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

From: Scott Wood <[email-masked]>
Date: Wed, 29 May 2013 18:14:32 -0500

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, =20
> struct
> >> >> >> >>> kvm_device_attr)
> >> >> >> >>> #define KVM_HAS_DEVICE_ATTR      _IOW(KVMIO,  0xe3, =20
> struct
> >> >> >> >>> kvm_device_attr)
> >> >> >> >>>
> >> >> >> >>> +/* ioctl for SPAPR TCE IOMMU */
> >> >> >> >>> +#define KVM_CREATE_SPAPR_TCE_IOMMU _IOW(KVMIO,  0xe4, =20
> 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 =20
> 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.  =20
> 0xe0
> > begins a different section.
>=20
> 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 =20
ioctl number conflict mess in the vm-ioctl section, but at least that =20
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=