As per "AMD64 Architecture Programmer's Manual Volume 3: General-Purpose and System Instructions", MWAITX EAX[7:4]+1 specifies the optional hint of the optimized C-state. For C0 state, EAX[7:4] should be set to 0xf.
Currently, a value of 0xf is set for EAX[3:0] instead of EAX[7:4]. Fix this by changing MWAITX_DISABLE_CSTATES from 0xf to 0xf0. Signed-off-by: Janakarajan Natarajan <janakarajan.natara...@amd.com> --- arch/x86/include/asm/mwait.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/include/asm/mwait.h b/arch/x86/include/asm/mwait.h index e28f8b723b5c..9d5252c9685c 100644 --- a/arch/x86/include/asm/mwait.h +++ b/arch/x86/include/asm/mwait.h @@ -21,7 +21,7 @@ #define MWAIT_ECX_INTERRUPT_BREAK 0x1 #define MWAITX_ECX_TIMER_ENABLE BIT(1) #define MWAITX_MAX_LOOPS ((u32)-1) -#define MWAITX_DISABLE_CSTATES 0xf +#define MWAITX_DISABLE_CSTATES 0xf0 static inline void __monitor(const void *eax, unsigned long ecx, unsigned long edx) -- 2.17.1