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>
--- 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 )
--- a/xen/arch/x86/genapic/probe.c
+++ b/xen/arch/x86/genapic/probe.c
@@ -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()) {
--- a/xen/arch/x86/genapic/x2apic.c
+++ b/xen/arch/x86/genapic/x2apic.c
@@ -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();
+ }
+}
--- a/xen/include/asm-x86/apic.h
+++ b/xen/include/asm-x86/apic.h
@@ -25,6 +25,7 @@ extern int apic_verbosity;
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);
x86-x2apic-check-preenabled.patch
Description: Text document
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