@@ -18,7 +18,7 @@ TARGETS_C_32BIT_ONLY := entry_from_vm86 test_syscall_vdso unwind_vdso \
test_FCMOV test_FCOMI test_FISTTP \
vdso_restorer
TARGETS_C_64BIT_ONLY := fsgsbase sysret_rip syscall_numbering \
- corrupt_xstate_header amx xsave_signal_handle
+ corrupt_xstate_header amx xsave_signal_handle xsave_fork_test
# Some selftests require 32bit support enabled also on 64bit systems
TARGETS_C_32BIT_NEEDED := ldt_gdt ptrace_syscall
new file mode 100644
@@ -0,0 +1,127 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * It's for XSAVE fork test.
+ */
+
+#define _GNU_SOURCE
+
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <x86intrin.h>
+#include <string.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include <sched.h>
+
+#include "xsave_common.h"
+
+static unsigned char *xsave_buf0, *xsave_buf1, *xsave_buf2;
+static int xsave_size, read_result[2];
+static const char *fork_test = "xsave fork for xsave context switch test";
+
+void set_xstates(void)
+{
+ /* 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");
+
+ populate_xstate_regs();
+}
+
+void clear_avx(void)
+{
+ asm volatile("vzeroall");
+}
+
+/* use fork to create pid and trigger context switch test */
+int test_fork(void)
+{
+ pid_t child;
+ int status, fd[2], result[2];
+ const char *test_xsave_child = "Child xstate was same as parent";
+ const char *test_process_swich = "Xstate after process switch was same";
+
+ /* Use pipe to transfer test result of child process to parent process */
+ if (pipe(fd) < 0)
+ execution_failed("FAIL: create pipe failed\n");
+
+ XSAVE(xsave_buf0, XSAVE_TEST_MASK);
+ child = fork();
+ if (child < 0)
+ execution_failed("fork failed\n");
+ if (child == 0) {
+ XSAVE(xsave_buf1, XSAVE_TEST_MASK);
+ result[0] = compare_xsave_buf(xsave_buf0, xsave_buf1, xsave_size,
+ fork_test, NO_CHANGE);
+ close(fd[0]);
+ if (!write(fd[1], &result, sizeof(result)))
+ execution_failed("FAIL: write fd failed.\n");
+
+ XSAVE(xsave_buf1, XSAVE_TEST_MASK);
+ pid_t grandchild;
+
+ /* fork grandchild will trigger process switching in child */
+ grandchild = fork();
+ if (grandchild == 0) {
+ ksft_print_msg("Grandchild pid:%d clean it's XMM YMM ZMM xstates\n",
+ getpid());
+ clear_avx();
+ return 0;
+ }
+ if (grandchild)
+ waitpid(grandchild, NULL, 0);
+
+ /* After swich back to child process and check xstate */
+ XSAVE(xsave_buf2, XSAVE_TEST_MASK);
+ ksft_print_msg("Child pid:%d check xstate after swtich back\n",
+ getpid());
+ result[1] = compare_xsave_buf(xsave_buf1, xsave_buf2, xsave_size,
+ fork_test, NO_CHANGE);
+ if (!write(fd[1], &result, sizeof(result)))
+ execution_failed("FAIL: write fd failed.\n");
+
+ return 0;
+ }
+
+ if (child) {
+ if (waitpid(child, &status, 0) != child || !WIFEXITED(status))
+ ksft_test_result_fail("Child exit with error, status:0x%x\n",
+ status);
+ else {
+ ksft_print_msg("Parent pid:%d get results\n", getpid());
+ close(fd[1]);
+ if (!read(fd[0], &read_result, sizeof(read_result)))
+ execution_failed("FAIL: read fd failed.\n");
+ }
+ }
+
+ ksft_set_plan(2);
+ check_result(read_result[0], test_xsave_child);
+ check_result(read_result[1], test_process_swich);
+
+ return 0;
+}
+
+int main(int argc, char *argv[])
+{
+ cpu_set_t set;
+
+ xsave_size = get_xsave_size();
+ ksft_print_header();
+
+ CPU_ZERO(&set);
+ CPU_SET(0, &set);
+
+ set_xstates();
+ test_fork();
+
+ ksft_exit(!ksft_get_fail_cnt());
+}
It will change FPU, AVX2, AVX512, PKRU xstates before process switch test to ensure that the entire processing of these xstates works as expected. In order to ensure the above XSAVE content is not affected after process switch, this case tests that: 1. The xstates content of the child process should same as xstates of parent process. 2. The xstates content of the child process should not change after process switch back, even grandchild process cleaned up it's own XMM, YMM and ZMM xstates. Signed-off-by: Pengfei Xu <pengfei.xu@intel.com> --- tools/testing/selftests/x86/Makefile | 2 +- tools/testing/selftests/x86/xsave_fork_test.c | 127 ++++++++++++++++++ 2 files changed, 128 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/x86/xsave_fork_test.c