From mboxrd@z Thu Jan 1 00:00:00 1970 From: Janosch Frank Subject: Re: [PATCH v3 3/3] KVM: s390: vsie: Make use of CRYCB FORMAT2 clear Date: Thu, 23 Aug 2018 14:11:00 +0200 Message-ID: <91ccca7d-2c17-15ce-9450-439bcf797b9d@linux.ibm.com> References: <1535019956-23539-1-git-send-email-pmorel@linux.ibm.com> <1535019956-23539-4-git-send-email-pmorel@linux.ibm.com> <912d013c-c925-fb3e-ed1d-2d778a60c189@linux.ibm.com> <58427761-072c-e420-a881-4decbe9088bb@linux.ibm.com> <6fb830bb-0241-dd3c-6356-6b9d4ce676ee@linux.ibm.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="MW1CpoAT4Q1oK77EUmv5jn1LEIM13W3K7" Cc: linux-kernel@vger.kernel.org, cohuck@redhat.com, linux-s390@vger.kernel.org, kvm@vger.kernel.org, akrowiak@linux.ibm.com, borntraeger@de.ibm.com, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com To: David Hildenbrand , pmorel@linux.ibm.com Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --MW1CpoAT4Q1oK77EUmv5jn1LEIM13W3K7 Content-Type: multipart/mixed; boundary="zPvFN7ypImUmEk1vUgiJV6bY8Bdf0jcrZ"; protected-headers="v1" From: Janosch Frank To: David Hildenbrand , pmorel@linux.ibm.com Cc: linux-kernel@vger.kernel.org, cohuck@redhat.com, linux-s390@vger.kernel.org, kvm@vger.kernel.org, akrowiak@linux.ibm.com, borntraeger@de.ibm.com, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com Message-ID: <91ccca7d-2c17-15ce-9450-439bcf797b9d@linux.ibm.com> Subject: Re: [PATCH v3 3/3] KVM: s390: vsie: Make use of CRYCB FORMAT2 clear References: <1535019956-23539-1-git-send-email-pmorel@linux.ibm.com> <1535019956-23539-4-git-send-email-pmorel@linux.ibm.com> <912d013c-c925-fb3e-ed1d-2d778a60c189@linux.ibm.com> <58427761-072c-e420-a881-4decbe9088bb@linux.ibm.com> <6fb830bb-0241-dd3c-6356-6b9d4ce676ee@linux.ibm.com> In-Reply-To: --zPvFN7ypImUmEk1vUgiJV6bY8Bdf0jcrZ Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 8/23/18 2:03 PM, David Hildenbrand wrote: > On 23.08.2018 13:53, Janosch Frank wrote: >> On 8/23/18 1:47 PM, Pierre Morel wrote: >>> On 23/08/2018 13:33, Janosch Frank wrote: >>>> On 8/23/18 1:21 PM, David Hildenbrand wrote: >>>>> On 23.08.2018 13:05, Janosch Frank wrote: >>>>>> On 8/23/18 12:25 PM, Pierre Morel wrote: >>>>>>> The comment preceding the shadow_crycb function is >>>>>>> misleading, we effectively accept FORMAT2 CRYCB in the >>>>>>> guest. >>>>>> >>>>>> I beg to differ: >>>>>> >>>>>> if (!(crycbd_o & vcpu->arch.sie_block->crycbd & CRYCB_FORMAT1)) >>>>>> return 0; >>>>> >>>>> FORMAT2 includes bit FORMAT1 (backwards compatible) >>>> >>>> Right, this check is very misleading because of the constant, we >>>> effectively test against Format 0 and Format 2. >>>> >>>> Can we make this clearer by explicitly ANDing 0x01 or adding a comme= nt? >>> >>> yes, done, I modified the comment in front of the function. >> >> Which is not what I want, what I want is: >> >> /* CRYCB_FORMAT2 includes the bit for CRYCB_FORMAT1, so we allow both >> formats here */ >> if (!(crycbd_o & vcpu->arch.sie_block->crycbd & CRYCB_FORMAT1)) >> return 0; >=20 > While it's not wrong, it is also not required. And it might soon be > obsolete again (with APXA, as you said, there we always have to check).= >=20 > But I'll leave that to you >=20 I have not checked the vfio-ap patches, Pierre just told me that it goes away in a few weeks anyway, so let's leave it out. --zPvFN7ypImUmEk1vUgiJV6bY8Bdf0jcrZ-- --MW1CpoAT4Q1oK77EUmv5jn1LEIM13W3K7 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 iQIcBAEBCAAGBQJbfqRUAAoJEBcO/8Q8ZEV5D9QP/j6BQnrF7UzdDmWWIjNY2LAo wJV/x6pXOu7Cx/UjUOpAoBQGLysuLvnmH8ORyLl1uS85wj8xvovqXns2w0ze8rIt NWzljAmpIchYNAWxb8jPtgRkKNq/As/yhAjF7BZoXMgW0KPvPEECS5pt0v2h3rKv GISF9lP1iCZI0QbrelFCYqeKNSsXi+YYM7eZGfec2Qe94u10/skzJectIaE87aGb Vt50Q2MmldABdCOjVPudKVm+OIoq4kT9Slu/MkHBunSJOKJGAbPTROpLsWvmNiHX JxnwKOfjsQMIo7yJJz9b3vg8wOs5Rcw9xl3qIWPLjF4UddUMnnHcXO/tP0SS3OsV vXIs+zZ/sjlxNgXIryNNTaNxvmFUrGAGFCFR66njWYc6d9G4COdTMhFlKOFPIh9O R/0LHDox+I00AGrrMzsEYw++MF5VCbKiN6xYIHUehMTkxR9U/VAEpO57v8qV/Yyn F2XpuIsy3rrMsZpmSis01Z5iuPI9jSUr6uoPj5sQ6w+a5Wh8VpESXtzdN3HkzA9p fl8POs5TSOENleEKuiIrCpKWZFxTAuaNEbohP1h7WLkENwCbFhY0z/8gN2dXy1oX uq8mWXP/Q7YjzLRJAecLd3gH0g703su4RMDv7gSx8z7dUNXOpS6bNKzL2zZpiO30 KaqIEnKREMtV9vG/qVEo =I4i7 -----END PGP SIGNATURE----- --MW1CpoAT4Q1oK77EUmv5jn1LEIM13W3K7--