these need
'if': 'CONFIG_CXL_MEM_DEVICE',
?
If I make this change I get a bunch of
./qapi/qapi-types-cxl.h:18:13: error: attempt to use poisoned
"CONFIG_CXL_MEM_DEVICE"
18 | #if defined(CONFIG_CXL_MEM_DEVICE)
Err, I meant the generic CONFIG_CXL, not CONFIG_CXL_MEM_DEVICE.
It's a target specific define (I think) as built alongside PCI_EXPRESS
Only CXL_ACPI is specifically included by x86 and arm64 (out of tree)
To be honest though I don't fully understand the QEMU build system so the reason
for the error might be wrong.
You need to restrict to system emulation (the 'have_system' check):
This doesn't help - still have
attempt to used poisoned "CONFIG_CXL"
Not sure how the QAPI generator works, but target specific config switches can only be
used in target specific json files there, so that's machine-target.json and
misc-target.json currently, as far as I know. Not sure how the QAPI generator
distinguishes between common and target specific code, though ... just by the
"-target" suffix? Maybe Markus or Marc-André can comment on that.
Whenever you use a poisoned macro in a conditional, all the code
generated for this .json file (we call it a "QAPI schema module")
becomes target-dependent. The QAPI code generator itself is blissfully
unaware of this.
Since target-dependent code needs to be compiled differently, the build
process needs to be know which modules are target-dependent. We do this
in one of the stupidest ways that could possibly work: a module is
target-dependent if its name ends with "-target". There are just two
right now: qapi/machine-target.json and qapi/misc-target.json.
The logic resides in qapi/meson.build. Look for
if module.endswith('-target')
Thanks for all the pointers.
Questions?
Is it sensible to make the cxl stuff all target dependent and do the following?
I like that we can get rid of the stubs if we do this but I'm sure there are
disadvantages. Only alternative I can currently see is continue to have
stubs and not make the qmp commands conditional on them doing anything useful.