[PATCH] KVM: selftests: Ensure sysreg-defs.h is generated at the expected path

[Oliver Upton <oliver.upton@linux.dev>]

Building the KVM selftests from the main selftests Makefile (as opposed
to the kvm subdirectory) doesn't work as OUTPUT is set, forcing the
generated header to spill into the selftests directory. Additionally,
relative paths do not work when building outside of the srctree, as the
canonical selftests path is replaced with 'kselftest' in the output.

Work around both of these issues by explicitly overriding OUTPUT on the
submake cmdline. Move the whole fragment below the point lib.mk gets
included such that $(abs_objdir) is available.

Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
---
 tools/testing/selftests/kvm/Makefile | 26 ++++++++++++++++----------
 1 file changed, 16 insertions(+), 10 deletions(-)

diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
index 52c59bad7213..5f4f6be7a866 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -17,16 +17,6 @@ else
 	ARCH_DIR := $(ARCH)
 endif
 
-ifeq ($(ARCH),arm64)
-tools_dir := $(top_srcdir)/tools
-arm64_tools_dir := $(tools_dir)/arch/arm64/tools/
-GEN_HDRS := $(top_srcdir)/tools/arch/arm64/include/generated/
-CFLAGS += -I$(GEN_HDRS)
-
-$(GEN_HDRS): $(wildcard $(arm64_tools_dir)/*)
-	$(MAKE) -C $(arm64_tools_dir) O=$(tools_dir)
-endif
-
 LIBKVM += lib/assert.c
 LIBKVM += lib/elf.c
 LIBKVM += lib/guest_modes.c
@@ -234,6 +224,22 @@ CFLAGS += -Wall -Wstrict-prototypes -Wuninitialized -O2 -g -std=gnu99 \
 ifeq ($(ARCH),s390)
 	CFLAGS += -march=z10
 endif
+ifeq ($(ARCH),arm64)
+tools_dir := $(top_srcdir)/tools
+arm64_tools_dir := $(tools_dir)/arch/arm64/tools/
+
+ifneq ($(abs_objdir),)
+arm64_hdr_outdir := $(abs_objdir)/tools/
+else
+arm64_hdr_outdir := $(tools_dir)/
+endif
+
+GEN_HDRS := $(arm64_hdr_outdir)arch/arm64/include/generated/
+CFLAGS += -I$(GEN_HDRS)
+
+$(GEN_HDRS): $(wildcard $(arm64_tools_dir)/*)
+	$(MAKE) -C $(arm64_tools_dir) OUTPUT=$(arm64_hdr_outdir)
+endif
 
 no-pie-option := $(call try-run, echo 'int main(void) { return 0; }' | \
         $(CC) -Werror $(CFLAGS) -no-pie -x c - -o "$$TMP", -no-pie)

base-commit: 33cc938e65a98f1d29d0a18403dbbee050dcad9a
-- 
2.43.0.472.g3155946c3a-goog