[Xen-changelog] [xen-unstable] x86: restore x2apic pre-enabled check logic

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

# HG changeset patch
# User Keir Fraser <keir@xxxxxxx>
# Date 1294746050 0
# Node ID 2ff199e2842b7e4f08ea99558afc32536a77280c
# Parent  ca10302ac2859b43a41afe425d79ae0df29f2a9c
x86: restore x2apic pre-enabled check logic

c/s 22475 removed the early checking without replacement, neglecting
the fact that x2apic_enabled must be set early for APIC register
accesses done during second stage ACPI table parsing (rooted at
acpi_boot_init()) to work correctly. Without this, particularly
determination of the boot CPU won't work, resulting in an attempt to
bring up that CPU again as a secondary one (which fails).

Restore the functionality, now calling it from generic_apic_probe().

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>
---
 xen/arch/x86/apic.c           |    9 ---------
 xen/arch/x86/genapic/probe.c  |    6 ++++--
 xen/arch/x86/genapic/x2apic.c |   19 +++++++++++++++++++
 xen/include/asm-x86/apic.h    |    1 +
 4 files changed, 24 insertions(+), 11 deletions(-)

diff -r ca10302ac285 -r 2ff199e2842b xen/arch/x86/apic.c
--- a/xen/arch/x86/apic.c       Tue Jan 11 11:27:37 2011 +0000
+++ b/xen/arch/x86/apic.c       Tue Jan 11 11:40:50 2011 +0000
@@ -957,18 +957,9 @@ void __init x2apic_bsp_setup(void)
 void __init x2apic_bsp_setup(void)
 {
     struct IO_APIC_route_entry **ioapic_entries = NULL;
-    uint64_t msr_content;
 
     if ( !cpu_has_x2apic )
         return;
-
-    /* Check whether x2apic mode was already enabled by the BIOS. */
-    rdmsrl(MSR_IA32_APICBASE, msr_content);
-    if ( msr_content & MSR_IA32_APICBASE_EXTD )
-    {
-        printk("x2APIC mode is already enabled by BIOS.\n");
-        x2apic_enabled = 1;
-    }
 
     if ( !opt_x2apic )
     {
diff -r ca10302ac285 -r 2ff199e2842b xen/arch/x86/genapic/probe.c
--- a/xen/arch/x86/genapic/probe.c      Tue Jan 11 11:27:37 2011 +0000
+++ b/xen/arch/x86/genapic/probe.c      Tue Jan 11 11:40:50 2011 +0000
@@ -59,8 +59,10 @@ custom_param("apic", genapic_apic_force)
 
 void __init generic_apic_probe(void) 
 { 
-       int i;
-       int changed = cmdline_apic = (genapic != NULL);
+       int i, changed;
+
+       check_x2apic_preenabled();
+       cmdline_apic = changed = (genapic != NULL);
 
        for (i = 0; !changed && apic_probe[i]; i++) { 
                if (apic_probe[i]->probe()) {
diff -r ca10302ac285 -r 2ff199e2842b xen/arch/x86/genapic/x2apic.c
--- a/xen/arch/x86/genapic/x2apic.c     Tue Jan 11 11:27:37 2011 +0000
+++ b/xen/arch/x86/genapic/x2apic.c     Tue Jan 11 11:40:50 2011 +0000
@@ -24,6 +24,8 @@
 #include <asm/genapic.h>
 #include <asm/apic.h>
 #include <asm/io_apic.h>
+#include <asm/msr.h>
+#include <asm/processor.h>
 #include <xen/smp.h>
 #include <asm/mach-default/mach_mpparse.h>
 
@@ -123,3 +125,20 @@ const struct genapic *__init apic_x2apic
 {
     return x2apic_phys ? &apic_x2apic_phys : &apic_x2apic_cluster;
 }
+
+void __init check_x2apic_preenabled(void)
+{
+    u32 lo, hi;
+
+    if ( !cpu_has_x2apic )
+        return;
+
+    /* Check whether x2apic mode was already enabled by the BIOS. */
+    rdmsr(MSR_IA32_APICBASE, lo, hi);
+    if ( lo & MSR_IA32_APICBASE_EXTD )
+    {
+        printk("x2APIC mode is already enabled by BIOS.\n");
+        x2apic_enabled = 1;
+        genapic = apic_x2apic_probe();
+    }
+}
diff -r ca10302ac285 -r 2ff199e2842b xen/include/asm-x86/apic.h
--- a/xen/include/asm-x86/apic.h        Tue Jan 11 11:27:37 2011 +0000
+++ b/xen/include/asm-x86/apic.h        Tue Jan 11 11:40:50 2011 +0000
@@ -25,6 +25,7 @@ extern bool_t x2apic_enabled;
 extern bool_t x2apic_enabled;
 extern bool_t directed_eoi_enabled;
 
+void check_x2apic_preenabled(void);
 void x2apic_bsp_setup(void);
 void x2apic_ap_setup(void);
 const struct genapic *apic_x2apic_probe(void);

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