[PATCH v1 2/7] KVM: s390: Fix guest / virtual address confusion in _essa_clear_cbrl()

[Claudio Imbrenda]

Until now, gmap_helper_zap_one_page() was being called with the guest
absolute address, but it expects a userspace virtual address.

This meant that in the best case the requested pages were not being
discarded, and in the worst case that the wrong pages were being
discarded.

Fix this by converting the guest absolute address to host virtual
before passing it to gmap_helper_zap_one_page().

Fixes: e38c884df921 ("KVM: s390: Switch to new gmap")
Signed-off-by: Claudio Imbrenda <imbrenda@xxxxxxxxxxxxx>
---
 arch/s390/kvm/priv.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c
index cc0553da14cb..447ec7ed423d 100644
--- a/arch/s390/kvm/priv.c
+++ b/arch/s390/kvm/priv.c
@@ -1188,6 +1188,7 @@ static void _essa_clear_cbrl(struct kvm_vcpu *vcpu, unsigned long *cbrl, int len
 	union crste *crstep;
 	union pgste pgste;
 	union pte *ptep;
+	hva_t hva;
 	int i;
 
 	lockdep_assert_held(&vcpu->kvm->mmu_lock);
@@ -1199,8 +1200,11 @@ static void _essa_clear_cbrl(struct kvm_vcpu *vcpu, unsigned long *cbrl, int len
 		if (!ptep || ptep->s.pr)
 			continue;
 		pgste = pgste_get_lock(ptep);
-		if (pgste.usage == PGSTE_GPS_USAGE_UNUSED || pgste.zero)
-			gmap_helper_zap_one_page(vcpu->kvm->mm, cbrl[i]);
+		if (pgste.usage == PGSTE_GPS_USAGE_UNUSED || pgste.zero) {
+			hva = gpa_to_hva(vcpu->kvm, cbrl[i]);
+			if (!kvm_is_error_hva(hva))
+				gmap_helper_zap_one_page(vcpu->kvm->mm, hva);
+		}
 		pgste_set_unlock(ptep, pgste);
 	}
 }
-- 
2.54.0