virtio: allow finalize_features to fail

This will make it easy for transports to validate features and return
failure.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

3 files changed, 20 insertions, 9 deletions

diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c
index 224f85442f3f..e1673a511d17 100644
--- a/drivers/virtio/virtio.c
+++ b/drivers/virtio/virtio.c
@@ -212,7 +212,9 @@ static int virtio_dev_probe(struct device *_d)
                 if (device_features & (1ULL << i))
                         __virtio_set_bit(dev, i);
 
-        dev->config->finalize_features(dev);
+        err = dev->config->finalize_features(dev);
+        if (err)
+                goto err;
 
         if (virtio_has_feature(dev, VIRTIO_F_VERSION_1)) {
                 add_status(dev, VIRTIO_CONFIG_S_FEATURES_OK);
@@ -354,6 +356,7 @@ EXPORT_SYMBOL_GPL(virtio_device_freeze);
 int virtio_device_restore(struct virtio_device *dev)
 {
         struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
+        int ret;
 
         /* We always start by resetting the device, in case a previous
          * driver messed it up. */
@@ -373,14 +376,14 @@ int virtio_device_restore(struct virtio_device *dev)
         /* We have a driver! */
         add_status(dev, VIRTIO_CONFIG_S_DRIVER);
 
-        dev->config->finalize_features(dev);
+        ret = dev->config->finalize_features(dev);
+        if (ret)
+                goto err;
 
         if (drv->restore) {
-                int ret = drv->restore(dev);
-                if (ret) {
-                        add_status(dev, VIRTIO_CONFIG_S_FAILED);
-                        return ret;
-                }
+                ret = drv->restore(dev);
+                if (ret)
+                        goto err;
         }
 
         /* Finally, tell the device we're all set */
@@ -389,6 +392,10 @@ int virtio_device_restore(struct virtio_device *dev)
         virtio_config_enable(dev);
 
         return 0;
+
+err:
+        add_status(dev, VIRTIO_CONFIG_S_FAILED);
+        return ret;
 }
 EXPORT_SYMBOL_GPL(virtio_device_restore);
 #endif
diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c
index aec1daee9ada..5219210d31ce 100644
--- a/drivers/virtio/virtio_mmio.c
+++ b/drivers/virtio/virtio_mmio.c
@@ -152,7 +152,7 @@ static u64 vm_get_features(struct virtio_device *vdev)
         return readl(vm_dev->base + VIRTIO_MMIO_HOST_FEATURES);
 }
 
-static void vm_finalize_features(struct virtio_device *vdev)
+static int vm_finalize_features(struct virtio_device *vdev)
 {
         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
 
@@ -164,6 +164,8 @@ static void vm_finalize_features(struct virtio_device *vdev)
 
         writel(0, vm_dev->base + VIRTIO_MMIO_GUEST_FEATURES_SEL);
         writel(vdev->features, vm_dev->base + VIRTIO_MMIO_GUEST_FEATURES);
+
+        return 0;
 }
 
 static void vm_get(struct virtio_device *vdev, unsigned offset,
diff --git a/drivers/virtio/virtio_pci.c b/drivers/virtio/virtio_pci.c
index dd6df979862b..9be59d9f2f19 100644
--- a/drivers/virtio/virtio_pci.c
+++ b/drivers/virtio/virtio_pci.c
@@ -112,7 +112,7 @@ static u64 vp_get_features(struct virtio_device *vdev)
 }
 
 /* virtio config->finalize_features() implementation */
-static void vp_finalize_features(struct virtio_device *vdev)
+static int vp_finalize_features(struct virtio_device *vdev)
 {
         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 
@@ -124,6 +124,8 @@ static void vp_finalize_features(struct virtio_device *vdev)
 
         /* We only support 32 feature bits. */
         iowrite32(vdev->features, vp_dev->ioaddr + VIRTIO_PCI_GUEST_FEATURES);
+
+        return 0;
 }
 
 /* virtio config->get() implementation */