/* * Copyright (C) 2018 Intel Corporation. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * * Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * * Neither the name of Intel Corporation nor the names of its * contributors may be used to endorse or promote products derived * from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #include #include #include #include #include #include #include #include #include #ifdef CONFIG_EFI_STUB extern uint32_t efi_physical_available_ap_bitmap; #endif uint64_t tsc_clock_freq = 1000000000; spinlock_t cpu_secondary_spinlock = { .head = 0, .tail = 0 }; spinlock_t up_count_spinlock = { .head = 0, .tail = 0 }; void *per_cpu_data_base_ptr; int phy_cpu_num = 0; unsigned long pcpu_sync = 0; uint32_t up_count = 0; /* physical cpu active bitmap, support up to 64 cpus */ uint64_t pcpu_active_bitmap = 0; DEFINE_CPU_DATA(uint8_t[STACK_SIZE], stack) __aligned(16); DEFINE_CPU_DATA(uint8_t, lapic_id); DEFINE_CPU_DATA(void *, vcpu); DEFINE_CPU_DATA(int, state); /* TODO: add more capability per requirement */ /*APICv features*/ #define VAPIC_FEATURE_VIRT_ACCESS (1 << 0) #define VAPIC_FEATURE_VIRT_REG (1 << 1) #define VAPIC_FEATURE_INTR_DELIVERY (1 << 2) #define VAPIC_FEATURE_TPR_SHADOW (1 << 3) #define VAPIC_FEATURE_POST_INTR (1 << 4) #define VAPIC_FEATURE_VX2APIC_MODE (1 << 5) struct cpu_capability { uint8_t vapic_features; }; static struct cpu_capability cpu_caps; struct cpuinfo_x86 boot_cpu_data; static void vapic_cap_detect(void); static void cpu_xsave_init(void); static void cpu_set_logical_id(uint32_t logical_id); static void print_hv_banner(void); int cpu_find_logical_id(uint32_t lapic_id); #ifndef CONFIG_EFI_STUB static void start_cpus(void); #endif static void pcpu_sync_sleep(unsigned long *sync, int mask_bit); int ibrs_type; inline bool cpu_has_cap(uint32_t bit) { int feat_idx = bit >> 5; int feat_bit = bit & 0x1f; if (feat_idx >= FEATURE_WORDS) return false; return !!(boot_cpu_data.cpuid_leaves[feat_idx] & (1 << feat_bit)); } static inline bool get_monitor_cap(void) { if (cpu_has_cap(X86_FEATURE_MONITOR)) { /* don't use monitor for CPU (family: 0x6 model: 0x5c) * in hypervisor, but still expose it to the guests and * let them handle it correctly */ if (boot_cpu_data.x86 != 0x6 || boot_cpu_data.x86_model != 0x5c) return true; } return false; } static uint64_t get_address_mask(uint8_t limit) { return ((1ULL << limit) - 1) & CPU_PAGE_MASK; } static void get_cpu_capabilities(void) { uint32_t eax, unused; uint32_t max_extended_function_idx; uint32_t family, model; cpuid(CPUID_FEATURES, &eax, &unused, &boot_cpu_data.cpuid_leaves[FEAT_1_ECX], &boot_cpu_data.cpuid_leaves[FEAT_1_EDX]); family = (eax >> 8) & 0xff; if (family == 0xF) family += (eax >> 20) & 0xff; boot_cpu_data.x86 = family; model = (eax >> 4) & 0xf; if (family >= 0x06) model += ((eax >> 16) & 0xf) << 4; boot_cpu_data.x86_model = model; cpuid(CPUID_EXTEND_FEATURE, &unused, &boot_cpu_data.cpuid_leaves[FEAT_7_0_EBX], &boot_cpu_data.cpuid_leaves[FEAT_7_0_ECX], &boot_cpu_data.cpuid_leaves[FEAT_7_0_EDX]); cpuid(CPUID_MAX_EXTENDED_FUNCTION, &max_extended_function_idx, &unused, &unused, &unused); boot_cpu_data.cpuid_leaves[FEAT_8000_0000_EAX] = max_extended_function_idx; if (max_extended_function_idx < CPUID_EXTEND_ADDRESS_SIZE) { panic("CPU w/o CPUID.80000008H is not supported"); } cpuid(CPUID_EXTEND_FUNCTION_1, &unused, &unused, &boot_cpu_data.cpuid_leaves[FEAT_8000_0001_ECX], &boot_cpu_data.cpuid_leaves[FEAT_8000_0001_EDX]); cpuid(CPUID_EXTEND_ADDRESS_SIZE, &eax, &unused, &unused, &unused); boot_cpu_data.cpuid_leaves[FEAT_8000_0008_EAX] = eax; /* EAX bits 07-00: #Physical Address Bits * bits 15-08: #Linear Address Bits */ boot_cpu_data.physical_address_mask = get_address_mask(eax & 0xff); /* For speculation defence. * The default way is to set IBRS at vmexit and then do IBPB at vcpu * context switch(ibrs_type == IBRS_RAW). * Now provide an optimized way (ibrs_type == IBRS_OPT) which set * STIBP and do IBPB at vmexit,since having STIBP always set has less * impact than having IBRS always set. Also since IBPB is already done * at vmexit, it is no necessary to do so at vcpu context switch then. */ ibrs_type = IBRS_NONE; /* Currently for APL, if we enabled retpoline, then IBRS should not * take effect * TODO: add IA32_ARCH_CAPABILITIES[1] check, if this bit is set, IBRS * should be set all the time instead of relying on retpoline */ #ifndef CONFIG_RETPOLINE if (cpu_has_cap(X86_FEATURE_IBRS_IBPB)) { ibrs_type = IBRS_RAW; if (cpu_has_cap(X86_FEATURE_STIBP)) ibrs_type = IBRS_OPT; } #endif } static void alloc_phy_cpu_data(int pcpu_num) { phy_cpu_num = pcpu_num; per_cpu_data_base_ptr = calloc(1, PER_CPU_DATA_SIZE * pcpu_num); ASSERT(per_cpu_data_base_ptr != NULL, ""); } int __attribute__((weak)) parse_madt(uint8_t *lapic_id_base) { static const uint32_t lapic_id[] = {0, 2, 4, 6}; uint32_t i; for (i = 0; i < ARRAY_SIZE(lapic_id); i++) *lapic_id_base++ = lapic_id[i]; return ARRAY_SIZE(lapic_id); } static int init_phy_cpu_storage(void) { int i, pcpu_num = 0; int bsp_cpu_id; uint8_t bsp_lapic_id = 0; uint8_t *lapic_id_base; /* * allocate memory to save all lapic_id detected in parse_mdt. * We allocate 4K size which could save 4K CPUs lapic_id info. */ lapic_id_base = alloc_page(); ASSERT(lapic_id_base != NULL, "fail to alloc page"); pcpu_num = parse_madt(lapic_id_base); alloc_phy_cpu_data(pcpu_num); for (i = 0; i < pcpu_num; i++) { per_cpu(lapic_id, i) = *lapic_id_base++; #ifdef CONFIG_EFI_STUB efi_physical_available_ap_bitmap |= 1 << per_cpu(lapic_id, i); #endif } /* free memory after lapic_id are saved in per_cpu data */ free(lapic_id_base); bsp_lapic_id = get_cur_lapic_id(); #ifdef CONFIG_EFI_STUB efi_physical_available_ap_bitmap &= ~(1 << bsp_lapic_id); #endif bsp_cpu_id = cpu_find_logical_id(bsp_lapic_id); ASSERT(bsp_cpu_id >= 0, "fail to get phy cpu id"); return bsp_cpu_id; } static void cpu_set_current_state(uint32_t logical_id, int state) { spinlock_obtain(&up_count_spinlock); /* Check if state is initializing */ if (state == CPU_STATE_INITIALIZING) { /* Increment CPU up count */ up_count++; /* Save this CPU's logical