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From: Scott Wood <scottwood@freescale.com>
To: Alexander Graf <agraf@suse.de>
Cc: "<kvm-ppc@vger.kernel.org>" <kvm-ppc@vger.kernel.org>,
	kvm list <kvm@vger.kernel.org>, Avi Kivity <avi@redhat.com>,
	Marcelo Tosatti <mtosatti@redhat.com>
Subject: Re: [PATCH] KVM: PPC: Add generic single register ioctls
Date: Mon, 9 Jan 2012 13:07:03 -0600	[thread overview]
Message-ID: <4F0B3AD7.9050609@freescale.com> (raw)
In-Reply-To: <FC1F2E3F-AF70-4DC6-BB37-5CA26E4EAC82@suse.de>

On 01/06/2012 06:52 PM, Alexander Graf wrote:
> 
> 
> On 06.01.2012, at 20:32, Scott Wood <scottwood@freescale.com> wrote:
> 
>> On 01/05/2012 10:15 PM, Alexander Graf wrote:
>>
>>> +/*
>>> + * Architecture specific registers are to be defined in arch headers and
>>> + * ORed with the arch identifier.
>>> + */
>>> +#define KVM_REG_PPC        0x1000000000000000ULL
>>> +#define KVM_REG_X86        0x2000000000000000ULL
>>> +#define KVM_REG_IA64        0x3000000000000000ULL
>>> +#define KVM_REG_ARM        0x4000000000000000ULL
>>> +#define KVM_REG_S390        0x5000000000000000ULL
>>> +
>>> +#define KVM_REG_SIZE_SHIFT    52
>>> +#define KVM_REG_SIZE_MASK    0x00f0000000000000ULL
>>> +#define KVM_REG_SIZE_U8        0x0000000000000000ULL
>>> +#define KVM_REG_SIZE_U16    0x0010000000000000ULL
>>> +#define KVM_REG_SIZE_U32    0x0020000000000000ULL
>>> +#define KVM_REG_SIZE_U64    0x0030000000000000ULL
>>> +#define KVM_REG_SIZE_U128    0x0040000000000000ULL
>>> +#define KVM_REG_SIZE_U256    0x0050000000000000ULL
>>> +#define KVM_REG_SIZE_U512    0x0060000000000000ULL
>>> +#define KVM_REG_SIZE_U1024    0x0070000000000000ULL
>>
>> Why not just encode directly as number of bytes?
> 
> Because this is 1 << n bytes :)

Some registers may not be a power-of-2 number of bytes (e.g. x86 segment
descriptors), and we've got plenty of space to spare in the id.

It's probably not worth another respin, though -- we can just document
right/left justification in the event that we have such a register.

-Scott


  reply	other threads:[~2012-01-09 19:07 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-01-06  3:59 [PATCH 0/3] GET/SET_ONE_REG and HIOR patches v2 Alexander Graf
2012-01-06  3:59 ` [PATCH 1/3] KVM: PPC: Add generic single register ioctls Alexander Graf
2012-01-06  3:49   ` Alexander Graf
2012-01-06  4:15     ` [PATCH] " Alexander Graf
2012-01-06 19:32       ` Scott Wood
2012-01-07  0:52         ` Alexander Graf
2012-01-09 19:07           ` Scott Wood [this message]
2012-01-09 20:11             ` Alexander Graf
2012-01-09 20:12               ` Scott Wood
2012-01-09 20:14                 ` Alexander Graf
2012-01-06  3:59 ` [PATCH 2/3] KVM: PPC: Add support for explicit HIOR setting Alexander Graf
2012-01-06 18:42   ` Scott Wood
2012-04-01 19:51   ` Andreas Schwab
2012-04-16 16:54     ` Alexander Graf
2012-04-16 21:42       ` Paul Mackerras
2012-01-06  3:59 ` [PATCH 3/3] KVM: PPC: Move kvm_vcpu_ioctl_[gs]et_one_reg down to platform-specific code Alexander Graf

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