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Subject[PATCH V4 3/3] vdpa: introduce virtio pci driver
Date
This patch introduce a vDPA driver for virtio-pci device. It bridges
the virtio-pci control command to the vDPA bus. This will be used for
features prototyping and testing.

Note that get/restore virtqueue state is not supported which needs
extension on the virtio specification.

Signed-off-by: Jason Wang <jasowang@redhat.com>
---
drivers/vdpa/Kconfig | 7 +
drivers/vdpa/Makefile | 1 +
drivers/vdpa/virtio_pci/Makefile | 2 +
drivers/vdpa/virtio_pci/vp_vdpa.c | 458 ++++++++++++++++++++++++++++++
4 files changed, 468 insertions(+)
create mode 100644 drivers/vdpa/virtio_pci/Makefile
create mode 100644 drivers/vdpa/virtio_pci/vp_vdpa.c

diff --git a/drivers/vdpa/Kconfig b/drivers/vdpa/Kconfig
index ffd1e098bfd2..a245809c99d0 100644
--- a/drivers/vdpa/Kconfig
+++ b/drivers/vdpa/Kconfig
@@ -52,4 +52,11 @@ config MLX5_VDPA_NET
be executed by the hardware. It also supports a variety of stateless
offloads depending on the actual device used and firmware version.

+config VP_VDPA
+ tristate "Virtio PCI bridge vDPA driver"
+ select VIRTIO_PCI_LIB
+ depends on PCI_MSI
+ help
+ This kernel module bridges virtio PCI device to vDPA bus.
+
endif # VDPA
diff --git a/drivers/vdpa/Makefile b/drivers/vdpa/Makefile
index d160e9b63a66..67fe7f3d6943 100644
--- a/drivers/vdpa/Makefile
+++ b/drivers/vdpa/Makefile
@@ -3,3 +3,4 @@ obj-$(CONFIG_VDPA) += vdpa.o
obj-$(CONFIG_VDPA_SIM) += vdpa_sim/
obj-$(CONFIG_IFCVF) += ifcvf/
obj-$(CONFIG_MLX5_VDPA) += mlx5/
+obj-$(CONFIG_VP_VDPA) += virtio_pci/
diff --git a/drivers/vdpa/virtio_pci/Makefile b/drivers/vdpa/virtio_pci/Makefile
new file mode 100644
index 000000000000..231088d3af7d
--- /dev/null
+++ b/drivers/vdpa/virtio_pci/Makefile
@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_VP_VDPA) += vp_vdpa.o
diff --git a/drivers/vdpa/virtio_pci/vp_vdpa.c b/drivers/vdpa/virtio_pci/vp_vdpa.c
new file mode 100644
index 000000000000..1321a2fcd088
--- /dev/null
+++ b/drivers/vdpa/virtio_pci/vp_vdpa.c
@@ -0,0 +1,458 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * vDPA bridge driver for modern virtio-pci device
+ *
+ * Copyright (c) 2020, Red Hat Inc. All rights reserved.
