From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Hildenbrand Subject: Re: [PATCH v2 5/5] KVM: s390: vsie: Do the CRYCB validation first Date: Thu, 23 Aug 2018 09:31:32 +0200 Message-ID: <18c65e67-c5e6-9c2f-e7ab-962376427369@redhat.com> References: <1534956717-14087-1-git-send-email-pmorel@linux.ibm.com> <1534956717-14087-6-git-send-email-pmorel@linux.ibm.com> <01047750-cdc6-b462-1e4f-c79c1036ab94@linux.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <01047750-cdc6-b462-1e4f-c79c1036ab94@linux.ibm.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-Archive: List-Post: To: pmorel@linux.ibm.com 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 List-ID: On 23.08.2018 09:17, Pierre Morel wrote: > On 22/08/2018 19:15, David Hildenbrand wrote: >> On 22.08.2018 18:51, Pierre Morel wrote: >>> When entering the SIE the CRYCB validation better >>> be done independently of the instruction's >>> availability. >>> >>> Signed-off-by: Pierre Morel >>> --- >>> arch/s390/kvm/vsie.c | 11 ++++++----- >>> 1 file changed, 6 insertions(+), 5 deletions(-) >>> >>> diff --git a/arch/s390/kvm/vsie.c b/arch/s390/kvm/vsie.c >>> index 7ee4329..fca25aa 100644 >>> --- a/arch/s390/kvm/vsie.c >>> +++ b/arch/s390/kvm/vsie.c >>> @@ -164,17 +164,18 @@ static int shadow_crycb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) >>> /* format-1 is supported with message-security-assist extension 3 */ >>> if (!test_kvm_facility(vcpu->kvm, 76)) >>> return 0; >>> - /* we may only allow it if enabled for guest 2 */ >>> - ecb3_flags = scb_o->ecb3 & vcpu->arch.sie_block->ecb3 & >>> - (ECB3_AES | ECB3_DEA); >>> - if (!ecb3_flags) >>> - return 0; >>> >>> if ((crycb_addr & PAGE_MASK) != ((crycb_addr + 128) & PAGE_MASK)) >>> return set_validity_icpt(scb_s, 0x003CU); >>> if (!crycb_addr) >>> return set_validity_icpt(scb_s, 0x0039U); >>> >>> + /* we may only allow it if enabled for guest 2 */ >>> + ecb3_flags = scb_o->ecb3 & vcpu->arch.sie_block->ecb3 & >>> + (ECB3_AES | ECB3_DEA); >>> + if (!ecb3_flags) >>> + return 0; >>> + >>> /* copy only the wrapping keys */ >>> if (read_guest_real(vcpu, crycb_addr + 72, >>> vsie_page->crycb.dea_wrapping_key_mask, 56)) >>> >> >> That makes sense, especially if ECB3_AES is used but effectively turned >> off by us. >> >> What is the expected behavior if ECB3_AES | ECB3_DEA are not set by g2 >> for g3? >> > > The use of functions PCKMO-Encrypt-DEA/AES induce a specification error. > > However other MSA3 function will continue to be usable. No, I meant which checks should be performed here. > > Regards, > Pierre > -- Thanks, David / dhildenb