[RFC,v2,1/2] selftests/xsave: test basic XSAVE architecture functionality

diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
index fb010a35d61a..4c0ddb8228e1 100644
--- a/tools/testing/selftests/Makefile
+++ b/tools/testing/selftests/Makefile
@@ -73,6 +73,7 @@  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..c555f9d289a3
--- /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 "Form of XRSTOR": Bytes 63:16 of the XSAVE header should 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());
+}