On 23.08.2018 10:34, Janosch Frank wrote: > On 23.08.2018 10:01, Pierre Morel wrote: >> On 23/08/2018 09:31, David Hildenbrand wrote: >>> 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 <pmorel@xxxxxxxxxxxxx> >>>>>> --- >>>>>> 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. >> >> The SIE should check the validity of the CRYCB. >> >> However since we do not copy the key masks we do not >> expect any access error on crycb_o >> >> So it is more a philosophical problem, should the >> hypervizor enforce an error here to act as the firmware? > > No it's not philosophical, that's actually regulated in the SIE > documentation for the validity intercepts. > > CRYCB is checked if (any of these is true): ECA.28, CRYCB Format is one, > APXA installed and CRYCB Format field is three. So independent of setting of ECB3 AES/DEA by g2. That's what I wanted to know, thanks :) > > ECB3 AES/DEA bits are handled like the matrix, i.e. they are ANDed over > the different levels. > > If that's still not what David meant to ask, then I must apologize for > my caffeine deprived brain. -- Thanks, David / dhildenb
