[RFC PATCH v4 0/2] Introduce XSAVE/XRSTOR self-test

[RFC PATCH v4 0/2] Introduce XSAVE/XRSTOR self-test

[Pengfei Xu]

The XSAVE feature set supports the saving and restoring of state components,
which is used for process context switching. The state components include
x87 state for FPU execution environment, SSE state, AVX state and so on. In
order to ensure that XSAVE works correctly, add XSAVE basic test for
XSAVE architecture functionality.

This patch set tests and verifies the basic functions of XSAVE/XRSTOR in
user space; during and after signal processing on the x86 platform, the
XSAVE contents of the process should not be changed.

This series introduces only the most basic XSAVE tests.  In the
future, the intention is to continue expanding the scope of
these selftests to include more kernel XSAVE-related functionality
and XSAVE-managed features like AMX and shadow stacks.

========
- Change from v3 to v4:
  - Improve the comment in patch 1.

- Change from v2 to v3:
  - Improve the description of patch 2 git log.

- Change from v1 to v2:
  - Improve the cover-letter. (Dave Hansen)

Pengfei Xu (2):
  selftests/xsave: test basic XSAVE architecture functionality
  selftests/xsave: add xsave test during and after signal handling

 tools/testing/selftests/Makefile              |   1 +
 tools/testing/selftests/xsave/.gitignore      |   3 +
 tools/testing/selftests/xsave/Makefile        |   6 +
 tools/testing/selftests/xsave/xsave_common.h  | 246 ++++++++++++++++++
 .../selftests/xsave/xsave_instruction.c       |  83 ++++++
 .../selftests/xsave/xsave_signal_handle.c     | 184 +++++++++++++
 6 files changed, 523 insertions(+)
 create mode 100644 tools/testing/selftests/xsave/.gitignore
 create mode 100644 tools/testing/selftests/xsave/Makefile
 create mode 100644 tools/testing/selftests/xsave/xsave_common.h
 create mode 100644 tools/testing/selftests/xsave/xsave_instruction.c
 create mode 100644 tools/testing/selftests/xsave/xsave_signal_handle.c

-- 
2.20.1

[RFC PATCH v4 1/2] selftests/xsave: test basic XSAVE architecture functionality

[Pengfei Xu]

The XSAVE feature set supports the saving and restoring of state components,
and XSAVE feature is used for process context switching. XSAVE state
components include FPU-related x87 state, SSE state, AVX state, etc.

This case tests and verifies the basic functions of XSAVE/XRSTOR in user
space: display and test the content changes of XSAVE; when the xstate in the
same process on the x86 platform is unchanged, the contents of XRSTOR and
XSAVE should be the same. This case is the most basic test of XSAVE function.

Signed-off-by: Pengfei Xu <pengfei.xu@intel.com>
Reported-by: kernel test robot <lkp@intel.com> # compile issues during review
---
 tools/testing/selftests/Makefile              |   1 +
 tools/testing/selftests/xsave/.gitignore      |   2 +
 tools/testing/selftests/xsave/Makefile        |   6 +
 tools/testing/selftests/xsave/xsave_common.h  | 246 ++++++++++++++++++
 .../selftests/xsave/xsave_instruction.c       |  83 ++++++
 5 files changed, 338 insertions(+)
 create mode 100644 tools/testing/selftests/xsave/.gitignore
 create mode 100644 tools/testing/selftests/xsave/Makefile
 create mode 100644 tools/testing/selftests/xsave/xsave_common.h
 create mode 100644 tools/testing/selftests/xsave/xsave_instruction.c

diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
index c852eb40c4f7..266e2bb982a1 100644
--- a/tools/testing/selftests/Makefile
+++ b/tools/testing/selftests/Makefile
@@ -75,6 +75,7 @@ TARGETS += user
 TARGETS += vDSO
 TARGETS += vm
 TARGETS += x86
+TARGETS += xsave
 TARGETS += zram
 #Please keep the TARGETS list alphabetically sorted
 # Run "make quicktest=1 run_tests" or
diff --git a/tools/testing/selftests/xsave/.gitignore b/tools/testing/selftests/xsave/.gitignore
new file mode 100644
index 000000000000..00b9970360c4
--- /dev/null
+++ b/tools/testing/selftests/xsave/.gitignore
@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0-only
+xsave_instruction
diff --git a/tools/testing/selftests/xsave/Makefile b/tools/testing/selftests/xsave/Makefile
new file mode 100644
index 000000000000..dafdb0abdeb3
--- /dev/null
+++ b/tools/testing/selftests/xsave/Makefile
@@ -0,0 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0-only
+CFLAGS := -g -Wall -mxsave -O2
+
+TEST_GEN_PROGS := xsave_instruction
+
+include ../lib.mk
diff --git a/tools/testing/selftests/xsave/xsave_common.h b/tools/testing/selftests/xsave/xsave_common.h
new file mode 100644
index 000000000000..2d3feae8096c
--- /dev/null
+++ b/tools/testing/selftests/xsave/xsave_common.h
@@ -0,0 +1,246 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <x86intrin.h>
+#include <string.h>
+#include <signal.h>
+#include <unistd.h>
+#include "../kselftest.h"
+
+#ifdef __i386__
+#define XSAVE _xsave
+#else
+#define XSAVE _xsave64
+#endif
+
+#ifdef __i386__
+#define XRSTOR _xrstor
+#else
+#define XRSTOR _xrstor64
+#endif
+
+#define SAVE_MASK 0xffffffffffffffff
+#define RESULT_PASS 0
+#define RESULT_FAIL 1
+#define RESULT_ERROR 3
+#define CHANGE 10
+#define NO_CHANGE 11
+
+/* Copied from Linux kernel */
+static inline void native_cpuid(unsigned int *eax, unsigned int *ebx,
+				unsigned int *ecx, unsigned int *edx)
+{
+	/* ecx is often an input as well as an output. */
+	asm volatile("cpuid"
+		: "=a" (*eax),
+		  "=b" (*ebx),
+		  "=c" (*ecx),
+		  "=d" (*edx)
+		: "0" (*eax), "2" (*ecx)
+		: "memory");
+}
+
+void execution_failed(char *reason)
+{
+	ksft_test_result_xfail("%s", reason);
+	ksft_exit_fail();
+}
+
+int get_xsave_size(void)
+{
+	unsigned int eax, ebx, ecx, edx;
+
+	eax = 0x0d;
+	ebx = 0;
+	ecx = 0;
+	edx = 0;
+	native_cpuid(&eax, &ebx, &ecx, &edx);
+
+	return (int)ecx;
+}
+
+void dump_buffer(unsigned char *buf, int size)
+{
+	int i, j;
+
+	printf("xsave size = %d (%03xh)\n", size, size);
+
+	for (i = 0; i < size; i += 16) {
+		printf("%04x: ", i);
+
+		for (j = i; ((j < i + 16) && (j < size)); j++)
+			printf("%02x ", buf[j]);
+		printf("\n");
+	}
+}
+
+void show_part_buf(unsigned char *buf0, unsigned char *buf1, int start,
+		int size)
+{
+	int c;
+
+	printf("%04x: ", start);
+	for (c = start; ((c < start + 16) && (c < size)); c++)
+		printf("%02x ", buf0[c]);
+	printf(" ->  ");
+	for (c = start; ((c < start + 16) && (c < size)); c++)
+		printf("%02x ", buf1[c]);
+	printf("\n");
+}
+
+int show_buf_diff(unsigned char *buf0, unsigned char *buf1, int size)
+{
+	int a, b, result_buf = RESULT_PASS;
+
+	for (a = 0; a < size; a += 16) {
+		/* SDM "XSAVE Area": XSAVE feature set does not use bytes 511:416 */
+		if ((a >= 416) && (a <= 511))
