From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH 1/1] direct mmio for passthrough - kernel part Date: Tue, 01 Apr 2008 16:30:00 +0300 Message-ID: <47F238D8.7040608@qumranet.com> References: <1207050734-13166-1-git-send-email-benami@il.ibm.com> <1207050734-13166-2-git-send-email-benami@il.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel@lists.sourceforge.net, andrea@qumranet.com, allen.m.kay@intel.com To: benami@il.ibm.com Return-path: In-Reply-To: <1207050734-13166-2-git-send-email-benami@il.ibm.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces@lists.sourceforge.net Errors-To: kvm-devel-bounces@lists.sourceforge.net List-Id: kvm.vger.kernel.org benami@il.ibm.com wrote: > From: Ben-Ami Yassour > > Enable a guest to access a device's memory mapped I/O regions directly. > Userspace sends the mmio regions that the guest can access. On the first > page fault for an access to an mmio address the host translates the gva to hpa, > and updates the sptes. > > Can you explain why you're not using the regular memory slot mechanism? i.e. have userspace mmap(/dev/mem) and create a memslot containing that at the appropriate guest physical address? There are some issues with refcounting, but Andrea has some tricks to deal with that. -- Any sufficiently difficult bug is indistinguishable from a feature. ------------------------------------------------------------------------- Check out the new SourceForge.net Marketplace. It's the best place to buy or sell services for just about anything Open Source. http://ad.doubleclick.net/clk;164216239;13503038;w?http://sf.net/marketplace