Re: [PATCH] KVM: selftests: Install sanitised kernel headers before compilation

[Sean Christopherson <seanjc@google.com>]

On Mon, Dec 19, 2022, Like Xu wrote:
> From: Like Xu <likexu@tencent.com>
> 
> On many automated test boxes, selftests in a completely clean src tree
> will be compiled independently: "make -j -C tools/testing/selftests/kvm".
> Sometimes the compilation will fail and produce a false positive just
> due to missing kernel headers (or others hidden behind the complete
> kernel compilation or installation).
> 
> Optimize this situation by explicitly adding the installation of sanitised
> kernel headers before compilation to the Makefile.
> 
> Reported-by: Sean Christopherson <seanjc@google.com>
> Signed-off-by: Like Xu <likexu@tencent.com>
> ---
>  tools/testing/selftests/kvm/Makefile | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
> index 947676983da1..a33e2f72d745 100644
> --- a/tools/testing/selftests/kvm/Makefile
> +++ b/tools/testing/selftests/kvm/Makefile
> @@ -202,6 +202,11 @@ TEST_GEN_PROGS_EXTENDED += $(TEST_GEN_PROGS_EXTENDED_$(UNAME_M))
>  LIBKVM += $(LIBKVM_$(UNAME_M))
>  
>  INSTALL_HDR_PATH = $(top_srcdir)/usr
> +
> +ifeq ($(shell make -j -C ../../../.. headers_install),)
> +	$(error "Please install sanitised kernel headers manually.")
> +endif

Auto-installation of headers was recently removed[*], presumably whatever problem
existed with KSFT_KHDR_INSTALL also exists with this approach.

FWIW, I also find the need to manually do headers_install annoying, but it's easy
to workaround via bash aliases.

[*] https://lore.kernel.org/lkml/cover.1657296695.git.guillaume.tucker@collabora.com