On 2020/6/10 下午4:51, Michael S. Tsirkin wrote:
On Wed, Jun 10, 2020 at 04:25:06PM +0800, Jason Wang wrote:
+
+#define VP_VDPA_FEATURES \
+       ((1ULL << VIRTIO_F_ANY_LAYOUT)                    | \
This is presumably for transitional devices only.  In fact looking at
code it seems that only net in legacy mode accepts VIRTIO_F_ANY_LAYOUT.
Spec violation I guess ... but what should we do? Relax the spec
or fix drivers?

I don't get how it violates the spec.
Spec says transitional drivers must ack VIRTIO_F_ANY_LAYOUT


I don't see this in the spec, maybe you can point it to me?



But grep for VIRTIO_F_ANY_LAYOUT and you will see they don't.
Only legacy virtio net does.

Maybe it should have been
transitional drivers when using the lgacy interface, but there
you are.


+        (1ULL << VIRTIO_F_VERSION_1)                     | \
+        (1ULL << VIRTIO_F_ORDER_PLATFORM)                | \
+        (1ULL << VIRTIO_F_IOMMU_PLATFORM))
+
+struct vp_vring {
+       void __iomem *notify;
+       char msix_name[256];
+       resource_size_t notify_pa;
+       struct vdpa_callback cb;
+       int irq;
+};
+
+struct vp_vdpa {
+       struct vdpa_device vdpa;
+       struct pci_dev *pdev;
+
+       struct virtio_device_id id;
+
+       struct vp_vring vring[VP_VDPA_MAX_QUEUE];
+
+       /* The IO mapping for the PCI config space */
+       void __iomem * const *base;
+       struct virtio_pci_common_cfg __iomem *common;
+       void __iomem *device;
+       /* Base of vq notifications */
+       void __iomem *notify;
+
+       /* Multiplier for queue_notify_off. */
+       u32 notify_off_multiplier;
+
+       int modern_bars;
+       int vectors;
+};
+
+static struct vp_vdpa *vdpa_to_vp(struct vdpa_device *vdpa)
+{
+       return container_of(vdpa, struct vp_vdpa, vdpa);
+}
+
+/*
+ * Type-safe wrappers for io accesses.
+ * Use these to enforce at compile time the following spec requirement:
+ *
+ * The driver MUST access each field using the “natural” access
+ * method, i.e. 32-bit accesses for 32-bit fields, 16-bit accesses
+ * for 16-bit fields and 8-bit accesses for 8-bit fields.
+ */
+static inline u8 vp_ioread8(u8 __iomem *addr)
+{
+       return ioread8(addr);
+}
+static inline u16 vp_ioread16(__le16 __iomem *addr)
+{
+       return ioread16(addr);
+}
+
+static inline u32 vp_ioread32(__le32 __iomem *addr)
+{
+       return ioread32(addr);
+}
+
+static inline void vp_iowrite8(u8 value, u8 __iomem *addr)
+{
+       iowrite8(value, addr);
+}
+
+static inline void vp_iowrite16(u16 value, __le16 __iomem *addr)
+{
+       iowrite16(value, addr);
+}
+
+static inline void vp_iowrite32(u32 value, __le32 __iomem *addr)
+{
+       iowrite32(value, addr);
+}
+
+static void vp_iowrite64_twopart(u64 val,
+                                __le32 __iomem *lo, __le32 __iomem *hi)
+{
+       vp_iowrite32((u32)val, lo);
+       vp_iowrite32(val >> 32, hi);
+}
+
+static int find_capability(struct pci_dev *dev, u8 cfg_type,
+                          u32 ioresource_types, int *bars)
+{
+       int pos;
+
+       for (pos = pci_find_capability(dev, PCI_CAP_ID_VNDR);
+            pos > 0;
+            pos = pci_find_next_capability(dev, pos, PCI_CAP_ID_VNDR)) {
+               u8 type, bar;
+
+               pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
+                                                        cfg_type),
+                                    &type);
+               pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
+                                                        bar),
+                                    &bar);
+
+               /* Ignore structures with reserved BAR values */
+               if (bar > 0x5)
+                       continue;
+
+               if (type == cfg_type) {
+                       if (pci_resource_len(dev, bar) &&
