From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ankur Arora Subject: Re: [Xen-devel] [PATCH RFC 00/39] x86/KVM: Xen HVM guest support Date: Wed, 20 Feb 2019 16:31:53 -0800 Message-ID: <292773f7-5a4d-ba00-8398-0c8b81766b93@oracle.com> References: <20190220201609.28290-1-joao.m.martins@oracle.com> <20190220233941.GA5279@mail-itl> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Juergen Gross , Stefano Stabellini , xen-devel@lists.xenproject.org, =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= , x86@kernel.org, Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , Paolo Bonzini , Boris Ostrovsky , Thomas Gleixner To: =?UTF-8?Q?Marek_Marczykowski-G=c3=b3recki?= , Joao Martins Return-path: In-Reply-To: <20190220233941.GA5279@mail-itl> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On 2/20/19 3:39 PM, Marek Marczykowski-Górecki wrote: > On Wed, Feb 20, 2019 at 08:15:30PM +0000, Joao Martins wrote: >> 2. PV Driver support (patches 17 - 39) >> >> We start by redirecting hypercalls from the backend to routines >> which emulate the behaviour that PV backends expect i.e. grant >> table and interdomain events. Next, we add support for late >> initialization of xenbus, followed by implementing >> frontend/backend communication mechanisms (i.e. grant tables and >> interdomain event channels). Finally, introduce xen-shim.ko, >> which will setup a limited Xen environment. This uses the added >> functionality of Xen specific shared memory (grant tables) and >> notifications (event channels). > > Does it mean backends could be run in another guest, similarly as on > real Xen? AFAIK virtio doesn't allow that as virtio backends need I'm afraid not. For now grant operations (map/unmap) can only be done by backends to the local KVM instance. Ankur > arbitrary write access to guest memory. But grant tables provide enough > abstraction to do that safely. >