From mboxrd@z Thu Jan 1 00:00:00 1970 From: Amit Shah Subject: Re: [Alacrityvm-devel] [PATCH v2 2/4] KVM: introduce "xinterface" API for external interaction with guests Date: Wed, 7 Oct 2009 10:40:47 +0530 Message-ID: <20091007051047.GA24176@amit-x200.redhat.com> References: <20091002201159.4014.33268.stgit@dev.haskins.net> <20091002201927.4014.29432.stgit@dev.haskins.net> <4AC8780D.1060800@redhat.com> <4ACA87D7.1080206@gmail.com> <4ACB0F3C.1000705@redhat.com> <4ACB46AD.8010405@gmail.com> <4ACB6E21.8010109@redhat.com> <4ACB771E.8050404@gmail.com> <20091006181859.GD6386@ovro.caltech.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Gregory Haskins , Avi Kivity , David Howells , Gregory Haskins , linux-kernel@vger.kernel.org, kvm@vger.kernel.org, "alacrityvm-devel@lists.sourceforge.net" To: "Ira W. Snyder" Return-path: Content-Disposition: inline In-Reply-To: <20091006181859.GD6386@ovro.caltech.edu> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On (Tue) Oct 06 2009 [11:18:59], Ira W. Snyder wrote: > > The limitation I have is that memory made available from the host system > (PCI card) as PCI BAR1 must not be migrated around in memory. I can only > change the address decoding to hit a specific physical address. AFAIK, > this means it cannot be userspace memory (since the underlying physical > page could change, or it could be in swap), and must be allocated with > something like __get_free_pages() or dma_alloc_coherent(). If the dma area is just one page in size, that page can be pinned by the host (via a hypercall by the guest). If it's more, there is a reserve-ram patch by Andrea. That'll reserve some RAM area for the guest that's 1-1 mapped in the host address space. There was a patch posted on the list sometime back. Amit