Re: [PATCH 3/4] KVM: PPC: Add support for IOMMU in-kernel handling

From: Scott Wood
Date: Wed May 29 2013 - 19:15:31 EST


On 05/29/2013 06:10:33 PM, Alexey Kardashevskiy wrote:
On 05/30/2013 06:05 AM, Scott Wood wrote:
> On 05/28/2013 07:12:32 PM, Alexey Kardashevskiy wrote:
>> On 05/29/2013 09:35 AM, Scott Wood wrote:
>> > On 05/28/2013 06:30:40 PM, Alexey Kardashevskiy wrote:
>> >> >> >>> @@ -939,6 +940,9 @@ struct kvm_s390_ucas_mapping {
>> >> >> >>> #define KVM_GET_DEVICE_ATTR _IOW(KVMIO, 0xe2, struct
>> >> >> >>> kvm_device_attr)
>> >> >> >>> #define KVM_HAS_DEVICE_ATTR _IOW(KVMIO, 0xe3, struct
>> >> >> >>> kvm_device_attr)
>> >> >> >>>
>> >> >> >>> +/* ioctl for SPAPR TCE IOMMU */
>> >> >> >>> +#define KVM_CREATE_SPAPR_TCE_IOMMU _IOW(KVMIO, 0xe4, struct
>> >> >> >>> kvm_create_spapr_tce_iommu)
>> >> >> >>
>> >> >> >> Shouldn't this go under the vm ioctl section?
>> >> >>
>> >> >>
>> >> >> The KVM_CREATE_SPAPR_TCE_IOMMU ioctl (the version for emulated
>> >> devices) is
>> >> >> in this section so I decided to keep them together. Wrong?
>> >> >
>> >> > You decided to keep KVM_CREATE_SPAPR_TCE_IOMMU together with
>> >> > KVM_CREATE_SPAPR_TCE_IOMMU?
>> >>
>> >> Yes.
>> >
>> > Sigh. That's the same thing repeated. There's only one IOCTL.
>> Nothing is
>> > being "kept together".
>>
>> Sorry, I meant this ioctl - KVM_CREATE_SPAPR_TCE.
>
> But you didn't put it in the same section as KVM_CREATE_SPAPR_TCE. 0xe0
> begins a different section.

It is not really obvious that there are sections as no comment defines
those :)

There is a comment /* ioctls for fds returned by KVM_CREATE_DEVICE */

Putting KVM_CREATE_DEVICE in there was mainly to avoid dealing with the ioctl number conflict mess in the vm-ioctl section, but at least that one is related to the device control API. :-)

But yes, makes sense to move it up a bit and change the code to 0xad.

0xad is KVM_KVMCLOCK_CTRL

-Scott
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