Hi-- On 10/1/20 1:39 PM, Chang S. Bae wrote: > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > index a1068742a6df..742167c6f789 100644 > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -5838,6 +5838,21 @@ > which allow the hypervisor to 'idle' the guest on lock > contention. > > + xstate.enable= [X86-64] > + xstate.disable= [X86-64] > + The kernel is compiled with a default xstate bitmask -- > + enabling it to use the XSAVE hardware to efficiently > + save and restore thread states on context switch. > + xstate.enable allows adding to that default mask at > + boot-time without recompiling the kernel just to support > + the new thread state. (Note that the kernel will ignore > + any bits in the mask that do not correspond to features > + that are actually available in CPUID) xstate.disable in CPUID.) > + allows clearing bits in the default mask, forcing the > + kernel to forget that it supports the specified thread > + state. When a bit set for both, the kernel takes > + xstate.disable in a priority. as a priority. What do these bitmasks look like? what do the bits mean? Where does a user find this info? thanks. -- ~Randy
