virtio: Native virtio driver

Change-Id: Id7fccf2f805e578fb05032aeb2b649a74c3c0e56
Signed-off-by: Mohsin Kazmi <sykazmi@cisco.com>

1 files changed, 919 insertions, 0 deletions

diff --git a/src/vnet/devices/virtio/pci.c b/src/vnet/devices/virtio/pci.c
new file mode 100644
index 00000000000..63c8c54fdad
--- /dev/null
+++ b/src/vnet/devices/virtio/pci.c
@@ -0,0 +1,919 @@
+/*
+ * Copyright (c) 2018 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <fcntl.h>
+#include <sys/ioctl.h>
+#include <linux/virtio_net.h>
+#include <linux/virtio_ring.h>
+#include <linux/vhost.h>
+#include <sys/eventfd.h>
+#if defined(__x86_64__)
+#include <sys/io.h>
+#endif
+
+#include <vppinfra/types.h>
+#include <vlib/vlib.h>
+#include <vlib/pci/pci.h>
+#include <vnet/ethernet/ethernet.h>
+#include <vpp/app/version.h>
+#include <vnet/ip/ip4_packet.h>
+#include <vnet/ip/ip6_packet.h>
+#include <vnet/devices/virtio/virtio.h>
+#include <vnet/devices/virtio/pci.h>
+
+#define PCI_VENDOR_ID_VIRTIO				0x1af4
+#define PCI_DEVICE_ID_VIRTIO_NIC			0x1000
+/* Doesn't support modern device */
+#define PCI_DEVICE_ID_VIRTIO_NIC_MODERN			0x1041
+
+#define PCI_CAPABILITY_LIST     0x34
+#define PCI_CAP_ID_VNDR         0x09
+#define PCI_CAP_ID_MSIX         0x11
+
+#define PCI_MSIX_ENABLE 0x8000
+
+static u32 msix_enabled = 0;
+
+#define PCI_CONFIG_SIZE ((msix_enabled == VIRTIO_MSIX_ENABLED) ? \
+  24 : 20)
+
+static pci_device_id_t virtio_pci_device_ids[] = {
+  {
+   .vendor_id = PCI_VENDOR_ID_VIRTIO,
+   .device_id = PCI_DEVICE_ID_VIRTIO_NIC},
+  {
+   .vendor_id = PCI_VENDOR_ID_VIRTIO,
+   .device_id = PCI_DEVICE_ID_VIRTIO_NIC_MODERN},
+  {0},
+};
+
+static void
+virtio_pci_legacy_read_config (vlib_main_t * vm, virtio_if_t * vif, void *dst,
+			       int len, u32 addr)
+{
+  u32 size = 0;
+  vlib_pci_dev_handle_t h = vif->pci_dev_handle;
+
+  while (len > 0)
+    {
+      if (len >= 4)
+	{
+	  size = 4;
+	  vlib_pci_read_io_u32 (vm, h, PCI_CONFIG_SIZE + addr, dst);
+	}
+      else if (len >= 2)
+	{
+	  size = 2;
+	  vlib_pci_read_io_u16 (vm, h, PCI_CONFIG_SIZE + addr, dst);
+	}
+      else
+	{
+	  size = 1;
+	  vlib_pci_read_io_u8 (vm, h, PCI_CONFIG_SIZE + addr, dst);
+	}
+      dst = (u8 *) dst + size;
+      addr += size;
+      len -= size;
+    }
+}
+
+static void
+virtio_pci_legacy_write_config (vlib_main_t * vm, virtio_if_t * vif,
+				void *src, int len, u32 addr)
+{
+  u32 size = 0;
+  vlib_pci_dev_handle_t h = vif->pci_dev_handle;
+
+  while (len > 0)
+    {
+      if (len >= 4)
+	{
+	  size = 4;
+	  vlib_pci_write_io_u32 (vm, h, PCI_CONFIG_SIZE + addr, src);
+	}
+      else if (len >= 2)
+	{
+	  size = 2;
+	  vlib_pci_write_io_u16 (vm, h, PCI_CONFIG_SIZE + addr, src);
+	}
+      else
+	{
+	  size = 1;
+	  vlib_pci_write_io_u8 (vm, h, PCI_CONFIG_SIZE + addr, src);
+	}
+      src = (u8 *) src + size;
+      addr += size;
+      len -= size;
+    }
+}
+
+static u64
+virtio_pci_legacy_get_features (vlib_main_t * vm, virtio_if_t * vif)
+{
+  u32 features;
+  vlib_pci_read_io_u32 (vm, vif->pci_dev_handle, VIRTIO_PCI_HOST_FEATURES,
+			&features);
+  return features;
+}
+
+static u32
+virtio_pci_legacy_set_features (vlib_main_t * vm, virtio_if_t * vif,
