On 05/15/2018 08:41 AM, Fenghua Yu wrote: > On Tue, May 15, 2018 at 08:36:35AM -0700, Dave Hansen wrote: >> On 05/14/2018 11:52 AM, Fenghua Yu wrote: >>> +#include <linux/printk.h> >>> +#include <asm/msr.h> >>> + >>> +static bool split_lock_ac_supported; >> Was there a reason not to use an X86_FEATURE* bit for this? > The feature is not enumerated in cpuid. It's detected by writing 1 > to bit 29 in MSR 0x33. > > So it can't fit in X86_FEATURE, right?
We have X86_FEATURE_*'s for lots of things, even software constructs that have no representation in the hardware CPUID.
