From mboxrd@z Thu Jan  1 00:00:00 1970
From: Marc Zyngier <marc.zyngier@arm.com>
Subject: Re: [PATCH v2 03/10] KVM: arm/arm64: vgic: Convert struct vgic_lr
 to use bitfields
Date: Tue, 21 Jul 2015 19:02:25 +0100
Message-ID: <55AE8931.7020806@arm.com>
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Cc: "kvm@vger.kernel.org" <kvm@vger.kernel.org>,
	"kvmarm@lists.cs.columbia.edu" <kvmarm@lists.cs.columbia.edu>,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>,
	=?windows-1252?Q?Alex_Benn=E9e?= <alex.bennee@linaro.org>,
	Eric Auger <eric.auger@linaro.org>,
	Andre Przywara <Andre.Przywara@arm.com>
To: Christoffer Dall <christoffer.dall@linaro.org>
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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 Benn=E9e <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)
>> =20
>>  struct vgic_lr {
>> -	u16	irq;
>> -	u8	source;
>> -	u8	state;
>> +	unsigned irq:10;
>> +	union {
>> +		unsigned hwirq:10;
>> +		unsigned source:8;
>=20
> why 8?  why not 3?

Because I can't count :-).

>> +	};
>> +	unsigned state:4;
>>  };
>> =20
>>  struct vgic_vmcr {
>> --=20
>> 2.1.4
>>
>=20
> otherwise:
>=20
> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
>=20

Thanks,

	M.
--=20
Jazz is not dead. It just smells funny...