virtio, vhost: features, fixes

VF support for virtio.
 DMA barriers for virtio strong barriers.
 Bugfixes.
 
 Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost

Pull virtio updates from Michael Tsirkin:
 "virtio, vhost: features, fixes

   - PCI virtual function support for virtio

   - DMA barriers for virtio strong barriers

   - bugfixes"

* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
  virtio: update the comments for transport features
  virtio_pci: support enabling VFs
  vhost: fix info leak due to uninitialized memory
  virtio_ring: switch to dma_XX barriers for rpmsg

drivers/vhost/vhost.c

@@ -2349,6 +2349,9 @@ struct vhost_msg_node *vhost_new_msg(struct vhost_virtqueue *vq, int type)
 	struct vhost_msg_node *node = kmalloc(sizeof *node, GFP_KERNEL);
 	if (!node)
 		return NULL;
+
+	/* Make sure all padding within the structure is initialized. */
+	memset(&node->msg, 0, sizeof node->msg);
 	node->vq = vq;
 	node->msg.type = type;
 	return node;

drivers/virtio/virtio_pci_common.c

@@ -578,6 +578,8 @@ static void virtio_pci_remove(struct pci_dev *pci_dev)
 	struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev);
 	struct device *dev = get_device(&vp_dev->vdev.dev);
 
+	pci_disable_sriov(pci_dev);
+
 	unregister_virtio_device(&vp_dev->vdev);
 
 	if (vp_dev->ioaddr)
@@ -589,6 +591,33 @@ static void virtio_pci_remove(struct pci_dev *pci_dev)
 	put_device(dev);
 }
 
+static int virtio_pci_sriov_configure(struct pci_dev *pci_dev, int num_vfs)
+{
+	struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev);
+	struct virtio_device *vdev = &vp_dev->vdev;
+	int ret;
+
+	if (!(vdev->config->get_status(vdev) & VIRTIO_CONFIG_S_DRIVER_OK))
+		return -EBUSY;
+
+	if (!__virtio_test_bit(vdev, VIRTIO_F_SR_IOV))
+		return -EINVAL;
+
+	if (pci_vfs_assigned(pci_dev))
+		return -EPERM;
+
+	if (num_vfs == 0) {
+		pci_disable_sriov(pci_dev);
+		return 0;
+	}
+
+	ret = pci_enable_sriov(pci_dev, num_vfs);
+	if (ret < 0)
+		return ret;
+
+	return num_vfs;
+}
+
 static struct pci_driver virtio_pci_driver = {
 	.name		= "virtio-pci",
 	.id_table	= virtio_pci_id_table,
@@ -597,6 +626,7 @@ static struct pci_driver virtio_pci_driver = {
 #ifdef CONFIG_PM_SLEEP
 	.driver.pm	= &virtio_pci_pm_ops,
 #endif
+	.sriov_configure = virtio_pci_sriov_configure,
 };
 
 module_pci_driver(virtio_pci_driver);

drivers/virtio/virtio_pci_modern.c

@@ -153,14 +153,28 @@ static u64 vp_get_features(struct virtio_device *vdev)
 	return features;
 }
 
+static void vp_transport_features(struct virtio_device *vdev, u64 features)
+{
+	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
+	struct pci_dev *pci_dev = vp_dev->pci_dev;
+
+	if ((features & BIT_ULL(VIRTIO_F_SR_IOV)) &&
+			pci_find_ext_capability(pci_dev, PCI_EXT_CAP_ID_SRIOV))
+		__virtio_set_bit(vdev, VIRTIO_F_SR_IOV);
+}
+
 /* virtio config->finalize_features() implementation */
 static int vp_finalize_features(struct virtio_device *vdev)
 {
 	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
+	u64 features = vdev->features;
 
 	/* Give virtio_ring a chance to accept features. */
 	vring_transport_features(vdev);
 
+	/* Give virtio_pci a chance to accept features. */
+	vp_transport_features(vdev, features);
+
 	if (!__virtio_test_bit(vdev, VIRTIO_F_VERSION_1)) {
 		dev_err(&vdev->dev, "virtio: device uses modern interface "
 			"but does not have VIRTIO_F_VERSION_1\n");

include/linux/virtio_ring.h

@@ -35,7 +35,7 @@ static inline void virtio_rmb(bool weak_barriers)
 	if (weak_barriers)
 		virt_rmb();
 	else
-		rmb();
+		dma_rmb();
 }
 
 static inline void virtio_wmb(bool weak_barriers)
@@ -43,7 +43,7 @@ static inline void virtio_wmb(bool weak_barriers)
 	if (weak_barriers)
 		virt_wmb();
 	else
-		wmb();
+		dma_wmb();
 }
 
 static inline void virtio_store_mb(bool weak_barriers,

include/uapi/linux/virtio_config.h

@@ -45,11 +45,14 @@
 /* We've given up on this device. */
 #define VIRTIO_CONFIG_S_FAILED		0x80
 
-/* Some virtio feature bits (currently bits 28 through 32) are reserved for the
+/*
- * transport being used (eg. virtio_ring), the rest are per-device feature
+ * Virtio feature bits VIRTIO_TRANSPORT_F_START through
- * bits. */
+ * VIRTIO_TRANSPORT_F_END are reserved for the transport
+ * being used (e.g. virtio_ring, virtio_pci etc.), the
+ * rest are per-device feature bits.
+ */
 #define VIRTIO_TRANSPORT_F_START	28
-#define VIRTIO_TRANSPORT_F_END		34
+#define VIRTIO_TRANSPORT_F_END		38
 
 #ifndef VIRTIO_CONFIG_NO_LEGACY
 /* Do we get callbacks when the ring is completely used, even if we've
@@ -71,4 +74,9 @@
  * this is for compatibility with legacy systems.
  */
 #define VIRTIO_F_IOMMU_PLATFORM		33
+
+/*
+ * Does the device support Single Root I/O Virtualization?
+ */
+#define VIRTIO_F_SR_IOV			37
 #endif /* _UAPI_LINUX_VIRTIO_CONFIG_H */