On 05/26/2013 09:44:24 PM, Alexey Kardashevskiy wrote:
On 05/25/2013 12:45 PM, David Gibson wrote:
> On Wed, May 22, 2013 at 04:06:57PM -0500, Scott Wood wrote:
>> On 05/20/2013 10:06:46 PM, Alexey Kardashevskiy wrote:
>>> diff --git a/arch/powerpc/kvm/powerpc.c
b/arch/powerpc/kvm/powerpc.c
>>> index 8465c2a..da6bf61 100644
>>> --- a/arch/powerpc/kvm/powerpc.c
>>> @@ -396,6 +396,7 @@ int kvm_dev_ioctl_check_extension(long ext)
>>> +++ b/arch/powerpc/kvm/powerpc.c
>>> break;
>>> #endif
>>> case KVM_CAP_SPAPR_MULTITCE:
>>> + case KVM_CAP_SPAPR_TCE_IOMMU:
>>> r = 1;
>>> break;
>>> default:
>>
>> Don't advertise SPAPR capabilities if it's not book3s -- and
>> probably there's some additional limitation that would be
>> appropriate.
>
> So, in the case of MULTITCE, that's not quite right. PR KVM can
> emulate a PAPR system on a BookE machine, and there's no reason not
to
> allow TCE acceleration as well. We can't make it dependent on PAPR
> mode being selected, because that's enabled per-vcpu, whereas these
> capabilities are queried on the VM before the vcpus are created.
>
> CAP_SPAPR_TCE_IOMMU should be dependent on the presence of suitable
> host side hardware (i.e. a PAPR style IOMMU), though.
The capability says that the ioctl is supported. If there is no IOMMU
group
registered, than it will fail with a reasonable error and nobody gets
hurt.
What is the problem?
You could say that about a lot of the capabilities that just advertise
the existence of new ioctls. :-)
Sometimes it's nice to know in advance whether it's supported, before
actually requesting that something happen.
>>> @@ -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?
-Scott
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