[Xen-changelog] [xen-unstable] x86/AMD: Do not enable ARAT feature on AMD processors below family 0x12

[Xen patchbot-unstable <patchbot@xxxxxxx>]

# HG changeset patch
# User Boris Ostrovsky <boris.ostrovsky@xxxxxxx>
# Date 1317976335 -7200
# Node ID 08d6ba4e447d6c13c6dfac5c23e84b73961cb109
# Parent  159be83e5fe9111bb30d8b1f83127f5724d44424
x86/AMD: Do not enable ARAT feature on AMD processors below family 0x12

Determining whether an AMD processor is affected by erratum 400 may
have some corner cases and handling these cases is somewhat complicated.
In the interest of simplicity we won't claim ARAT support on processor
families below 0x12.

Mirrors Linux commit e9cdd343a5e42c43bcda01e609fa23089e026470

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxx>
Committed-by: Jan Beulich <jbeulich@xxxxxxxx>
---


diff -r 159be83e5fe9 -r 08d6ba4e447d xen/arch/x86/cpu/amd.c
--- a/xen/arch/x86/cpu/amd.c    Thu Oct 06 19:44:40 2011 +0100
+++ b/xen/arch/x86/cpu/amd.c    Fri Oct 07 10:32:15 2011 +0200
@@ -495,8 +495,11 @@
        }
 #endif
 
-       /* As a rule processors have APIC timer running in deep C states */
-       if (c->x86 > 0xf && !cpu_has_amd_erratum(c, AMD_ERRATUM_400))
+       /*
+        * Family 0x12 and above processors have APIC timer
+        * running in deep C states.
+        */
+       if (c->x86 > 0x11)
                set_bit(X86_FEATURE_ARAT, c->x86_capability);
 
        if (cpuid_edx(0x80000007) & (1 << 10)) {

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