[S390] kvm_s390: Fix oops in virtio device detection with "mem="

The current virtio model on s390 has the descriptor page above the main
memory. The guest virtio detection will oops if the mem= parameter is
used to reduce/change the memory size.
We have to use real_memory_size instead of max_pfn to detect the virtio
descriptor pages.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/drivers/s390/kvm/kvm_virtio.c b/drivers/s390/kvm/kvm_virtio.c
index ff4a6931bb8e..3d442444c618 100644
--- a/drivers/s390/kvm/kvm_virtio.c
+++ b/drivers/s390/kvm/kvm_virtio.c
@@ -322,13 +322,13 @@ static int __init kvm_devices_init(void)
                 return rc;
         }
 
-        rc = vmem_add_mapping(PFN_PHYS(max_pfn), PAGE_SIZE);
+        rc = vmem_add_mapping(real_memory_size, PAGE_SIZE);
         if (rc) {
                 s390_root_dev_unregister(kvm_root);
                 return rc;
         }
 
-        kvm_devices = (void *) PFN_PHYS(max_pfn);
+        kvm_devices = (void *) real_memory_size;
 
         ctl_set_bit(0, 9);
         register_external_interrupt(0x2603, kvm_extint_handler);