From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=33640 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1PaOPJ-0002Ri-JS for qemu-devel@nongnu.org; Wed, 05 Jan 2011 03:07:46 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1PaOPJ-0006Ls-Di for qemu-devel@nongnu.org; Wed, 05 Jan 2011 03:07:46 -0500 Received: from fmmailgate01.web.de ([217.72.192.221]:40670) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1PaOPJ-0006Lm-1T for qemu-devel@nongnu.org; Wed, 05 Jan 2011 03:07:45 -0500 Message-ID: <4D2426C8.6080402@web.de> Date: Wed, 05 Jan 2011 09:07:36 +0100 From: Jan Kiszka MIME-Version: 1.0 References: <2c5efab40d7088353c5147c41fb13b44a944679c.1294129949.git.jan.kiszka@web.de> <1294209751.22308.337.camel@yhuang-dev> In-Reply-To: <1294209751.22308.337.camel@yhuang-dev> Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig5101076DADC211BEEC5102DF" Sender: jan.kiszka@web.de Subject: [Qemu-devel] Re: [PATCH v3 12/21] kvm: x86: Drop MCE MSRs write back restrictions List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Huang Ying Cc: Marcelo Tosatti , Avi Kivity , "kvm@vger.kernel.org" , "qemu-devel@nongnu.org" This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig5101076DADC211BEEC5102DF Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Am 05.01.2011 07:42, Huang Ying wrote: > On Tue, 2011-01-04 at 16:32 +0800, Jan Kiszka wrote: >> From: Jan Kiszka >> >> There is no need to restrict writing back MCE MSRs to reset or full >> state updates as setting their values has no side effects. >=20 > Sorry for late. Don't worry. >=20 > The MCE MSRs contents is sticky for warm reset except MCG_STATUS, so > their content should be kept. And the following sequence may set > uncorrected value in MCE registers. >=20 > savevm -> loadvm -> (OS clear MCE registers) -> reset -> (MCE registers= > has new (uncorrected) value) Sorry, I can't follow. Unless I miss some subtle detail, the question is not when we transfer the mcg_* CPUState fields to the kernel, but when and how we manipulate them in user space, e.g. on reset. Where are those fields touched incorrectly between get and put msrs so that we cannot write them back? Jan --------------enig5101076DADC211BEEC5102DF Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.15 (GNU/Linux) Comment: Using GnuPG with SUSE - http://enigmail.mozdev.org/ iEYEARECAAYFAk0kJssACgkQitSsb3rl5xQfdACfX3TDRN2Nw1KZafHJxsHgOp8Z 0EUAoK6LhJyXq0osv/vxpPGL8iDJyaxV =8Cmp -----END PGP SIGNATURE----- --------------enig5101076DADC211BEEC5102DF--