+				u64 features)
+{
+  if ((features >> 32) != 0)
+    {
+      clib_warning ("only 32 bit features are allowed for legacy virtio!");
+    }
+  u32 feature = 0, guest_features = (u32) features;
+  vlib_pci_write_io_u32 (vm, vif->pci_dev_handle, VIRTIO_PCI_GUEST_FEATURES,
+			 &guest_features);
+  vlib_pci_read_io_u32 (vm, vif->pci_dev_handle, VIRTIO_PCI_GUEST_FEATURES,
+			&feature);
+  return feature;
+}
+
+static u8
+virtio_pci_legacy_get_status (vlib_main_t * vm, virtio_if_t * vif)
+{
+  u8 status = 0;
+  vlib_pci_read_io_u8 (vm, vif->pci_dev_handle, VIRTIO_PCI_STATUS, &status);
+  return status;
+}
+
+static void
+virtio_pci_legacy_set_status (vlib_main_t * vm, virtio_if_t * vif, u8 status)
+{
+  if (status != VIRTIO_CONFIG_STATUS_RESET)
+    status |= virtio_pci_legacy_get_status (vm, vif);
+  vlib_pci_write_io_u8 (vm, vif->pci_dev_handle, VIRTIO_PCI_STATUS, &status);
+}
+
+static u8
+virtio_pci_legacy_reset (vlib_main_t * vm, virtio_if_t * vif)
+{
+  virtio_pci_legacy_set_status (vm, vif, VIRTIO_CONFIG_STATUS_RESET);
+  return virtio_pci_legacy_get_status (vm, vif);
+}
+
+static u8
+virtio_pci_legacy_get_isr (vlib_main_t * vm, virtio_if_t * vif)
+{
+  u8 isr = 0;
+  vlib_pci_read_io_u8 (vm, vif->pci_dev_handle, VIRTIO_PCI_ISR, &isr);
+  return isr;
+}
+
+static u16
+virtio_pci_legacy_get_queue_num (vlib_main_t * vm, virtio_if_t * vif,
+				 u16 queue_id)
+{
+  u16 queue_num = 0;
+  vlib_pci_write_io_u16 (vm, vif->pci_dev_handle, VIRTIO_PCI_QUEUE_SEL,
+			 &queue_id);
+  vlib_pci_read_io_u16 (vm, vif->pci_dev_handle, VIRTIO_PCI_QUEUE_NUM,
+			&queue_num);
+  return queue_num;
+}
+
+
+static void
+virtio_pci_legacy_setup_queue (vlib_main_t * vm, virtio_if_t * vif,
+			       u16 queue_id, void *p)
+{
+  u64 addr = vlib_physmem_get_pa (vm, p) >> VIRTIO_PCI_QUEUE_ADDR_SHIFT;
+  vlib_pci_write_io_u16 (vm, vif->pci_dev_handle, VIRTIO_PCI_QUEUE_SEL,
+			 &queue_id);
+  vlib_pci_write_io_u32 (vm, vif->pci_dev_handle, VIRTIO_PCI_QUEUE_PFN,
+			 (u32 *) & addr);
+}
+
+static void
+virtio_pci_legacy_del_queue (vlib_main_t * vm, virtio_if_t * vif,
+			     u16 queue_id)
+{
+  u32 src = 0;
+  vlib_pci_write_io_u16 (vm, vif->pci_dev_handle, VIRTIO_PCI_QUEUE_SEL,
+			 &queue_id);
+  vlib_pci_write_io_u32 (vm, vif->pci_dev_handle, VIRTIO_PCI_QUEUE_PFN, &src);
+}
+
+inline void
+virtio_pci_legacy_notify_queue (vlib_main_t * vm, virtio_if_t * vif,
+				u16 queue_id)
+{
+  vlib_pci_write_io_u16 (vm, vif->pci_dev_handle, VIRTIO_PCI_QUEUE_NOTIFY,
+			 &queue_id);
+}
+
+/* Enable one vector (0) for Link State Intrerrupt */
+static u16
+virtio_pci_legacy_set_config_irq (vlib_main_t * vm, virtio_if_t * vif,
+				  u16 vec)
+{
+  vlib_pci_write_io_u16 (vm, vif->pci_dev_handle, VIRTIO_MSI_CONFIG_VECTOR,
+			 &vec);
+  vlib_pci_read_io_u16 (vm, vif->pci_dev_handle, VIRTIO_MSI_CONFIG_VECTOR,
+			&vec);
+  return vec;
+}
+
+static u16
+virtio_pci_legacy_set_queue_irq (vlib_main_t * vm, virtio_if_t * vif, u16 vec,
+				 u16 queue_id)
+{
+  vlib_pci_write_io_u16 (vm, vif->pci_dev_handle, VIRTIO_PCI_QUEUE_SEL,
+			 &queue_id);
+  vlib_pci_write_io_u16 (vm, vif->pci_dev_handle, VIRTIO_MSI_QUEUE_VECTOR,
+			 &vec);
