From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by ozlabs.org (Postfix) with ESMTP id 421A5B6F71 for ; Sun, 28 Aug 2011 23:14:45 +1000 (EST) Message-ID: <4E5A3F18.7050903@redhat.com> Date: Sun, 28 Aug 2011 16:14:00 +0300 From: Avi Kivity MIME-Version: 1.0 To: "Roedel, Joerg" Subject: Re: kvm PCI assignment & VFIO ramblings References: <1313859105.6866.192.camel@x201.home> <20110822172508.GJ2079@amd.com> <1314040622.6866.268.camel@x201.home> <20110823131441.GN2079@amd.com> <1314119311.2859.59.camel@bling.home> <20110824085213.GB2079@amd.com> <1314198467.2859.192.camel@bling.home> <20110825123146.GD1923@amd.com> <20110826042423.GF2308@yookeroo.fritz.box> <20110826092440.GO1923@amd.com> In-Reply-To: <20110826092440.GO1923@amd.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Cc: Alex Williamson , Alexey Kardashevskiy , "kvm@vger.kernel.org" , Paul Mackerras , "linux-pci@vger.kernel.org" , qemu-devel , Alexander Graf , chrisw , iommu , Anthony Liguori , linuxppc-dev , "benve@cisco.com" List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 08/26/2011 12:24 PM, Roedel, Joerg wrote: > > > > As I see it there are two options: (a) make subsequent accesses from > > userspace or the guest result in either a SIGBUS that userspace must > > either deal with or die, or (b) replace the mapping with a dummy RO > > mapping containing 0xff, with any trapped writes emulated as nops. > > The biggest problem with this approach is that it has to happen in the > context of the given process. Linux can't really modify an mm which > which belong to another context in a safe way. > Is use_mm() insufficient? -- error compiling committee.c: too many arguments to function