From f9e14dbbd454581061c736bf70bf5cbb15ac927c Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Tue, 19 Apr 2022 09:52:41 -0700 Subject: x86/cpu: Load microcode during restore_processor_state() When resuming from system sleep state, restore_processor_state() restores the boot CPU MSRs. These MSRs could be emulated by microcode. If microcode is not loaded yet, writing to emulated MSRs leads to unchecked MSR access error: ... PM: Calling lapic_suspend+0x0/0x210 unchecked MSR access error: WRMSR to 0x10f (tried to write 0x0...0) at rIP: ... (native_write_msr) Call Trace: ? restore_processor_state x86_acpi_suspend_lowlevel acpi_suspend_enter suspend_devices_and_enter pm_suspend.cold state_store kobj_attr_store sysfs_kf_write kernfs_fop_write_iter new_sync_write vfs_write ksys_write __x64_sys_write do_syscall_64 entry_SYSCALL_64_after_hwframe RIP: 0033:0x7fda13c260a7 To ensure microcode emulated MSRs are available for restoration, load the microcode on the boot CPU before restoring these MSRs. [ Pawan: write commit message and productize it. ] Fixes: e2a1256b17b1 ("x86/speculation: Restore speculation related MSRs during S3 resume") Reported-by: Kyle D. Pelton Signed-off-by: Borislav Petkov Signed-off-by: Pawan Gupta Tested-by: Kyle D. Pelton Cc: stable@vger.kernel.org Link: https://bugzilla.kernel.org/show_bug.cgi?id=215841 Link: https://lore.kernel.org/r/4350dfbf785cd482d3fafa72b2b49c83102df3ce.1650386317.git.pawan.kumar.gupta@linux.intel.com --- arch/x86/include/asm/microcode.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'arch/x86/include/asm/microcode.h') diff --git a/arch/x86/include/asm/microcode.h b/arch/x86/include/asm/microcode.h index d6bfdfb0f0af..0c3d3440fe27 100644 --- a/arch/x86/include/asm/microcode.h +++ b/arch/x86/include/asm/microcode.h @@ -131,10 +131,12 @@ extern void __init load_ucode_bsp(void); extern void load_ucode_ap(void); void reload_early_microcode(void); extern bool initrd_gone; +void microcode_bsp_resume(void); #else static inline void __init load_ucode_bsp(void) { } static inline void load_ucode_ap(void) { } static inline void reload_early_microcode(void) { } +static inline void microcode_bsp_resume(void) { } #endif #endif /* _ASM_X86_MICROCODE_H */ -- cgit v1.2.3