From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Hildenbrand Subject: Re: [PATCH v2 2/5] KVM: s390: vsie: Only accept FORMAT1 CRYCB for guest2 Date: Wed, 22 Aug 2018 18:55:46 +0200 Message-ID: References: <1534956717-14087-1-git-send-email-pmorel@linux.ibm.com> <1534956717-14087-3-git-send-email-pmorel@linux.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Cc: linux-kernel@vger.kernel.org, cohuck@redhat.com, linux-s390@vger.kernel.org, kvm@vger.kernel.org, frankja@linux.ibm.com, akrowiak@linux.ibm.com, borntraeger@de.ibm.com, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com To: Pierre Morel Return-path: In-Reply-To: <1534956717-14087-3-git-send-email-pmorel@linux.ibm.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On 22.08.2018 18:51, Pierre Morel wrote: > As the comment above the function suggested the shadowing > of the guest2 CRYCB can only accept a format 1 since > AP instructions are not supported in the guest. > > Let's modify the check which allowed to accept a format 2 too. As the bit is ignored without AP/APXA, it is perfectly valid to accept a format 2, we just have to interpret it as format 1 (which is what we do) What am I missing? > > Signed-off-by: Pierre Morel > --- > arch/s390/kvm/vsie.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/arch/s390/kvm/vsie.c b/arch/s390/kvm/vsie.c > index 12b9707..56a9d47 100644 > --- a/arch/s390/kvm/vsie.c > +++ b/arch/s390/kvm/vsie.c > @@ -156,7 +156,9 @@ static int shadow_crycb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) > u8 ecb3_flags; > > scb_s->crycbd = 0; > - if (!(crycbd_o & vcpu->arch.sie_block->crycbd & CRYCB_FORMAT1)) > + if (!(crycbd_o == CRYCB_FORMAT1)) > + return 0; huh, this looks very broken. The address is still in there. > + if (!(vcpu->arch.sie_block->crycbd & CRYCB_FORMAT1)) > return 0; > /* format-1 is supported with message-security-assist extension 3 */ > if (!test_kvm_facility(vcpu->kvm, 76)) > -- Thanks, David / dhildenb