Re: [PATCH 1/3] kvm: s390: Per-vm kvm device controls

[Christian Borntraeger <borntraeger@de.ibm.com>]

On 10/04/14 13:29, Alexander Graf wrote:
> 
> On 10.04.14 13:16, Christian Borntraeger wrote:
>> From: Dominik Dingel <dingel@linux.vnet.ibm.com>
>>
>> We sometimes need to get/set attributes specific to a virtual machine
>> and so need something else than ONE_REG.
>>
>> Let's copy the KVM_DEVICE approach, and define the respective ioctls
>> for the vm file descriptor.
>>
>> Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
>> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
>> ---
>>   Documentation/virtual/kvm/api.txt        |  8 ++---
>>   Documentation/virtual/kvm/devices/vm.txt |  6 ++++
>>   arch/s390/kvm/kvm-s390.c                 | 54 ++++++++++++++++++++++++++++++++
>>   include/uapi/linux/kvm.h                 |  1 +
>>   4 files changed, 65 insertions(+), 4 deletions(-)
>>   create mode 100644 Documentation/virtual/kvm/devices/vm.txt
>>
>> diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
>> index c24211d..f69731a 100644
>> --- a/Documentation/virtual/kvm/api.txt
>> +++ b/Documentation/virtual/kvm/api.txt
>> @@ -2314,8 +2314,8 @@ struct kvm_create_device {
>>     4.80 KVM_SET_DEVICE_ATTR/KVM_GET_DEVICE_ATTR
>>   -Capability: KVM_CAP_DEVICE_CTRL
>> -Type: device ioctl
>> +Capability: KVM_CAP_DEVICE_CTRL, KVM_CAP_VM_ATTRIBUTES for vm device
>> +Type: device ioctl, vm ioctl
>>   Parameters: struct kvm_device_attr
>>   Returns: 0 on success, -1 on error
>>   Errors:
>> @@ -2340,8 +2340,8 @@ struct kvm_device_attr {
>>     4.81 KVM_HAS_DEVICE_ATTR
>>   -Capability: KVM_CAP_DEVICE_CTRL
>> -Type: device ioctl
>> +Capability: KVM_CAP_DEVICE_CTRL, KVM_CAP_VM_ATTRIBUTES for vm device
>> +Type: device ioctl, vm ioctl
>>   Parameters: struct kvm_device_attr
>>   Returns: 0 on success, -1 on error
>>   Errors:
>> diff --git a/Documentation/virtual/kvm/devices/vm.txt b/Documentation/virtual/kvm/devices/vm.txt
>> new file mode 100644
>> index 0000000..4fe1532
>> --- /dev/null
>> +++ b/Documentation/virtual/kvm/devices/vm.txt
>> @@ -0,0 +1,6 @@
>> +Generic vm interface
>> +====================================
>> +
>> +The interface handles per-vm attributes, such as CMMA status on s390 and is
>> +similar in way to ONE_REG, but targeting the whole vm instead of one vcpu
>> +alone. It is available with KVM_CAP_VM_ATTRIBUTES.
> 
> This document doesn't sound impressively useful :).

Will be filled with patch3. I asked Dominik to split this out into this patch,
since we introduce the capability here.