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

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Date:   Fri, 26 Apr 2019 10:56:50 +0200
From:   Pierre Morel <pmorel@...ux.ibm.com>
To:     david@...hat.com
Cc:     linux-kernel@...r.kernel.org, cohuck@...hat.com,
        linux-s390@...r.kernel.org, kvm@...r.kernel.org,
        frankja@...ux.ibm.com, akrowiak@...ux.ibm.com,
        borntraeger@...ibm.com, schwidefsky@...ibm.com,
        heiko.carstens@...ibm.com
Subject: [PATCH] KVM: s390: vsie: Do not shadow CRYCB when no AP and no keys

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

Signed-off-by: Pierre Morel <pmorel@...ux.ibm.com>
Reported-by: Christian Borntraeger <borntraeger@...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);
-- 
2.7.4