From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kiszka Subject: Re: [kvm-devel] [RFC][PATCH 3/4] kvm-vmx: KVM_EXIT_DEBUG on #BP exceptions Date: Thu, 22 May 2008 15:31:46 +0200 Message-ID: <483575C2.1040303@web.de> References: <482D9198.7040801@web.de> <482DAFFD.8060500@web.de> <4834474B.7030600@qumranet.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig6B317DCD6CBEE064E8C9D01E" Cc: kvm-devel , Hollis Blanchard To: Avi Kivity Return-path: Received: from fmmailgate02.web.de ([217.72.192.227]:41690 "EHLO fmmailgate02.web.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760382AbYEVNeB (ORCPT ); Thu, 22 May 2008 09:34:01 -0400 In-Reply-To: <4834474B.7030600@qumranet.com> Sender: kvm-owner@vger.kernel.org List-ID: This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig6B317DCD6CBEE064E8C9D01E Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Avi Kivity wrote: > Jan Kiszka wrote: >> In order to allow the gdbstub of QEMU to push (soft) breakpoint handli= ng >> completely into the gdb frontend, this patch enables guest exits also >> for #BP exceptions - in case guest debugging was turned on. >> >> Along this enhancement, this patch also fixes the flag manipulation fo= r >> the singlestep mode. >> =20 >=20 > Suppose userspace determines the exception is due to a guest > breakpoint. How does it inject the debug exception? Good question. Is there no "inject exception #XX" mechanism in kvm yet? Will need this, as my current impression is that we better keep track of breakpoints at qemu level to tell guest soft-BPs apart from host injected ones. Would you suggest to add a separate IOCTL for exception injection then? Or should the new guest debug IOCTL contain a flag that signals "inject breakpoint trap" (both for guest soft-BP hits as well as guests already in single step mode)? Jan --------------enig6B317DCD6CBEE064E8C9D01E Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.4-svn0 (GNU/Linux) Comment: Using GnuPG with SUSE - http://enigmail.mozdev.org iD8DBQFINXXCniDOoMHTA+kRAr0VAJ43kqQVv8gdAMBoAcNMr9WyKjBCMACeLFWH hNUJ4EkYAiBwv7gvKyXG16Y= =Lf1R -----END PGP SIGNATURE----- --------------enig6B317DCD6CBEE064E8C9D01E--