[PATCH v3 5/5] KVM: s390: pci: Fix aisb calculation

[Farhan Ali <alifm@linux.ibm.com>]

From: Matthew Rosato <mjrosato@linux.ibm.com>

The current implementation of aisb calculation will erroneously index
via an unsigned long * as well as multiply by 8B for every 64-bits in
the offset; only one or the other is required.  This throws off aisb
calculations once the number of devices exceeds 64, and can result
in out-of-bounds access as well as failure to indicate summary bits
associated with those devices in guests.

Fix this by converting to a physical address before applying the
offset, as is already done in arch/s390/pci/pci_irq.c.

Fixes: 3c5a1b6f0a18 ("KVM: s390: pci: provide routines for enabling/disabling interrupt forwarding")
Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
Reviewed-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>
(cherry picked from commit 0cfe660559e857d7c00ab86c73e4510ce069086f)
[alifm@linux.ibm.com: Resolved merge conflict]
Signed-off-by: Farhan Ali <alifm@linux.ibm.com>
---
 arch/s390/kvm/pci.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/s390/kvm/pci.c b/arch/s390/kvm/pci.c
index 8b91f289226b..59e824a7eaaf 100644
--- a/arch/s390/kvm/pci.c
+++ b/arch/s390/kvm/pci.c
@@ -167,7 +167,7 @@ static int kvm_zpci_set_airq(struct zpci_dev *zdev)
 	fib.fmt0.noi = airq_iv_end(zdev->aibv);
 	fib.fmt0.aibv = virt_to_phys(zdev->aibv->vector);
 	fib.fmt0.aibvo = 0;
-	fib.fmt0.aisb = virt_to_phys(aift->sbv->vector + (zdev->aisb / 64) * 8);
+	fib.fmt0.aisb = virt_to_phys(aift->sbv->vector) + (zdev->aisb / 64) * 8;
 	fib.fmt0.aisbo = zdev->aisb & 63;
 	fib.gd = zdev->gisa;
 
-- 
2.43.0