On Mon, Dec 12, 2022 at 4:17 PM Sean Christopherson <seanjc@xxxxxxxxxx> wrote: > > Disable gnu-variable-sized-type-not-at-end so that tests and libraries > can create overlays of variable sized arrays at the end of structs when > using a fixed number of entries, e.g. to get/set a single MSR. > > It's possible to fudge around the warning, e.g. by defining a custom > struct that hardcodes the number of entries, but that is a burden for > both developers and readers of the code. > > lib/x86_64/processor.c:664:19: warning: field 'header' with variable sized type 'struct kvm_msrs' > not at the end of a struct or class is a GNU extension [-Wgnu-variable-sized-type-not-at-end] > struct kvm_msrs header; > ^ > lib/x86_64/processor.c:772:19: warning: field 'header' with variable sized type 'struct kvm_msrs' > not at the end of a struct or class is a GNU extension [-Wgnu-variable-sized-type-not-at-end] > struct kvm_msrs header; > ^ > lib/x86_64/processor.c:787:19: warning: field 'header' with variable sized type 'struct kvm_msrs' > not at the end of a struct or class is a GNU extension [-Wgnu-variable-sized-type-not-at-end] > struct kvm_msrs header; > ^ > 3 warnings generated. > > x86_64/hyperv_tlb_flush.c:54:18: warning: field 'hv_vp_set' with variable sized type 'struct hv_vpset' > not at the end of a struct or class is a GNU extension [-Wgnu-variable-sized-type-not-at-end] > struct hv_vpset hv_vp_set; > ^ > 1 warning generated. > > x86_64/xen_shinfo_test.c:137:25: warning: field 'info' with variable sized type 'struct kvm_irq_routing' > not at the end of a struct or class is a GNU extension [-Wgnu-variable-sized-type-not-at-end] > struct kvm_irq_routing info; > ^ > 1 warning generated. > > Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx> > --- > tools/testing/selftests/kvm/Makefile | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile > index 2487db21b177..9cff99a1cb2e 100644 > --- a/tools/testing/selftests/kvm/Makefile > +++ b/tools/testing/selftests/kvm/Makefile > @@ -196,6 +196,7 @@ else > LINUX_TOOL_ARCH_INCLUDE = $(top_srcdir)/tools/arch/$(ARCH)/include > endif > CFLAGS += -Wall -Wstrict-prototypes -Wuninitialized -O2 -g -std=gnu99 \ > + -Wno-gnu-variable-sized-type-not-at-end \ This is a clang-specific warning. This will need to be wrapped in a cc-option check. tools/build/Build.include seems to redefine that make macro, so be sure to test it first. > -fno-builtin-memcmp -fno-builtin-memcpy -fno-builtin-memset \ > -fno-stack-protector -fno-PIE -I$(LINUX_TOOL_INCLUDE) \ > -I$(LINUX_TOOL_ARCH_INCLUDE) -I$(LINUX_HDR_PATH) -Iinclude \ > -- > 2.39.0.rc1.256.g54fd8350bd-goog > > -- Thanks, ~Nick Desaulniers