ID to the TSC AUX MSR */ cpu_set_logical_id(logical_id); } /* Set state for the specified CPU */ per_cpu(state, logical_id) = state; spinlock_release(&up_count_spinlock); } #ifdef STACK_PROTECTOR struct stack_canary { /* Gcc generates extra code, using [fs:40] to access canary */ uint8_t reserved[40]; uint64_t canary; }; static DEFINE_CPU_DATA(struct stack_canary, stack_canary); static uint64_t get_random_value(void) { uint64_t random = 0; asm volatile ("1: rdrand %%rax\n" "jnc 1b\n" "mov %%rax, %0\n" : "=r"(random) :: ); return random; } static void set_fs_base(void) { struct stack_canary *psc = &get_cpu_var(stack_canary); psc->canary = get_random_value(); msr_write(MSR_IA32_FS_BASE, (uint64_t)psc); } #endif static void get_cpu_name(void) { cpuid(CPUID_EXTEND_FUNCTION_2, (uint32_t *)(boot_cpu_data.model_name), (uint32_t *)(boot_cpu_data.model_name + 4), (uint32_t *)(boot_cpu_data.model_name + 8), (uint32_t *)(boot_cpu_data.model_name + 12)); cpuid(CPUID_EXTEND_FUNCTION_3, (uint32_t *)(boot_cpu_data.model_name + 16), (uint32_t *)(boot_cpu_data.model_name + 20), (uint32_t *)(boot_cpu_data.model_name + 24), (uint32_t *)(boot_cpu_data.model_name + 28)); cpuid(CPUID_EXTEND_FUNCTION_4, (uint32_t *)(boot_cpu_data.model_name + 32), (uint32_t *)(boot_cpu_data.model_name + 36), (uint32_t *)(boot_cpu_data.model_name + 40), (uint32_t *)(boot_cpu_data.model_name + 44)); boot_cpu_data.model_name[48] = '\0'; } void bsp_boot_init(void) { uint64_t start_tsc = rdtsc(); /* Clear BSS */ memset(_ld_bss_start, 0, _ld_bss_end - _ld_bss_start); /* Build time sanity checks to make sure hard-coded offset * is matching the actual offset! */ _Static_assert(offsetof(struct cpu_regs, rax) == VMX_MACHINE_T_GUEST_RAX_OFFSET, "cpu_regs rax offset not match"); _Static_assert(offsetof(struct cpu_regs, rbx) == VMX_MACHINE_T_GUEST_RBX_OFFSET, "cpu_regs rbx offset not match"); _Static_assert(offsetof(struct cpu_regs, rcx) == VMX_MACHINE_T_GUEST_RCX_OFFSET, "cpu_regs rcx offset not match"); _Static_assert(offsetof(struct cpu_regs, rdx) == VMX_MACHINE_T_GUEST_RDX_OFFSET, "cpu_regs rdx offset not match"); _Static_assert(offsetof(struct cpu_regs, rbp) == VMX_MACHINE_T_GUEST_RBP_OFFSET, "cpu_regs rbp offset not match"); _Static_assert(offsetof(struct cpu_regs, rsi) == VMX_MACHINE_T_GUEST_RSI_OFFSET, "cpu_regs rsi offset not match"); _Static_assert(offsetof(struct cpu_regs, rdi) == VMX_MACHINE_T_GUEST_RDI_OFFSET, "cpu_regs rdi offset not match"); _Static_assert(offsetof(struct cpu_regs, r8) == VMX_MACHINE_T_GUEST_R8_OFFSET, "cpu_regs r8 offset not match"); _Static_assert(offsetof(struct cpu_regs, r9) == VMX_MACHINE_T_GUEST_R9_OFFSET, "cpu_regs r9 offset not match"); _Static_assert(offsetof(struct cpu_regs, r10) == VMX_MACHINE_T_GUEST_R10_OFFSET, "cpu_regs r10 offset not match"); _Static_assert(offsetof(struct cpu_regs, r11) == VMX_MACHINE_T_GUEST_R11_OFFSET, "cpu_regs r11 offset not match"); _Static_assert(offsetof(struct cpu_regs, r12) == VMX_MACHINE_T_GUEST_R12_OFFSET, "cpu_regs r12 offset not match"); _Static_assert(offsetof(struct