[dpdk-dev] [PATCH 21/28] drivers/virtio_vhost_user: use additional device resources

[Nikos Dragazis <ndragazis@arrikto.com>]

Enhance the virtio-vhost-user device driver so that it utilizes the
device's additional resource capabilities. In specific, this patch adds
support for the doorbells and shared_memory capabilities. The former is
used to find the location of the device doorbells. The latter is used to
find the location of the vhost memory regions in the device's memory
address space. Also, support has been added for the notification
capability, though this configuration structure is not currently being
used by the virtio-vhost-user driver due to DPDK's poll-mode nature.

Signed-off-by: Nikos Dragazis <ndragazis@arrikto.com>
---
 .../virtio_vhost_user/trans_virtio_vhost_user.c    | 22 ++++++++++++++--------
 drivers/virtio_vhost_user/virtio_pci.c             | 16 ++++++++++++++++
 drivers/virtio_vhost_user/virtio_pci.h             | 19 +++++++++++++++++++
 3 files changed, 49 insertions(+), 8 deletions(-)

diff --git a/drivers/virtio_vhost_user/trans_virtio_vhost_user.c b/drivers/virtio_vhost_user/trans_virtio_vhost_user.c
index 72018a4..45863bd 100644
--- a/drivers/virtio_vhost_user/trans_virtio_vhost_user.c
+++ b/drivers/virtio_vhost_user/trans_virtio_vhost_user.c
@@ -198,11 +198,14 @@ vvu_vring_call(struct virtio_net *dev, struct vhost_virtqueue *vq)
 	struct vvu_connection *conn =
 		container_of(dev, struct vvu_connection, device);
 	struct vvu_socket *vvu_socket = conn->vvu_socket;
+	struct virtio_hw *hw = &vvu_socket->pdev->hw;
 	uint16_t vq_idx = vq->vring_idx;
+	uint16_t *notify_addr = (void *)((uint8_t *)vvu_socket->doorbells +
+				vq_idx * hw->doorbell_off_multiplier);
 
 	RTE_LOG(DEBUG, VHOST_CONFIG, "%s vq_idx %u\n", __func__, vq_idx);
 
-	rte_write16(rte_cpu_to_le_16(vq_idx), &vvu_socket->doorbells[vq_idx]);
+	rte_write16(rte_cpu_to_le_16(vq_idx), notify_addr);
 	return 0;
 }
 
@@ -265,14 +268,14 @@ vvu_map_mem_regions(struct virtio_net *dev, struct VhostUserMsg *msg __rte_unuse
 	struct vvu_connection *conn =
 		container_of(dev, struct vvu_connection, device);
 	struct vvu_socket *vvu_socket = conn->vvu_socket;
-	struct rte_pci_device *pci_dev = vvu_socket->pdev->pci_dev;
+	struct virtio_hw *hw = &vvu_socket->pdev->hw;
 	uint8_t *mmap_addr;
 	uint32_t i;
 
-	/* Memory regions start after the doorbell registers */
-	mmap_addr = (uint8_t *)pci_dev->mem_resource[2].addr +
-		    RTE_ALIGN_CEIL((vvu_socket->max_vhost_queues + 1 /* log fd */) *
-				   sizeof(uint16_t), 4096);
+	/* Get the starting address of vhost memory regions from
+	 * the shared memory virtio PCI capability
+	 */
+	mmap_addr = hw->shared_memory_cfg;
 
 	for (i = 0; i < dev->mem->nregions; i++) {
 		struct rte_vhost_mem_region *reg = &dev->mem->regions[i];
@@ -780,10 +783,13 @@ vvu_virtio_pci_init_intr(struct vvu_socket *vvu_socket)
 static int
 vvu_virtio_pci_init_bar(struct vvu_socket *vvu_socket)
 {
-	struct rte_pci_device *pci_dev = vvu_socket->pdev->pci_dev;
+	struct virtio_hw *hw = &vvu_socket->pdev->hw;
 	struct virtio_net *dev = NULL; /* just for sizeof() */
 
-	vvu_socket->doorbells = pci_dev->mem_resource[2].addr;
+	/* Get the starting address of the doorbells from
+	 * the doorbell virtio PCI capability
+	 */
+	vvu_socket->doorbells = hw->doorbell_base;
 	if (!vvu_socket->doorbells) {
 		RTE_LOG(ERR, VHOST_CONFIG, "BAR 2 not available\n");
 		return -1;
diff --git a/drivers/virtio_vhost_user/virtio_pci.c b/drivers/virtio_vhost_user/virtio_pci.c
index 9c2c981..7996729 100644
--- a/drivers/virtio_vhost_user/virtio_pci.c
+++ b/drivers/virtio_vhost_user/virtio_pci.c
@@ -1,5 +1,6 @@
 /* SPDX-License-Identifier: BSD-3-Clause
  * Copyright(c) 2010-2014 Intel Corporation
+ * Copyright(c) 2019 Arrikto Inc.
  */
 #include <stdint.h>
 
