From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:42186) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1erOKJ-0006sV-Cr for qemu-devel@nongnu.org; Thu, 01 Mar 2018 08:32:54 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1erOKI-0008HH-GM for qemu-devel@nongnu.org; Thu, 01 Mar 2018 08:32:51 -0500 References: <000e01d3afad$b9a13830$2ce3a890$@codeaurora.org> <20180227104708.GA11391@cbox> <20180227124604.GA2373@cbox> <20180227132131.fipafmnb56a7fj76@kamzik.brq.redhat.com> <20180301105030.2b716e68@redhat.com> From: David Hildenbrand Message-ID: Date: Thu, 1 Mar 2018 14:32:39 +0100 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [Qemu-arm] VCPU hotplug on KVM/ARM List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Peter Maydell , Igor Mammedov Cc: bthakur@codeaurora.org, Christoffer Dall , Andrew Jones , Christoffer Dall , QEMU Developers , Christoffer Dall , qemu-arm , kvmarm@lists.cs.columbia.edu On 01.03.2018 11:05, Peter Maydell wrote: > On 1 March 2018 at 09:50, Igor Mammedov wrote: >> In QEMU on x86 (and I think ppc, s390 as well), we create vCPUs on demand.>> >> It would be nice if ARM would be able to do that too, >> so that it could take advantage of the same code. > > It's not clear to me how that would work, given that for > instance the interrupt controller wants to know up-front > how many CPUs it has to deal with. > So how is cpu hotplug handled in HW? Or doesn't it even exist there? (we have max_cpus for the interrupt controller, but not sure if that is what we want) > thanks > -- PMM > -- Thanks, David / dhildenb From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Hildenbrand Subject: Re: [Qemu-devel] [Qemu-arm] VCPU hotplug on KVM/ARM Date: Thu, 1 Mar 2018 14:32:39 +0100 Message-ID: References: <000e01d3afad$b9a13830$2ce3a890$@codeaurora.org> <20180227104708.GA11391@cbox> <20180227124604.GA2373@cbox> <20180227132131.fipafmnb56a7fj76@kamzik.brq.redhat.com> <20180301105030.2b716e68@redhat.com> 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 0B9DF402D3 for ; Thu, 1 Mar 2018 08:26:09 -0500 (EST) 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 vz+5W1+VvrcG for ; Thu, 1 Mar 2018 08:25:42 -0500 (EST) Received: from mx1.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by mm01.cs.columbia.edu (Postfix) with ESMTPS id D6D7D402C7 for ; Thu, 1 Mar 2018 08:25:42 -0500 (EST) In-Reply-To: Content-Language: en-US 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: Peter Maydell , Igor Mammedov Cc: Christoffer Dall , QEMU Developers , Christoffer Dall , qemu-arm , kvmarm@lists.cs.columbia.edu List-Id: kvmarm@lists.cs.columbia.edu On 01.03.2018 11:05, Peter Maydell wrote: > On 1 March 2018 at 09:50, Igor Mammedov wrote: >> In QEMU on x86 (and I think ppc, s390 as well), we create vCPUs on demand.>> >> It would be nice if ARM would be able to do that too, >> so that it could take advantage of the same code. > > It's not clear to me how that would work, given that for > instance the interrupt controller wants to know up-front > how many CPUs it has to deal with. > So how is cpu hotplug handled in HW? Or doesn't it even exist there? (we have max_cpus for the interrupt controller, but not sure if that is what we want) > thanks > -- PMM > -- Thanks, David / dhildenb