From mboxrd@z Thu Jan 1 00:00:00 1970 From: Julien Grall Subject: Re: PCI Pass-through in Xen ARM: Draft 4 Date: Fri, 14 Aug 2015 15:45:33 +0100 Message-ID: <55CDFF0D.4010101@citrix.com> References: <55CC668F.80104@caviumnetworks.com> <55CCD3F1020000780009AC34@prv-mh.provo.novell.com> <1439485284.23981.129.camel@citrix.com> <55CDD04F020000780009AEDC@prv-mh.provo.novell.com> <55CE103D020000780009B132@prv-mh.provo.novell.com> <55CE189A020000780009B1C3@prv-mh.provo.novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Stefano Stabellini , Jan Beulich Cc: "Prasun.kapoor@cavium.com" , Ian Campbell , Manish Jaggi , Vijaya Kumar , JulienGrall , Xen Devel List-Id: xen-devel@lists.xenproject.org On 14/08/15 15:37, Stefano Stabellini wrote: > On Fri, 14 Aug 2015, Jan Beulich wrote: >>>>> On 14.08.15 at 16:03, wrote: >>> On Fri, 14 Aug 2015, Jan Beulich wrote: >>>>>>> On 14.08.15 at 15:21, wrote: >>>>> On Fri, 14 Aug 2015, Jan Beulich wrote: >>>>>> it's even less clear how you'd expect to suppress this in other guest >>>>>> OSes (Windows - afaik - being able to run on ARM certainly makes it >>>>>> a candidate guest, even if maybe this doesn't work today), namely >>>>>> such not having any pcifront. And I hope this design discussion isn't >>>>>> limiting itself to Linux guests. >>>>> >>>>> We'll write down in the ABI documentation that BARs reassignments are >>>>> not supported. >>>> >>>> I.e. guests doing so Will Not Work (TM), with users (usually not reading >>>> ABI docs) learning it the hard way. Not nice, but a way to handle it. >>> >>> The target of the ABI docs is not users, but kernel developers, who >>> should most definitely read them and fix their kernels. >> >> ??? (We're talking of unmodified, closed source OSes here.) > > If you are thinking of Windows for ARM64, there isn't one yet. When/if > it will become available, there are going to be a number of issues to > address before we can run it as a guest on Xen on ARM with the current > architecture which doesn't do emulation. I am hopeful that we'll be able > to have a discussion on ABI issues such as this one. It may be worth to read [1] where the Xen ARM architecture is explained. Regards, [1] http://wiki.xen.org/wiki/Xen_ARM_with_Virtualization_Extensions_whitepaper -- Julien Grall