Re: [PATCH] perf kvm stat: Fix build error

[Namhyung Kim <namhyung@kernel.org>]

On Thu, Feb 26, 2026 at 08:44:51AM -0800, Ian Rogers wrote:
> On Thu, Feb 26, 2026 at 1:52 AM Leo Yan <leo.yan@arm.com> wrote:
> >
> > On Wed, Feb 25, 2026 at 10:36:26PM -0800, Ian Rogers wrote:
> >
> > [...]
> >
> > > Hmm.. it looks like something has gone screwy with the include paths.
> > > The header you've gotten is:
> > > https://web.git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools-next.git/tree/arch/x86/include/uapi/asm/svm.h#n137
> > > rather than:
> > > https://web.git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools-next.git/tree/tools/arch/x86/include/uapi/asm/svm.h#n137
> > > where the value differs between -1ull and -1.
> > >
> > > In Leo's change he has the include path as:
> > >   #include "../../arch/x86/include/uapi/asm/svm.h"
> > >
> > > but I think that is off by one and should be:
> > >   #include "../../../arch/x86/include/uapi/asm/svm.h"
> >
> > Sorry I did not check the header path carefully.  A bit thoughts:
> >
> > The perf build will not include headers in relative paths as we
> > expected.
> >
> > It tries to find headers with appending search paths.  As Ian said,
> > I saw .kvm-stat-x86.o.cmd that includes kernel headers:
> >
> >   /home/niayan01/Work/linux/tools/include/../../arch/x86/include/uapi/asm/svm.h \
> >   /home/niayan01/Work/linux/tools/include/../../arch/x86/include/uapi/asm/vmx.h \
> >   /home/niayan01/Work/linux/tools/include/../../arch/x86/include/uapi/asm/kvm.h \
> >
> > I'd suggest a fix in Makefile as below.  The idea is to give priority to
> > the lower level folders under perf, so that headers in the deeper perf
> > directories are searched first.  This avoids searching any kernel headers.

It fixes the problem, thanks!

Tested-by: Namhyung Kim <namhyung@kernel.org>

More comments below.

> 
> I'm not opposed to the change but I still think we should make the
> relative include be to the correct files. Some other thoughts below.
> 
> > diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
> > index a8dc72cfe48e..47359f672b6a 100644
> > --- a/tools/perf/Makefile.config
> > +++ b/tools/perf/Makefile.config
> > @@ -388,8 +388,10 @@ ifeq ($(DEBUG),0)
> >    endif
> >  endif
> >
> > -INC_FLAGS += -I$(src-perf)/util/include
> 
> Not clear to me why we need a util/include on top of everything else.
> It seems somewhat random what is in util/include rather than just in
> util.

It seems it tries to override some kernel headers but I'm curious we can
move the files to the tools/include and get rid of the directory.

> 
> >  INC_FLAGS += -I$(src-perf)/arch/$(SRCARCH)/include
> 
> Hopefully with the removal of the arch directory (and fixing of
> cross-platform profiling) in slow chunks by changes like:
> https://lore.kernel.org/lkml/20260224142938.26088-1-irogers@google.com/
> we can get rid of this one.
> 
> > +INC_FLAGS += -I$(src-perf)/util/include
> > +INC_FLAGS += -I$(src-perf)/util

I also hope to remove $(src-perf)/util too and use path relative to
$(src-perf) always for perf-specific headers.  But this is a separate
topic.


> > +INC_FLAGS += -I$(src-perf)
> 
> This:
> 
> >  INC_FLAGS += -I$(srctree)/tools/include/
> >  INC_FLAGS += -I$(srctree)/tools/arch/$(SRCARCH)/include/uapi
> >  INC_FLAGS += -I$(srctree)/tools/include/uapi
> 
> to here means that we prefer linux headers over uapi headers, which I
> think is the opposite of what a user-land process would expect. I
> think we should move these headers into two libraries, build them with
> an `install_headers` rule, and make the include path pick up the
> headers from where they are installed. As the linux and uapi headers
> are licensed differently, this would clarify the dependencies and
> licensing implications.

Sounds good.

Thanks,
Namhyung

> 
> There's another can of worms regarding whether libperf is something
> useful, outside of declarations in event.h.
> 
> Thanks,
> Ian
> 
> > @@ -403,9 +405,6 @@ INC_FLAGS += -I$(obj-perf)/util
> >  INC_FLAGS += -I$(obj-perf)
> >  endif
> >
> > -INC_FLAGS += -I$(src-perf)/util
> > -INC_FLAGS += -I$(src-perf)
> > -
> >  CORE_CFLAGS += -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -D_GNU_
> >
> > As a result, I can get the search paths in .kvm-stat-x86.o.cmd:
> >
> >   /home/niayan01/Work/linux/tools/perf/util/../../arch/x86/include/uapi/asm/svm.h \
> >   /home/niayan01/Work/linux/tools/perf/util/../../arch/x86/include/uapi/asm/vmx.h \
> >   /home/niayan01/Work/linux/tools/perf/util/../../arch/x86/include/uapi/asm/kvm.h \
> >
> > Please let me know if this makes sense.
> >
> > Thanks,
> > Leo