Re: [PATCH] KVM: s390: vsie: Do not shadow CRYCB when no AP and no keys

[Pierre Morel]

On 26/04/2019 11:04, David Hildenbrand wrote:

On 26.04.19 10:56, Pierre Morel wrote:

When the guest do not have AP instructions nor Key management
we should return without shadowing the CRYCB.

We did not check correctly in the past.

Fixes: b10bd9a256ae ("s390: vsie: Use effective CRYCBD.31 to check CRYCBD
validity")

We should really try to pay more attention, commit b10bd9a256ae already
was supposed to fix 6ee74098201b.

yes, sorry for that.

Unfortunately, I don't have access to documentation and can't verify.

Acked-by: David Hildenbrand <da...@redhat.com>

Thanks

Fixes: 6ee74098201b ("KVM: s390: vsie: allow CRYCB FORMAT-0")

Signed-off-by: Pierre Morel <pmo...@linux.ibm.com>
Reported-by: Christian Borntraeger <borntrae...@de.ibm.com>
---
  arch/s390/kvm/vsie.c | 6 ++++--
  1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/s390/kvm/vsie.c b/arch/s390/kvm/vsie.c
index c6983d9..ac411e9 100644
--- a/arch/s390/kvm/vsie.c
+++ b/arch/s390/kvm/vsie.c
@@ -290,6 +290,7 @@ static int shadow_crycb(struct kvm_vcpu *vcpu, struct 
vsie_page *vsie_page)
        u8 ecb3_flags;
        u32 ecd_flags;
        int apie_h;
+       int apie_s;
        int key_msk = test_kvm_facility(vcpu->kvm, 76);
        int fmt_o = crycbd_o & CRYCB_FORMAT_MASK;
        int fmt_h = vcpu->arch.sie_block->crycbd & CRYCB_FORMAT_MASK;
@@ -298,7 +299,8 @@ static int shadow_crycb(struct kvm_vcpu *vcpu, struct 
vsie_page *vsie_page)
        scb_s->crycbd = 0;

apie_h = vcpu->arch.sie_block->eca & ECA_APIE;

-       if (!apie_h && (!key_msk || fmt_o == CRYCB_FORMAT0))
+       apie_s = apie_h & scb_o->eca;
+       if (!apie_s && (!key_msk || (fmt_o == CRYCB_FORMAT0)))
                return 0;

if (!crycb_addr)

@@ -309,7 +311,7 @@ static int shadow_crycb(struct kvm_vcpu *vcpu, struct 
vsie_page *vsie_page)
                    ((crycb_addr + 128) & PAGE_MASK))
                        return set_validity_icpt(scb_s, 0x003CU);

- if (apie_h && (scb_o->eca & ECA_APIE)) {

+       if (apie_s) {
                ret = setup_apcb(vcpu, &vsie_page->crycb, crycb_addr,
                                 vcpu->kvm->arch.crypto.crycb,
                                 fmt_o, fmt_h);

--
Pierre Morel
Linux/KVM/QEMU in Böblingen - Germany