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@novell.com>

1 files changed, 0 insertions, 9 deletions

diff --git a/xen/arch/x86/apic.c b/xen/arch/x86/apic.c
index 37dfc79c2e..1590c3a171 100644
--- a/xen/arch/x86/apic.c
+++ b/xen/arch/x86/apic.c
@@ -957,19 +957,10 @@ void x2apic_ap_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 )
     {
         if ( !x2apic_enabled )