+			continue;
+
+		for (b = a; ((b < a + 16) && (b < size)); b++) {
+			if (buf0[b] != buf1[b]) {
+				show_part_buf(buf0, buf1, a, size);
+				result_buf = RESULT_FAIL;
+				break;
+			}
+		}
+	}
+
+	return result_buf;
+}
+
+int check_xsave_reserved_header(unsigned char *buf0,
+			unsigned char *buf1, int size, const char *test_name)
+{
+	int a, b, result_resv_header = RESULT_PASS;
+
+	/* SDM: Software should ensure that bytes 63:16 of the XSAVE header are 0 */
+	for (a = 528; a < 576 ; a += 16) {
+		for (b = a; ((b < a + 16) && (b < size)); b++) {
+			if ((buf0[b] != 0) || (buf1[b] != 0)) {
+				ksft_print_msg("%s FAIL: buf0[%d]:%d or buf1[%d]:%d not 0\n",
+					test_name, b, buf0[b], b, buf1[b]);
+				show_part_buf(buf0, buf1, a, size);
+				result_resv_header = RESULT_FAIL;
+				break;
+			}
+		}
+	}
+
+	return result_resv_header;
+}
+
+int check_xsave_buf(unsigned char *buf0, unsigned char *buf1,
+	int size, const char *test_name, int change)
+{
+	int result_buf = RESULT_ERROR, result_resv_header = RESULT_ERROR;
+
+	switch (change) {
+	case CHANGE:
+		if (show_buf_diff(buf0, buf1, size))
+			result_buf = RESULT_PASS;
+		else {
+			ksft_print_msg("%s FAIL: xsave content was same\n", test_name);
+			result_buf = RESULT_FAIL;
+		}
+		break;
+	case NO_CHANGE:
+		if (show_buf_diff(buf0, buf1, size)) {
+			ksft_print_msg("%s FAIL: xsave content changed\n", test_name);
+			show_buf_diff(buf0, buf1, size);
+			result_buf = RESULT_FAIL;
+		} else
+			result_buf = RESULT_PASS;
+		break;
+	default:
+		ksft_test_result_error("%s ERROR: invalid change:%d\n", test_name,
+			change);
+		break;
+	}
+
+	result_resv_header = check_xsave_reserved_header(buf0, buf1, size,
+		test_name);
+
+	return (result_buf || result_resv_header);
+}
+
+void check_result(int result, const char *test_name)
+{
+	switch (result) {
+	case RESULT_PASS:
+		ksft_test_result_pass("%s PASS\n", test_name);
+		break;
+	case RESULT_FAIL:
+		ksft_test_result_fail("%s FAIL\n", test_name);
+		break;
+	case RESULT_ERROR:
+		ksft_test_result_fail("%s ERROR\n", test_name);
+		break;
+	default:
+		ksft_test_result_error("%s ERROR: invalid result:%c\n",
+			test_name, result);
+		break;
+	}
+}
+
+void populate_fpu_regs(void)
+{
+	uint32_t ui32;
+	uint64_t ui64;
+
+	ui32 = 1;
+	ui64 = 0xBAB00500FAB7;
+
+	/* Initialize FPU and push different values onto FPU register stack: */
+	asm volatile ("finit");
+	asm volatile ("fldl %0" : : "m" (ui64));
+	asm volatile ("flds %0" : : "m" (ui32));
+	ui64 += 0x93ABE13;
+	asm volatile ("fldl %0" : : "m" (ui64));
+	ui64 += 0x93;
+	asm volatile ("fldl %0" : : "m" (ui64));
+	asm volatile ("flds %0" : : "m" (ui32));
+	asm volatile ("fldl %0" : : "m" (ui64));
+	ui64 -= 0x21;
+	asm volatile ("fldl %0" : : "m" (ui64));
+	asm volatile ("flds %0" : : "m" (ui32));
+	asm volatile ("fldl %0" : : "m" (ui64));
+
+	/* Fill each remaining YMM register with a different value: */
+	asm volatile ("vbroadcastss %0, %%ymm0" : : "m" (ui32));
+	ui32 = 0xFAFBABAF;
+	asm volatile ("vbroadcastss %0, %%ymm1" : : "m" (ui32));
+	ui32 -= 0xA;
+	asm volatile ("vbroadcastss %0, %%ymm2" : : "m" (ui32));
+	ui32 -= 0xB;
+	asm volatile ("vbroadcastss %0, %%ymm3" : : "m" (ui32));
+	ui32 -= 0x3;
+	asm volatile ("vbroadcastss %0, %%ymm4" : : "m" (ui32));
