[PATCH v3 4/5] KVM: s390: pci: Fix resource leak on IRQ registration failure

Currently if kvm_zpci_set_airq() fails, kvm_s390_pci_aif_enable() returns
the error code but doesn't do any resource cleanup thus leaking resources.
Fix this by cleaning up all the resources such as the GAITE, AIBV, AISB and
unpinning any pinned pages. While at it, remove dead code that stored FIB
values that were never referenced.

As part of the cleanup, we are also holding the aift_lock a bit longer, as
we hold the lock while executing the MPCIFC instruction. Though this is not
strictly necessary, it means we don't have to drop and re-acquire in the
error case.

Fixes: 3c5a1b6f0a18 ("KVM: s390: pci: provide routines for enabling/disabling interrupt forwarding")
Cc: [email protected]
Reviewed-by: Matthew Rosato <[email protected]>
Reviewed-by: Christian Borntraeger <[email protected]>
Signed-off-by: Farhan Ali <[email protected]>
Tested-by: Matthew Rosato <[email protected]>
Signed-off-by: Christian Borntraeger <[email protected]>
(cherry picked from commit 5580c9858f1e00f60191eb09c3add359836d60b6)
[[email protected]: Resolved merge conflict]
Signed-off-by: Farhan Ali <[email protected]>
---
 arch/s390/kvm/pci.c | 29 +++++++++++++++++++++--------
 1 file changed, 21 insertions(+), 8 deletions(-)

diff --git a/arch/s390/kvm/pci.c b/arch/s390/kvm/pci.c
index a6f6d5ddb0e3..8b91f289226b 100644
--- a/arch/s390/kvm/pci.c
+++ b/arch/s390/kvm/pci.c
@@ -359,19 +359,32 @@ static int kvm_s390_pci_aif_enable(struct zpci_dev *zdev, struct zpci_fib *fib,
 	aift->kzdev[zdev->aisb] = zdev->kzdev;
 	spin_unlock_irq(&aift->gait_lock);
 
-	/* Update guest FIB for re-issue */
-	fib->fmt0.aisbo = zdev->aisb & 63;
-	fib->fmt0.aisb = virt_to_phys(aift->sbv->vector + (zdev->aisb / 64) * 8);
-	fib->fmt0.isc = gisc;
-
 	/* Save some guest fib values in the host for later use */
-	zdev->kzdev->fib.fmt0.isc = fib->fmt0.isc;
+	zdev->kzdev->fib.fmt0.isc = gisc;
 	zdev->kzdev->fib.fmt0.aibv = fib->fmt0.aibv;
-	mutex_unlock(&aift->aift_lock);
 
 	/* Issue the clp to setup the irq now */
 	rc = kvm_zpci_set_airq(zdev);
-	return rc;
+	if (!rc) {
+		mutex_unlock(&aift->aift_lock);
+		return rc;
+	}
+
+	/* Start cleanup */
+	zdev->kzdev->fib.fmt0.isc = 0;
+	zdev->kzdev->fib.fmt0.aibv = 0;
+
+	spin_lock_irq(&aift->gait_lock);
+	gaite->count--;
+	gaite->aisb = 0;
+	gaite->gisc = 0;
+	gaite->aisbo = 0;
+	gaite->gisa = 0;
+	aift->kzdev[zdev->aisb] = NULL;
+	spin_unlock_irq(&aift->gait_lock);
+
+	airq_iv_release(zdev->aibv);
+	zdev->aibv = NULL;
 
 free_aisb:
 	airq_iv_free_bit(aift->sbv, zdev->aisb);
-- 
2.43.0