KVM: s390: VSIE: sort out virtual/physical address in pin_guest_page

pin_guest_page() used page_to_virt() to calculate the hpa of the pinned
page. This currently works, because virtual and physical addresses are
the same. Use page_to_phys() instead to resolve the virtual-real address
confusion.

One caller of pin_guest_page() actually expected the hpa to be a hva, so
add the missing phys_to_virt() conversion here.
Signed-off-by: Nico Boehr <nrb@linux.ibm.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Link: https://lore.kernel.org/r/20221025082039.117372-2-nrb@linux.ibm.com
Message-Id: <20221025082039.117372-2-nrb@linux.ibm.com>
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>

arch/s390/kvm/vsie.c

@@ -654,7 +654,7 @@ static int pin_guest_page(struct kvm *kvm, gpa_t gpa, hpa_t *hpa)
 	page = gfn_to_page(kvm, gpa_to_gfn(gpa));
 	if (is_error_page(page))
 		return -EINVAL;
-	*hpa = (hpa_t) page_to_virt(page) + (gpa & ~PAGE_MASK);
+	*hpa = (hpa_t)page_to_phys(page) + (gpa & ~PAGE_MASK);
 	return 0;
 }
 
@@ -869,7 +869,7 @@ static int pin_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page,
 		WARN_ON_ONCE(rc);
 		return 1;
 	}
-	vsie_page->scb_o = (struct kvm_s390_sie_block *) hpa;
+	vsie_page->scb_o = phys_to_virt(hpa);
 	return 0;
 }