+	ui32 += 0xA;
+	asm volatile ("vbroadcastss %0, %%ymm5" : : "m" (ui32));
+	ui32 -= 0x7;
+	asm volatile ("vbroadcastss %0, %%ymm6" : : "m" (ui32));
+	ui32 -= 0xABABA;
+	asm volatile ("vbroadcastss %0, %%ymm7" : : "m" (ui32));
+
+	#ifndef __i386__
+	ui32 += 0xF7;
+	asm volatile ("vbroadcastss %0, %%ymm8" : : "m" (ui32));
+	ui32 -= 0x7;
+	asm volatile ("vbroadcastss %0, %%ymm9" : : "m" (ui32));
+	ui32 += 0x2;
+	asm volatile ("vbroadcastss %0, %%ymm10" : : "m" (ui32));
+	ui32 += 0xD;
+	asm volatile ("vbroadcastss %0, %%ymm11" : : "m" (ui32));
+	ui32 -= 0x4;
+	asm volatile ("vbroadcastss %0, %%ymm12" : : "m" (ui32));
+	ui32 -= 0xDD;
+	asm volatile ("vbroadcastss %0, %%ymm13" : : "m" (ui32));
+	ui32 -= 0xABD;
+	asm volatile ("vbroadcastss %0, %%ymm14" : : "m" (ui32));
+	ui32 += 0xBEBABF456;
+	asm volatile ("vbroadcastss %0, %%ymm15" : : "m" (ui32));
+	#endif
+}
diff --git a/tools/testing/selftests/xsave/xsave_instruction.c b/tools/testing/selftests/xsave/xsave_instruction.c
new file mode 100644
index 000000000000..2b610101511d
--- /dev/null
+++ b/tools/testing/selftests/xsave/xsave_instruction.c
@@ -0,0 +1,83 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Test kernel support for XSAVE-managed features.
+ */
+
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <x86intrin.h>
+#include <string.h>
+#include <signal.h>
+#include <unistd.h>
+
+#include "../kselftest.h"
+#include "xsave_common.h"
+
+static unsigned char *xsave_buf0, *xsave_buf1;
+
+static void set_ymm0_reg(uint32_t ui32)
+{
+	asm volatile ("vbroadcastss %0, %%ymm0" : : "m" (ui32));
+}
+
+static void dump_xsave_content(int xsave_size)
+{
+	XSAVE(xsave_buf0, SAVE_MASK);
+	dump_buffer(xsave_buf0, xsave_size);
+	ksft_print_msg("Entire contents of XSAVE is as above\n");
+}
+
+static void test_xsave_ymm_change(int xsave_size)
+{
+	const char *test_name = "xsave test after ymm change";
+	uint32_t ui32_set = 0x1234, ui32_change = 0x5678;
+	int result = RESULT_ERROR;
+
+	set_ymm0_reg(ui32_set);
+	XSAVE(xsave_buf0, SAVE_MASK);
+	set_ymm0_reg(ui32_change);
+	XSAVE(xsave_buf1, SAVE_MASK);
+	result = check_xsave_buf(xsave_buf0, xsave_buf1, xsave_size, test_name,
+				CHANGE);
+	check_result(result, test_name);
+}
+
+static void test_xsave_xrstor(int xsave_size)
+{
+	const char *test_name = "xsave after xrstor test";
+	int result = RESULT_ERROR;
+
+	XSAVE(xsave_buf0, SAVE_MASK);
+	XRSTOR(xsave_buf0, SAVE_MASK);
+	XSAVE(xsave_buf1, SAVE_MASK);
+	result = check_xsave_buf(xsave_buf0, xsave_buf1, xsave_size, test_name,
+				NO_CHANGE);
+	check_result(result, test_name);
+}
+
+int main(void)
+{
+	int xsave_size;
+
+	ksft_print_header();
+	ksft_set_plan(2);
+
+	xsave_size = get_xsave_size();
+	/* SDM XSAVE: misalignment to a 64-byte boundary will result in #GP */
+	xsave_buf0 = aligned_alloc(64, xsave_size);
+	if (!xsave_buf0)
+		execution_failed("aligned_alloc xsave_buf0 failed\n");
+	xsave_buf1 = aligned_alloc(64, xsave_size);
+	if (!xsave_buf1)
+		execution_failed("aligned_alloc xsave_buf1 failed\n");
+
+	populate_fpu_regs();
+	/* Show the entire contents of xsave for issue debug */
+	dump_xsave_content(xsave_size);
+
+	test_xsave_ymm_change(xsave_size);
+	test_xsave_xrstor(xsave_size);
+
+	ksft_exit(!ksft_get_fail_cnt());
+}
-- 
2.20.1

