On Dec 23, 2020, at 10:37, Randy Dunlap [off-list ref] wrote:

On 12/23/20 7:57 AM, Chang S. Bae wrote:

quoted

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 44fde25bb221..a67ae04d43c5 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt

@@ -6002,6 +6002,21 @@

			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

			                               CPUID.)

quoted

+			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.
?

Thank you. I fixed those typos in my tree.

Chang