On Fri, Apr 26, 2019 at 08:00:10AM +0200, Ingo Molnar wrote: > > * Fenghua Yu <fenghua.yu@xxxxxxxxx> wrote: > > > On Thu, Apr 25, 2019 at 10:08:30PM +0200, Ingo Molnar wrote: > > > > > > * Fenghua Yu <fenghua.yu@xxxxxxxxx> wrote: > > > > > > > On Thu, Apr 25, 2019 at 09:47:14PM +0200, Ingo Molnar wrote: > > > > > > > > > > * Fenghua Yu <fenghua.yu@xxxxxxxxx> wrote: > > > > > > > > > > > On Thu, Apr 25, 2019 at 07:45:11AM +0200, Ingo Molnar wrote: > > > > > > > > > > > > > > * Fenghua Yu <fenghua.yu@xxxxxxxxx> wrote: > > > > > > > > > > > > > > > A new MSR_IA32_CORE_CAPABILITY (0xcf) is defined. Each bit in the MSR > > > > > > > > enumerates a model specific feature. Currently bit 5 enumerates split > > > > > > > > lock detection. When bit 5 is 1, split lock detection is supported. > > > > > > > > When the bit is 0, split lock detection is not supported. > > > > > > > > > > > > > > > > Please check the latest Intel 64 and IA-32 Architectures Software > > > > > > > > Developer's Manual for more detailed information on the MSR and the > > > > > > > > split lock detection bit. > > > > > > > > > > > > > > > > Signed-off-by: Fenghua Yu <fenghua.yu@xxxxxxxxx> > > > > > > > > --- > > > > > > > > arch/x86/include/asm/msr-index.h | 3 +++ > > > > > > > > 1 file changed, 3 insertions(+) > > > > > > > > > > > > > > > > diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h > > > > > > > > index ca5bc0eacb95..f65ef6f783d2 100644 > > > > > > > > --- a/arch/x86/include/asm/msr-index.h > > > > > > > > +++ b/arch/x86/include/asm/msr-index.h > > > > > > > > @@ -59,6 +59,9 @@ > > > > > > > > #define MSR_PLATFORM_INFO_CPUID_FAULT_BIT 31 > > > > > > > > #define MSR_PLATFORM_INFO_CPUID_FAULT BIT_ULL(MSR_PLATFORM_INFO_CPUID_FAULT_BIT) > > > > > > > > > > > > > > > > +#define MSR_IA32_CORE_CAPABILITY 0x000000cf > > > > > > > > +#define CORE_CAP_SPLIT_LOCK_DETECT BIT(5) /* Detect split lock */ > > > > > > > > > > > > > > Please don't put comments into definitions. > > > > > > > > > > > > I'll remove the comment and change definitions of the MSR and the split lock > > > > > > detection bit as following: > > > > > > > > > > > > +#define MSR_IA32_CORE_CAPABILITY 0x000000cf > > > > > > +#define MSR_IA32_CORE_CAPABILITY_SPLIT_LOCK_DETECT_BIT 5 > > > > > > +#define MSR_IA32_CORE_CAPABILITY_SPLIT_LOCK_DETECT BIT(MSR_IA32_CORE_CAPABILITY_SPLIT_LOCK_DETECT_BIT) > > > > > > > > > > > > Are these right changes? > > > > > > > > > > I suspect it could be shortened to CORE_CAP as you (partly) did it > > > > > originally. > > > > > > > > IA32_CORE_CAPABILITY is the MSR's exact name in the latest SDM (in Table 2-14): > > > > https://software.intel.com/en-us/download/intel-64-and-ia-32-architectures-sdm-combined-volumes-1-2a-2b-2c-2d-3a-3b-3c-3d-and-4 > > > > > > > > So can I define the MSR and the bits as follows? > > > > > > > > +#define MSR_IA32_CORE_CAP 0x000000cf > > > > +#define MSR_IA32_CORE_CAP_SPLIT_LOCK_DETECT_BIT 5 > > > > +#define MSR_IA32_CORE_CAP_SPLIT_LOCK_DETECT BIT(MSR_IA32_CORE_CAP_SPLIT_LOCK_DETECT_BIT) > > > > > > Yeah, I suppose that looks OK. > > > > Should I also change the feature definition 'X86_FEATURE_CORE_CAPABILITY' to > > 'X86_FEATURE_CORE_CAP' in cpufeatures.h in patch #0006 to match the > > MSR definition here? Or should I still keep the current feature definition? > > > > Thanks. > > Hm, no, for CPU features it's good to follow the vendor convention. > > So I guess the long-form CPU_CAPABILITY for all of these is the best > after all. Since MSR_IA32_CORE_CAP_SPLIT_LOCK_DETECT_BIT is not used anywhere else except in this patch, is it OK not to define this macro? So this patch will only has two shorter lines: +#define MSR_IA32_CORE_CAP 0x000000cf +#define MSR_IA32_CORE_CAP_SPLIT_LOCK_DETECT BIT(5) Is this OK for this patch to only define these two macros? Thanks. -Fenghua