+  vlib_pci_read_io_u16 (vm, vif->pci_dev_handle, VIRTIO_MSI_QUEUE_VECTOR,
+			&vec);
+  return vec;
+}
+
+static u32
+virtio_pci_flag_change (vnet_main_t * vnm, vnet_hw_interface_t * hw,
+			u32 flags)
+{
+  return 0;
+}
+
+static clib_error_t *
+virtio_pci_get_max_virtqueue_pairs (vlib_main_t * vm, virtio_if_t * vif)
+{
+  virtio_net_config_t config;
+  clib_error_t *error = 0;
+  u16 max_queue_pairs = 1;
+
+  if (vif->features & VIRTIO_FEATURE (VIRTIO_NET_F_MQ))
+    {
+      virtio_pci_legacy_read_config (vm, vif, &config.max_virtqueue_pairs,
+				     sizeof (config.max_virtqueue_pairs), 8);
+      max_queue_pairs = config.max_virtqueue_pairs;
+    }
+
+  if (max_queue_pairs < 1 || max_queue_pairs > 0x8000)
+    clib_error_return (error, "max queue pair is %x", max_queue_pairs);
+
+  vif->max_queue_pairs = max_queue_pairs;
+  return error;
+}
+
+static void
+virtio_pci_set_mac (vlib_main_t * vm, virtio_if_t * vif)
+{
+  virtio_pci_legacy_write_config (vm, vif, vif->mac_addr,
+				  sizeof (vif->mac_addr), 0);
+}
+
+static u32
+virtio_pci_get_mac (vlib_main_t * vm, virtio_if_t * vif)
+{
+  if (vif->remote_features & VIRTIO_FEATURE (VIRTIO_NET_F_MAC))
+    {
+      virtio_pci_legacy_read_config (vm, vif, vif->mac_addr,
+				     sizeof (vif->mac_addr), 0);
+      return 0;
+    }
+  return 1;
+}
+
+static u16
+virtio_pci_is_link_up (vlib_main_t * vm, virtio_if_t * vif)
+{
+  /*
+   * Minimal driver: assumes link is up
+   */
+  u16 status = 1;
+  if (vif->remote_features & VIRTIO_FEATURE (VIRTIO_NET_F_STATUS))
+    virtio_pci_legacy_read_config (vm, vif, &status, sizeof (status),	/* mac */
+				   6);
+  return status;
+}
+
+static void
+virtio_pci_irq_0_handler (vlib_main_t * vm, vlib_pci_dev_handle_t h, u16 line)
+{
+  vnet_main_t *vnm = vnet_get_main ();
+  virtio_main_t *vmxm = &virtio_main;
+  uword pd = vlib_pci_get_private_data (vm, h);
+  virtio_if_t *vif = pool_elt_at_index (vmxm->interfaces, pd);
+  u16 qid = line;
+
+  vnet_device_input_set_interrupt_pending (vnm, vif->hw_if_index, qid);
+}
+
+static void
+virtio_pci_irq_1_handler (vlib_main_t * vm, vlib_pci_dev_handle_t h, u16 line)
+{
+  vnet_main_t *vnm = vnet_get_main ();
+  virtio_main_t *vmxm = &virtio_main;
+  uword pd = vlib_pci_get_private_data (vm, h);
+  virtio_if_t *vif = pool_elt_at_index (vmxm->interfaces, pd);
+
+  if (virtio_pci_is_link_up (vm, vif) & VIRTIO_NET_S_LINK_UP)
+    {
+      vif->flags |= VIRTIO_IF_FLAG_ADMIN_UP;
+      vnet_hw_interface_set_flags (vnm, vif->hw_if_index,
+				   VNET_HW_INTERFACE_FLAG_LINK_UP);
+    }
+  else
+    {
+      vif->flags &= ~VIRTIO_IF_FLAG_ADMIN_UP;
+      vnet_hw_interface_set_flags (vnm, vif->hw_if_index, 0);
+    }
+}
+
+static void
+virtio_pci_irq_handler (vlib_main_t * vm, vlib_pci_dev_handle_t h)
+{
+  virtio_main_t *vmxm = &virtio_main;
+  uword pd = vlib_pci_get_private_data (vm, h);
+  virtio_if_t *vif = pool_elt_at_index (vmxm->interfaces, pd);
+  u8 isr = 0;
+  u16 line = 0;
+
+  isr = virtio_pci_legacy_get_isr (vm, vif);
+
+  /*
+   * If the lower bit is set: look through the used rings of
+   * all virtqueues for the device, to see if any progress has
+   * been made by the device which requires servicing.
