From mboxrd@z Thu Jan 1 00:00:00 1970 From: Boris Ostrovsky Subject: Re: [PATCH] xen/x86: Adjust stack pointer in xen_sysexit Date: Mon, 16 Nov 2015 15:48:37 -0500 Message-ID: <564A4125.8000603__44003.5796528265$1447707062$gmane$org@oracle.com> References: <1447456706-24347-1-git-send-email-boris.ostrovsky@oracle.com> <56468D24.8030801@oracle.com> <564A0371.2040104@oracle.com> <20151116195906.GB20137@pd.tnic> <20151116202232.GC20137@pd.tnic> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20151116202232.GC20137@pd.tnic> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Borislav Petkov , Andy Lutomirski , "H. Peter Anvin" Cc: David Vrabel , "linux-kernel@vger.kernel.org" , xen-devel List-Id: xen-devel@lists.xenproject.org On 11/16/2015 03:22 PM, Borislav Petkov wrote: > On Mon, Nov 16, 2015 at 12:11:11PM -0800, Andy Lutomirski wrote: > >> Are there really multiple feature bits for this stuff? I'd like to >> imagine that the entry code is all either Xen PV or native/PVH/PVHVM >> -- i.e. I assumed that PVH works like native for all entries. Almost. For PVH we will have a small stub to set up bootparams and such but then we jump to startup_{32|64} code. > I just reacted to Boris' statement: > > "We don't currently have a Xen-specific CPU feature. We could, in > principle, add it but we can't replace all of current paravirt patching > with a single feature since PVH guests use a subset of existing pv ops > (and in the future it may become even more fine-grained)." Actually, nevermind this --- I was thinking about APIC ops and they are not pv ops. Note though that there are other users of pv ops --- lguest and looks like KVM (for one op) use them too. -boris