+                           pci_resource_flags(dev, bar) & ioresource_types) {
+                               *bars |= (1 << bar);
+                               return pos;
+                       }
+               }
+       }
+       return 0;
+}
+
+static void __iomem *map_capability(struct vp_vdpa *vp_vdpa, int off,
+                                   resource_size_t *pa)
+{
+       struct pci_dev *pdev = vp_vdpa->pdev;
+       u32 offset;
+       u8 bar;
+
+       pci_read_config_byte(pdev,
+                            off + offsetof(struct virtio_pci_cap, bar),
+                            &bar);
+       pci_read_config_dword(pdev,
+                             off + offsetof(struct virtio_pci_cap, offset),
+                             &offset);
+
+       if (pa)
+               *pa = pci_resource_start(pdev, bar) + offset;
+
+       return vp_vdpa->base[bar] + offset;
+}
+
+static u64 vp_vdpa_get_features(struct vdpa_device *vdpa)
+{
+       struct vp_vdpa *vp_vdpa = vdpa_to_vp(vdpa);
+       u64 features;
+
+       vp_iowrite32(0, &vp_vdpa->common->device_feature_select);
+       features = vp_ioread32(&vp_vdpa->common->device_feature);
+       vp_iowrite32(1, &vp_vdpa->common->device_feature_select);
+       features |= ((u64)vp_ioread32(&vp_vdpa->common->device_feature) << 32);
+       features &= VP_VDPA_FEATURES;
+
+       return features;
+}
+
+static int vp_vdpa_set_features(struct vdpa_device *vdpa, u64 features)
+{
+       struct vp_vdpa *vp_vdpa = vdpa_to_vp(vdpa);
+
+       vp_iowrite32(0, &vp_vdpa->common->guest_feature_select);
+       vp_iowrite32((u32)features, &vp_vdpa->common->guest_feature);
+       vp_iowrite32(1, &vp_vdpa->common->guest_feature_select);
+       vp_iowrite32(features >> 32, &vp_vdpa->common->guest_feature);
+
+       return 0;
+}
+
+static u8 vp_vdpa_get_status(struct vdpa_device *vdpa)
+{
+       struct vp_vdpa *vp_vdpa = vdpa_to_vp(vdpa);
+
+       return vp_ioread8(&vp_vdpa->common->device_status);
+}
+
+static void vp_vdpa_free_irq(struct vp_vdpa *vp_vdpa)
+{
+       struct pci_dev *pdev = vp_vdpa->pdev;
+       int i;
+
+       for (i = 0; i < VP_VDPA_MAX_QUEUE; i++) {
+               if (vp_vdpa->vring[i].irq != -1) {
+                       vp_iowrite16(i, &vp_vdpa->common->queue_select);
+                       vp_iowrite16(VIRTIO_MSI_NO_VECTOR,
+                                    &vp_vdpa->common->queue_msix_vector);
+                       devm_free_irq(&pdev->dev, vp_vdpa->vring[i].irq,
+                                     &vp_vdpa->vring[i]);
+                       vp_vdpa->vring[i].irq = -1;
+               }
+       }
+
+       if (vp_vdpa->vectors) {
+               pci_free_irq_vectors(pdev);
+               vp_vdpa->vectors = 0;
+       }
+}
+
+static irqreturn_t vp_vdpa_intr_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 int vp_vdpa_request_irq(struct vp_vdpa *vp_vdpa)
+{
+       struct pci_dev *pdev = vp_vdpa->pdev;
+       int i, ret, irq;
+
+       ret = pci_alloc_irq_vectors(pdev, VP_VDPA_MAX_QUEUE,
+                                   VP_VDPA_MAX_QUEUE, PCI_IRQ_MSIX);
+       if (ret != VP_VDPA_MAX_QUEUE) {
+               dev_err(&pdev->dev, "vp_vdpa: fail to allocate irq vectors\n");
+               return ret;
+       }
+
+       vp_vdpa->vectors = VP_VDPA_MAX_QUEUE;
+
+       for (i = 0; i < VP_VDPA_MAX_QUEUE; i++) {
+               snprintf(vp_vdpa->vring[i].msix_name, 256,
+                       "vp-vdpa[%s]-%d\n", pci_name(pdev), i);
+               irq = pci_irq_vector(pdev, i);
+               ret = devm_request_irq(&pdev->dev, irq,
+                                      vp_vdpa_intr_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_iowrite16(i, &vp_vdpa->common->queue_select);
+               vp_iowrite16(i, &vp_vdpa->common->queue_msix_vector);
