From: David Hildenbrand <dahi@xxxxxxxxxxxxxxxxxx>
As soon as we forward an ibc to guest 2 (indicated via
kvm->arch.model.ibc), he can also use it for guest 3. Let's properly round
the ibc up/down, so we avoid any potential validity icpts from the
underlying SIE, if it doesn't simply round the values.
Acked-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
Signed-off-by: David Hildenbrand <dahi@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
---
arch/s390/kvm/vsie.c | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)
diff --git a/arch/s390/kvm/vsie.c b/arch/s390/kvm/vsie.c
index 2839efc..1165baf 100644
--- a/arch/s390/kvm/vsie.c
+++ b/arch/s390/kvm/vsie.c
@@ -102,6 +102,26 @@ static int prepare_cpuflags(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
return 0;
}
+/* shadow (round up/down) the ibc to avoid validity icpt */
+static void prepare_ibc(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
+{
+ struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
+ struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
+ __u64 min_ibc = (sclp.ibc >> 16) & 0x0fffU;
+
+ scb_s->ibc = 0;
+ /* ibc installed in g2 and requested for g3 */
+ if (vcpu->kvm->arch.model.ibc && (scb_o->ibc & 0x0fffU)) {
+ scb_s->ibc = scb_o->ibc & 0x0fffU;
+ /* takte care of the minimum ibc level of the machine */
+ if (scb_s->ibc < min_ibc)
+ scb_s->ibc = min_ibc;
+ /* take care of the maximum ibc level set for the guest */
+ if (scb_s->ibc > vcpu->kvm->arch.model.ibc)
+ scb_s->ibc = vcpu->kvm->arch.model.ibc;
+ }
+}
+
/* unshadow the scb, copying parameters back to the real scb */
static void unshadow_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
{
@@ -214,6 +234,7 @@ static int shadow_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
/* MVPG and Protection Exception Interpretation are always available */
scb_s->eca |= scb_o->eca & 0x01002000U;
+ prepare_ibc(vcpu, vsie_page);
out:
if (rc)
unshadow_scb(vcpu, vsie_page);
--
2.5.5
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