From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:6554 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727584AbfKSKJZ (ORCPT ); Tue, 19 Nov 2019 05:09:25 -0500 Received: from pps.filterd (m0098420.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id xAJA9KHo083457 for ; Tue, 19 Nov 2019 05:09:23 -0500 Received: from e06smtp02.uk.ibm.com (e06smtp02.uk.ibm.com [195.75.94.98]) by mx0b-001b2d01.pphosted.com with ESMTP id 2way6avtcm-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Tue, 19 Nov 2019 05:09:22 -0500 Received: from localhost by e06smtp02.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 19 Nov 2019 10:08:40 -0000 Subject: Re: [RFC 23/37] KVM: s390: protvirt: Make sure prefix is always protected References: <20191024114059.102802-1-frankja@linux.ibm.com> <20191024114059.102802-24-frankja@linux.ibm.com> <20191118173942.0252b731.cohuck@redhat.com> <20191119104528.3f3c2620.cohuck@redhat.com> From: Janosch Frank Date: Tue, 19 Nov 2019 11:08:36 +0100 MIME-Version: 1.0 In-Reply-To: <20191119104528.3f3c2620.cohuck@redhat.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="iw8GvkYJ1VK8Sh1gF4dFKK03mUZa2LDZd" Message-Id: Sender: linux-s390-owner@vger.kernel.org List-ID: To: Cornelia Huck Cc: kvm@vger.kernel.org, linux-s390@vger.kernel.org, thuth@redhat.com, david@redhat.com, borntraeger@de.ibm.com, imbrenda@linux.ibm.com, mihajlov@linux.ibm.com, mimu@linux.ibm.com, gor@linux.ibm.com This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --iw8GvkYJ1VK8Sh1gF4dFKK03mUZa2LDZd Content-Type: multipart/mixed; boundary="hUTNCY5HXLYf7wRdxkG0joeKNNVWmRRf4" --hUTNCY5HXLYf7wRdxkG0joeKNNVWmRRf4 Content-Type: text/plain; charset=windows-1252 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 11/19/19 10:45 AM, Cornelia Huck wrote: > On Tue, 19 Nov 2019 09:11:11 +0100 [...] >>> >>> So, what happens if we have an error other than -EEXIST (which >>> presumably means that we already protected it) here? The page is not >>> protected, and further accesses will get an error? (Another question:= >>> what can actually go wrong here?) =20 >> >> If KVM or QEMU write into a lowcore, we will fail the integrity check = on >> import and this cpu will never run again. >=20 > From the guest's POV, is that similar to a cpu going into xstop? Not really, I'm wondering what happens, if we try to send a restart to such a cpu. > =20 >> In retrospect a warn_on_once might be the wrong error handling here. >> >>> =20 >>>> + } >>>> if (rc) { >>>> kvm_make_request(KVM_REQ_MMU_RELOAD, vcpu); >>>> return rc; =20 >>> =20 >> >> >=20 --hUTNCY5HXLYf7wRdxkG0joeKNNVWmRRf4-- --iw8GvkYJ1VK8Sh1gF4dFKK03mUZa2LDZd Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEwGNS88vfc9+v45Yq41TmuOI4ufgFAl3TvyQACgkQ41TmuOI4 ufhHjw/7BaXIre2ND8lvliazh0c4CiNaTTdBI2DHm75ayM4Nsen03uqp4J54yHMn sRyax174VJpGJeK8ds0f8azzdSZdxhJC+k5lDDK5vVbwskyCS5F9cynsiRVY/lKn z/SVHRvjfz0nRFgZAdDsBtOBSTJtIhL3h6fqFZEfaoQX6eYjYdC9HhJ2+jN+IUWx NxgebOmya6Tej7M6NCpUiEwVg1L1dluvzq4wi1523YJ9qaTNoo29SJ/YfFP6z8/l ov52EnofMwyTO726D59GaLhPItDme347IeZWL81eSW4EbCCb3fG/crkkjew/HlsZ 02B29rEfQFybQDhKi1cu1zI+Wx9LpVfknVgA4ZsOmohzGL5pl81HTa8/dB51WBW/ IjKeAyPY3z9u23IbgHgS8ecxlER7n14NdcaQ75GLv/9Gq1g7hUHA4yAmb+HH7e8Z fzRgxWfCuXpHtFefvOmhA7FuVxC8zMVjdeCXixzpRlWhvRDgP50zI9ImX8U7wr8x VnQLn6aTSIxf9Kp1+9zPsZFmaYRFa5fUeMpZxheIL4yKB3vqrsqI+/DlMuLZcVe8 IAFDMIHT8JVu144acLeeQSWtXNJqOOo2C9hPeAXS2cDq5JimPAw9l5oUd2a4Rv4R rURVuaIQKiEBLHXSIOQF89DX69cEZ4Iae1xVzRtDfra14BkvNGA= =UVRR -----END PGP SIGNATURE----- --iw8GvkYJ1VK8Sh1gF4dFKK03mUZa2LDZd--