[RFC PATCH v4 2/2] selftests/xsave: add xsave test during and after signal handling

[Pengfei Xu]

In order to ensure that the XSAVE content in the same process is not affected
by signal handling, this case tests that the XSAVE content of the process
should not change during and after the nested signal handling.

Signed-off-by: Pengfei Xu <pengfei.xu@intel.com>
---
 tools/testing/selftests/xsave/.gitignore      |   1 +
 tools/testing/selftests/xsave/Makefile        |   2 +-
 .../selftests/xsave/xsave_signal_handle.c     | 184 ++++++++++++++++++
 3 files changed, 186 insertions(+), 1 deletion(-)
 create mode 100644 tools/testing/selftests/xsave/xsave_signal_handle.c

diff --git a/tools/testing/selftests/xsave/.gitignore b/tools/testing/selftests/xsave/.gitignore
index 00b9970360c4..b448d36186f3 100644
--- a/tools/testing/selftests/xsave/.gitignore
+++ b/tools/testing/selftests/xsave/.gitignore
@@ -1,2 +1,3 @@
 # SPDX-License-Identifier: GPL-2.0-only
 xsave_instruction
+xsave_signal_handle
diff --git a/tools/testing/selftests/xsave/Makefile b/tools/testing/selftests/xsave/Makefile
index dafdb0abdeb3..fedae2778297 100644
--- a/tools/testing/selftests/xsave/Makefile
+++ b/tools/testing/selftests/xsave/Makefile
@@ -1,6 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0-only
 CFLAGS := -g -Wall -mxsave -O2
 
-TEST_GEN_PROGS := xsave_instruction
+TEST_GEN_PROGS := xsave_instruction xsave_signal_handle
 
