svn commit: r266552 - head/sys/amd64/amd64

[John Baldwin]

Author: jhb
Date: Thu May 22 18:22:02 2014
New Revision: 266552
URL: http://svnweb.freebsd.org/changeset/base/266552

Log:
  Don't permit users to request a subset of the AVX512 or MPX xsave masks.
  
  These masks are documented in the Intel Architecture Instruction Set
  Extensions Programming Reference (March 2014).
  
  Reviewed by:	kib
  MFC after:	1 month

Modified:
  head/sys/amd64/amd64/fpu.c

Modified: head/sys/amd64/amd64/fpu.c
==============================================================================
--- head/sys/amd64/amd64/fpu.c	Thu May 22 18:13:17 2014	(r266551)
+++ head/sys/amd64/amd64/fpu.c	Thu May 22 18:22:02 2014	(r266552)
@@ -199,6 +199,10 @@ fpuinit_bsp1(void)
 	TUNABLE_ULONG_FETCH("hw.xsave_mask", &xsave_mask_user);
 	xsave_mask_user |= XFEATURE_ENABLED_X87 | XFEATURE_ENABLED_SSE;
 	xsave_mask &= xsave_mask_user;
+	if ((xsave_mask & XFEATURE_AVX512) != XFEATURE_AVX512)
+		xsave_mask &= ~XFEATURE_AVX512;
+	if ((xsave_mask & XFEATURE_MPX) != XFEATURE_MPX)
+		xsave_mask &= ~XFEATURE_MPX;
 
 	cpuid_count(0xd, 0x1, cp);
 	if ((cp[0] & CPUID_EXTSTATE_XSAVEOPT) != 0) {