+   */
+  if (isr & VIRTIO_PCI_ISR_INTR)
+    virtio_pci_irq_0_handler (vm, h, line);
+
+  if (isr & VIRTIO_PCI_ISR_CONFIG)
+    virtio_pci_irq_1_handler (vm, h, line);
+}
+
+inline void
+device_status (vlib_main_t * vm, virtio_if_t * vif)
+{
+  struct status_struct
+  {
+    u8 bit;
+    char *str;
+  };
+  struct status_struct *status_entry;
+  static struct status_struct status_array[] = {
+#define _(s,b) { .str = #s, .bit = b, },
+    foreach_virtio_config_status_flags
+#undef _
+    {.str = NULL}
+  };
+
+  vlib_cli_output (vm, "  status 0x%x", vif->status);
+
+  status_entry = (struct status_struct *) &status_array;
+  while (status_entry->str)
+    {
+      if (vif->status & status_entry->bit)
+	vlib_cli_output (vm, "    %s (%x)", status_entry->str,
+			 status_entry->bit);
+      status_entry++;
+    }
+}
+
+inline void
+debug_device_config_space (vlib_main_t * vm, virtio_if_t * vif)
+{
+  u32 data_u32;
+  u16 data_u16;
+  u8 data_u8;
+  vlib_pci_read_io_u32 (vm, vif->pci_dev_handle, VIRTIO_PCI_HOST_FEATURES,
+			&data_u32);
+  vlib_cli_output (vm, "remote features 0x%lx", data_u32);
+  vlib_pci_read_io_u32 (vm, vif->pci_dev_handle, VIRTIO_PCI_GUEST_FEATURES,
+			&data_u32);
+  vlib_cli_output (vm, "guest features 0x%lx", data_u32);
+  vlib_pci_read_io_u32 (vm, vif->pci_dev_handle, VIRTIO_PCI_QUEUE_PFN,
+			&data_u32);
+  vlib_cli_output (vm, "queue address 0x%lx", data_u32);
+  vlib_pci_read_io_u16 (vm, vif->pci_dev_handle, VIRTIO_PCI_QUEUE_NUM,
+			&data_u16);
+  vlib_cli_output (vm, "queue size 0x%x", data_u16);
+  vlib_pci_read_io_u16 (vm, vif->pci_dev_handle, VIRTIO_PCI_QUEUE_SEL,
+			&data_u16);
+  vlib_cli_output (vm, "queue select 0x%x", data_u16);
+  vlib_pci_read_io_u16 (vm, vif->pci_dev_handle, VIRTIO_PCI_QUEUE_NOTIFY,
+			&data_u16);
+  vlib_cli_output (vm, "queue notify 0x%x", data_u16);
+  vlib_pci_read_io_u8 (vm, vif->pci_dev_handle, VIRTIO_PCI_STATUS, &data_u8);
+  vlib_cli_output (vm, "status 0x%x", data_u8);
+  vlib_pci_read_io_u8 (vm, vif->pci_dev_handle, VIRTIO_PCI_ISR, &data_u8);
+  vlib_cli_output (vm, "isr 0x%x", data_u8);
+
+  u8 mac[6];
+  virtio_pci_legacy_read_config (vm, vif, mac, sizeof (mac), 0);
+  vlib_cli_output (vm, "mac %U", format_ethernet_address, mac);
+  virtio_pci_legacy_read_config (vm, vif, &data_u16, sizeof (u16),	/* offset to status */
+				 6);
+  vlib_cli_output (vm, "link up/down status 0x%x", data_u16);
+  virtio_pci_legacy_read_config (vm, vif, &data_u16, sizeof (u16),
+				 /* offset to max_virtqueue */ 8);
+  vlib_cli_output (vm, "num of virtqueue 0x%x", data_u16);
+  virtio_pci_legacy_read_config (vm, vif, &data_u16, sizeof (u16),	/* offset to mtu */
+				 10);
+  vlib_cli_output (vm, "mtu 0x%x", data_u16);
+
+  u32 i = PCI_CONFIG_SIZE + 12, a = 4;
+  i += a;
+  i &= ~a;
+  for (; i < 64; i += 4)
+    {
+      u32 data = 0;
+      vlib_pci_read_io_u32 (vm, vif->pci_dev_handle, i, &data);
+      vlib_cli_output (vm, "0x%lx", data);
+    }
+}
+
+static u8
+virtio_pci_queue_size_valid (u16 qsz)
+{
+  if (qsz < 64 || qsz > 4096)
+    return 0;
+  if ((qsz % 64) != 0)
+    return 0;
+  return 1;
+}
+
+clib_error_t *
+virtio_pci_vring_init (vlib_main_t * vm, virtio_if_t * vif, u16 idx)
+{
+  clib_error_t *error = 0;
+  u16 queue_size = 0;
+  virtio_vring_t *vring;
+  struct vring vr;
+  u32 i = 0;
+  void *ptr;
+