+ * Author: Jason Wang <jasowang@redhat.com>
+ *
+ * Based on virtio_pci_modern.c.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/vdpa.h>
+#include <linux/virtio.h>
+#include <linux/virtio_config.h>
+#include <linux/virtio_ring.h>
+#include <linux/virtio_pci.h>
+#include <linux/virtio_pci_modern.h>
+
+#define VP_VDPA_QUEUE_MAX 256
+#define VP_VDPA_DRIVER_NAME "vp_vdpa"
+#define VP_VDPA_NAME_SIZE 256
+
+struct vp_vring {
+ void __iomem *notify;
+ char msix_name[VP_VDPA_NAME_SIZE];
+ struct vdpa_callback cb;
+ int irq;
+};
+
+struct vp_vdpa {
+ struct vdpa_device vdpa;
+ struct virtio_pci_modern_device mdev;
+ struct vp_vring *vring;
+ struct vdpa_callback config_cb;
+ char msix_name[VP_VDPA_NAME_SIZE];
+ int config_irq;
+ int queues;
+ int vectors;
+};
+
+static struct vp_vdpa *vdpa_to_vp(struct vdpa_device *vdpa)
+{
+ return container_of(vdpa, struct vp_vdpa, vdpa);
+}
+
+static struct virtio_pci_modern_device *vdpa_to_mdev(struct vdpa_device *vdpa)
+{
+ struct vp_vdpa *vp_vdpa = vdpa_to_vp(vdpa);
+
+ return &vp_vdpa->mdev;
+}
+
+static u64 vp_vdpa_get_features(struct vdpa_device *vdpa)
+{
+ struct virtio_pci_modern_device *mdev = vdpa_to_mdev(vdpa);
+
+ return vp_modern_get_features(mdev);
+}
+
+static int vp_vdpa_set_features(struct vdpa_device *vdpa, u64 features)
+{
+ struct virtio_pci_modern_device *mdev = vdpa_to_mdev(vdpa);
+
+ vp_modern_set_features(mdev, features);
+
+ return 0;
+}
+
+static u8 vp_vdpa_get_status(struct vdpa_device *vdpa)
+{
+ struct virtio_pci_modern_device *mdev = vdpa_to_mdev(vdpa);
+
+ return vp_modern_get_status(mdev);
+}
+
+static void vp_vdpa_free_irq(struct vp_vdpa *vp_vdpa)
+{
+ struct virtio_pci_modern_device *mdev = &vp_vdpa->mdev;
+ struct pci_dev *pdev = mdev->pci_dev;
+ int i;
+
+ for (i = 0; i < vp_vdpa->queues; i++) {
+ if (vp_vdpa->vring[i].irq != VIRTIO_MSI_NO_VECTOR) {
+ vp_modern_queue_vector(mdev, i, VIRTIO_MSI_NO_VECTOR);
+ devm_free_irq(&pdev->dev, vp_vdpa->vring[i].irq,
+ &vp_vdpa->vring[i]);
+ vp_vdpa->vring[i].irq = VIRTIO_MSI_NO_VECTOR;
+ }
+ }
+
+ if (vp_vdpa->config_irq != VIRTIO_MSI_NO_VECTOR) {
+ vp_modern_config_vector(mdev, VIRTIO_MSI_NO_VECTOR);
+ devm_free_irq(&pdev->dev, vp_vdpa->config_irq, vp_vdpa);
+ vp_vdpa->config_irq = VIRTIO_MSI_NO_VECTOR;
+ }
+
+ if (vp_vdpa->vectors) {
+ pci_free_irq_vectors(pdev);
+ vp_vdpa->vectors = 0;
+ }
+}
+
+static irqreturn_t vp_vdpa_vq_handler(int irq, void *arg)
+{
+ struct vp_vring *vring = arg;
+
+ if (vring->cb.callback)
+ return vring->cb.callback(vring->cb.private);
+
+ return IRQ_HANDLED;
+}
+
+static irqreturn_t vp_vdpa_config_handler(int irq, void *arg)
+{
+ struct vp_vdpa *vp_vdpa = arg;
+
+ if (vp_vdpa->config_cb.callback)
