From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pavel Fedin Subject: RE: KVM Live migration with GICv3 Date: Tue, 11 Aug 2015 09:41:42 +0300 Message-ID: <009101d0d400$c92925f0$5b7b71d0$@samsung.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id ACEFB5A854 for ; Tue, 11 Aug 2015 02:28:45 -0400 (EDT) Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id PZjIDqxFWagE for ; Tue, 11 Aug 2015 02:28:43 -0400 (EDT) Received: from mailout2.w1.samsung.com (mailout2.w1.samsung.com [210.118.77.12]) by mm01.cs.columbia.edu (Postfix) with ESMTPS id CD82D5A850 for ; Tue, 11 Aug 2015 02:28:43 -0400 (EDT) Received: from eucpsbgm2.samsung.com (unknown [203.254.199.245]) by mailout2.w1.samsung.com (Oracle Communications Messaging Server 7.0.5.31.0 64bit (built May 5 2014)) with ESMTP id <0NSW00KUDNXJBE90@mailout2.w1.samsung.com> for kvmarm@lists.cs.columbia.edu; Tue, 11 Aug 2015 07:41:43 +0100 (BST) In-reply-to: Content-language: ru List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu To: 'Vijay Kilari' , kvmarm@lists.cs.columbia.edu, 'Christoffer Dall' , =?UTF-8?Q?'Alex_Benn=C3=A9e'?= List-Id: kvmarm@lists.cs.columbia.edu Hello! > I have prototyped Live migration with GICv3. This is interesting of course, i will need this for my project too and i was also going to take a look at this later. > For this I have made following changes > > 1) Save and Restore of GICv3 registers in QEMU. > - For GICv2, QEMU is saving/restoring GICD, GICC registers. For GICv3, > we have to save/restore GICD, GICR and ICC registers. > However ICC registers are system registers which cannot be > accessed @ EL0 level (SRE=1). So these ICC registers should be > accessed as mmio registers by QEMU, for this we have to add ioctl to > access ICC @ EL1 level similar to GICC registers of GICv2. Sorry, your description is a bit fuzzy. What ioctl's did you have to add and why? The kernel already has KVM_GET_ONE_REG and KVM_SET_ONE_REG ioctl's. And they can be used to access anything inside the VM, including system registers. I believe you would need only to implement handlers for GICv3 registers. > Please provide your initial feedback. Would be nice to take a look at patches. > I am attending KVM-forum next week @ Seattle. We can discuss there as well. I would love to go there, and my company wanted to send me there. But it appears to be extremely difficult for a tech specialist from Russia to get a US visa. They are still considering me and the time is running out, so i'm unlikely to attend, unfortunately. Kind regards, Pavel Fedin Expert Engineer Samsung Electronics Research center Russia