From mboxrd@z Thu Jan 1 00:00:00 1970 From: Julien Grall Subject: Re: [PATCH v3 12/13] xen/arm: Add the property "protected-devices" in the hypervisor node Date: Fri, 04 Apr 2014 11:25:03 +0100 Message-ID: <533E887F.9050106@linaro.org> References: <1394552999-14171-1-git-send-email-julien.grall@linaro.org> <1394552999-14171-13-git-send-email-julien.grall@linaro.org> <1395161280.11824.21.camel@kazak.uk.xensource.com> <5328A7E3.3070402@linaro.org> <1395225206.10203.43.camel@kazak.uk.xensource.com> <533DD7C7.8090803@linaro.org> <1396604406.4211.179.camel@kazak.uk.xensource.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 1WW1J3-0003D1-UA for xen-devel@lists.xenproject.org; Fri, 04 Apr 2014 10:25:06 +0000 Received: by mail-we0-f179.google.com with SMTP id x48so3236834wes.10 for ; Fri, 04 Apr 2014 03:25:04 -0700 (PDT) In-Reply-To: <1396604406.4211.179.camel@kazak.uk.xensource.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, tim@xen.org, stefano.stabellini@citrix.com List-Id: xen-devel@lists.xenproject.org On 04/04/2014 10:40 AM, Ian Campbell wrote: > We really need to be able to manage this transition in a compatible way, > that means new kernels working on old hypervisors as well as old kernels > working on new hypervisors (it's obviously fine for this case to bounce > when it doesn't need to). It's not possible because a same platform can have both protected and non-protected devices. The Linux has to know in some way if the DMA has to be program with IPA or PA. The only way is to disable the IOMMU, or don't use partition disk for guest, until the DOM0 will be able to disable swiotlb. -- Julien Grall