@@ -407,6 +408,18 @@ virtio_read_caps(struct rte_pci_device *dev, struct virtio_hw *hw)
 		case VIRTIO_PCI_CAP_ISR_CFG:
 			hw->isr = get_cfg_addr(dev, &cap);
 			break;
+		case VIRTIO_PCI_CAP_DOORBELL_CFG:
+			rte_pci_read_config(dev, &hw->doorbell_off_multiplier,
+					4, pos + sizeof(cap));
+			hw->doorbell_base = get_cfg_addr(dev, &cap);
+			rte_pci_read_config(dev, &hw->doorbell_length, 4, pos + 10);
+			break;
+		case VIRTIO_PCI_CAP_NOTIFICATION_CFG:
+			hw->notify_cfg = get_cfg_addr(dev, &cap);
+			break;
+		case VIRTIO_PCI_CAP_SHARED_MEMORY_CFG:
+			hw->shared_memory_cfg = get_cfg_addr(dev, &cap);
+			break;
 		}
 
 next:
@@ -426,6 +439,9 @@ virtio_read_caps(struct rte_pci_device *dev, struct virtio_hw *hw)
 	RTE_LOG(DEBUG, VIRTIO_PCI_CONFIG, "isr cfg mapped at: %p\n", hw->isr);
 	RTE_LOG(DEBUG, VIRTIO_PCI_CONFIG, "notify base: %p, notify off multiplier: %u\n",
 		hw->notify_base, hw->notify_off_multiplier);
+	RTE_LOG(DEBUG, VIRTIO_PCI_CONFIG, "doorbell base: %p, doorbell off multiplier: %u\n", hw->doorbell_base, hw->doorbell_off_multiplier);
+	RTE_LOG(DEBUG, VIRTIO_PCI_CONFIG, "notification cfg mapped at: %p\n", hw->notify_cfg);
+	RTE_LOG(DEBUG, VIRTIO_PCI_CONFIG, "shared memory region mapped at: %p\n", hw->shared_memory_cfg);
 
 	return 0;
 }
diff --git a/drivers/virtio_vhost_user/virtio_pci.h b/drivers/virtio_vhost_user/virtio_pci.h
index 018e0b7..12373d1 100644
--- a/drivers/virtio_vhost_user/virtio_pci.h
+++ b/drivers/virtio_vhost_user/virtio_pci.h
@@ -1,5 +1,6 @@
 /* SPDX-License-Identifier: BSD-3-Clause
  * Copyright(c) 2010-2014 Intel Corporation
+ * Copyright(c) 2019 Arrikto Inc.
  */
 
 /* XXX This file is based on drivers/net/virtio/virtio_pci.h.  It would be
@@ -117,6 +118,10 @@ struct virtqueue;
 #define VIRTIO_PCI_CAP_DEVICE_CFG	4
 /* PCI configuration access */
 #define VIRTIO_PCI_CAP_PCI_CFG		5
+/* Additional capabilities for the virtio-vhost-user device */
+#define VIRTIO_PCI_CAP_DOORBELL_CFG    6
+#define VIRTIO_PCI_CAP_NOTIFICATION_CFG 7
+#define VIRTIO_PCI_CAP_SHARED_MEMORY_CFG 8
 
 /* This is the PCI capability header: */
 struct virtio_pci_cap {
@@ -161,6 +166,12 @@ struct virtio_pci_common_cfg {
 	uint32_t queue_used_hi;		/* read-write */
 };
 
+/* Fields in VIRTIO_PCI_CAP_NOTIFICATION_CFG */
+struct virtio_pci_notification_cfg {
+	uint16_t notification_select;              /* read-write */
+	uint16_t notification_msix_vector;         /* read-write */
+};
+
 struct virtio_hw;
 
 struct virtio_pci_ops {
@@ -200,6 +211,14 @@ struct virtio_hw {
 	uint16_t    *notify_base;
 	struct virtio_pci_common_cfg *common_cfg;
 	void	    *dev_cfg;
+	/* virtio-vhost-user additional device resource capabilities
+	 * https://stefanha.github.io/virtio/vhost-user-slave.html#x1-2830007
+	 */
+	uint32_t    doorbell_off_multiplier;
+	uint16_t    *doorbell_base;
+	uint32_t     doorbell_length;
+	struct virtio_pci_notification_cfg *notify_cfg;
+	uint8_t     *shared_memory_cfg;
 	/*
 	 * App management thread and virtio interrupt handler thread
 	 * both can change device state, this lock is meant to avoid
-- 
2.7.4