dm: virtio: add vhost support

This patch adds the vhost support to the device model virtio. A vhost
proxy is implemented based on the virtio framework and vhost char dev.
Key data structures and external interfaces are implemented in this
patch.

Tracked-On: #1329
Signed-off-by: Jian Jun Chen <jian.jun.chen@intel.com>
Acked-by: Yu Wang <yu1.wang@intel.com>

devicemodel/Makefile

@@ -62,6 +62,7 @@ SRCS += hw/usb_core.c
 SRCS += hw/uart_core.c
 SRCS += hw/pci/virtio/virtio.c
 SRCS += hw/pci/virtio/virtio_kernel.c
+SRCS += hw/pci/virtio/vhost.c
 SRCS += hw/platform/usb_mouse.c
 SRCS += hw/platform/usb_pmapper.c
 SRCS += hw/platform/atkbdc.c

devicemodel/hw/pci/virtio/vhost.c

@@ -0,0 +1,328 @@
+/*
+ * Copyright (C) 2018 Intel Corporation. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ */
+
+#include <sys/cdefs.h>
+#include <sys/param.h>
+#include <sys/uio.h>
+#include <sys/ioctl.h>
+#include <sys/eventfd.h>
+#include <errno.h>
+#include <stdarg.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <unistd.h>
+#include <pthread.h>
+#include <linux/vhost.h>
+
+#include "dm.h"
+#include "pci_core.h"
+#include "irq.h"
+#include "vmmapi.h"
+#include "vhost.h"
+
+static int vhost_debug;
+#define LOG_TAG "vhost: "
+#define DPRINTF(fmt, args...) \
+	do { if (vhost_debug) printf(LOG_TAG fmt, ##args); } while (0)
+#define WPRINTF(fmt, args...) printf(LOG_TAG fmt, ##args)
+
+static void
+vhost_kernel_init(struct vhost_dev *vdev, struct virtio_base *base,
+		  int fd, int vq_idx, uint32_t busyloop_timeout)
+{
+	/* to be implemented */
+}
+
+static void
+vhost_kernel_deinit(struct vhost_dev *vdev)
+{
+	/* to be implemented */
+}
+
+static int
+vhost_kernel_set_vring_busyloop_timeout(struct vhost_dev *vdev,
+					struct vhost_vring_state *s)
+{
+	/* to be implemented */
+	return -1;
+}
+
+static int
+vhost_kernel_set_features(struct vhost_dev *vdev,
+			  uint64_t features)
+{
+	/* to be implemented */
+	return -1;
+}
+
+static int
+vhost_kernel_get_features(struct vhost_dev *vdev,
+			  uint64_t *features)
+{
+	/* to be implemented */
+	return -1;
+}
+
+static int
+vhost_kernel_set_owner(struct vhost_dev *vdev)
+{
+	/* to be implemented */
+	return -1;
+}
+
+static int
+vhost_kernel_reset_device(struct vhost_dev *vdev)
+{
+	/* to be implemented */
+	return -1;
+}
+
+static int
+vhost_kernel_net_set_backend(struct vhost_dev *vdev,
+			     struct vhost_vring_file *file)
+{
+	/* to be implemented */
+	return -1;
+}
+
+static int
+vhost_vq_init(struct vhost_dev *vdev, int idx)
+{
+	/* to be implemented */
+	return -1;
+}
+
+static int
+vhost_vq_deinit(struct vhost_vq *vq)
+{
+	/* to be implemented */
+	return -1;
+}
+
+static int
+vhost_vq_start(struct vhost_dev *vdev, int idx)
+{
+	/* to be implemented */
+	return -1;
+}
+
+static int
+vhost_vq_stop(struct vhost_dev *vdev, int idx)
+{
+	/* to be implemented */
+	return -1;
+}
+
+static int
+vhost_set_mem_table(struct vhost_dev *vdev)
+{
+	/* to be implemented */
+	return -1;
+}
+
+int
+vhost_dev_init(struct vhost_dev *vdev,
+	       struct virtio_base *base,
+	       int fd,
+	       int vq_idx,
+	       uint64_t vhost_features,
+	       uint64_t vhost_ext_features,
+	       uint32_t busyloop_timeout)
+{
+	uint64_t features;
+	int i, rc;
+
+	/* sanity check */
+	if (!base || !base->queues || !base->vops) {
+		WPRINTF("virtio_base is not initialized\n");
+		goto fail;
+	}
+
+	if (!vdev->vqs || vdev->nvqs == 0) {
+		WPRINTF("virtqueue is not initialized\n");
+		goto fail;
+	}
+
+	if (vq_idx + vdev->nvqs > base->vops->nvq) {
+		WPRINTF("invalid vq_idx: %d\n", vq_idx);
+		goto fail;
+	}
+
