Re: [PATCH v6 01/18] KVM: selftests: Build and link selftests/vfio/lib into KVM selftests

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:
- [Low] Including `libvfio.mk` breaks the `make clean all` sequence for KVM selftests because `libvfio.mk` eagerly creates output directories during Makefile parsing and deletes them during `clean`.
- [Low] The commit message incorrectly states the output directory for VFIO object files.
--

commit 603b6019849c316e7022070d57840b9b75c1791c
Author: David Matlack <dmatlack@google.com>

KVM: selftests: Build and link selftests/vfio/lib into KVM selftests

This patch includes libvfio.mk into the KVM selftests Makefile and links it
into all KVM selftests.

> Note that KVM selftests build their own copy of selftests/vfio/lib and
> the resulting object files are placed in $(OUTPUT)/lib. This allows the
> KVM and VFIO selftests to apply different CFLAGS when building without
> conflicting with each other.

[Severity: Low]
This isn't a bug, but the commit message states the output directory is
$(OUTPUT)/lib. Looking at tools/testing/selftests/vfio/lib/libvfio.mk,
LIBVFIO_OUTPUT is actually set to $(OUTPUT)/libvfio. Could the commit
message be updated to match the code?

> diff --git a/tools/testing/selftests/kvm/Makefile.kvm b/tools/testing/selftests/kvm/Makefile.kvm
> index e0ddd3ff9472d..14316358fd9fb 100644
> --- a/tools/testing/selftests/kvm/Makefile.kvm
> +++ b/tools/testing/selftests/kvm/Makefile.kvm
> @@ -257,6 +257,7 @@ OVERRIDE_TARGETS = 1
>  # which causes the environment variable to override the makefile).
>  include ../lib.mk
>  include ../cgroup/lib/libcgroup.mk
> +include ../vfio/lib/libvfio.mk

[Severity: Low]
Does including libvfio.mk here break the "make clean all" sequence for KVM 
selftests?

In tools/testing/selftests/vfio/lib/libvfio.mk, the output directory is
eagerly created at parse time:

LIBVFIO_O_DIRS := $(shell dirname $(LIBVFIO_O) | uniq)
$(shell mkdir -p $(LIBVFIO_O_DIRS))

The directory is also added to EXTRA_CLEAN. 

If a developer runs "make clean all", Make will parse the included libvfio.mk 
and run the shell mkdir command at parse time. Then it executes the clean 
target, which deletes the newly created libvfio directory. Finally, it 
executes the all target, but the compilation fails with a "No such file or 
directory" error because the output directory was deleted and isn't recreated
in the build recipe.

>  
>  INSTALL_HDR_PATH = $(top_srcdir)/usr

[ ... ]

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260610005338.2967132-1-seanjc@google.com?part=1