[Xen-changelog] [xen-4.1-testing] x86/AMD: Do not enable ARAT feature on AMD processors below family 0x12

[Xen patchbot-4.1-testing <patchbot@xxxxxxx>]

# HG changeset patch
# User Boris Ostrovsky <boris.ostrovsky@xxxxxxx>
# Date 1319728973 -3600
# Node ID 849bf4ab5fe0b9006d59965edc2de630d2976118
# Parent  9a38e30e54599b958382ad19a70a48567a38f816
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>
xen-unstable changeset:   23925:08d6ba4e447d
xen-unstable date:        Fri Oct 07 10:32:15 2011 +0200
---


diff -r 9a38e30e5459 -r 849bf4ab5fe0 xen/arch/x86/cpu/amd.c
--- a/xen/arch/x86/cpu/amd.c    Thu Oct 27 16:14:36 2011 +0100
+++ b/xen/arch/x86/cpu/amd.c    Thu Oct 27 16:22:53 2011 +0100
@@ -608,8 +608,11 @@
        }
 #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);
 
        /* Prevent TSC drift in non single-processor, single-core platforms. */

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