[v2,03/10] KVM: arm/arm64: vgic: Convert struct vgic_lr to use bitfields
diff mbox

Message ID 1436378202-20224-4-git-send-email-marc.zyngier@arm.com
State New
Headers show

Commit Message

Marc Zyngier July 8, 2015, 5:56 p.m. UTC
As we're about to cram more information in the vgic_lr structure
(HW interrupt number and additional state information), we switch
to a layout similar to the HW's:

- use bitfields to save space (we don't need more than 10 bits
  to represent the irq numbers)
- source CPU and HW interrupt can share the same field, as
  a SGI doesn't have a physical line.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
---
 include/kvm/arm_vgic.h | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

Comments

Christoffer Dall July 17, 2015, 10:15 p.m. UTC | #1
On Wed, Jul 08, 2015 at 06:56:35PM +0100, Marc Zyngier wrote:
> As we're about to cram more information in the vgic_lr structure
> (HW interrupt number and additional state information), we switch
> to a layout similar to the HW's:
> 
> - use bitfields to save space (we don't need more than 10 bits
>   to represent the irq numbers)
> - source CPU and HW interrupt can share the same field, as
>   a SGI doesn't have a physical line.
> 
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
> Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
> ---
>  include/kvm/arm_vgic.h | 10 +++++++---
>  1 file changed, 7 insertions(+), 3 deletions(-)
> 
> diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
> index 133ea00..4f9fa1d 100644
> --- a/include/kvm/arm_vgic.h
> +++ b/include/kvm/arm_vgic.h
> @@ -95,11 +95,15 @@ enum vgic_type {
>  #define LR_STATE_ACTIVE		(1 << 1)
>  #define LR_STATE_MASK		(3 << 0)
>  #define LR_EOI_INT		(1 << 2)
> +#define LR_HW			(1 << 3)
>  
>  struct vgic_lr {
> -	u16	irq;
> -	u8	source;
> -	u8	state;
> +	unsigned irq:10;
> +	union {
> +		unsigned hwirq:10;
> +		unsigned source:8;

why 8?  why not 3?

> +	};
> +	unsigned state:4;
>  };
>  
>  struct vgic_vmcr {
> -- 
> 2.1.4
> 

otherwise:

Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
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Marc Zyngier July 21, 2015, 6:02 p.m. UTC | #2
On 17/07/15 23:15, Christoffer Dall wrote:
> On Wed, Jul 08, 2015 at 06:56:35PM +0100, Marc Zyngier wrote:
>> As we're about to cram more information in the vgic_lr structure
>> (HW interrupt number and additional state information), we switch
>> to a layout similar to the HW's:
>>
>> - use bitfields to save space (we don't need more than 10 bits
>>   to represent the irq numbers)
>> - source CPU and HW interrupt can share the same field, as
>>   a SGI doesn't have a physical line.
>>
>> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
>> Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
>> ---
>>  include/kvm/arm_vgic.h | 10 +++++++---
>>  1 file changed, 7 insertions(+), 3 deletions(-)
>>
>> diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
>> index 133ea00..4f9fa1d 100644
>> --- a/include/kvm/arm_vgic.h
>> +++ b/include/kvm/arm_vgic.h
>> @@ -95,11 +95,15 @@ enum vgic_type {
>>  #define LR_STATE_ACTIVE		(1 << 1)
>>  #define LR_STATE_MASK		(3 << 0)
>>  #define LR_EOI_INT		(1 << 2)
>> +#define LR_HW			(1 << 3)
>>  
>>  struct vgic_lr {
>> -	u16	irq;
>> -	u8	source;
>> -	u8	state;
>> +	unsigned irq:10;
>> +	union {
>> +		unsigned hwirq:10;
>> +		unsigned source:8;
> 
> why 8?  why not 3?

Because I can't count :-).

>> +	};
>> +	unsigned state:4;
>>  };
>>  
>>  struct vgic_vmcr {
>> -- 
>> 2.1.4
>>
> 
> otherwise:
> 
> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
> 

Thanks,

	M.

Patch
diff mbox

diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
index 133ea00..4f9fa1d 100644
--- a/include/kvm/arm_vgic.h
+++ b/include/kvm/arm_vgic.h
@@ -95,11 +95,15 @@  enum vgic_type {
 #define LR_STATE_ACTIVE		(1 << 1)
 #define LR_STATE_MASK		(3 << 0)
 #define LR_EOI_INT		(1 << 2)
+#define LR_HW			(1 << 3)
 
 struct vgic_lr {
-	u16	irq;
-	u8	source;
-	u8	state;
+	unsigned irq:10;
+	union {
+		unsigned hwirq:10;
+		unsigned source:8;
+	};
+	unsigned state:4;
 };
 
 struct vgic_vmcr {