[Xen-devel] [PATCH]: tools/CPUID: remove vendor specific CPUID bits masking

[Andre Przywara <andre.przywara@xxxxxxx>]

Hi,

I don't see the point of removing userspace level CPUID bits in vendor 
specific paths. Since we base our bits on the host one's, there is no 
need for masking.
This already broke POPCNT support on recent Intel boxes and may break 
future SSE level implementations on AMD processors.
Attached patch removes this leaf 1 check.

Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx>

--
Andre Przywara
AMD-Operating System Research Center (OSRC), Dresden, Germany
Tel: +49 351 448 3567 12
----to satisfy European Law for business letters:
Advanced Micro Devices GmbH
Karl-Hammerschmidt-Str. 34, 85609 Dornach b. Muenchen
Geschaeftsfuehrer: Thomas M. McCoy; Giuliano Meroni
Sitz: Dornach, Gemeinde Aschheim, Landkreis Muenchen
Registergericht Muenchen, HRB Nr. 43632

diff -r 8b0f1f37e145 tools/libxc/xc_cpuid_x86.c
--- a/tools/libxc/xc_cpuid_x86.c        Sun Aug 16 08:46:08 2009 +0100
+++ b/tools/libxc/xc_cpuid_x86.c        Wed Aug 19 10:39:08 2009 +0200
@@ -71,13 +71,6 @@
 {
     switch ( input[0] )
     {
-    case 0x00000001:
-        /* Mask Intel-only features. */
-        regs[2] &= ~(bitmaskof(X86_FEATURE_SSSE3) |
-                     bitmaskof(X86_FEATURE_SSE4_1) |
-                     bitmaskof(X86_FEATURE_SSE4_2));
-        break;
-
     case 0x00000002:
     case 0x00000004:
         regs[0] = regs[1] = regs[2] = 0;
@@ -126,11 +119,6 @@
 {
     switch ( input[0] )
     {
-    case 0x00000001:
-        /* Mask AMD-only features. */
-        regs[2] &= ~(bitmaskof(X86_FEATURE_POPCNT));
-        break;
-
     case 0x00000004:
         /*
          * EAX[31:26] is Maximum Cores Per Package (minus one).

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