msix: Assert that specified vector is in range

There were several different ways to deal with the situation where the
vector specified for a msix function is out of bound:
- early return a function and keep progresssing
- propagate the error to the caller
- mark msix unusable
- assert it is in bound
- just ignore

An out-of-bound vector should not be specified if the device
implementation is correct so let msix functions always assert that the
specified vector is in range.

An exceptional case is virtio-pci, which allows the guest to configure
vectors. For virtio-pci, it is more appropriate to introduce its own
checks because it is sometimes too late to check the vector range in
msix functions.

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Message-Id: <20220829083524.143640-1-akihiko.odaki@daynix.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Yuval Shaia <yuval.shaia.ml@gmail.com>
Signed-off-by: Akihiko Odaki &lt;<a href="mailto:akihiko.odaki@daynix.com" target="_blank">akihiko.odaki@daynix.com</a>&gt;<br>

1 files changed, 3 insertions, 20 deletions

diff --git a/hw/net/rocker/rocker.c b/hw/net/rocker/rocker.c
index d8f3f16fe8..281d43e6cf 100644
--- a/hw/net/rocker/rocker.c
+++ b/hw/net/rocker/rocker.c
@@ -1212,24 +1212,14 @@ static void rocker_msix_vectors_unuse(Rocker *r,
     }
 }
 
-static int rocker_msix_vectors_use(Rocker *r,
-                                   unsigned int num_vectors)
+static void rocker_msix_vectors_use(Rocker *r, unsigned int num_vectors)
 {
     PCIDevice *dev = PCI_DEVICE(r);
-    int err;
     int i;
 
     for (i = 0; i < num_vectors; i++) {
-        err = msix_vector_use(dev, i);
-        if (err) {
-            goto rollback;
-        }
+        msix_vector_use(dev, i);
     }
-    return 0;
-
-rollback:
-    rocker_msix_vectors_unuse(r, i);
-    return err;
 }
 
 static int rocker_msix_init(Rocker *r, Error **errp)
@@ -1247,16 +1237,9 @@ static int rocker_msix_init(Rocker *r, Error **errp)
         return err;
     }
 
-    err = rocker_msix_vectors_use(r, ROCKER_MSIX_VEC_COUNT(r->fp_ports));
-    if (err) {
-        goto err_msix_vectors_use;
-    }
+    rocker_msix_vectors_use(r, ROCKER_MSIX_VEC_COUNT(r->fp_ports));
 
     return 0;
-
-err_msix_vectors_use:
-    msix_uninit(dev, &r->msix_bar, &r->msix_bar);
-    return err;
 }
 
 static void rocker_msix_uninit(Rocker *r)