From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759045AbZEFNSA (ORCPT ); Wed, 6 May 2009 09:18:00 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753655AbZEFNRt (ORCPT ); Wed, 6 May 2009 09:17:49 -0400 Received: from victor.provo.novell.com ([137.65.250.26]:43571 "EHLO victor.provo.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752856AbZEFNRr (ORCPT ); Wed, 6 May 2009 09:17:47 -0400 Message-ID: <4A018DF2.6010301@novell.com> Date: Wed, 06 May 2009 09:17:38 -0400 From: Gregory Haskins User-Agent: Thunderbird 2.0.0.21 (Macintosh/20090302) MIME-Version: 1.0 To: Chris Wright CC: Gregory Haskins , Avi Kivity , linux-kernel@vger.kernel.org, kvm@vger.kernel.org Subject: Re: [RFC PATCH 0/3] generic hypercall support References: <20090505132005.19891.78436.stgit@dev.haskins.net> <4A0040C0.1080102@redhat.com> <4A0041BA.6060106@novell.com> <4A004676.4050604@redhat.com> <4A0049CD.3080003@gmail.com> <20090505231718.GT3036@sequoia.sous-sol.org> <4A010927.6020207@novell.com> <20090506072212.GV3036@sequoia.sous-sol.org> In-Reply-To: <20090506072212.GV3036@sequoia.sous-sol.org> X-Enigmail-Version: 0.95.7 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig03409896EE9ACA4014921DE9" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig03409896EE9ACA4014921DE9 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Chris Wright wrote: > * Gregory Haskins (ghaskins@novell.com) wrote: > =20 >> Chris Wright wrote: >> =20 >>> But a free-form hypercall(unsigned long nr, unsigned long *args, size= _t count) >>> means hypercall number and arg list must be the same in order for cod= e >>> to call hypercall() in a hypervisor agnostic way. >>> =20 >> Yes, and that is exactly the intention. I think its perhaps the point= >> you are missing. >> =20 > > Yes, I was reading this as purely any hypercall, but it seems a bit > more like: > pv_io_ops->iomap() > pv_io_ops->ioread() > pv_io_ops->iowrite() > =20 Right. > > =20 >> Today, there is no equivelent of a platform agnostic "iowrite32()" for= >> hypercalls so the driver would look like the pseudocode above except >> substitute with kvm_hypercall(), lguest_hypercall(), etc. The proposa= l >> is to allow the hypervisor to assign a dynamic vector to resources in >> the backend and convey this vector to the guest (such as in PCI >> config-space as mentioned in my example use-case). The provides the >> "address negotiation" function that would normally be done for somethi= ng >> like a pio port-address. The hypervisor agnostic driver can then use= >> this globally recognized address-token coupled with other device-priva= te >> ABI parameters to communicate with the device. This can all occur >> without the core hypervisor needing to understand the details beyond t= he >> addressing. >> =20 > > VF drivers can also have this issue (and typically use mmio). > I at least have a better idea what your proposal is, thanks for > explanation. Are you able to demonstrate concrete benefit with it yet > (improved latency numbers for example)? > =20 I had a test-harness/numbers for this kind of thing, but its a bit crufty since its from ~1.5 years ago. I will dig it up, update it, and generate/post new numbers. Thanks Chris, -Greg --------------enig03409896EE9ACA4014921DE9 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG/MacGPG2 v2.0.11 (Darwin) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iEYEARECAAYFAkoBjfIACgkQlOSOBdgZUxlBkACfa34bmCmX02A6/wjjyOAd93Pk m9kAnAjSZv8wpWi6TsI9te8qiy7nym4s =bFzj -----END PGP SIGNATURE----- --------------enig03409896EE9ACA4014921DE9--