cpu_regs, r13) == VMX_MACHINE_T_GUEST_R13_OFFSET, "cpu_regs r13 offset not match"); _Static_assert(offsetof(struct cpu_regs, r14) == VMX_MACHINE_T_GUEST_R14_OFFSET, "cpu_regs r14 offset not match"); _Static_assert(offsetof(struct cpu_regs, r15) == VMX_MACHINE_T_GUEST_R15_OFFSET, "cpu_regs r15 offset not match"); _Static_assert(offsetof(struct run_context, cr2) == VMX_MACHINE_T_GUEST_CR2_OFFSET, "run_context cr2 offset not match"); _Static_assert(offsetof(struct run_context, ia32_spec_ctrl) == VMX_MACHINE_T_GUEST_SPEC_CTRL_OFFSET, "run_context ia32_spec_ctrl offset not match"); bitmap_set(CPU_BOOT_ID, &pcpu_active_bitmap); /* Get CPU capabilities thru CPUID, including the physical address bit * limit which is required for initializing paging. */ get_cpu_capabilities(); get_cpu_name(); load_cpu_state_data(); /* Initialize the hypervisor paging */ init_paging(); early_init_lapic(); init_phy_cpu_storage(); load_gdtr_and_tr(); /* Switch to run-time stack */ CPU_SP_WRITE(&get_cpu_var(stack)[STACK_SIZE - 1]); #ifdef STACK_PROTECTOR set_fs_base(); #endif vapic_cap_detect(); cpu_xsave_init(); /* Set state for this CPU to initializing */ cpu_set_current_state(CPU_BOOT_ID, CPU_STATE_INITIALIZING); /* Perform any necessary BSP initialization */ init_bsp(); /* Initialize Serial */ serial_init(); /* Initialize console */ console_init(); /* Print Hypervisor Banner */ print_hv_banner(); /* Make sure rdtsc is enabled */ check_tsc(); /* Calculate TSC Frequency */ tsc_clock_freq = tsc_cycles_in_period(1000) / 1000 * 1000000; /* Enable logging */ init_logmsg(LOG_BUF_SIZE, LOG_DESTINATION); if (HV_RC_VERSION) printf("HV version %d.%d-rc%d-%s-%s build by %s, start time %lluus\r\n", HV_MAJOR_VERSION, HV_MINOR_VERSION, HV_RC_VERSION, HV_BUILD_TIME, HV_BUILD_VERSION, HV_BUILD_USER, TICKS_TO_US(start_tsc)); else printf("HV version %d.%d-%s-%s build by %s, start time %lluus\r\n", HV_MAJOR_VERSION, HV_MINOR_VERSION, HV_BUILD_TIME, HV_BUILD_VERSION, HV_BUILD_USER, TICKS_TO_US(start_tsc)); printf("API version %d.%d\r\n", HV_API_MAJOR_VERSION, HV_API_MINOR_VERSION); printf("Detect processor: %s\n", boot_cpu_data.model_name); pr_dbg("Core %d is up", CPU_BOOT_ID); /* Warn for security feature not ready */ if (!cpu_has_cap(X86_FEATURE_IBRS_IBPB) && !cpu_has_cap(X86_FEATURE_STIBP)) { pr_fatal("SECURITY WARNING!!!!!!"); pr_fatal("Please apply the latest CPU uCode patch!"); } /* Initialize the shell */ shell_init(); /* Initialize interrupts */ interrupt_init(CPU_BOOT_ID); timer_init(); setup_notification(); ptdev_init(); init_scheduler(); #ifndef CONFIG_EFI_STUB /* Start all secondary cores */ start_cpus(); /* Trigger event to allow secondary CPUs to continue */ bitmap_set(0, &pcpu_sync); #else memcpy_s(_ld_cpu_secondary_reset_start, (unsigned long)&_ld_cpu_secondary_reset_size, _ld_cpu_secondary_reset_load, (unsigned long)&_ld_cpu_secondary_reset_size); #endif ASSERT(get_cpu_id() == CPU_BOOT_ID, ""); init_iommu(); console_setup_timer(); /* Start initializing the VM for this CPU */ hv_main(CPU_BOOT_ID); /* Control should not come here */ cpu_dead(CPU_BOOT_ID); } void cpu_secondary_init(void) { /* NOTE: Use of local / stack variables in this function is problematic * since the stack is switched in the middle of the function. For this * reason, the logical id is only temporarily stored in a static * variable, but this will be over-written once subsequent CPUs * start-up. Once the spin-lock is released, the cpu_logical_id_get() * API is used to obtain the logical ID */ /* Switch this CPU to use the same page tables set-up by the * primary/boot CPU */ enable_paging(get_paging_pml4()); early_init_lapic(); /* Find the logical ID of this CPU given the LAPIC ID * temp_logical_id = * cpu_find_logical_id(get_cur_lapic_id()); */ cpu_find_logical_id(get_cur_lapic_id()); /* Set state for this CPU to initializing */ cpu_set_current_state(cpu_find_logical_id (get_cur_lapic_id()), CPU_STATE_INITIALIZING); bitmap_set(get_cpu_id(), &pcpu_active_bitmap); /* Switch to run-time stack */ CPU_SP_WRITE(&get_cpu_var(stack)[STACK_SIZE - 1]); #ifdef STACK_PROTECTOR set_fs_base(); #endif load_gdtr_and_tr(); /* Make sure rdtsc is enabled */ check_tsc(); pr_dbg("Core %d is up", get_cpu_id()); cpu_xsave_init(); /* Release secondary boot spin-lock to allow one of the next CPU(s) to * perform this common initialization */ spinlock_release(&cpu_secondary_spinlock); /* Initialize secondary processor interrupts. */ interrupt_init(get_cpu_id()); timer_init(); /* Wait for boot processor to signal all secondary cores to continue */ pcpu_sync_sleep(&pcpu_sync, 0); #ifdef CONFIG_EFI_STUB bitmap_clr(0, &pcpu_sync); #endif hv_main(get_cpu_id()); /* Control will only come here for secondary CPUs not configured for * use or if an error occurs in hv_main */ cpu_dead(get_cpu_id()); } int cpu_find_logical_id(uint32_t lapic_id) { int i; for (i = 0; i < phy_cpu_num; i++) { if (per_cpu(lapic_id, i) == lapic_id) return i; } return -1; } #ifndef CONFIG_EFI_STUB /* * Start all secondary CPUs. */ static void start_cpus() { uint32_t timeout; uint32_t expected_up; /*Copy segment for AP initialization code below 1MB */ memcpy_s(_ld_cpu_secondary_reset_start, (unsigned long)&_ld_cpu_secondary_reset_size, _ld_cpu_secondary_reset_load, (unsigned long)&_ld_cpu_secondary_reset_size); /* Set flag showing number of CPUs expected to be up to all * cpus */ expected_up = phy_cpu_num; /* Broadcast IPIs to all other CPUs */ send_startup_ipi(INTR_CPU_STARTUP_ALL_EX_SELF, -1U, ((uint64_t) cpu_secondary_reset)); /* Wait until global count is equal to expected CPU up count or * configured time-out has expired */ timeout = CPU_UP_TIMEOUT * 1000; while ((up_count != expected_up) && (timeout != 0)) { /* Delay 10us */ udelay(10); /* Decrement timeout value */ timeout -= 10; } /* Check to see if all expected CPUs are actually up */ if (up_count != expected_up) { /* Print error */ pr_fatal("Secondary CPUs failed to come up"); /* Error condition - loop endlessly for now */ do { } while (1); } } #endif void cpu_dead(uint32_t logical_id) { /* For debug purposes, using a stack variable in the while loop enables * us to