KVM: s390: pci: fix virtual-physical confusion on module unload/load

When the kvm module is unloaded, zpci_setup_aipb() perists some data in the
zpci_aipb structure in s390 pci code. Note that this struct is also passed
to firmware in the zpci_set_irq_ctrl() call and thus the GAIT must be a
physical address.

On module re-insertion, the GAIT is restored from this structure in
zpci_reset_aipb(). But it is a physical address, hence this may cause
issues when the kvm module is unloaded and loaded again.

Fix virtual vs physical address confusion (which currently are the same) by
adding the necessary physical-to-virtual-conversion in zpci_reset_aipb().

Signed-off-by: Nico Boehr <nrb@linux.ibm.com>
Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Link: https://lore.kernel.org/r/20230222155503.43399-1-nrb@linux.ibm.com
Message-Id: <20230222155503.43399-1-nrb@linux.ibm.com>

Author: Nico Boehr

arch/s390/kvm/pci.c

@@ -112,7 +112,7 @@ static int zpci_reset_aipb(u8 nisc)
 		return -EINVAL;
 
 	aift->sbv = zpci_aif_sbv;
-	aift->gait = (struct zpci_gaite *)zpci_aipb->aipb.gait;
+	aift->gait = phys_to_virt(zpci_aipb->aipb.gait);
 
 	return 0;
 }