Re: [PATCH 3/3] kvm: s390: Exploiting generic userspace interface for cmma\

[Alexander Graf <agraf@suse.de>]

On 16.04.14 20:49, Marcelo Tosatti wrote:
> On Thu, Apr 10, 2014 at 01:16:44PM +0200, Christian Borntraeger wrote:
>> From: Dominik Dingel <dingel@linux.vnet.ibm.com>
>>
>> To enable CMMA and to reset its state we use the vm kvm_device ioctls,
>> encapsulating attributes within the KVM_S390_VM_MEM_CTRL group.
>>
>> Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
>> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
>> ---
>>   Documentation/virtual/kvm/devices/vm.txt | 18 ++++++++++++++
>>   arch/s390/include/uapi/asm/kvm.h         |  7 ++++++
>>   arch/s390/kvm/kvm-s390.c                 | 42 ++++++++++++++++++++++++++++++++
>>   3 files changed, 67 insertions(+)
> Sounds awkward to use these three ioctls for something not
> returned by KVM_CREATE_DEVICE.
>
> /* ioctls for fds returned by KVM_CREATE_DEVICE */
> #define KVM_SET_DEVICE_ATTR       _IOW(KVMIO,  0xe1, struct kvm_device_attr)
> #define KVM_GET_DEVICE_ATTR       _IOW(KVMIO,  0xe2, struct kvm_device_attr)
> #define KVM_HAS_DEVICE_ATTR       _IOW(KVMIO,  0xe3, struct kvm_device_attr)
>
> Is that much of a problem to introduce
>
> struct kvm_vm_attr and
>
> /* ioctls for fds returned by KVM_CREATE_VM */
> #define KVM_SET_VM_ATTR       _IOW(KVMIO,  0xa, struct kvm_vm_attr)
> #define KVM_GET_VM_ATTR       _IOW(KVMIO,  0xb, struct kvm_vm_attr)
> #define KVM_HAS_VM_ATTR       _IOW(KVMIO,  0xc, struct kvm_vm_attr)
>
> ?

We could just alias them, no?

#define KVM_SET_VM_ATTR KVM_SET_DEVICE_ATTR

But I don't feel strongly either way.


Alex

> Other than that (which would be mostly organizational issue) per-vm
> attributes seem fine to me.
>