From mboxrd@z Thu Jan 1 00:00:00 1970 From: Julien Grall Subject: Re: [RFC + Queries] Flow of PCI passthrough in ARM Date: Fri, 07 Nov 2014 10:29:52 +0000 Message-ID: <545C9F20.5000702@linaro.org> References: <20141008124657.GB13391@laptop.dumpdata.com> <1412775916.24894.15.camel@citrix.com> <20141008145107.GC18573@laptop.dumpdata.com> <545B9B96.6080102@linaro.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" 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: manish jaggi , Stefano Stabellini Cc: Ian Campbell , Vijay Kilari , Prasun Kapoor , manish.jaggi@caviumnetworks.com, Ryan Wilson , xen-devel , Jan Beulich List-Id: xen-devel@lists.xenproject.org Hi Manish, On 06/11/2014 16:20, manish jaggi wrote: > On 6 November 2014 21:37, Stefano Stabellini > wrote: >> On Thu, 6 Nov 2014, Julien Grall wrote: >>> Hi Manish, >>> >>> On 06/11/2014 15:55, manish jaggi wrote: >>>> On 6 November 2014 21:18, Stefano Stabellini >>>> wrote: >>>>> On Thu, 6 Nov 2014, manish jaggi wrote: >>>>>> On 20 October 2014 20:24, Stefano Stabellini >>>>>> wrote: >>>>>>> On Mon, 20 Oct 2014, manish jaggi wrote: >>>>>>>> On 8 October 2014 20:21, Konrad Rzeszutek Wilk >>>>>>>> wrote: >>>>>>>>> On Wed, Oct 08, 2014 at 07:17:48PM +0530, manish jaggi wrote: >>>>>>>>>> On 8 October 2014 19:15, Ian Campbell >>>>>>>>>> wrote: >>>>>>>>>>> On Wed, 2014-10-08 at 19:07 +0530, manish jaggi wrote: >>>>>>>>>>>> Thanks for replying. As detailed in this thread, I need to >>>>>>>>>>>> create a >>>>>>>>>>>> hypercall that would send the following information to Xen >>>>>>>>>>>> at the time >>>>>>>>>>>> of PCI attach >>>>>>>>>>>> { sbdf , domU sbdf, domainId }. >>>>>>>>>>>> I am not able to find a way to get the domU sbdf from dom0 >>>>>>>>>>>> at the time >>>>>>>>>>>> of pci-attach. >>>>>>>>>>> >>>>>>>>>>> I think it would need to be done by the pciback driver in the >>>>>>>>>>> dom0 >>>>>>>>>>> kernel, which AFAIK is the thing which consistently knows both >>>>>>>>>>> physical >>>>>>>>>>> and virtual sbdf for a given assigned device. >>>>>>>>>>> >>>>>>>>>>> Ian. >>>>>>>>>>> >>>>>>>>>> Correct, can you point out which data structure holds the domU >>>>>>>>>> sbdf >>>>>>>>>> corresponding to the actual sbdf in pciback. >>>>>>>>> >>>>>>>>> See 'xen_pcibk_export_device' or 'xen_pcibk_publish_pci_root' >>>>>>>>> is that what you are referring to? >>>>>>>> >>>>>>>> Xen docs also mention about xen-pciback.passthrough=1. If I set this >>>>>>>> in dom0 i see that the device is enumerated as the same sbdf in >>>>>>>> domU, >>>>>>>> but >>>>>>>> a) it is not shown in lspci >>>>>>>> b) no front-back communication is done for reading devices >>>>>>>> configuration space >>>>>>>> . >>>>>>>> Is option useful / fully implemented for ARM ? >>>>>>> >>>>>>> I don't think this option is very useful. I wouldn't worry about it >>>>>>> for >>>>>>> now. >>>>>> >>>>>> Stefano / Ian / Konard / Julien, >>>>>> >>>>>> Attached is a first raw code FYI RFC Patches of PCI passthrough support >>>>>> on ARM. >>>>>> - Linux Patch (3.18) >>>>>> - Xen Patch (4.5 staging) >>>>>> ---(Smmu changes not included, thats a separate patch altogether) >>>>>> This patches show the logic, at places need of improvements in code >>>>>> organization/quality. I wanted to share to get initial comments. >>>>>> This is working with SRIOV as well. >>>>>> >>>>>> Please have a look and let me know your positive comments >>>>> >>>>> Please send as individual inline patches. not attachments. >>>>> Please also add a proper description to each patch and an entry 0/N email >>>>> with the high level explanation of your work. >>>>> >>>>> See http://wiki.xenproject.org/wiki/Submitting_Xen_Project_Patches >>>> Stefano I just wanted to share the patches as reference to our >>>> discussion on the approach. Please recall I had shared in this mail a >>>> design flow. These are just an extension to it. I wanted to move this >>>> discussion to a conclusion >>>> There are not patches which I am submitting to xen git. >>>> If you are ok with the approach I will formally send the patches post >>>> 4.5 release. >>> >>> In this case you can send the patch series tagged "[RFC]" in the subject. >> >> That's right. It is difficult to give even just an early feedback >> without the patch descriptions. >> > I assumed that the context is preserved in this mail thread. I shared > the flow in the first few mails and am sharing the code after a lot of > discussion in this thread. There is about 30 mails in this discussion. It's better if you give a summary, it will avoid us to read again all the mails to find the conclusion. > Anyhow I will share the code as RFC in some time. Thanks, Regards, -- Julien Grall