[v1] Arm: Enable GICv3 for AArch32

[RFC PATCH v1 12/12] Arm: GICv3: Enable GICv3 for AArch32

Posted by Ayan Kumar Halder 3 years, 3 months ago

Refer ARM DDI 0487G.b ID072021,
D13.2.86 -
ID_PFR1_EL1, AArch32 Processor Feature Register 1

GIC, bits[31:28] == 0b0001 for GIC3.0 on Aarch32

One can now enable GICv3 on AArch32 systems.

Signed-off-by: Ayan Kumar Halder <ayankuma@amd.com>
---
 xen/arch/arm/Kconfig                  | 2 +-
 xen/arch/arm/include/asm/cpufeature.h | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/xen/arch/arm/Kconfig b/xen/arch/arm/Kconfig
index 1fe5faf847..5eaf21b8e0 100644
--- a/xen/arch/arm/Kconfig
+++ b/xen/arch/arm/Kconfig
@@ -41,7 +41,7 @@ config ARM_EFI
 
 config GICV3
 	bool "GICv3 driver"
-	depends on ARM_64 && !NEW_VGIC
+	depends on (ARM_64 || ARM_32) && !NEW_VGIC
 	default y
 	---help---
 
diff --git a/xen/arch/arm/include/asm/cpufeature.h b/xen/arch/arm/include/asm/cpufeature.h
index c86a2e7f29..c8ca09d1c3 100644
--- a/xen/arch/arm/include/asm/cpufeature.h
+++ b/xen/arch/arm/include/asm/cpufeature.h
@@ -31,6 +31,7 @@
 #define cpu_has_jazelle   (boot_cpu_feature32(jazelle) > 0)
 #define cpu_has_thumbee   (boot_cpu_feature32(thumbee) == 1)
 #define cpu_has_aarch32   (cpu_has_arm || cpu_has_thumb)
+#define cpu_has_gicv3     (boot_cpu_feature32(gic) >= 1)
 
 #ifdef CONFIG_ARM_32
 #define cpu_has_gentimer  (boot_cpu_feature32(gentimer) == 1)
-- 
2.17.1

Re: [RFC PATCH v1 12/12] Arm: GICv3: Enable GICv3 for AArch32

Posted by Julien Grall 3 years, 3 months ago

Hi,

On 21/10/2022 16:31, Ayan Kumar Halder wrote:
> Refer ARM DDI 0487G.b ID072021,
> D13.2.86 -
> ID_PFR1_EL1, AArch32 Processor Feature Register 1
> 
> GIC, bits[31:28] == 0b0001 for GIC3.0 on Aarch32
> 
> One can now enable GICv3 on AArch32 systems.
> 
> Signed-off-by: Ayan Kumar Halder <ayankuma@amd.com>
> ---
>   xen/arch/arm/Kconfig                  | 2 +-
>   xen/arch/arm/include/asm/cpufeature.h | 1 +
>   2 files changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/xen/arch/arm/Kconfig b/xen/arch/arm/Kconfig
> index 1fe5faf847..5eaf21b8e0 100644
> --- a/xen/arch/arm/Kconfig
> +++ b/xen/arch/arm/Kconfig
> @@ -41,7 +41,7 @@ config ARM_EFI
>   
>   config GICV3
>   	bool "GICv3 driver"
> -	depends on ARM_64 && !NEW_VGIC
> +	depends on (ARM_64 || ARM_32) && !NEW_VGIC

(ARM_64 || ARM_32) will always be true. So this can be dropped.

Furthermore, I wonder whether we should update SUPPORT.md with the 
support state for GICv3 on 32-bit. I would be fine if we already mark it 
as "supported, not security supported". But I am not sure about security 
supported until further testing.

Any opinions?

Cheers,

-- 
Julien Grall