From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755760AbdLTRdV (ORCPT ); Wed, 20 Dec 2017 12:33:21 -0500 Received: from mx2.suse.de ([195.135.220.15]:45389 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754619AbdLTRdU (ORCPT ); Wed, 20 Dec 2017 12:33:20 -0500 Subject: Re: [PATCH v3] xen/balloon: Mark unallocated host memory as UNUSABLE To: Boris Ostrovsky , xen-devel@lists.xen.org, linux-kernel@vger.kernel.org Cc: helgaas@kernel.org, christian.koenig@amd.com, JBeulich@suse.com References: <1513778746-6155-1-git-send-email-boris.ostrovsky@oracle.com> From: Juergen Gross Message-ID: <14100e87-ba75-3ebd-e39d-f1df2b298c8c@suse.com> Date: Wed, 20 Dec 2017 18:33:17 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.5.0 MIME-Version: 1.0 In-Reply-To: <1513778746-6155-1-git-send-email-boris.ostrovsky@oracle.com> Content-Type: text/plain; charset=utf-8 Content-Language: de-DE Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 20/12/17 15:05, Boris Ostrovsky wrote: > Commit f5775e0b6116 ("x86/xen: discard RAM regions above the maximum > reservation") left host memory not assigned to dom0 as available for > memory hotplug. > > Unfortunately this also meant that those regions could be used by > others. Specifically, commit fa564ad96366 ("x86/PCI: Enable a 64bit BAR > on AMD Family 15h (Models 00-1f, 30-3f, 60-7f)") may try to map those > addresses as MMIO. > > To prevent this mark unallocated host memory as E820_TYPE_UNUSABLE (thus > effectively reverting f5775e0b6116) and keep track of that region as > a hostmem resource that can be used for the hotplug. > > Signed-off-by: Boris Ostrovsky Reviewed-by: Juergen Gross Juergen