Re: [PATCH v3 1/2] x86/tsx: Add feature bit for TSX control MSR support

[Dave Hansen]

On 11/15/22 11:17, Pawan Gupta wrote:
> Support for TSX control MSR is enumerated in MSR_IA32_ARCH_CAPABILITIES.
> This is different from how other CPU features are enumerated i.e. via
> CPUID. Currently a call to tsx_ctrl_is_supported() is required for
> enumerating the feature. In the absence of feature bit for TSX control,
> any code that relies on checking feature bits directly will not work.
> 
> In preparation for adding a feature bit check in MSR save/restore during
> suspend/resume, set a new feature bit X86_FEATURE_TSX_CTRL when
> MSR_IA32_TSX_CTRL is present. Also make tsx_ctrl_is_supported() use the
> new feature bit to avoid any overhead of reading the MSR.


Reviewed-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>