+  queue_size = virtio_pci_legacy_get_queue_num (vm, vif, idx);
+  if (!virtio_pci_queue_size_valid (queue_size))
+    clib_warning ("queue size is not valid");
+
+  if (!is_pow2 (queue_size))
+    return clib_error_return (0, "ring size must be power of 2");
+
+  if (queue_size > 32768)
+    return clib_error_return (0, "ring size must be 32768 or lower");
+
+  if (queue_size == 0)
+    queue_size = 256;
+
+  vec_validate_aligned (vif->vrings, idx, CLIB_CACHE_LINE_BYTES);
+  vring = vec_elt_at_index (vif->vrings, idx);
+
+  i = vring_size (queue_size, VIRTIO_PCI_VRING_ALIGN);
+  i = round_pow2 (i, VIRTIO_PCI_VRING_ALIGN);
+  ptr = vlib_physmem_alloc_aligned (vm, i, VIRTIO_PCI_VRING_ALIGN);
+  memset (ptr, 0, i);
+  vring_init (&vr, queue_size, ptr, VIRTIO_PCI_VRING_ALIGN);
+  vring->desc = vr.desc;
+  vring->avail = vr.avail;
+  vring->used = vr.used;
+  vring->queue_id = idx;
+  vring->avail->flags = VIRTIO_RING_FLAG_MASK_INT;
+
+  ASSERT (vring->buffers == 0);
+  vec_validate_aligned (vring->buffers, queue_size, CLIB_CACHE_LINE_BYTES);
+  ASSERT (vring->indirect_buffers == 0);
+  vec_validate_aligned (vring->indirect_buffers, queue_size,
+			CLIB_CACHE_LINE_BYTES);
+  if (idx % 2)
+    {
+      u32 n_alloc = 0;
+      do
+	{
+	  if (n_alloc < queue_size)
+	    n_alloc =
+	      vlib_buffer_alloc (vm, vring->indirect_buffers + n_alloc,
+				 queue_size - n_alloc);
+	}
+      while (n_alloc != queue_size);
+      vif->tx_ring_sz = queue_size;
+    }
+  else
+    vif->rx_ring_sz = queue_size;
+  vring->size = queue_size;
+
+  virtio_pci_legacy_setup_queue (vm, vif, idx, ptr);
+  vring->kick_fd = -1;
+
+  return error;
+}
+
+static void
+virtio_negotiate_features (vlib_main_t * vm, virtio_if_t * vif,
+			   u64 req_features)
+{
+  /*
+   * if features are not requested
+   * default: all supported features
+   */
+  u64 supported_features = VIRTIO_FEATURE (VIRTIO_NET_F_MTU)
+    | VIRTIO_FEATURE (VIRTIO_NET_F_MAC)
+    | VIRTIO_FEATURE (VIRTIO_NET_F_MRG_RXBUF)
+    | VIRTIO_FEATURE (VIRTIO_NET_F_STATUS)
+    | VIRTIO_FEATURE (VIRTIO_F_ANY_LAYOUT)
+    | VIRTIO_FEATURE (VIRTIO_RING_F_INDIRECT_DESC);
+
+  if (req_features == 0)
+    {
+      req_features = supported_features;
+    }
+
+  vif->features = req_features & vif->remote_features & supported_features;
+
+  if (vif->
+      remote_features & vif->features & VIRTIO_FEATURE (VIRTIO_NET_F_MTU))
+    {
+      virtio_net_config_t config;
+      virtio_pci_legacy_read_config (vm, vif, &config.mtu,
+				     sizeof (config.mtu), 10);
+      if (config.mtu < 64)
+	vif->features &= ~VIRTIO_FEATURE (VIRTIO_NET_F_MTU);
+    }
+
+  vif->features = virtio_pci_legacy_set_features (vm, vif, vif->features);
+}
+
+void
+virtio_pci_read_device_feature (vlib_main_t * vm, virtio_if_t * vif)
+{
+  vif->remote_features = virtio_pci_legacy_get_features (vm, vif);
+}
+
+int
+virtio_pci_reset_device (vlib_main_t * vm, virtio_if_t * vif)
+{
+  u8 status = 0;
+
+  /*
+   * Reset the device
+   */
+  status = virtio_pci_legacy_reset (vm, vif);
+
+  /*
+   * Set the Acknowledge status bit
+   */
+  virtio_pci_legacy_set_status (vm, vif, VIRTIO_CONFIG_STATUS_ACK);
+
+  /*
+   * Set the Driver status bit
+   */
+  virtio_pci_legacy_set_status (vm, vif, VIRTIO_CONFIG_STATUS_DRIVER);
+
+  /*
+   * Read the status and verify it
+   */
+  status = virtio_pci_legacy_get_status (vm, vif);
+  if (!
