From mboxrd@z Thu Jan 1 00:00:00 1970 From: Julien Grall Subject: Re: [PATCH v3 13/24] xen/arm: Implement hypercall PHYSDEVOP_{, un}map_pirq Date: Mon, 23 Feb 2015 16:11:58 +0000 Message-ID: <54EB514E.5010604@linaro.org> References: <1421159133-31526-1-git-send-email-julien.grall@linaro.org> <1421159133-31526-14-git-send-email-julien.grall@linaro.org> <54C932BF.5070009@linaro.org> <54CA2709.9080409@linaro.org> <1424451224.30924.357.camel@citrix.com> <54EB01E102000078000625CB@mail.emea.novell.com> <1424705290.27930.161.camel@citrix.com> <54EB4CE7.3040509@linaro.org> <1424707450.27930.191.camel@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail6.bemta5.messagelabs.com ([195.245.231.135]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1YPvcT-00022J-Bt for xen-devel@lists.xenproject.org; Mon, 23 Feb 2015 16:12:29 +0000 Received: by wesw62 with SMTP id w62so19495919wes.12 for ; Mon, 23 Feb 2015 08:12:27 -0800 (PST) In-Reply-To: <1424707450.27930.191.camel@citrix.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Ian Campbell Cc: xen-devel@lists.xenproject.org, stefano.stabellini@citrix.com, tim@xen.org, Jan Beulich , Stefano Stabellini List-Id: xen-devel@lists.xenproject.org On 23/02/15 16:04, Ian Campbell wrote: > On Mon, 2015-02-23 at 15:53 +0000, Julien Grall wrote: >> Hi Ian, >> >> On 23/02/15 15:28, Ian Campbell wrote: >>> On Mon, 2015-02-23 at 09:33 +0000, Jan Beulich wrote: >>>>>>> On 20.02.15 at 17:53, wrote: >>>>> Jan, do you have any feeling for how this is going to play out on x86 >>>>> with the vapic stuff? >>>> >>>> The vapic logic shouldn't require any physdevop involvement, so if >>>> I read right what you propose (not having such a requirement / >>>> connection on ARM) either, I agree that a new domctl should be all >>>> that's needed (if XEN_DOMCTL_{,un}bind_pt_irq can't be re-used). >>> >>> Actually, I think bind_pt_irq with a new PT_IRQ_TYPE_* would be a good >>> option. >>> >>> An ARM SPI is a bit like an ISA IRQ, but not close enough to reuse IMHO >>> (and the datatype would need widening). >> >> We have to think about MSI and other type too... >> >> In any case a DOMCTL is not suitable here because a guest kernel may >> need to map/unmap IRQ too (think about ACPI or device passthrough). > > I don't follow, setting up device passthrough is very much a toolstack > operation, isn't it? Where does the guest kernel get involved? Sorry I meant the DOM0 kernel. Not really. On platform device pass-through there is no way to know the IRQ, so for now the routing is done by the toolstack. But we could decide to implement a driver in DOM0 which will unbind/bind/reset device. In this case it will require to assign/deassign the IRQ from DOM0. There is also the case of MSI. > As for ACPI, I think dom0 propagating ACPI derived platform info to Xen > should be handled differently (at the hypercall interface at least) > separate from passthrough. There is no difference between routing because of ACPI and/or because pass-through. So this should be done the same way. Regards, -- Julien Grall