KVM: selftests: Use canonical $(ARCH) paths for KVM selftests directories

Use the kernel's canonical $(ARCH) paths instead of the raw target triple
for KVM selftests directories.  KVM selftests are quite nearly the only
place in the entire kernel that using the target triple for directories,
tools/testing/selftests/drivers/s390x being the lone holdout.

Using the kernel's preferred nomenclature eliminates the minor, but
annoying, friction of having to translate to KVM's selftests directories,
e.g. for pattern matching, opening files, running selftests, etc.

Opportunsitically delete file comments that reference the full path of the
file, as they are obviously prone to becoming stale, and serve no known
purpose.

Reviewed-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Acked-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Acked-by: Andrew Jones <ajones@ventanamicro.com>
Link: https://lore.kernel.org/r/20241128005547.4077116-16-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

Author: sean-jc

MAINTAINERS

@@ -12605,8 +12605,8 @@ F:	arch/arm64/include/asm/kvm*
 F:	arch/arm64/include/uapi/asm/kvm*
 F:	arch/arm64/kvm/
 F:	include/kvm/arm_*
-F:	tools/testing/selftests/kvm/*/aarch64/
-F:	tools/testing/selftests/kvm/aarch64/
+F:	tools/testing/selftests/kvm/*/arm64/
+F:	tools/testing/selftests/kvm/arm64/
 
 KERNEL VIRTUAL MACHINE FOR LOONGARCH (KVM/LoongArch)
 M:	Tianrui Zhao <zhaotianrui@loongson.cn>
@@ -12677,8 +12677,8 @@ F:	arch/s390/kvm/
 F:	arch/s390/mm/gmap.c
 F:	drivers/s390/char/uvdevice.c
 F:	tools/testing/selftests/drivers/s390x/uvdevice/
-F:	tools/testing/selftests/kvm/*/s390x/
-F:	tools/testing/selftests/kvm/s390x/
+F:	tools/testing/selftests/kvm/*/s390/
+F:	tools/testing/selftests/kvm/s390/
 
 KERNEL VIRTUAL MACHINE FOR X86 (KVM/x86)
 M:	Sean Christopherson <seanjc@google.com>
@@ -12695,8 +12695,8 @@ F:	arch/x86/include/uapi/asm/svm.h
 F:	arch/x86/include/uapi/asm/vmx.h
 F:	arch/x86/kvm/
 F:	arch/x86/kvm/*/
-F:	tools/testing/selftests/kvm/*/x86_64/
-F:	tools/testing/selftests/kvm/x86_64/
+F:	tools/testing/selftests/kvm/*/x86/
+F:	tools/testing/selftests/kvm/x86/
 
 KERNFS
 M:	Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tools/testing/selftests/kvm/Makefile

@@ -4,16 +4,12 @@ include $(top_srcdir)/scripts/subarch.include
 ARCH            ?= $(SUBARCH)
 
 ifeq ($(ARCH),$(filter $(ARCH),arm64 s390 riscv x86 x86_64))
-ifeq ($(ARCH),x86)
-	ARCH_DIR := x86_64
-else ifeq ($(ARCH),arm64)
-	ARCH_DIR := aarch64
-else ifeq ($(ARCH),s390)
-	ARCH_DIR := s390x
+# Top-level selftests allows ARCH=x86_64 :-(
+ifeq ($(ARCH),x86_64)
+	ARCH_DIR := x86
 else
 	ARCH_DIR := $(ARCH)
 endif
-
 include Makefile.kvm
 else
 # Empty targets for unsupported architectures