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Subject[patch 05/23] x86/apic: Make disable x2apic work really
If x2apic_preenabled is not enabled, then disable_x2apic() is not
called from various places which results in x2apic_disabled not being
set. So other code pathes can happily reenable the x2apic.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
arch/x86/kernel/apic/apic.c | 14 +++++---------
1 file changed, 5 insertions(+), 9 deletions(-)

Index: tip/arch/x86/kernel/apic/apic.c
===================================================================
--- tip.orig/arch/x86/kernel/apic/apic.c
+++ tip/arch/x86/kernel/apic/apic.c
@@ -1479,8 +1479,6 @@ static bool nox2apic __initdata;

#ifdef CONFIG_X86_X2APIC
int x2apic_mode;
-/* x2apic enabled before OS handover */
-static int x2apic_preenabled;
static int x2apic_disabled;
static int __init setup_nox2apic(char *str)
{
@@ -1535,18 +1533,19 @@ static __init void disable_x2apic(void)
setup_clear_cpu_cap(X86_FEATURE_X2APIC);
}

- x2apic_disabled = 1;
x2apic_mode = 0;

register_lapic_address(mp_lapic_addr);
}
+
+ x2apic_disabled = 1;
}

void check_x2apic(void)
{
if (x2apic_enabled()) {
pr_info("x2apic enabled by BIOS, switching to x2apic ops\n");
- x2apic_preenabled = x2apic_mode = 1;
+ x2apic_mode = 1;
}
}

@@ -1569,8 +1568,6 @@ void enable_x2apic(void)
wrmsrl(MSR_IA32_APICBASE, msr | X2APIC_ENABLE);
}
}
-#else
-#define x2apic_preenabled (0)
#endif /* CONFIG_X86_X2APIC */

static int __init try_to_enable_IR(void)
@@ -1599,8 +1596,7 @@ static __init void try_to_enable_x2apic(
(IS_ENABLED(CONFIG_HYPERVISOR_GUEST) &&
!hypervisor_x2apic_available())) {
pr_info("IRQ remapping doesn't support X2APIC mode, disable x2apic.\n");
- if (x2apic_preenabled)
- disable_x2apic();
+ disable_x2apic();
return;
}

@@ -1643,7 +1639,7 @@ void __init enable_IR_x2apic(void)
legacy_pic->mask_all();
mask_ioapic_entries();

- if (x2apic_preenabled && nox2apic)
+ if (nox2apic)
disable_x2apic();
/* If irq_remapping_prepare() succeded, try to enable it */
if (ir_stat >= 0)



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