+               vp_vdpa->vring[i].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);
+       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_iowrite8(status, &vp_vdpa->common->device_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)
+{
+       struct vp_vdpa *vp_vdpa = vdpa_to_vp(vdpa);
+
+       return vp_ioread16(&vp_vdpa->common->queue_size);
+}
+
+static u64 vp_vdpa_get_vq_state(struct vdpa_device *vdpa, u16 qid)
+{
+       return 0;
+}
+
+static struct vdpa_notification_area
+vp_vdpa_get_vq_notification(struct vdpa_device *vdpa, u16 qid)
+{
+       struct vp_vdpa *vp_vdpa = vdpa_to_vp(vdpa);
+       struct vdpa_notification_area notify;
+
+       notify.addr = vp_vdpa->vring[qid].notify_pa;
+       notify.size = vp_vdpa->notify_off_multiplier;
+
+       return notify;
+}
+
+static int vp_vdpa_set_vq_state(struct vdpa_device *vdpa, u16 qid,
+                               u64 num)
+{
+       /* Note that this is not supported by virtio specification, so
+        * we return -ENOTSUPP here. This means we can't support live
+        * migration, vhost device start/stop.
+        */
+
+       return -ENOTSUPP;
+}
+
+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 vp_vdpa *vp_vdpa = vdpa_to_vp(vdpa);
+
+       vp_iowrite16(qid, &vp_vdpa->common->queue_select);
+       vp_iowrite16(ready, &vp_vdpa->common->queue_enable);
+}
+
+static bool vp_vdpa_get_vq_ready(struct vdpa_device *vdpa, u16 qid)
+{
+       struct vp_vdpa *vp_vdpa = vdpa_to_vp(vdpa);
+
+       vp_iowrite16(qid, &vp_vdpa->common->queue_select);
+
+       return vp_ioread16(&vp_vdpa->common->queue_enable);
+}
+
+static void vp_vdpa_set_vq_num(struct vdpa_device *vdpa, u16 qid,
+                              u32 num)
+{
+       struct vp_vdpa *vp_vdpa = vdpa_to_vp(vdpa);
+
+       vp_iowrite16(num, &vp_vdpa->common->queue_size);
+}
+
+static int vp_vdpa_set_vq_address(struct vdpa_device *vdpa, u16 qid,
+                                 u64 desc_area, u64 driver_area,
+                                 u64 device_area)
+{
+       struct vp_vdpa *vp_vdpa = vdpa_to_vp(vdpa);
+       struct virtio_pci_common_cfg __iomem *cfg = vp_vdpa->common;
+
+       vp_iowrite16(qid, &cfg->queue_select);
+       vp_iowrite64_twopart(desc_area,
+                            &cfg->queue_desc_lo, &cfg->queue_desc_hi);
+       vp_iowrite64_twopart(driver_area,
+                            &cfg->queue_avail_lo, &cfg->queue_avail_hi);
+       vp_iowrite64_twopart(device_area,
+                            &cfg->queue_used_lo, &cfg->queue_used_hi);
+
+       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 vp_vdpa *vp_vdpa = vdpa_to_vp(vdpa);
+
+       return vp_ioread8(&vp_vdpa->common->config_generation);
+}
+
+static u32 vp_vdpa_get_device_id(struct vdpa_device *vdpa)
+{
+       struct vp_vdpa *vp_vdpa = vdpa_to_vp(vdpa);
+
+       return vp_vdpa->id.device;
+}
+
+static u32 vp_vdpa_get_vendor_id(struct vdpa_device *vdpa)
+{
+       struct vp_vdpa *vp_vdpa = vdpa_to_vp(vdpa);
+
+       return vp_vdpa->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);
+       u8 old, new;
+       u8 *p;
+       int i;
+
+       do {
+               old = vp_ioread8(&vp_vdpa->common->config_generation);
+               p = buf;
+               for (i = 0; i < len; i++)
+                       *p++ = vp_ioread8(vp_vdpa->device + offset + i);
+
+               new = vp_ioread8(&vp_vdpa->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);
+       const u8 *p = buf;
+       int i;
+
+       for (i = 0; i < len; i++)
+               vp_iowrite8(*p++, vp_vdpa->device + offset + i);
+}
+
+static void vp_vdpa_set_config_cb(struct vdpa_device *vdpa,
+                                 struct vdpa_callback *cb)
+{
+       /* We don't support config interrupt */
Breaks things like balloon or migration notifications with virtio net, doesn't 
it?

