From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: [PATCH v3 1/1] Shared memory uio_pci driver Date: Thu, 25 Mar 2010 18:40:52 +0200 Message-ID: <20100325164052.GB16506@redhat.com> References: <1269497376-21903-1-git-send-email-cam@cs.ualberta.ca> <20100325091552.GB11153@redhat.com> <8286e4ee1003250918x659e87ai9e5ca7c68c23a7c3@mail.gmail.com> <4BAB8DE9.9080603@codemonkey.ws> <4BAB900F.5030104@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Anthony Liguori , Cam Macdonell , kvm@vger.kernel.org, qemu-devel@nongnu.org, virtualization@lists.linux-foundation.org To: Avi Kivity Return-path: Received: from mx1.redhat.com ([209.132.183.28]:64613 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752934Ab0CYQpF (ORCPT ); Thu, 25 Mar 2010 12:45:05 -0400 Content-Disposition: inline In-Reply-To: <4BAB900F.5030104@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On Thu, Mar 25, 2010 at 06:32:15PM +0200, Avi Kivity wrote: > On 03/25/2010 06:23 PM, Anthony Liguori wrote: >>> There has been previous discussion of virtio, however while virtio is >>> good for exporting guest memory, it's not ideal for importing memory >>> into a guest. >> >> virtio is a DMA-based API which means that it doesn't assume cache >> coherent shared memory. The PCI transport takes advantage of cache >> coherent shared memory but it's not strictly required. > > Aren't we violating this by not using dma_alloc_coherent() for the queues? I don't see what changing this would buys us though, unless a non-cache coherent architecture implements kvm. TCG runs everything on a single processor so there are no cache coherency issues. > -- > error compiling committee.c: too many arguments to function