From mboxrd@z Thu Jan 1 00:00:00 1970 From: Keir Fraser Subject: Re: Fwd: [PATCH 0/18] Nested Virtualization: Overview Date: Thu, 15 Apr 2010 15:57:40 +0100 Message-ID: References: <201004151520.31527.Christoph.Egger@amd.com> Mime-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <201004151520.31527.Christoph.Egger@amd.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Christoph Egger , "xen-devel@lists.xensource.com" List-Id: xen-devel@lists.xenproject.org On 15/04/2010 14:20, "Christoph Egger" wrote: > patch 03: change local_event_delivery_* to take vcpu argument. > This prevents spurious xen crashes on guest shutdown/destroy > with nestedhvm enabled. Can you give an example of how this bug manifests? I don't really see how nestedhvm would interact so unexpectedly with this rather pv-oriented subsystem. > patch 04: obsolete gfn_to_mfn_current and remove it. > gfn_to_mfn_current is redundant to > gfn_to_mfn(current->domain, ...) > This patch reduces the size of patch 17. This one (at least -- there may be others) needs an ack from Tim. > patch 05: hvm_set_cr0: Allow guest to switch into paged real mode. > This makes hvmloader boot when we use xen in xen. What if we are not running a nestedhvm guest, or otherwise on a system not supporting paged real mode? Is it wise to remove the check in that case? Even where we *do* support nestedhvm, should all guest writes to CR0 be allowed to bypass that check (Isn't paged real mode architecturally only allowed to be entered via VMRUN)? More generally, I will allow these patches to sit for a week or two to give time for potential reviewers to digest them. Thanks, Keir