+ return vp_vdpa->config_cb.callback(vp_vdpa->config_cb.private);
+
+ return IRQ_HANDLED;
+}
+
+static int vp_vdpa_request_irq(struct vp_vdpa *vp_vdpa)
+{
+ struct virtio_pci_modern_device *mdev = &vp_vdpa->mdev;
+ struct pci_dev *pdev = mdev->pci_dev;
+ int i, ret, irq;
+ int queues = vp_vdpa->queues;
+ int vectors = queues + 1;
+
+ ret = pci_alloc_irq_vectors(pdev, vectors, vectors, PCI_IRQ_MSIX);
+ if (ret != vectors) {
+ dev_err(&pdev->dev,
+ "vp_vdpa: fail to allocate irq vectors want %d but %d\n",
+ vectors, ret);
+ return ret;
+ }
+
+ vp_vdpa->vectors = vectors;
+
+ for (i = 0; i < queues; i++) {
+ snprintf(vp_vdpa->vring[i].msix_name, VP_VDPA_NAME_SIZE,
+ "vp-vdpa[%s]-%d\n", pci_name(pdev), i);
+ irq = pci_irq_vector(pdev, i);
+ ret = devm_request_irq(&pdev->dev, irq,
+ vp_vdpa_vq_handler,
+ 0, vp_vdpa->vring[i].msix_name,
+ &vp_vdpa->vring[i]);
+ if (ret) {
+ dev_err(&pdev->dev,
+ "vp_vdpa: fail to request irq for vq %d\n", i);
+ goto err;
+ }
+ vp_modern_queue_vector(mdev, i, i);
+ vp_vdpa->vring[i].irq = irq;
+ }
+
+ snprintf(vp_vdpa->msix_name, VP_VDPA_NAME_SIZE, "vp-vdpa[%s]-config\n",
+ pci_name(pdev));
+ irq = pci_irq_vector(pdev, queues);
+ ret = devm_request_irq(&pdev->dev, irq, vp_vdpa_config_handler, 0,
+ vp_vdpa->msix_name, vp_vdpa);
+ if (ret) {
+ dev_err(&pdev->dev,
+ "vp_vdpa: fail to request irq for vq %d\n", i);
+ goto err;
+ }
+ vp_modern_config_vector(mdev, queues);
+ vp_vdpa->config_irq = irq;
+
+ return 0;
+err:
+ vp_vdpa_free_irq(vp_vdpa);
+ return ret;
+}
+
+static void vp_vdpa_set_status(struct vdpa_device *vdpa, u8 status)
+{
+ struct vp_vdpa *vp_vdpa = vdpa_to_vp(vdpa);
+ struct virtio_pci_modern_device *mdev = &vp_vdpa->mdev;
+ u8 s = vp_vdpa_get_status(vdpa);
+
+ if (status & VIRTIO_CONFIG_S_DRIVER_OK &&
+ !(s & VIRTIO_CONFIG_S_DRIVER_OK)) {
+ vp_vdpa_request_irq(vp_vdpa);
+ }
+
+ vp_modern_set_status(mdev, status);
+
+ if (!(status & VIRTIO_CONFIG_S_DRIVER_OK) &&
+ (s & VIRTIO_CONFIG_S_DRIVER_OK))
+ vp_vdpa_free_irq(vp_vdpa);
+}
+
+static u16 vp_vdpa_get_vq_num_max(struct vdpa_device *vdpa)
+{
+ return VP_VDPA_QUEUE_MAX;
+}
+
+static int vp_vdpa_get_vq_state(struct vdpa_device *vdpa, u16 qid,
+ struct vdpa_vq_state *state)
+{
+ /* Note that this is not supported by virtio specification, so
+ * we return -EOPNOTSUPP here. This means we can't support live
+ * migration, vhost device start/stop.
+ */
+ return -EOPNOTSUPP;
+}
+
+static int vp_vdpa_set_vq_state(struct vdpa_device *vdpa, u16 qid,
+ const struct vdpa_vq_state *state)
+{
+ /* Note that this is not supported by virtio specification, so
+ * we return -ENOPOTSUPP here. This means we can't support live
+ * migration, vhost device start/stop.
