@@ -13,7 +13,7 @@ CAN_BUILD_WITH_NOPIE := $(shell ./check_cc.sh "$(CC)" trivial_program.c -no-pie)
TARGETS_C_BOTHBITS := single_step_syscall sysret_ss_attrs syscall_nt test_mremap_vdso \
check_initial_reg_state sigreturn iopl ioperm \
test_vsyscall mov_ss_trap \
- syscall_arg_fault fsgsbase_restore sigaltstack
+ syscall_arg_fault fsgsbase_restore sigaltstack suspend_msr_restore
TARGETS_C_32BIT_ONLY := entry_from_vm86 test_syscall_vdso unwind_vdso \
test_FCMOV test_FCOMI test_FISTTP \
vdso_restorer
new file mode 100644
@@ -0,0 +1,193 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2022 Intel Corporation
+ *
+ * This test caches some chosen MSRs, does a suspend cycle and reports failure
+ * if the MSRs are not restored to the values before suspend.
+ */
+
+#define _GNU_SOURCE
+
+#include <fcntl.h>
+#include <sched.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+#include <sys/stat.h>
+#include <sys/timerfd.h>
+#include <sys/sysinfo.h>
+
+#include "../kselftest.h"
+
+#define MSR_IA32_SPEC_CTRL 0x00000048
+#define MSR_IA32_TSX_CTRL 0x00000122
+#define MSR_TSX_FORCE_ABORT 0x0000010F
+#define MSR_IA32_MCU_OPT_CTRL 0x00000123
+#define MSR_AMD64_LS_CFG 0xc0011020
+#define MSR_AMD64_DE_CFG 0xc0011029
+
+struct msr_cache {
+ unsigned int msr_id;
+ unsigned long long msr_val;
+ bool valid;
+};
+
+int suspend(void)
+{
+ struct itimerspec spec = {};
+ int power_state_fd;
+ int timerfd;
+ int ret = -1;
+
+ power_state_fd = open("/sys/power/state", O_RDWR);
+ if (power_state_fd < 0) {
+ ksft_test_result_error("open(\"/sys/power/state\") failed %s)\n", strerror(errno));
+ goto exit;
+ }
+
+ timerfd = timerfd_create(CLOCK_BOOTTIME_ALARM, 0);
+ if (timerfd < 0) {
+ ksft_test_result_error("timerfd_create() failed\n");
+ goto cleanup_power_state;
+ }
+
+ spec.it_value.tv_sec = 15;
+ ret = timerfd_settime(timerfd, 0, &spec, NULL);
+ if (ret < 0) {
+ ksft_test_result_error("timerfd_settime() failed\n");
+ goto cleanup_timer;
+ }
+
+ if (write(power_state_fd, "mem", strlen("mem")) != strlen("mem")) {
+ ksft_test_result_error("Failed to enter Suspend state\n");
+ ret = -1;
+ goto cleanup_timer;
+ }
+
+ ret = 0;
+
+cleanup_timer:
+ close(timerfd);
+cleanup_power_state:
+ close(power_state_fd);
+exit:
+ return ret;
+}
+
+int msr_read(int cpu, unsigned int msr_id, unsigned long long *msr_val)
+{
+ char msr_file_name[32];
+ int fd, ret;
+
+ snprintf(msr_file_name, 32, "/dev/cpu/%d/msr", cpu);
+ fd = open(msr_file_name, O_RDONLY);
+
+ if (fd == -1) {
+ perror("Failed to open");
+ return -ENODEV;
+ }
+
+ ret = pread(fd, msr_val, sizeof(long long), msr_id);
+ close(fd);
+
+ return ret != sizeof(long long);
+}
+
+int main(void)
+{
+ /* List of MSRs to tests */
+ unsigned int msr_id[] = {
+ MSR_IA32_SPEC_CTRL,
+ MSR_IA32_TSX_CTRL,
+ MSR_TSX_FORCE_ABORT,
+ MSR_IA32_MCU_OPT_CTRL,
+ MSR_AMD64_LS_CFG,
+ MSR_AMD64_DE_CFG,
+ };
+ int i, cpu, err, max_cpus, msr_idx, total_tests = 0;
+ int num_msrs = ARRAY_SIZE(msr_id);
+ unsigned long long msr_val;
+ cpu_set_t available_cpus;
+ struct msr_cache *msrs;
+ bool succeeded = true;
+