+      ((status & VIRTIO_CONFIG_STATUS_ACK)
+       && (status & VIRTIO_CONFIG_STATUS_DRIVER)))
+    return -1;
+  vif->status = status;
+
+  return 0;
+}
+
+clib_error_t *
+virtio_pci_read_caps (vlib_main_t * vm, virtio_if_t * vif)
+{
+  clib_error_t *error = 0;
+  struct virtio_pci_cap cap;
+  u8 pos, common_cfg = 0, notify_base = 0, dev_cfg = 0, isr = 0;
+  vlib_pci_dev_handle_t h = vif->pci_dev_handle;
+
+  if ((error = vlib_pci_read_config_u8 (vm, h, PCI_CAPABILITY_LIST, &pos)))
+    clib_error_return (error, "error in reading capabilty list position");
+
+  while (pos)
+    {
+      if ((error =
+	   vlib_pci_read_write_config (vm, h, VLIB_READ, pos, &cap,
+				       sizeof (cap))))
+	clib_error_return (error, "error in reading the capability at [%2x]",
+			   pos);
+
+      if (cap.cap_vndr == PCI_CAP_ID_MSIX)
+	{
+	  u16 flags;
+	  if ((error =
+	       vlib_pci_read_write_config (vm, h, VLIB_READ, pos + 2, &flags,
+					   sizeof (flags))))
+	    clib_error_return (error,
+			       "error in reading the capability at [%2x]",
+			       pos + 2);
+
+	  if (flags & PCI_MSIX_ENABLE)
+	    msix_enabled = VIRTIO_MSIX_ENABLED;
+	  else
+	    msix_enabled = VIRTIO_MSIX_DISABLED;
+	}
+
+      if (cap.cap_vndr != PCI_CAP_ID_VNDR)
+	{
+	  clib_warning ("[%2x] skipping non VNDR cap id: %2x", pos,
+			cap.cap_vndr);
+	  goto next;
+	}
+
+      switch (cap.cfg_type)
+	{
+	case VIRTIO_PCI_CAP_COMMON_CFG:
+	  common_cfg = 1;
+	  break;
+	case VIRTIO_PCI_CAP_NOTIFY_CFG:
+	  notify_base = 1;
+	  break;
+	case VIRTIO_PCI_CAP_DEVICE_CFG:
+	  dev_cfg = 1;
+	  break;
+	case VIRTIO_PCI_CAP_ISR_CFG:
+	  isr = 1;
+	  break;
+	}
+    next:
+      pos = cap.cap_next;
+    }
+
+  if (common_cfg == 0 || notify_base == 0 || dev_cfg == 0 || isr == 0)
+    {
+      clib_warning ("no modern virtio pci device found");
+      return error;
+    }
+
+  return clib_error_return (error, "modern virtio pci device found");
+}
+
+static clib_error_t *
+virtio_pci_device_init (vlib_main_t * vm, virtio_if_t * vif,
+			virtio_pci_create_if_args_t * args)
+{
+  clib_error_t *error = 0;
+  u8 status = 0;
+
+  virtio_pci_read_caps (vm, vif);
+
+  if (virtio_pci_reset_device (vm, vif) < 0)
+    clib_error_return (error, "Failed to reset the device");
+
+  /*
+   * read device features and negotiate (user) requested features
+   */
+  virtio_pci_read_device_feature (vm, vif);
+  virtio_negotiate_features (vm, vif, args->features);
+
+  /*
+   * After FEATURE_OK, driver should not accept new feature bits
+   */
+  virtio_pci_legacy_set_status (vm, vif, VIRTIO_CONFIG_STATUS_FEATURES_OK);
+  status = virtio_pci_legacy_get_status (vm, vif);
+  if (!(status & VIRTIO_CONFIG_STATUS_FEATURES_OK))
+    clib_error_return (error, "Device doesn't support requested features");
+
+  vif->status = status;
+
+  if (virtio_pci_get_mac (vm, vif))
+    {
+      f64 now = vlib_time_now (vm);
+      u32 rnd;
+      rnd = (u32) (now * 1e6);
+      rnd = random_u32 (&rnd);
+
+      memcpy (vif->mac_addr + 2, &rnd, sizeof (rnd));
