On Tue, Mar 30, 2021 at 12:56:41PM +0800, Xiaoyao Li wrote: > On 3/27/2021 8:18 AM, Kuppuswamy Sathyanarayanan wrote: > > In non-root TDX guest mode, MWAIT, MONITOR and WBINVD instructions > > are not supported. So handle #VE due to these instructions as no ops. > > > > Signed-off-by: Kuppuswamy Sathyanarayanan > > <sathyanarayanan.kuppusw...@linux.intel.com> > > Reviewed-by: Andi Kleen <a...@linux.intel.com> > > --- > > > > Changes since previous series: > > * Suppressed MWAIT feature as per Andi's comment. > > * Added warning debug log for MWAIT #VE exception. > > > > arch/x86/kernel/tdx.c | 23 +++++++++++++++++++++++ > > 1 file changed, 23 insertions(+) > > > > diff --git a/arch/x86/kernel/tdx.c b/arch/x86/kernel/tdx.c > > index e936b2f88bf6..fb7d22b846fc 100644 > > --- a/arch/x86/kernel/tdx.c > > +++ b/arch/x86/kernel/tdx.c > > @@ -308,6 +308,9 @@ void __init tdx_early_init(void) > > setup_force_cpu_cap(X86_FEATURE_TDX_GUEST); > > + /* MWAIT is not supported in TDX platform, so suppress it */ > > + setup_clear_cpu_cap(X86_FEATURE_MWAIT); > > In fact, MWAIT bit returned by CPUID instruction is zero for TD guest. This > is enforced by SEAM module.
Good point. > > Do we still need to safeguard it by setup_clear_cpu_cap() here? I guess it doesn't hurt to do it explicitly. -Andi
