msix: make [un]use vectors on reset/load optional

The facility to use/unuse vectors dynamically is helpful
for virtio but little else: everyone just seems to use
vectors in their init function.

Avoid clearing msix vector use info on reset and load.
For virtio, clear it explicitly.
This should fix regressions reported with ivshmem - though
I didn't test this, I verified that virtio keeps
working like it did.
Tested-by: NCam Macdonell <cam@cs.ualberta.ca>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

hw/msix.c

@@ -336,6 +336,15 @@ static void msix_free_irq_entries(PCIDevice *dev)
     }
 }
 
+static void msix_clear_all_vectors(PCIDevice *dev)
+{
+    int vector;
+
+    for (vector = 0; vector < dev->msix_entries_nr; ++vector) {
+        msix_clr_pending(dev, vector);
+    }
+}
+
 /* Clean up resources for the device. */
 void msix_uninit(PCIDevice *dev, MemoryRegion *table_bar, MemoryRegion *pba_bar)
 {
@@ -390,7 +399,7 @@ void msix_load(PCIDevice *dev, QEMUFile *f)
         return;
     }
 
-    msix_free_irq_entries(dev);
+    msix_clear_all_vectors(dev);
     qemu_get_buffer(f, dev->msix_table, n * PCI_MSIX_ENTRY_SIZE);
     qemu_get_buffer(f, dev->msix_pba, (n + 7) / 8);
     msix_update_function_masked(dev);
@@ -436,7 +445,7 @@ void msix_reset(PCIDevice *dev)
     if (!msix_present(dev)) {
         return;
     }
-    msix_free_irq_entries(dev);
+    msix_clear_all_vectors(dev);
     dev->config[dev->msix_cap + MSIX_CONTROL_OFFSET] &=
 	    ~dev->wmask[dev->msix_cap + MSIX_CONTROL_OFFSET];
     memset(dev->msix_table, 0, dev->msix_entries_nr * PCI_MSIX_ENTRY_SIZE);

hw/virtio-pci.c

@@ -131,6 +131,7 @@ static int virtio_pci_load_config(void * opaque, QEMUFile *f)
     if (ret) {
         return ret;
     }
+    msix_unuse_all_vectors(&proxy->pci_dev);
     msix_load(&proxy->pci_dev, f);
     if (msix_present(&proxy->pci_dev)) {
         qemu_get_be16s(f, &proxy->vdev->config_vector);
@@ -246,6 +247,7 @@ void virtio_pci_reset(DeviceState *d)
     VirtIOPCIProxy *proxy = container_of(d, VirtIOPCIProxy, pci_dev.qdev);
     virtio_pci_stop_ioeventfd(proxy);
     virtio_reset(proxy->vdev);
+    msix_unuse_all_vectors(&proxy->pci_dev);
     proxy->flags &= ~VIRTIO_PCI_FLAG_BUS_MASTER_BUG;
 }