From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kiszka Subject: Re: Debugging an inconsistent shadow page table Date: Sun, 26 Apr 2009 13:36:22 +0200 Message-ID: <49F44736.6000001@web.de> References: <49F2E79A.6070602@web.de> <49F43846.40807@redhat.com> <49F4416C.4090204@web.de> <20090426112749.GT24095@redhat.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enigB8E4F58D4018D1213E7B5428" Cc: Avi Kivity , kvm-devel To: Gleb Natapov Return-path: Received: from fmmailgate02.web.de ([217.72.192.227]:44104 "EHLO fmmailgate02.web.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750898AbZDZLgg (ORCPT ); Sun, 26 Apr 2009 07:36:36 -0400 In-Reply-To: <20090426112749.GT24095@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enigB8E4F58D4018D1213E7B5428 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Gleb Natapov wrote: > On Sun, Apr 26, 2009 at 01:11:40PM +0200, Jan Kiszka wrote: >> That raise a question for a kvm-mmu newbie like me: >> >> If a page of the qemu process gets pushed around (here likely due to >> fork()->exec(smbd)->COW), how will kvm's shadow table catch up? Via >> MMU_NOTIFIER? >> >> I'm on a 2.6.25 kernel, and that means without CONFIG_MMU_NOTIFIER. So= >> far I assumed that kernels without this feature do not work optimally,= >> but they won't break my guests... >> > Guest memory is not COWed on fork (madvise(MADV_DONTFORK)) Yeah... but that's missing upstream! Will cross-check and then post a fix for qemu. Out of curiosity: What's the mechanism to update the shadow table after swap-out/swap-in? Jan --------------enigB8E4F58D4018D1213E7B5428 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.9 (GNU/Linux) Comment: Using GnuPG with SUSE - http://enigmail.mozdev.org iEYEARECAAYFAkn0R0IACgkQniDOoMHTA+nuVwCfWFO60ncYOLv8omIHSZQnkg4D IPkAmgOAXsobT1LluYrmcQ+NVA9dpBvD =f93z -----END PGP SIGNATURE----- --------------enigB8E4F58D4018D1213E7B5428--