From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kiszka Subject: Re: [PATCH] KVM: SVM: Keep intercepting task switching with NPT enabled Date: Tue, 01 Nov 2011 19:22:56 +0100 Message-ID: <4EB03900.6000700@web.de> References: <4E9DA7EF.30804@siemens.com> <20111018163516.GO2198@amd.com> <4E9DB95C.1030105@redhat.com> <20111101111335.GD13244@amd.com> <4EAFF6A5.8050308@web.de> <20111101153019.GH13244@amd.com> <4EB01516.2070402@web.de> <20111101161537.GI13244@amd.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enigED6925F83AB7252AB1BD680F" Cc: Avi Kivity , Marcelo Tosatti , kvm , Gleb Natapov To: "Roedel, Joerg" Return-path: Received: from fmmailgate01.web.de ([217.72.192.221]:50614 "EHLO fmmailgate01.web.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751951Ab1KASX3 (ORCPT ); Tue, 1 Nov 2011 14:23:29 -0400 Received: from moweb001.kundenserver.de (moweb001.kundenserver.de [172.19.20.114]) by fmmailgate01.web.de (Postfix) with ESMTP id 4B3661A2D21DC for ; Tue, 1 Nov 2011 19:23:28 +0100 (CET) In-Reply-To: <20111101161537.GI13244@amd.com> Sender: kvm-owner@vger.kernel.org List-ID: This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enigED6925F83AB7252AB1BD680F Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable On 2011-11-01 17:15, Roedel, Joerg wrote: > On Tue, Nov 01, 2011 at 11:49:42AM -0400, Jan Kiszka wrote: >> On 2011-11-01 16:30, Roedel, Joerg wrote: >>> On Tue, Nov 01, 2011 at 09:39:49AM -0400, Jan Kiszka wrote: >>>>> So SVM does not guarantee that an intercept during a task-switch ca= n be >>>>> restarted. >>>> >>>> Not a bug but still a deficit as it makes hardware-assisted task >>>> switching practically useless, no? >>> >>> Not entirely. For hypervisors that can guarantee that there will be n= o >>> intercept (NPT pre-mapped, no exceptions intercepted) it will still >>> work. >> >> Yes, but that only covers the niche of simple static ones (partitionin= g >> hypervisors). >=20 > No, also a hypervisor that creates the nested page-page on advance fall= s > into this category. Doesn't this means all guest memory has to be backed with host memory? That's what I meant with "static". Jan --------------enigED6925F83AB7252AB1BD680F Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.18 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAk6wOR4ACgkQitSsb3rl5xQKZgCgkkUuaMJRvdBIJAp2Fa077+Sq c6sAnjsJj5Hw35sTKO7/8VrVfdOg50Jp =OFnb -----END PGP SIGNATURE----- --------------enigED6925F83AB7252AB1BD680F--