Merge tag 'kvm-x86-selftests-6.17' of https://github.com/kvm-x86/linux into HEAD

KVM selftests changes for 6.17

- Fix a comment typo.

- Verify KVM is loaded when getting any KVM module param so that attempting to
run a selftest without kvm.ko loaded results in a SKIP message about KVM not
being loaded/enabled, versus some random parameter not existing.

- SKIP tests that hit EACCES when attempting to access a file, with a "Root
required?" help message. In most cases, the test just needs to be run with
elevated permissions.

tools/testing/selftests/kvm/access_tracking_perf_test.c

···
 		if (ret)
 			return ret;
 	} else {
-		page_idle_fd = open("/sys/kernel/mm/page_idle/bitmap", O_RDWR);
-		__TEST_REQUIRE(page_idle_fd >= 0,
-			       "Couldn't open /sys/kernel/mm/page_idle/bitmap. "
-			       "Is CONFIG_IDLE_PAGE_TRACKING enabled?");
-
+		page_idle_fd = __open_path_or_exit("/sys/kernel/mm/page_idle/bitmap", O_RDWR,
+						   "Is CONFIG_IDLE_PAGE_TRACKING enabled?");
 		close(page_idle_fd);
 
 		puts("Using page_idle for aging");

tools/testing/selftests/kvm/include/kvm_util.h

···
 };
 extern const struct vm_guest_mode_params vm_guest_mode_params[];
 
+int __open_path_or_exit(const char *path, int flags, const char *enoent_help);
 int open_path_or_exit(const char *path, int flags);
 int open_kvm_dev_path_or_exit(void);
 

tools/testing/selftests/kvm/include/x86/processor.h

···
 
 void kvm_get_cpu_address_width(unsigned int *pa_bits, unsigned int *va_bits);
 void kvm_init_vm_address_properties(struct kvm_vm *vm);
-bool vm_is_unrestricted_guest(struct kvm_vm *vm);
 
 struct ex_regs {
 	uint64_t rax, rcx, rdx, rbx;
···
 static inline bool kvm_is_forced_emulation_enabled(void)
 {
 	return !!get_kvm_param_integer("force_emulation_prefix");
+}
+
+static inline bool kvm_is_unrestricted_guest_enabled(void)
+{
+	return get_kvm_intel_param_bool("unrestricted_guest");
 }
 
 uint64_t *__vm_get_page_table_entry(struct kvm_vm *vm, uint64_t vaddr,

tools/testing/selftests/kvm/lib/kvm_util.c

···
 
 static int vcpu_mmap_sz(void);
 
-int open_path_or_exit(const char *path, int flags)
+int __open_path_or_exit(const char *path, int flags, const char *enoent_help)
 {
 	int fd;
 
 	fd = open(path, flags);
-	__TEST_REQUIRE(fd >= 0 || errno != ENOENT, "Cannot open %s: %s", path, strerror(errno));
-	TEST_ASSERT(fd >= 0, "Failed to open '%s'", path);
+	if (fd < 0)
+		goto error;
 
 	return fd;
+
+error:
+	if (errno == EACCES || errno == ENOENT)
+		ksft_exit_skip("- Cannot open '%s': %s.  %s\n",
+			       path, strerror(errno),
+			       errno == EACCES ? "Root required?" : enoent_help);
+	TEST_FAIL("Failed to open '%s'", path);
+}
+
+int open_path_or_exit(const char *path, int flags)
+{
+	return __open_path_or_exit(path, flags, "");
 }
 
 /*
···
  */
 static int _open_kvm_dev_path_or_exit(int flags)
 {
-	return open_path_or_exit(KVM_DEV_PATH, flags);
+	return __open_path_or_exit(KVM_DEV_PATH, flags, "Is KVM loaded and enabled?");
 }
 
 int open_kvm_dev_path_or_exit(void)
···
 	char path[path_size];
 	ssize_t bytes_read;
 	int fd, r;
+
+	/* Verify KVM is loaded, to provide a more helpful SKIP message. */
+	close(open_kvm_dev_path_or_exit());
 
 	r = snprintf(path, path_size, "/sys/module/%s/parameters/%s",
 		     module_name, param);

tools/testing/selftests/kvm/lib/sparsebit.c

···
  *
  *   + A node with all mask bits set only occurs when the last bit
  *     described by the previous node is not equal to this nodes
- *     starting index - 1.  All such occurences of this condition are
+ *     starting index - 1.  All such occurrences of this condition are
  *     avoided by moving the setting of the nodes mask bits into
  *     the previous nodes num_after setting.
  *
···
  *
  *   + A node with all mask bits set only occurs when the last bit
  *     described by the previous node is not equal to this nodes
- *     starting index - 1.  All such occurences of this condition are
+ *     starting index - 1.  All such occurrences of this condition are
  *     avoided by moving the setting of the nodes mask bits into
  *     the previous nodes num_after setting.
  */

tools/testing/selftests/kvm/lib/x86/processor.c

···
 	return min(max_gfn, ht_gfn - 1);
 }
 
-/* Returns true if kvm_intel was loaded with unrestricted_guest=1. */
-bool vm_is_unrestricted_guest(struct kvm_vm *vm)
-{
-	/* Ensure that a KVM vendor-specific module is loaded. */
-	if (vm == NULL)
-		close(open_kvm_dev_path_or_exit());
-
-	return get_kvm_intel_param_bool("unrestricted_guest");
-}
-
 void kvm_selftest_arch_init(void)
 {
 	host_cpu_is_intel = this_cpu_is_intel();

tools/testing/selftests/kvm/x86/vmx_exception_with_invalid_guest_state.c

···
 	struct kvm_vm *vm;
 
 	TEST_REQUIRE(host_cpu_is_intel);
-	TEST_REQUIRE(!vm_is_unrestricted_guest(NULL));
+	TEST_REQUIRE(!kvm_is_unrestricted_guest_enabled());
 
 	vm = vm_create_with_one_vcpu(&vcpu, guest_code);
 	get_set_sigalrm_vcpu(vcpu);