> > + /* > > + * Don't check the FRED stack level, the call stack leading to this > > + * helper is effectively constant and shallow (relatively speaking). > > It's more that we don't need to protect from reentrancy. The external > interrupt uses stack level 0 so no adjustment would be needed anyway, > and NMI does not use an IST even in the non-FRED case. I will incorporate this comment. I think a VMX NMI is kind of like a user level NMI, and we don't need to worry about nested NMIs. > > > + * Emulate the FRED-defined redzone and stack alignment. > > + */ > > + sub $(FRED_CONFIG_REDZONE_AMOUNT << 6), %rsp > > + and $FRED_STACK_FRAME_RSP_MASK, %rsp
