From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755959AbcJNTvw (ORCPT ); Fri, 14 Oct 2016 15:51:52 -0400 Received: from userp1040.oracle.com ([156.151.31.81]:24439 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751425AbcJNTvp (ORCPT ); Fri, 14 Oct 2016 15:51:45 -0400 Date: Fri, 14 Oct 2016 15:51:34 -0400 From: Konrad Rzeszutek Wilk To: Boris Ostrovsky Cc: david.vrabel@citrix.com, JGross@suse.com, xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org, roger.pau@citrix.com Subject: Re: [Xen-devel] [PATCH 6/8] xen/pvh: Initialize grant table for PVH guests Message-ID: <20161014195134.GA22782@char.us.oracle.com> References: <1476468318-24422-1-git-send-email-boris.ostrovsky@oracle.com> <1476468318-24422-7-git-send-email-boris.ostrovsky@oracle.com> <20161014191923.GD16777@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.6.2 (2016-07-01) X-Source-IP: aserv0021.oracle.com [141.146.126.233] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Oct 14, 2016 at 03:43:19PM -0400, Boris Ostrovsky wrote: > On 10/14/2016 03:19 PM, Konrad Rzeszutek Wilk wrote: > > On Fri, Oct 14, 2016 at 02:05:16PM -0400, Boris Ostrovsky wrote: > > > > Perhaps add in here: > > > > PVH is like PV in that there are no PCI devices - which HVM > > code would piggyback on to find the Xen PCI platform device and > > use its MMIO space to stash the grants in. > > > > For PVH we balloon out memory and stash the grants in there. > > > > (Which begs the next question - where and when do we balloon out the > > normal memory back in?) > > Are you saying that we should get back memory that we gave to grant tables? Yes. In pure HVM that area is MMIO - which hvmloader has balloonned out. The hvmloader then balloons that number of pages back at the end of guest memory (after 4GB).