From mboxrd@z Thu Jan  1 00:00:00 1970
From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Subject: Re: [PATCH] xen/x86: Adjust stack pointer in xen_sysexit
Date: Mon, 16 Nov 2015 16:03:14 -0500
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To: Andy Lutomirski <luto@amacapital.net>, Joao Martins <joao.m.martins@oracle.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, xen-devel <xen-devel@lists.xen.org>, Borislav Petkov <bp@alien8.de>, David Vrabel <david.vrabel@citrix.com>, "H. Peter Anvin" <hpa@zytor.com>, Boris Ostrovsky <boris.ostrovsky@oracle.com>
List-Id: xen-devel@lists.xenproject.org

On Mon, Nov 16, 2015 at 12:50:19PM -0800, Andy Lutomirski wrote:
> On Mon, Nov 16, 2015 at 12:48 PM, Boris Ostrovsky
> <boris.ostrovsky@oracle.com> wrote:
> > 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.
> >
> 
> Honestly, I think we should just delete lguest some time soon.  And
> KVM uses this stuff so lightly that we shouldn't need all of the pvop
> stuff.  (In fact, I'm slowly working on removing KVM_GUEST's
> dependency on PARAVIRT.)

Even for the pvclock?

(sorry for stealing this thread on this subject).