Re: [RFC PATCH] arm/gicv2: make GICv2 driver and vGICv2 optional

[Luca Fancellu <Luca.Fancellu@xxxxxxx>]

Hi Julien,

>> +
>>  config GICV3
>>   bool "GICv3 driver"
>>   depends on !NEW_VGIC
>> @@ -92,6 +100,11 @@ config HAS_ITS
>>          bool "GICv3 ITS MSI controller support (UNSUPPORTED)" if UNSUPPORTED
>>          depends on GICV3 && !NEW_VGIC && !ARM_32
>>  +config VGICV2
>> + bool "vGICv2 interface for guests"
> 
> This description is a bit misleading as the vGICv2 will also be used for dom0 
> in the case of vGICv2.
> 
>> + default y
> 
> Please add a longer help.
> 
>> + depends on (GICV2 || GICV3) && !NEW_VGIC
> 
> In the near future, I don't expect anyone to introduce a new non-GIC of 
> interrupt controller for Arm. But I would expect new version of the GIC. So I 
> would drop (GICV2 || GICV3).
> 
> Also when !NEW_VGIC is selected, this will make VGICV2 will be unselected. I 
> was actually expecting the other way around given that new vGIC only offer v2 
> support.
> 
> The rest of the changes LGTM.

Thanks a lot for having a look on this patch, you are right the NEW_VGIC is 
offering only v2 support at the moment, does this changes captures your
Comments?

diff --git a/xen/arch/arm/Kconfig b/xen/arch/arm/Kconfig
index 5cdba07df964..1c600b3b8d04 100644
--- a/xen/arch/arm/Kconfig
+++ b/xen/arch/arm/Kconfig
@@ -110,15 +110,19 @@ config HAS_ITS
         depends on GICV3 && !NEW_VGIC && !ARM_32
 
 config VGICV2
-       bool "vGICv2 interface for guests"
+       bool "vGICv2 interface for domains"
        default y
-       depends on (GICV2 || GICV3) && !NEW_VGIC
+       help
+         Provides a virtualised interface for the Generic Interrupt Controller 
that
+         can be used by Xen's domains.
+         If unsure, say Y
 
 config HVM
         def_bool y
 
 config NEW_VGIC
        bool "Use new VGIC implementation"
+       select VGICV2
        ---help---
 
        This is an alternative implementation of the ARM GIC interrupt
diff --git a/xen/arch/arm/vgic/Makefile b/xen/arch/arm/vgic/Makefile
index 806826948e20..60cbf7f2f94a 100644
--- a/xen/arch/arm/vgic/Makefile
+++ b/xen/arch/arm/vgic/Makefile
@@ -1,5 +1,5 @@
 obj-y += vgic.o
-obj-y += vgic-v2.o
+obj-$(CONFIG_VGICV2) += vgic-v2.o
 obj-y += vgic-mmio.o
-obj-y += vgic-mmio-v2.o
+obj-$(CONFIG_VGICV2) += vgic-mmio-v2.o
 obj-y += vgic-init.o



> 
> Cheers,
> 
> -- 
> Julien Grall