If 'idle=nomwait' is specified or process matching what's in processor_idle_dmi_table, we should't use MWAIT at bootup stage before cpuidle driver loaded, even if it's preferred by default on Intel.
Add a check so that HALT instruction is used in those cases. Signed-off-by: Zhenzhong Duan <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: "H. Peter Anvin" <[email protected]> Cc: Boris Ostrovsky <[email protected]> --- arch/x86/kernel/process.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index 5e94c43..37fc577 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -667,6 +667,10 @@ static void amd_e400_idle(void) */ static int prefer_mwait_c1_over_halt(const struct cpuinfo_x86 *c) { + /* Don't use MWAIT-C1 if explicitly requested */ + if (boot_option_idle_override == IDLE_NOMWAIT) + return 0; + if (c->x86_vendor != X86_VENDOR_INTEL) return 0; -- 1.8.3.1
