From: Lan Tianyu <Tianyu.Lan@microsoft.com>
Date: Wed, 27 Feb 2019 22:54:03 +0800
Patch-mainline: v5.1-rc1
Subject: x86/Hyper-V: Set x2apic destination mode to physical when x2apic is available
Git-commit: 84fdfafab849036b5aefa52824b5cb42e887ef0e
References: fate#327171, bsc#1122822
Hyper-V doesn't provide irq remapping for IO-APIC. To enable x2apic,
set x2apic destination mode to physcial mode when x2apic is available
and Hyper-V IOMMU driver makes sure cpus assigned with IO-APIC irqs have
8-bit APIC id.
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Lan Tianyu <Tianyu.Lan@microsoft.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Acked-by: Olaf Hering <ohering@suse.de>
---
arch/x86/kernel/cpu/mshyperv.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -328,6 +328,18 @@ static void __init ms_hyperv_init_platform(void)
# ifdef CONFIG_SMP
smp_ops.smp_prepare_boot_cpu = hv_smp_prepare_boot_cpu;
# endif
+
+ /*
+ * Hyper-V doesn't provide irq remapping for IO-APIC. To enable x2apic,
+ * set x2apic destination mode to physcial mode when x2apic is available
+ * and Hyper-V IOMMU driver makes sure cpus assigned with IO-APIC irqs
+ * have 8-bit APIC id.
+ */
+# ifdef CONFIG_X86_X2APIC
+ if (x2apic_supported())
+ x2apic_phys = 1;
+# endif
+
#endif
}