+ */
+ return -EOPNOTSUPP;
+}
+
+static void vp_vdpa_set_vq_cb(struct vdpa_device *vdpa, u16 qid,
+ struct vdpa_callback *cb)
+{
+ struct vp_vdpa *vp_vdpa = vdpa_to_vp(vdpa);
+
+ vp_vdpa->vring[qid].cb = *cb;
+}
+
+static void vp_vdpa_set_vq_ready(struct vdpa_device *vdpa,
+ u16 qid, bool ready)
+{
+ struct virtio_pci_modern_device *mdev = vdpa_to_mdev(vdpa);
+
+ vp_modern_set_queue_enable(mdev, qid, ready);
+}
+
+static bool vp_vdpa_get_vq_ready(struct vdpa_device *vdpa, u16 qid)
+{
+ struct virtio_pci_modern_device *mdev = vdpa_to_mdev(vdpa);
+
+ return vp_modern_get_queue_enable(mdev, qid);
+}
+
+static void vp_vdpa_set_vq_num(struct vdpa_device *vdpa, u16 qid,
+ u32 num)
+{
+ struct virtio_pci_modern_device *mdev = vdpa_to_mdev(vdpa);
+
+ vp_modern_set_queue_size(mdev, qid, num);
+}
+
+static int vp_vdpa_set_vq_address(struct vdpa_device *vdpa, u16 qid,
+ u64 desc_area, u64 driver_area,
+ u64 device_area)
+{
+ struct virtio_pci_modern_device *mdev = vdpa_to_mdev(vdpa);
+
+ vp_modern_queue_address(mdev, qid, desc_area,
+ driver_area, device_area);
+
+ return 0;
+}
+
+static void vp_vdpa_kick_vq(struct vdpa_device *vdpa, u16 qid)
+{
+ struct vp_vdpa *vp_vdpa = vdpa_to_vp(vdpa);
+
+ vp_iowrite16(qid, vp_vdpa->vring[qid].notify);
+}
+
+static u32 vp_vdpa_get_generation(struct vdpa_device *vdpa)
+{
+ struct virtio_pci_modern_device *mdev = vdpa_to_mdev(vdpa);
+
+ return vp_modern_generation(mdev);
+}
+
+static u32 vp_vdpa_get_device_id(struct vdpa_device *vdpa)
+{
+ struct virtio_pci_modern_device *mdev = vdpa_to_mdev(vdpa);
+
+ return mdev->id.device;
+}
+
+static u32 vp_vdpa_get_vendor_id(struct vdpa_device *vdpa)
+{
+ struct virtio_pci_modern_device *mdev = vdpa_to_mdev(vdpa);
+
+ return mdev->id.vendor;
+}
+
+static u32 vp_vdpa_get_vq_align(struct vdpa_device *vdpa)
+{
+ return PAGE_SIZE;
+}
+
+static void vp_vdpa_get_config(struct vdpa_device *vdpa,
+ unsigned int offset,
+ void *buf, unsigned int len)
+{
+ struct vp_vdpa *vp_vdpa = vdpa_to_vp(vdpa);
+ struct virtio_pci_modern_device *mdev = &vp_vdpa->mdev;
+ u8 old, new;
+ u8 *p;
+ int i;
+
+ do {
+ old = vp_ioread8(&mdev->common->config_generation);
+ p = buf;
+ for (i = 0; i < len; i++)
+ *p++ = vp_ioread8(mdev->device + offset + i);
+
+ new = vp_ioread8(&mdev->common->config_generation);
+ } while (old != new);
+}
+
+static void vp_vdpa_set_config(struct vdpa_device *vdpa,
+ unsigned int offset, const void *buf,
+ unsigned int len)
+{
+ struct vp_vdpa *vp_vdpa = vdpa_to_vp(vdpa);
+ struct virtio_pci_modern_device *mdev = &vp_vdpa->mdev;
+ const u8 *p = buf;
+ int i;
+
+ for (i = 0; i < len; i++)
+ vp_iowrite8(*p++, mdev->device + offset + i);
+}
+
+static void vp_vdpa_set_config_cb(struct vdpa_device *vdpa,
+ struct vdpa_callback *cb)
+{
+ struct vp_vdpa *vp_vdpa = vdpa_to_vp(vdpa);
+
+ vp_vdpa->config_cb = *cb;
+}
+
+static const struct vdpa_config_ops vp_vdpa_ops = {
+ .get_features = vp_vdpa_get_features,
+ .set_features = vp_vdpa_set_features,
+ .get_status = vp_vdpa_get_status,
+ .set_status = vp_vdpa_set_status,
