Patchwork [V6,1/3] x86/Hyper-V: Set x2apic destination mode to physical when x2apic is available

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Submitter 蓝天宇
Date Feb. 27, 2019, 2:54 p.m.
Message ID <1551279245-25888-2-git-send-email-Tianyu.Lan@microsoft.com>
Download mbox | patch
Permalink /patch/737019/
State New
Headers show

Comments

蓝天宇 - Feb. 27, 2019, 2:54 p.m.
From: Lan Tianyu <Tianyu.Lan@microsoft.com>

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>
---
Change since v5:
       - Fix comile error due to x2apic_phys

Change since v2:
       - Fix compile error due to x2apic_phys
       - Fix comment indent
Change since v1:
       - Remove redundant extern for x2apic_phys
---
 arch/x86/kernel/cpu/mshyperv.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)
Benjamin Serebrin via iommu - Feb. 27, 2019, 5:30 p.m.
From: Tianyu Lan <lantianyu1986@gmail.com> Sent: Wednesday, February 27, 2019 6:54 AM
> 
> 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>
> ---
> Change since v5:
>        - Fix comile error due to x2apic_phys
> 
> Change since v2:
>        - Fix compile error due to x2apic_phys
>        - Fix comment indent
> Change since v1:
>        - Remove redundant extern for x2apic_phys
> ---
>  arch/x86/kernel/cpu/mshyperv.c | 12 ++++++++++++
>  1 file changed, 12 insertions(+)

Reconfirming my reviewed-by after the change to fix the
compile error detected by the kbuild test robot.

Reviewed-by: Michael Kelley <mikelley@microsoft.com>

Patch

diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index e81a2db..3fa238a 100644
--- 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
 }