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? > > 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; > >> >> Code makes sense: >> Reviewed-by: Janosch Frank <frankja@xxxxxxxxxxxxx> > > Thanks, > > regards, > Pierre > >> >>> >>>> >>>>> >>>>> When using FORMAT2 in the host we do not need to or with >>>>> FORMAT1. >>>>> >>>>> Signed-off-by: Pierre Morel <pmorel@xxxxxxxxxxxxx> >>>>> --- >>>>> 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 *vcpu, 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 format-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); >>>>> >>>>> scb_s->ecb3 |= ecb3_flags; >>>>> - scb_s->crycbd = ((__u32)(__u64) &vsie_page->crycb) | CRYCB_FORMAT1 | >>>>> - CRYCB_FORMAT2; >>>>> + scb_s->crycbd = ((__u32)(__u64) &vsie_page->crycb) | CRYCB_FORMAT2; >>>> >>>> That's purely cosmetic but valid. >>>> >>>>> >>>>> /* xor both blocks in one run */ >>>>> b1 = (unsigned long *) vsie_page->crycb.dea_wrapping_key_mask; >>> >>> Reviewed-by: David Hildenbrand <david@xxxxxxxxxx> >>> >> >> > >
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