+ if (getuid() != 0)
+ ksft_exit_skip("Please re-run the test as root\n");
+
+ if (access("/dev/cpu/0/msr", R_OK))
+ ksft_exit_skip("Can't read MSRs\n");
+
+ if (access("/sys/power/state", W_OK))
+ ksft_exit_skip("/sys/power/state not writable\n");
+
+ ksft_print_header();
+
+ err = sched_getaffinity(0, sizeof(available_cpus), &available_cpus);
+ if (err < 0)
+ ksft_exit_fail_msg("sched_getaffinity() failed\n");
+
+ max_cpus = get_nprocs_conf();
+
+ msrs = calloc(sizeof(struct msr_cache), max_cpus * num_msrs);
+ if (!msrs)
+ ksft_exit_fail_msg("Memory allocation failed\n");
+
+ for (cpu = 0; cpu < max_cpus; cpu++) {
+ if (!CPU_ISSET(cpu, &available_cpus))
+ continue;
+ msr_idx = cpu * num_msrs;
+ for (i = 0; i < num_msrs; i++, msr_idx++) {
+ if (!msr_read(cpu, msr_id[i], &msr_val)) {
+ msrs[msr_idx].valid = true;
+ msrs[msr_idx].msr_id = msr_id[i];
+ msrs[msr_idx].msr_val = msr_val;
+ total_tests++;
+ }
+ }
+ }
+
+ ksft_set_plan(total_tests);
+
+ if (suspend()) {
+ succeeded = false;
+ goto cleanup;
+ }
+
+ for (cpu = 0; cpu < max_cpus; cpu++) {
+ if (!CPU_ISSET(cpu, &available_cpus))
+ continue;
+
+ msr_idx = cpu * num_msrs;
+ for (i = 0; i < num_msrs; i++, msr_idx++) {
+ if (!msrs[msr_idx].valid)
+ continue;
+ if (msr_read(cpu, msr_id[i], &msr_val)) {
+ ksft_test_result_fail("Not able to read msr=0x%x on CPU=%d\n",
+ msr_id[i], cpu);
+ succeeded = false;
+ continue;
+ }
+ if (msrs[msr_idx].msr_val != msr_val) {
+ ksft_test_result_fail("CPU%d: msr=0x%x value after resume=[0x%llx] != suspend=[0x%llx]\n",
+ cpu, msr_id[i], msr_val, msrs[msr_idx].msr_val);
+ succeeded = false;
+ continue;
+ }
+
+ ksft_test_result_pass("CPU%d: MSR[0x%x] restored to 0x%llx\n",
+ cpu, msr_id[i], msr_val);
+ }
+ }
+
+cleanup:
+ free(msrs);
+
+ if (succeeded)
+ ksft_exit_pass();
+ else
+ ksft_exit_fail();
+}
There are certain security related MSRs that must be restored after a suspend cycle. There have been quite a few fixes done to restore these MSRs: commit e2a1256b17b1 ("x86/speculation: Restore speculation related MSRs during S3 resume") commit 50bcceb7724e ("x86/pm: Add enumeration check before spec MSRs save/restore setup") commit 66065157420c ("x86/bugs: Make sure MSR_SPEC_CTRL is updated properly upon resume from S3") commit 2632daebafd0 ("x86/cpu: Restore AMD's DE_CFG MSR after resume") commit 73924ec4d560 ("x86/pm: Save the MSR validity status at context setup") commit f9e14dbbd454 ("x86/cpu: Load microcode during restore_processor_state()") In order to catch regressions early add a selftest that keeps a copy of below MSRs for all CPUs: MSR_IA32_SPEC_CTRL MSR_IA32_TSX_CTRL MSR_TSX_FORCE_ABORT MSR_IA32_MCU_OPT_CTRL MSR_AMD64_LS_CFG MSR_AMD64_DE_CFG The test does a suspend/resume and reports failure if the MSRs are not restored to the value before suspend. Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com> --- tools/testing/selftests/x86/Makefile | 2 +- .../selftests/x86/suspend_msr_restore.c | 193 ++++++++++++++++++ 2 files changed, 194 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/x86/suspend_msr_restore.c