 include ../lib.mk
diff --git a/tools/testing/selftests/xsave/xsave_signal_handle.c b/tools/testing/selftests/xsave/xsave_signal_handle.c
new file mode 100644
index 000000000000..0afcba3a1bd5
--- /dev/null
+++ b/tools/testing/selftests/xsave/xsave_signal_handle.c
@@ -0,0 +1,184 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * It's for xsave/xrstor during signal handling tests
+ */
+
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <x86intrin.h>
+#include <string.h>
+#include <signal.h>
+#include <unistd.h>
+#include <sched.h>
+#include <sys/wait.h>
+#include <time.h>
+
+#include "../kselftest.h"
+#include "xsave_common.h"
+
+static unsigned char *xsave_buf0, *xsave_buf1, *xsave_buf2, *xsave_buf3;
+static int result[2];
+
+static void change_fpu_content(uint32_t ui32_random, double flt)
+{
+	asm volatile ("fldl %0" : : "m" (flt));
+	asm volatile ("vbroadcastss %0, %%ymm0" : : "m" (ui32_random));
+	asm volatile ("vbroadcastss %0, %%ymm1" : : "m" (ui32_random));
+	asm volatile ("vbroadcastss %0, %%ymm2" : : "m" (ui32_random));
+	asm volatile ("vbroadcastss %0, %%ymm3" : : "m" (ui32_random));
+	asm volatile ("vbroadcastss %0, %%ymm4" : : "m" (ui32_random));
+	asm volatile ("vbroadcastss %0, %%ymm5" : : "m" (ui32_random));
+	asm volatile ("vbroadcastss %0, %%ymm6" : : "m" (ui32_random));
+	asm volatile ("vbroadcastss %0, %%ymm7" : : "m" (ui32_random));
+	#ifndef __i386__
+	asm volatile ("vbroadcastss %0, %%ymm8" : : "m" (ui32_random));
+	asm volatile ("vbroadcastss %0, %%ymm9" : : "m" (ui32_random));
+	asm volatile ("vbroadcastss %0, %%ymm10" : : "m" (ui32_random));
+	asm volatile ("vbroadcastss %0, %%ymm11" : : "m" (ui32_random));
+	asm volatile ("vbroadcastss %0, %%ymm12" : : "m" (ui32_random));
+	asm volatile ("vbroadcastss %0, %%ymm13" : : "m" (ui32_random));
+	asm volatile ("vbroadcastss %0, %%ymm14" : : "m" (ui32_random));
+	asm volatile ("vbroadcastss %0, %%ymm15" : : "m" (ui32_random));
+	#endif
+}
+
+static void usr1_handler(int signum, siginfo_t *info, void *__ctxp)
+{
+	uint32_t ui32_random;
+	double flt;
+	int xsave_size;
+	const char *test_name = "Child XSAVE should not change in nested signal";
+
+	ui32_random = rand();
+	flt = ui32_random/10000.0;
+	if (signum == SIGUSR1) {
+		ksft_print_msg("SIGUSR1:0x%x changed fld:%f & ymm0-15:0x%x\n",
+			SIGUSR1, flt, ui32_random);
+		change_fpu_content(ui32_random, flt);
+	}
+	xsave_size = get_xsave_size();
+	XSAVE(xsave_buf2, SAVE_MASK);
+	raise(SIGUSR2);
+	XSAVE(xsave_buf3, SAVE_MASK);
+	result[0] = check_xsave_buf(xsave_buf2, xsave_buf2, xsave_size, test_name,
+				NO_CHANGE);
+}
+
+static void usr2_handler(int signum, siginfo_t *info, void *__ctxp)
+{
+	uint32_t ui32_random;
+	double flt;
+
+	ui32_random = rand();
+	flt = ui32_random/10000.0;
+	if (signum == SIGUSR2) {
+		ksft_print_msg("SIGUSR2:0x%x changed fld:%f & ymm0-15:0x%x\n",
+			SIGUSR2, flt, ui32_random);
+		change_fpu_content(ui32_random, flt);
+	}
+}
+
+static void set_signal_handle(void)
+{
+	struct sigaction sigact;
+
+	memset(&sigact, 0, sizeof(sigact));
+	if (sigemptyset(&sigact.sa_mask))
+		execution_failed("FAIL: sigemptyset error\n");
+
+	sigact.sa_flags = SA_SIGINFO;
+
+	sigact.sa_sigaction = usr1_handler;
+	if (sigaction(SIGUSR1, &sigact, NULL))
+		execution_failed("FAIL: SIGUSR1 handling failed\n");
+
+	sigact.sa_sigaction = usr2_handler;
+	if (sigaction(SIGUSR2, &sigact, NULL))
+		execution_failed("FAIL: SIGUSR2 handling failed\n");
+}
+
+static void sig_handle_xsave_test(void)
+{
+	int i, loop_times = 100, xsave_size;
+	const char *sig_test_name0 = "Child XSAVE was same in nested signal test";
+	const char *sig_test_name1 = "Child XSAVE content was same after signal";
+
+	xsave_size = get_xsave_size();
+	/* SDM XSAVE: misalignment to a 64-byte boundary will result in #GP */
+	xsave_buf0 = aligned_alloc(64, xsave_size);
+	if (!xsave_buf0)
+		execution_failed("aligned_alloc xsave_buf0 failed\n");
+	xsave_buf1 = aligned_alloc(64, xsave_size);
+	if (!xsave_buf1)
+		execution_failed("aligned_alloc xsave_buf1 failed\n");
+	xsave_buf2 = aligned_alloc(64, xsave_size);
+	if (!xsave_buf2)
+		execution_failed("aligned_alloc xsave_buf2 failed\n");
+	xsave_buf3 = aligned_alloc(64, xsave_size);
+	if (!xsave_buf3)
+		execution_failed("aligned_alloc xsave_buf3 failed\n");
+
+	srand(time(NULL));
+	result[0] = RESULT_PASS;
+	result[1] = RESULT_PASS;
+
+	XSAVE(xsave_buf0, SAVE_MASK);
+	for (i = 1; i <= loop_times; i++) {
+		raise(SIGUSR1);
+		XSAVE(xsave_buf1, SAVE_MASK);
+		result[1] = check_xsave_buf(xsave_buf0, xsave_buf1, xsave_size,
+						sig_test_name1, NO_CHANGE);
+		if (result[1] != RESULT_PASS)
+			break;
+	}
+
+	check_result(result[0], sig_test_name0);
+	check_result(result[1], sig_test_name1);
+}
+
+static void test_xsave_sig_handle(void)
+{
+	const char *test_name0 = "xsave in child nested signal handling test";
+	const char *test_name1 = "xsave after child signal handling test";
+	pid_t child;
+	int status, fd[2], readbuf[2];
+
+	set_signal_handle();
+
+	/* Use pipe to transfer test result of child process to parent process */
+	if (pipe(fd) < 0)
+		execution_failed("FAIL: create pipe failed\n");
+
+	/* Use child process testing to avoid abnormal blocking the next test */
+	child = fork();
+	if (child < 0)
+		execution_failed("FAIL: create child pid failed\n");
+	else if	(child == 0) {
+		populate_fpu_regs();
+		sig_handle_xsave_test();
+		close(fd[0]);
+		write(fd[1], &result, sizeof(result));
+	} else {
+		if (waitpid(child, &status, 0) != child ||
+			!WIFEXITED(status))
+			execution_failed("FAIL: Child died unexpectedly\n");
+		else {
+			close(fd[1]);
+			read(fd[0], &readbuf, sizeof(readbuf));
+
+			check_result(readbuf[0], test_name0);
+			check_result(readbuf[1], test_name1);
+		}
+	}
+}
+
+int main(void)
+{
+	ksft_print_header();
+	ksft_set_plan(2);
+
+	test_xsave_sig_handle();
+
+	ksft_exit(!ksft_get_fail_cnt());
+}
-- 
2.20.1