On Tue, 2013-11-05 at 10:20 +0100, Goswin von Brederlow wrote:> Hi, > > this might be an FAQ but I''m looking for the documentation for the xen > guest API/ABI exposed to domU kernels on arm.Which port are you asking about? http://wiki.xen.org/wiki/Xen_ARM_with_Virtualization_Extensions or http://wiki.xen.org/wiki/Xen_ARM_%28PV%29 ? I only know about the former and it sounds like this is the one you mean? Adding xen-devel which is the right venue for virt extensions questions, xen-arm@ is for the PV port.> The wiki says it isn''t > yet set in stone and WIP but I hope someone is already working on > documenting it. Any pointers?For the hardware extensions port the interfaces are documented in xen.git (xen/include/public/) and exposed via http://xenbits.xen.org/docs/unstable/hypercall/arm/index.html I think it is mostly set in stone right now, although there is a pending issue with Linux netfront/back possibly using a broken ABI due to struct packing oddities. Other than that I don''t expect there to be any further changes before 4.4 (where I hope we can declare it frozen). Ian.
Goswin von Brederlow
2013-Nov-05 19:11 UTC
Re: [XenARM] probably FAQ: latest xen PV api/abi specs
On Tue, Nov 05, 2013 at 09:48:39AM +0000, Ian Campbell wrote:> On Tue, 2013-11-05 at 10:20 +0100, Goswin von Brederlow wrote: > > Hi, > > > > this might be an FAQ but I''m looking for the documentation for the xen > > guest API/ABI exposed to domU kernels on arm. > > Which port are you asking about? > http://wiki.xen.org/wiki/Xen_ARM_with_Virtualization_Extensions or > http://wiki.xen.org/wiki/Xen_ARM_%28PV%29 ? I only know about the former > and it sounds like this is the one you mean? > > Adding xen-devel which is the right venue for virt extensions questions, > xen-arm@ is for the PV port.I''m interested in older arm cpus like the RaspberryPI, which doesn''t have the virtualization extension. Therefore I''m interested in the PV port. Or would it be feasable and make more sense to emulate the HVC instruction in the undefined handler? Probably not given the extensive use of hardware facilities. MfG Goswin
On Tue, 2013-11-05 at 20:11 +0100, Goswin von Brederlow wrote:> On Tue, Nov 05, 2013 at 09:48:39AM +0000, Ian Campbell wrote: > > On Tue, 2013-11-05 at 10:20 +0100, Goswin von Brederlow wrote: > > > Hi, > > > > > > this might be an FAQ but I''m looking for the documentation for the xen > > > guest API/ABI exposed to domU kernels on arm. > > > > Which port are you asking about? > > http://wiki.xen.org/wiki/Xen_ARM_with_Virtualization_Extensions or > > http://wiki.xen.org/wiki/Xen_ARM_%28PV%29 ? I only know about the former > > and it sounds like this is the one you mean? > > > > Adding xen-devel which is the right venue for virt extensions questions, > > xen-arm@ is for the PV port. > > I''m interested in older arm cpus like the RaspberryPI, which doesn''t > have the virtualization extension. Therefore I''m interested in the PV > port.OK. I think the statement you''ve seen regarding API/ABI stability all refer to the hardware based port. That said I know nothing about the stated (or otherwise) stability of the API/ABI of the PV port. Its developers have not been active for several years now. I''m afraid I think you''d be wasting your time pursuing it on the RPi.> Or would it be feasable and make more sense to emulate the HVC > instruction in the undefined handler? Probably not given the extensive > use of hardware facilities.I''m sure it could be done at a technical level, but it would effectively be an entirely new port... Ian.