+      vif->mac_addr[0] = 2;
+      vif->mac_addr[1] = 0xfe;
+      virtio_pci_set_mac (vm, vif);
+    }
+
+  virtio_set_net_hdr_size (vif);
+
+  if ((error = virtio_pci_get_max_virtqueue_pairs (vm, vif)))
+    goto error;
+
+  if ((error = virtio_pci_vring_init (vm, vif, 0)))
+    goto error;
+
+  if ((error = virtio_pci_vring_init (vm, vif, 1)))
+    goto error;
+
+  if (msix_enabled == VIRTIO_MSIX_ENABLED)
+    {
+      virtio_pci_legacy_set_config_irq (vm, vif, VIRTIO_MSI_NO_VECTOR);
+      virtio_pci_legacy_set_queue_irq (vm, vif, VIRTIO_MSI_NO_VECTOR, 0);
+    }
+  virtio_pci_legacy_set_status (vm, vif, VIRTIO_CONFIG_STATUS_DRIVER_OK);
+  vif->status = virtio_pci_legacy_get_status (vm, vif);
+error:
+  return error;
+}
+
+void
+virtio_pci_create_if (vlib_main_t * vm, virtio_pci_create_if_args_t * args)
+{
+  vnet_main_t *vnm = vnet_get_main ();
+  virtio_main_t *vmxm = &virtio_main;
+  virtio_if_t *vif;
+  vlib_pci_dev_handle_t h;
+  clib_error_t *error = 0;
+
+  if (args->rxq_size == 0)
+    args->rxq_size = VIRTIO_NUM_RX_DESC;
+  if (args->txq_size == 0)
+    args->txq_size = VIRTIO_NUM_TX_DESC;
+
+  if (!virtio_pci_queue_size_valid (args->rxq_size) ||
+      !virtio_pci_queue_size_valid (args->txq_size))
+    {
+      args->rv = VNET_API_ERROR_INVALID_VALUE;
+      args->error =
+	clib_error_return (error,
+			   "queue size must be <= 4096, >= 64, "
+			   "and multiples of 64");
+      return;
+    }
+
+  /* *INDENT-OFF* */
+  pool_foreach (vif, vmxm->interfaces, ({
+    if (vif->pci_addr.as_u32 == args->addr)
+      {
+	args->rv = VNET_API_ERROR_INVALID_VALUE;
+	args->error =
+	  clib_error_return (error, "PCI address in use");
+	return;
+      }
+  }));
+  /* *INDENT-ON* */
+
+  pool_get (vmxm->interfaces, vif);
+  vif->dev_instance = vif - vmxm->interfaces;
+  vif->per_interface_next_index = ~0;
+  vif->pci_addr.as_u32 = args->addr;
+
+  if ((vif->fd = open ("/dev/vhost-net", O_RDWR | O_NONBLOCK)) < 0)
+    {
+      args->rv = VNET_API_ERROR_SYSCALL_ERROR_1;
+      args->error = clib_error_return_unix (0, "open '/dev/vhost-net'");
+      goto error;
+    }
+
+  if ((error =
+       vlib_pci_device_open (vm, (vlib_pci_addr_t *) & vif->pci_addr,
+			     virtio_pci_device_ids, &h)))
+    {
+      pool_put (vmxm->interfaces, vif);
+      args->rv = VNET_API_ERROR_INVALID_INTERFACE;
+      args->error =
+	clib_error_return (error, "pci-addr %U", format_vlib_pci_addr,
+			   &vif->pci_addr);
+      return;
+    }
+  vif->pci_dev_handle = h;
+  vlib_pci_set_private_data (vm, h, vif->dev_instance);
+
+  if ((error = vlib_pci_bus_master_enable (vm, h)))
+    goto error;
+
+  if ((error = vlib_pci_io_region (vm, h, 0)))
+    goto error;
+
+  if ((error = virtio_pci_device_init (vm, vif, args)))
+    goto error;
+
+  if (msix_enabled == VIRTIO_MSIX_ENABLED)
+    {
+      if ((error = vlib_pci_register_msix_handler (vm, h, 0, 1,
+						   &virtio_pci_irq_0_handler)))
+	goto error;
+
+      if ((error = vlib_pci_register_msix_handler (vm, h, 1, 1,
+						   &virtio_pci_irq_1_handler)))
