From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:39701) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WV0FO-0007nh-J8 for qemu-devel@nongnu.org; Tue, 01 Apr 2014 11:05:16 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WV0FF-0006om-29 for qemu-devel@nongnu.org; Tue, 01 Apr 2014 11:05:06 -0400 Received: from e06smtp16.uk.ibm.com ([195.75.94.112]:39240) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WV0FE-0006nz-OG for qemu-devel@nongnu.org; Tue, 01 Apr 2014 11:04:56 -0400 Received: from /spool/local by e06smtp16.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 1 Apr 2014 16:04:55 +0100 Received: from b06cxnps3075.portsmouth.uk.ibm.com (d06relay10.portsmouth.uk.ibm.com [9.149.109.195]) by d06dlp03.portsmouth.uk.ibm.com (Postfix) with ESMTP id 6B8CB1B08066 for ; Tue, 1 Apr 2014 16:04:48 +0100 (BST) Received: from d06av10.portsmouth.uk.ibm.com (d06av10.portsmouth.uk.ibm.com [9.149.37.251]) by b06cxnps3075.portsmouth.uk.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id s31F4eCp655690 for ; Tue, 1 Apr 2014 15:04:40 GMT Received: from d06av10.portsmouth.uk.ibm.com (localhost [127.0.0.1]) by d06av10.portsmouth.uk.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id s31F4p5P002969 for ; Tue, 1 Apr 2014 09:04:52 -0600 Message-ID: <533AD593.5020804@de.ibm.com> Date: Tue, 01 Apr 2014 17:04:51 +0200 From: Christian Borntraeger MIME-Version: 1.0 References: <1396363663-50450-1-git-send-email-borntraeger@de.ibm.com> <1396363663-50450-2-git-send-email-borntraeger@de.ibm.com> <533AD42D.8060504@suse.de> In-Reply-To: <533AD42D.8060504@suse.de> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH/RFC] KVM: s390: Add S390 configuration and control kvm device List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Alexander Graf Cc: linux-s390 , Michael Mueller , KVM , Ekaterina Tumanova , qemu-devel , Jens Freimann , Cornelia Huck On 01/04/14 16:58, Alexander Graf wrote: > On 04/01/2014 04:47 PM, Christian Borntraeger wrote: >> From: Ekaterina Tumanova >> >> Add KVM_DEV_TYPE_S390_CONFIG kvm device that contains >> configuration and control attributes of particular vm. >> The device is created by KVM_CREATE_DEVICE ioctl. >> The attributes may be retrieved and stored by calling >> KVM_GET_DEVICE_ATTR and KVM_SET_DEVICE_ATTR ioctls. >> >> Signed-off-by: Ekaterina Tumanova >> Signed-off-by: Christian Borntraeger > > I don't think a device is particularly the best fit. A device can usually be instantiated multiple times. The configuration device can only be created once. A device also gets created by user space which enables it to receive the fd to drive it. Your device has to be created during VM creation. I remember some discussion a year or 2 ago, and IIRC a config device was actually your idea ;-) (The other idea that we had, was ONE_REG for the VM) > > I think VM configuration is common enough to just make this a separate interface. So you propose to define a new base ioctl (e.g. VM_REG) on the vm fd, instead? Seems like an easy enough change. Would you reuse the kvm_attr structure for that? > > > Alex >