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 13:53:06 +0200 Message-ID: <6fb830bb-0241-dd3c-6356-6b9d4ce676ee@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> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="KQg9l9Lwy1vunDtYJCwkA03sqJcVbIv0J" Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-Archive: List-Post: To: pmorel@linux.ibm.com, David Hildenbrand 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 List-ID: This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --KQg9l9Lwy1vunDtYJCwkA03sqJcVbIv0J Content-Type: multipart/mixed; boundary="WRugImPLHTVTnw3U9ddTvarTN6D2cM2Hy"; protected-headers="v1" From: Janosch Frank To: pmorel@linux.ibm.com, David Hildenbrand 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: <6fb830bb-0241-dd3c-6356-6b9d4ce676ee@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> In-Reply-To: --WRugImPLHTVTnw3U9ddTvarTN6D2cM2Hy Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable 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 comment= ? >=20 > 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 >> >> Code makes sense: >> Reviewed-by: Janosch Frank >=20 > Thanks, >=20 > regards, > Pierre >=20 >> >>> >>>> >>>>> >>>>> When using FORMAT2 in the host we do not need to or with >>>>> FORMAT1. >>>>> >>>>> Signed-off-by: Pierre Morel >>>>> --- >>>>> arch/s390/kvm/vsie.c | 6 +++--- >>>>> 1 file changed, 3 insertions(+), 3 deletions(-) >>>>> >>>>> diff --git a/arch/s390/kvm/vsie.c b/arch/s390/kvm/vsie.c >>>>> index 38ea5da..e0e6fbf 100644 >>>>> --- a/arch/s390/kvm/vsie.c >>>>> +++ b/arch/s390/kvm/vsie.c >>>>> @@ -140,7 +140,8 @@ static int prepare_cpuflags(struct kvm_vcpu *vc= pu, struct vsie_page *vsie_page) >>>>> * Create a shadow copy of the crycb block and setup key wrapping= , if >>>>> * requested for guest 3 and enabled for guest 2. >>>>> * >>>>> - * We only accept format-1 (no AP in g2), but convert it into form= at-2 >>>>> + * We accept format-1 or format-2, but we treat it as a format-1 (= no AP in g2), >>>>> + * and we convert it into format-2 in the shadow CRYCB. >>>>> * There is nothing to do for format-0. >>>>> * >>>>> * Returns: - 0 if shadowed or nothing to do >>>>> @@ -179,8 +180,7 @@ static int shadow_crycb(struct kvm_vcpu *vcpu, = struct vsie_page *vsie_page) >>>>> return set_validity_icpt(scb_s, 0x0035U); >>>>> =20 >>>>> scb_s->ecb3 |=3D ecb3_flags; >>>>> - scb_s->crycbd =3D ((__u32)(__u64) &vsie_page->crycb) | CRYCB_FORM= AT1 | >>>>> - CRYCB_FORMAT2; >>>>> + scb_s->crycbd =3D ((__u32)(__u64) &vsie_page->crycb) | CRYCB_FORM= AT2; >>>> >>>> That's purely cosmetic but valid. >>>> >>>>> =20 >>>>> /* xor both blocks in one run */ >>>>> b1 =3D (unsigned long *) vsie_page->crycb.dea_wrapping_key_mask;= >>> >>> Reviewed-by: David Hildenbrand >>> >> >> >=20 >=20 --WRugImPLHTVTnw3U9ddTvarTN6D2cM2Hy-- --KQg9l9Lwy1vunDtYJCwkA03sqJcVbIv0J 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 iQIcBAEBCAAGBQJbfqAiAAoJEBcO/8Q8ZEV5dqMP/inmsp5Fw/ifYd22PYsX6ExS 1O/dToGFGBI/7d09hsmZi7+wWiTbNDR9sIeRFo1cXuwx15aX/XEmwPxmcRlG8xdq J/MJinsjzGdzHvJ6lZPLQuG7So+pv2Rzf84eNjU/T2sua+OaAbt64j7KZZeW+PXP DDz5L8Zi7BgQwBLPmsMUyUBfR8k/7wiN+bM3odgT4SQEYVW7EmZOFuzMCL8ZsGkB WKfoUkuQVtI76I4k/tyLYHFvrya0mgely+ZnMGztEJbt9I7UHm6ztqDBdSSqIAmj 47R0QZjYQ2NMC2DIQpzCvR3TUzhwJV4pXwBlDME8okhiWpbOeeWMRLnHZF1BvOYH hUmJI13oPQ7yXg8bCV/3wqYf3fp4ewFli7hgqrMf/9QDjtdJbeV0tpLyJScz9fAd zAPBtJrVKLySw7J6fwK9+1nbwLBq2/gKPVsvXeuygHUjAzfYiH6tBg1byUNndRq7 x46j4EvcQB5G2hIrKykqqDfSnY+OuTzsm7Gu9OyyoQV/l3nVyCLj+fjRVbkLEIhY y/NBC5jqnu66Kr81GXvstQ82g7JOeK+oexOkSZAPR+KJmUHYHi5jYR7puckoNbOq DUGZlnKUbKSIT6AmSvs8+cWqM6qUCNZqwSg0C5qR+dFsZUAbyiVy8phynZSdmd1T SDamcfcUaJ0lzVvIm5KR =j6sh -----END PGP SIGNATURE----- --KQg9l9Lwy1vunDtYJCwkA03sqJcVbIv0J--