[Patch v2 11/16] x86/apic: Only disable CPU x2apic mode when necessary
From: Jiang Liu
Date: Wed Jan 07 2015 - 02:31:55 EST
When interrupt remapping hardware is not in X2APIC, CPU X2APIC mode
will be disabled if:
1) Maximum CPU APIC ID is bigger than 255
2) hypervisior doesn't support x2apic mode.
But we should only check whether hypervisor supports X2APIC mode when
hypervisor(CONFIG_HYPERVISOR_GUEST) is enabled, otherwise X2APIC will
always be disabled when CONFIG_HYPERVISOR_GUEST is disabled and IR
doesn't work in X2APIC mode.
Signed-off-by: Jiang Liu <jiang.liu@xxxxxxxxxxxxxxx>
---
arch/x86/kernel/apic/apic.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index 09ac1e4ef86b..d714e72ed6d5 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -1601,7 +1601,8 @@ static __init void try_to_enable_x2apic(int ir_stat)
* under KVM
*/
if (max_physical_apicid > 255 ||
- !hypervisor_x2apic_available()) {
+ (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();
--
1.7.10.4
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