+	goto error;
+
+      if ((error = vlib_pci_enable_msix_irq (vm, h, 0, 2)))
+	goto error;
+    }
+  else
+    {
+      vlib_pci_register_intx_handler (vm, h, &virtio_pci_irq_handler);
+    }
+
+  if ((error = vlib_pci_intr_enable (vm, h)))
+    goto error;
+
+  vif->type = VIRTIO_IF_TYPE_PCI;
+  /* create interface */
+  error = ethernet_register_interface (vnm, virtio_device_class.index,
+				       vif->dev_instance, vif->mac_addr,
+				       &vif->hw_if_index,
+				       virtio_pci_flag_change);
+
+  if (error)
+    goto error;
+
+  vnet_sw_interface_t *sw = vnet_get_hw_sw_interface (vnm, vif->hw_if_index);
+  vif->sw_if_index = sw->sw_if_index;
+  args->sw_if_index = sw->sw_if_index;
+
+  vnet_hw_interface_t *hw = vnet_get_hw_interface (vnm, vif->hw_if_index);
+  hw->flags |= VNET_HW_INTERFACE_FLAG_SUPPORTS_INT_MODE;
+  vnet_hw_interface_set_input_node (vnm, vif->hw_if_index,
+				    virtio_input_node.index);
+  vnet_hw_interface_assign_rx_thread (vnm, vif->hw_if_index, 0, ~0);
+
+  if (virtio_pci_is_link_up (vm, vif) & VIRTIO_NET_S_LINK_UP)
+    {
+      vif->flags |= VIRTIO_IF_FLAG_ADMIN_UP;
+      vnet_hw_interface_set_flags (vnm, vif->hw_if_index,
+				   VNET_HW_INTERFACE_FLAG_LINK_UP);
+    }
+  else
+    vnet_hw_interface_set_flags (vnm, vif->hw_if_index, 0);
+  return;
+
+error:
+  virtio_pci_delete_if (vm, vif);
+  args->rv = VNET_API_ERROR_INVALID_INTERFACE;
+  args->error = error;
+}
+
+int
+virtio_pci_delete_if (vlib_main_t * vm, virtio_if_t * vif)
+{
+  vnet_main_t *vnm = vnet_get_main ();
+  virtio_main_t *vmxm = &virtio_main;
+  u32 i = 0;
+
+  if (vif->type != VIRTIO_IF_TYPE_PCI)
+    return VNET_API_ERROR_INVALID_INTERFACE;
+
+  vlib_pci_intr_disable (vm, vif->pci_dev_handle);
+
+  virtio_pci_legacy_del_queue (vm, vif, 0);
+  virtio_pci_legacy_del_queue (vm, vif, 1);
+
+  virtio_pci_legacy_reset (vm, vif);
+
+  if (vif->hw_if_index)
+    {
+      vnet_hw_interface_set_flags (vnm, vif->hw_if_index, 0);
+      vnet_hw_interface_unassign_rx_thread (vnm, vif->hw_if_index, 0);
+      ethernet_delete_interface (vnm, vif->hw_if_index);
+    }
+
+  vlib_pci_device_close (vm, vif->pci_dev_handle);
+
+  vec_foreach_index (i, vif->vrings)
+  {
+    virtio_vring_t *vring = vec_elt_at_index (vif->vrings, i);
+    if (vring->kick_fd != -1)
+      close (vring->kick_fd);
+    if (vring->used)
+      {
+	if ((i & 1) == 1)
+	  virtio_free_used_desc (vm, vring);
+	else
+	  virtio_free_rx_buffers (vm, vring);
+      }
+    if (vring->queue_id % 2)
+      {
+	vlib_buffer_free_no_next (vm, vring->indirect_buffers, vring->size);
+      }
+    vec_free (vring->buffers);
+    vec_free (vring->indirect_buffers);
+    vlib_physmem_free (vm, vring->desc);
+  }
+
+  vec_free (vif->vrings);
+
+  if (vif->fd != -1)
+    close (vif->fd);
+  if (vif->tap_fd != -1)
+    vif->tap_fd = -1;
+  clib_error_free (vif->error);
+  memset (vif, 0, sizeof (*vif));
+  pool_put (vmxm->interfaces, vif);
+
+  return 0;
+}
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */