[Xen-changelog] [xen-unstable] x86: propagate disabled APIC state to Dom0

[Xen patchbot-unstable <patchbot-unstable@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1231930578 0
# Node ID 3fb43f23f64ccc1687d1dc348a9eb454397d4887
# Parent  59274c49a0298fd73f60759c0842a293b5816057
x86: propagate disabled APIC state to Dom0

This in particular eliminates the need to specify "noapic" to Dom0
when "noapic" is passed to Xen, provided the kernel side gets slightly
modified to make use of this information (Linux side patch cannot
easily be provided for the 2.6.18 tree, but this is being used by our
2.6.27-based one).

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>
---
 xen/arch/x86/traps.c |    6 ++++++
 1 files changed, 6 insertions(+)

diff -r 59274c49a029 -r 3fb43f23f64c xen/arch/x86/traps.c
--- a/xen/arch/x86/traps.c      Wed Jan 14 10:55:40 2009 +0000
+++ b/xen/arch/x86/traps.c      Wed Jan 14 10:56:18 2009 +0000
@@ -723,6 +723,8 @@ static void pv_cpuid(struct cpu_user_reg
     {
         /* Modify Feature Information. */
         __clear_bit(X86_FEATURE_VME, &d);
+        if ( !cpu_has_apic )
+            __clear_bit(X86_FEATURE_APIC, &d);
         if ( !opt_allow_hugepage )
             __clear_bit(X86_FEATURE_PSE, &d);
         __clear_bit(X86_FEATURE_PGE, &d);
@@ -755,6 +757,8 @@ static void pv_cpuid(struct cpu_user_reg
         __clear_bit(X86_FEATURE_XTPR % 32, &c);
         __clear_bit(X86_FEATURE_PDCM % 32, &c);
         __clear_bit(X86_FEATURE_DCA % 32, &c);
+        if ( !cpu_has_apic )
+           __clear_bit(X86_FEATURE_X2APIC % 32, &c);
         __set_bit(X86_FEATURE_HYPERVISOR % 32, &c);
         break;
     case 0x80000001:
@@ -773,6 +777,8 @@ static void pv_cpuid(struct cpu_user_reg
         __clear_bit(X86_FEATURE_RDTSCP % 32, &d);
 
         __clear_bit(X86_FEATURE_SVME % 32, &c);
+        if ( !cpu_has_apic )
+           __clear_bit(X86_FEATURE_EXTAPICSPACE % 32, &c);
         __clear_bit(X86_FEATURE_OSVW % 32, &c);
         __clear_bit(X86_FEATURE_IBS % 32, &c);
         __clear_bit(X86_FEATURE_SKINIT % 32, &c);

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