modify the value using a JTAG probe and resume if needed. */ int halt = 1; /* Set state to show CPU is halted */ cpu_set_current_state(logical_id, CPU_STATE_HALTED); bitmap_clr(get_cpu_id(), &pcpu_active_bitmap); /* Halt the CPU */ do { asm volatile ("hlt"); } while (halt); } static void cpu_set_logical_id(uint32_t logical_id) { /* Write TSC AUX register */ msr_write(MSR_IA32_TSC_AUX, (uint64_t) logical_id); } static void print_hv_banner(void) { char *boot_msg = "ACRN Hypervisor\n\r"; /* Print the boot message */ printf(boot_msg); } static void pcpu_sync_sleep(unsigned long *sync, int mask_bit) { int wake_sync = (1 << mask_bit); if (get_monitor_cap()) { /* Wait for the event to be set using monitor/mwait */ asm volatile ("1: cmpl %%ebx,(%%eax)\n" " je 2f\n" " monitor\n" " mwait\n" " jmp 1b\n" "2:\n" : : "a" (sync), "d"(0), "c"(0), "b"(wake_sync) : "cc"); } else { /* Wait for the event to be set using pause */ asm volatile ("1: cmpl %%ebx,(%%eax)\n" " je 2f\n" " pause\n" " jmp 1b\n" "2:\n" : : "a" (sync), "d"(0), "c"(0), "b"(wake_sync) : "cc"); } } /*check allowed ONEs setting in vmx control*/ static bool is_ctrl_setting_allowed(uint64_t msr_val, uint32_t ctrl) { /* * Intel SDM Appendix A.3 * - bitX in ctrl can be set 1 * only if bit 32+X in msr_val is 1 */ return ((((uint32_t)(msr_val >> 32)) & ctrl) == ctrl); } static void vapic_cap_detect(void) { uint8_t features; uint64_t msr_val; features = 0; msr_val = msr_read(MSR_IA32_VMX_PROCBASED_CTLS); if (!is_ctrl_setting_allowed(msr_val, VMX_PROCBASED_CTLS_TPR_SHADOW)) { cpu_caps.vapic_features = 0; return; } features |= VAPIC_FEATURE_TPR_SHADOW; msr_val = msr_read(MSR_IA32_VMX_PROCBASED_CTLS2); if (!is_ctrl_setting_allowed(msr_val, VMX_PROCBASED_CTLS2_VAPIC)) { cpu_caps.vapic_features = features; return; } features |= VAPIC_FEATURE_VIRT_ACCESS; if (is_ctrl_setting_allowed(msr_val, VMX_PROCBASED_CTLS2_VAPIC_REGS)) features |= VAPIC_FEATURE_VIRT_REG; if (is_ctrl_setting_allowed(msr_val, VMX_PROCBASED_CTLS2_VX2APIC)) features |= VAPIC_FEATURE_VX2APIC_MODE; if (is_ctrl_setting_allowed(msr_val, VMX_PROCBASED_CTLS2_VIRQ)) { features |= VAPIC_FEATURE_INTR_DELIVERY; msr_val = msr_read(MSR_IA32_VMX_PINBASED_CTLS); if (is_ctrl_setting_allowed(msr_val, VMX_PINBASED_CTLS_POST_IRQ)) features |= VAPIC_FEATURE_POST_INTR; } cpu_caps.vapic_features = features; } bool is_vapic_supported(void) { return ((cpu_caps.vapic_features & VAPIC_FEATURE_VIRT_ACCESS) != 0); } bool is_vapic_intr_delivery_supported(void) { return ((cpu_caps.vapic_features & VAPIC_FEATURE_INTR_DELIVERY) != 0); } bool is_vapic_virt_reg_supported(void) { return ((cpu_caps.vapic_features & VAPIC_FEATURE_VIRT_REG) != 0); } static void cpu_xsave_init(void) { uint64_t val64; if (cpu_has_cap(X86_FEATURE_XSAVE)) { CPU_CR_READ(cr4, &val64); val64 |= CR4_OSXSAVE; CPU_CR_WRITE(cr4, val64); if (get_cpu_id() == CPU_BOOT_ID) { uint32_t ecx, unused; cpuid(CPUID_FEATURES, &unused, &unused, &ecx, &unused); /* if set, update it */ if (ecx & CPUID_ECX_OSXSAVE) boot_cpu_data.cpuid_leaves[FEAT_1_ECX] |= CPUID_ECX_OSXSAVE; } } }