From: ddugger@redhat.com <ddugger@redhat.com>
Date: Tue, 21 Apr 2009 13:01:40 -0600
Subject: [xen] clear X86_FEATURE_APIC in cpuid when apic disabled
Message-id: 200904211901.n3LJ1euO028414@sobek.n0ano.com
O-Subject: [RHEL5.4 PATCH 6/6 V2] BZ496873: xen: clear X86_FEATURE_APIC in dom0 cpuid when apic disabled
Bugzilla: 496873
RH-Acked-by: Rik van Riel <riel@redhat.com>
RH-Acked-by: Gerd Hoffmann <kraxel@redhat.com>
RH-Acked-by: Justin M. Forbes <jforbes@redhat.com>

Backport that part of the Xen changeset that clears the feature bit
when the APIC is disabled.

Upstream Status: accepted (CS 19039)

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Qing He <qing.he@intel.com>
Signed-off-by: Gerd Hoffman <kraxel@redhat.com>
Signed-off-by: Don Dugger <donald.d.dugger@intel.com>

Yet Another Resend - resolve the conflicting BZs between the Subject line
(correct) and the message body (incorrect).

diff --git a/arch/x86/traps.c b/arch/x86/traps.c
index 5de70ee..bc67f70 100644
--- a/arch/x86/traps.c
+++ b/arch/x86/traps.c
@@ -608,6 +608,8 @@ static int emulate_forced_invalid_op(struct cpu_user_regs *regs)
     {
         /* Modify Feature Information. */
         clear_bit(X86_FEATURE_VME, &d);
+        if ( !cpu_has_apic )
+            clear_bit(X86_FEATURE_APIC, &d);
         clear_bit(X86_FEATURE_DE,  &d);
         clear_bit(X86_FEATURE_PSE, &d);
         clear_bit(X86_FEATURE_PGE, &d);