+	vhost_kernel_init(vdev, base, fd, vq_idx, busyloop_timeout);
+
+	rc = vhost_kernel_get_features(vdev, &features);
+	if (rc < 0) {
+		WPRINTF("vhost_get_features failed\n");
+		goto fail;
+	}
+
+	for (i = 0; i < vdev->nvqs; i++) {
+		rc = vhost_vq_init(vdev, i);
+		if (rc < 0)
+			goto fail;
+	}
+
+	/* specific backend features to vhost */
+	vdev->vhost_ext_features = vhost_ext_features & features;
+
+	/* features supported by vhost */
+	vdev->vhost_features = vhost_features & features;
+
+	/*
+	 * If the features bits are not supported by either vhost kernel
+	 * mediator or configuration of device model(specified by
+	 * vhost_features), they should be disabled in device_caps,
+	 * which expose as virtio host_features for virtio FE driver.
+	 */
+	vdev->base->device_caps &= ~(vhost_features ^ features);
+	vdev->started = false;
+
+	return 0;
+
+fail:
+	vhost_dev_deinit(vdev);
+	return -1;
+}
+
+int
+vhost_dev_deinit(struct vhost_dev *vdev)
+{
+	int i;
+
+	if (!vdev->base || !vdev->base->queues || !vdev->base->vops)
+		return -1;
+
+	for (i = 0; i < vdev->nvqs; i++)
+		vhost_vq_deinit(&vdev->vqs[i]);
+
+	vhost_kernel_deinit(vdev);
+
+	return 0;
+}
+
+int
+vhost_dev_start(struct vhost_dev *vdev)
+{
+	struct vhost_vring_state state;
+	uint64_t features;
+	int i, rc;
+
+	if (vdev->started)
+		return 0;
+
+	/* sanity check */
+	if (!vdev->base || !vdev->base->queues || !vdev->base->vops) {
+		WPRINTF("virtio_base is not initialized\n");
+		goto fail;
+	}
+
+	if ((vdev->base->status & VIRTIO_CR_STATUS_DRIVER_OK) == 0) {
+		WPRINTF("status error 0x%x\n", vdev->base->status);
+		goto fail;
+	}
+
+	rc = vhost_kernel_set_owner(vdev);
+	if (rc < 0) {
+		WPRINTF("vhost_set_owner failed\n");
+		goto fail;
+	}
+
+	/* set vhost internal features */
+	features = (vdev->base->negotiated_caps & vdev->vhost_features) |
+		vdev->vhost_ext_features;
+	rc = vhost_kernel_set_features(vdev, features);
+	if (rc < 0) {
+		WPRINTF("set_features failed\n");
+		goto fail;
+	}
+	DPRINTF("set_features: 0x%lx\n", features);
+
+	/* set memory table */
+	rc = vhost_set_mem_table(vdev);
+	if (rc < 0) {
+		WPRINTF("set_mem_table failed\n");
+		goto fail;
+	}
+
+	/* config busyloop timeout */
+	if (vdev->busyloop_timeout) {
+		state.num = vdev->busyloop_timeout;
+		for (i = 0; i < vdev->nvqs; i++) {
+			state.index = i;
+			rc = vhost_kernel_set_vring_busyloop_timeout(vdev,
+				&state);
+			if (rc < 0) {
+				WPRINTF("set_busyloop_timeout failed\n");
+				goto fail;
+			}
+		}
+	}
+
+	/* start vhost virtqueue */
+	for (i = 0; i < vdev->nvqs; i++) {
+		rc = vhost_vq_start(vdev, i);
+		if (rc < 0)
+			goto fail_vq;
+	}
+
+	vdev->started = true;
+	return 0;
+
+fail_vq:
+	while (--i >= 0)
+		vhost_vq_stop(vdev, i);
+fail:
+	return -1;
+}
+
+int
+vhost_dev_stop(struct vhost_dev *vdev)
+{
+	int i, rc = 0;
+
+	for (i = 0; i < vdev->nvqs; i++)
+		vhost_vq_stop(vdev, i);
+
+	/* the following are done by this ioctl:
+	 * 1) resources of the vhost dev are freed
+	 * 2) vhost virtqueues are reset
+	 */
+	rc = vhost_kernel_reset_device(vdev);
+	if (rc < 0) {
+		WPRINTF("vhost_reset_device failed\n");
+		rc = -1;
+	}
+
+	vdev->started = false;
+	return rc;
+}
+
+int
+vhost_net_set_backend(struct vhost_dev *vdev, int backend_fd)
+{
+	struct vhost_vring_file file;
+	int rc, i;
+
+	file.fd = backend_fd;
+	for (i = 0; i < vdev->nvqs; i++) {
+		file.index = i;
+		rc = vhost_kernel_net_set_backend(vdev, &file);
+		if (rc < 0)
+			goto fail;
+	}
+
+	return 0;
+fail:
+	file.fd = -1;
+	while (--i >= 0) {
+		file.index = i;
+		vhost_kernel_net_set_backend(vdev, &file);
+	}
+
+	return -1;
+}

devicemodel/include/vhost.h

@@ -0,0 +1,136 @@
+/*
+ * Copyright (C) 2018 Intel Corporation. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ */
+
+#ifndef __VHOST_H__
+#define __VHOST_H__
+
+#include "virtio.h"
+#include "mevent.h"
+
+struct vhost_vq {
+	int kick_fd;		/**< fd of kick eventfd */
+	int call_fd;		/**< fd of call eventfd */
+	int idx;		/**< index of this vq in vhost dev */
+	struct mevent *mevp;	/**< mevent for call eventfd */
+	struct vhost_dev *dev;	/**< pointer to vhost_dev */
+};
+
+struct vhost_dev {
+	/**
+	 * backpointer to virtio_base
+	 */
+	struct virtio_base *base;
+
+	/**
+	 * pointer to vhost_vq array
+	 */
+	struct vhost_vq *vqs;
+
+	/**
+	 * number of virtqueues
+	 */
+	int nvqs;
+
+	/**
+	 * vhost chardev fd
+	 */
+	int fd;
+
+	/**
+	 * first vq's index in virtio_vq_info
+	 */
+	int vq_idx;
+
+	/**
+	 * supported virtio defined features
+	 */
+	uint64_t vhost_features;
+
+	/**
+	 * vhost self-defined internal features bits used for
+	 * communicate between vhost user-space and kernel-space modules
+	 */
+	uint64_t vhost_ext_features;
+
+	/**
+	 * vq busyloop timeout in us
+	 */
+	uint32_t busyloop_timeout;
+
+	/**
+	 * whether vhost is started
+	 */
+	bool started;
+};
+
+/**
+ * @brief vhost_dev initialization.
+ *
+ * This interface is called to initialize the vhost_dev. It must be called
+ * before the actual feature negoitiation with the guest OS starts.
+ *
+ * @param vdev Pointer to struct vhost_dev.
+ * @param base Pointer to struct virtio_base.
+ * @param fd fd of the vhost chardev.
+ * @param vq_idx The first virtqueue which would be used by this vhost dev.
+ * @param vhost_features Subset of vhost features which would be enabled.
+ * @param vhost_ext_features Specific vhost internal features to be enabled.
+ * @param busyloop_timeout Busy loop timeout in us.
+ *
+ * @return 0 on success and -1 on failure.
+ */
+int vhost_dev_init(struct vhost_dev *vdev, struct virtio_base *base, int fd,
+		   int vq_idx, uint64_t vhost_features,
+		   uint64_t vhost_ext_features, uint32_t busyloop_timeout);
+
+/**
+ * @brief vhost_dev cleanup.
+ *
+ * This interface is called to cleanup the vhost_dev.
+ *
+ * @param vdev Pointer to struct vhost_dev.
+ *
+ * @return 0 on success and -1 on failure.
+ */
+int vhost_dev_deinit(struct vhost_dev *vdev);
+
+/**
+ * @brief start vhost data plane.
+ *
+ * This interface is called to start the data plane in vhost.
+ *
+ * @param vdev Pointer to struct vhost_dev.
+ *
+ * @return 0 on success and -1 on failure.
+ */
+int vhost_dev_start(struct vhost_dev *vdev);
+
+/**
+ * @brief stop vhost data plane.
+ *
+ * This interface is called to stop the data plane in vhost.
+ *
+ * @param vdev Pointer to struct vhost_dev.
+ *
+ * @return 0 on success and -1 on failure.
+ */
+int vhost_dev_stop(struct vhost_dev *vdev);
+
+/**
+ * @brief set backend fd of vhost net.
+ *
+ * This interface is called to set the backend fd (for example tap fd)
+ * to vhost.
+ *
+ * @param vdev Pointer to struct vhost_dev.
+ * @param backend_fd fd of backend (for example tap fd).
+ *
+ * @return 0 on success and -1 on failure.
+ */
+int vhost_net_set_backend(struct vhost_dev *vdev, int backend_fd);
+
+#endif