+ .get_vq_num_max = vp_vdpa_get_vq_num_max,
+ .get_vq_state = vp_vdpa_get_vq_state,
+ .set_vq_state = vp_vdpa_set_vq_state,
+ .set_vq_cb = vp_vdpa_set_vq_cb,
+ .set_vq_ready = vp_vdpa_set_vq_ready,
+ .get_vq_ready = vp_vdpa_get_vq_ready,
+ .set_vq_num = vp_vdpa_set_vq_num,
+ .set_vq_address = vp_vdpa_set_vq_address,
+ .kick_vq = vp_vdpa_kick_vq,
+ .get_generation = vp_vdpa_get_generation,
+ .get_device_id = vp_vdpa_get_device_id,
+ .get_vendor_id = vp_vdpa_get_vendor_id,
+ .get_vq_align = vp_vdpa_get_vq_align,
+ .get_config = vp_vdpa_get_config,
+ .set_config = vp_vdpa_set_config,
+ .set_config_cb = vp_vdpa_set_config_cb,
+};
+
+static void vp_vdpa_free_irq_vectors(void *data)
+{
+ pci_free_irq_vectors(data);
+}
+
+static int vp_vdpa_probe(struct pci_dev *pdev, const struct pci_device_id *id)
+{
+ struct virtio_pci_modern_device *mdev;
+ struct device *dev = &pdev->dev;
+ struct vp_vdpa *vp_vdpa;
+ u16 notify_off;
+ int ret, i;
+
+ ret = pcim_enable_device(pdev);
+ if (ret)
+ return ret;
+
+ vp_vdpa = vdpa_alloc_device(struct vp_vdpa, vdpa,
+ dev, &vp_vdpa_ops, NULL);
+ if (vp_vdpa == NULL) {
+ dev_err(dev, "vp_vdpa: Failed to allocate vDPA structure\n");
+ return -ENOMEM;
+ }
+
+ mdev = &vp_vdpa->mdev;
+ mdev->pci_dev = pdev;
+
+ ret = vp_modern_probe(mdev);
+ if (ret) {
+ dev_err(&pdev->dev, "Failed to probe modern PCI device\n");
+ goto err;
+ }
+
+ pci_set_master(pdev);
+ pci_set_drvdata(pdev, vp_vdpa);
+
+ vp_vdpa->vdpa.dma_dev = &pdev->dev;
+ vp_vdpa->queues = vp_modern_get_num_queues(mdev);
+
+ ret = devm_add_action_or_reset(dev, vp_vdpa_free_irq_vectors, pdev);
+ if (ret) {
+ dev_err(&pdev->dev,
+ "Failed for adding devres for freeing irq vectors\n");
+ goto err;
+ }
+
+ vp_vdpa->vring = devm_kcalloc(&pdev->dev, vp_vdpa->queues,
+ sizeof(*vp_vdpa->vring),
+ GFP_KERNEL);
+ if (!vp_vdpa->vring) {
+ ret = -ENOMEM;
+ dev_err(&pdev->dev, "Fail to allocate virtqueues\n");
+ goto err;
+ }
+
+ for (i = 0; i < vp_vdpa->queues; i++) {
+ notify_off = vp_modern_get_queue_notify_off(mdev, i);
+ vp_vdpa->vring[i].irq = VIRTIO_MSI_NO_VECTOR;
+ vp_vdpa->vring[i].notify = mdev->notify_base +
+ notify_off * mdev->notify_offset_multiplier;
+ }
+ vp_vdpa->config_irq = VIRTIO_MSI_NO_VECTOR;
+
+ ret = vdpa_register_device(&vp_vdpa->vdpa, vp_vdpa->queues);
+ if (ret) {
+ dev_err(&pdev->dev, "Failed to register to vdpa bus\n");
+ goto err;
+ }
+
+ return 0;
+
+err:
+ put_device(&vp_vdpa->vdpa.dev);
+ return ret;
+}
+
+static void vp_vdpa_remove(struct pci_dev *pdev)
+{
+ struct vp_vdpa *vp_vdpa = pci_get_drvdata(pdev);
+
+ vdpa_unregister_device(&vp_vdpa->vdpa);
+ vp_modern_remove(&vp_vdpa->mdev);
+}
+
+static struct pci_driver vp_vdpa_driver = {
+ .name = "vp-vdpa",
+ .id_table = NULL, /* only dynamic ids */
+ .probe = vp_vdpa_probe,
+ .remove = vp_vdpa_remove,
+};
+
+module_pci_driver(vp_vdpa_driver);
+
+MODULE_AUTHOR("Jason Wang <jasowang@redhat.com>");
+MODULE_DESCRIPTION("vp-vdpa");
+MODULE_LICENSE("GPL");
+MODULE_VERSION("1");
--
2.25.1
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