Right, will fix.


+}
+
+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,
+       .get_vq_notification = vp_vdpa_get_vq_notification,
+       .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 int vp_vdpa_probe(struct pci_dev *pdev, const struct pci_device_id *id)
+{
+       struct device *dev = &pdev->dev;
+       struct vp_vdpa *vp_vdpa;
+       int common, notify, device, ret, i;
+       struct virtio_device_id virtio_id;
+       resource_size_t notify_pa;
+       u16 notify_off;
+
+       /* We only own devices >= 0x1000 and <= 0x107f: leave the rest. */
+       if (pdev->device < 0x1000 || pdev->device > 0x107f)
+               return -ENODEV;
+
+       if (pdev->device < 0x1040) {
+               /* Transitional devices: use the PCI subsystem device id as
+                * virtio device id, same as legacy driver always did.
+                */
+               virtio_id.device = pdev->subsystem_device;
+       } else {
+               /* Modern devices: simply use PCI device id,
+                * but start from 0x1040.
+                */
+               virtio_id.device = pdev->device - 0x1040;
+       }
+       virtio_id.vendor = pdev->subsystem_vendor;
+
+       ret = pcim_enable_device(pdev);
+       if (ret) {
+               dev_err(dev, "vp_vdpa: Fail to enable PCI device\n");
+               return ret;
+       }
+
+       vp_vdpa = vdpa_alloc_device(struct vp_vdpa, vdpa,
+                                   dev, &vp_vdpa_ops);
+       if (vp_vdpa == NULL) {
+               dev_err(dev, "vp_vdpa: Failed to allocate vDPA structure\n");
+               return -ENOMEM;
+       }
+
+       pci_set_master(pdev);
+       pci_set_drvdata(pdev, vp_vdpa);
+
+       vp_vdpa->pdev = pdev;
+       vp_vdpa->vdpa.dma_dev = &pdev->dev;
+
+       common = find_capability(pdev, VIRTIO_PCI_CAP_COMMON_CFG,
+                                IORESOURCE_IO | IORESOURCE_MEM,
+                                &vp_vdpa->modern_bars);
+       if (!common) {
+               dev_err(&pdev->dev,
+                       "vp_vdpa: legacy device is not supported\n");
+               ret = -ENODEV;
+               goto err;
+       }
+
+       notify = find_capability(pdev, VIRTIO_PCI_CAP_NOTIFY_CFG,
+                                IORESOURCE_IO | IORESOURCE_MEM,
+                                &vp_vdpa->modern_bars);
+       if (!notify) {
+               dev_err(&pdev->dev,
+                       "vp_vdpa: missing notification capabilities\n");
+               ret = -EINVAL;
+               goto err;
+       }
+
+       device = find_capability(pdev, VIRTIO_PCI_CAP_DEVICE_CFG,
+                                IORESOURCE_IO | IORESOURCE_MEM,
+                                &vp_vdpa->modern_bars);
+       if (!device) {
+               dev_err(&pdev->dev,
+                       "vp_vdpa: missing device capabilities\n");
+               ret = -EINVAL;
+               goto err;
+       }
+
+       ret = pcim_iomap_regions(pdev, vp_vdpa->modern_bars,
+                                VP_VDPA_DRIVER_NAME);
+       if (ret)
+               goto err;
+
+       vp_vdpa->base = pcim_iomap_table(pdev);
+
+       ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64));
+       if (ret)
+               ret = dma_set_mask_and_coherent(&pdev->dev,
+                                               DMA_BIT_MASK(32));
+       if (ret)
+               dev_warn(&pdev->dev, "Failed to enable 64-bit or 32-bit DMA.  Trying 
to continue, but this might not work.\n");
+
+       vp_vdpa->device = map_capability(vp_vdpa, device, NULL);
+       vp_vdpa->notify = map_capability(vp_vdpa, notify, &notify_pa);
+       vp_vdpa->common = map_capability(vp_vdpa, common, NULL);
+       vp_vdpa->id = virtio_id;
+
+       ret = vdpa_register_device(&vp_vdpa->vdpa);
+       if (ret) {
+               dev_err(&pdev->dev, "Failed to register to vdpa bus\n");
+               goto err;
+       }
+
+       pci_read_config_dword(pdev, notify + sizeof(struct virtio_pci_cap),
+                             &vp_vdpa->notify_off_multiplier);
+
+       for (i = 0; i < VP_VDPA_MAX_QUEUE; i++) {
+               vp_iowrite16(i, &vp_vdpa->common->queue_select);
+               notify_off = vp_ioread16(&vp_vdpa->common->queue_notify_off);
+               vp_vdpa->vring[i].irq = -1;
+               vp_vdpa->vring[i].notify = vp_vdpa->notify +
+                       notify_off * vp_vdpa->notify_off_multiplier;
+               vp_vdpa->vring[i].notify_pa = notify_pa +
+                       notify_off * vp_vdpa->notify_off_multiplier;
+       }
+
+       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);
+}
+
+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 <jasow...@redhat.com>");
+MODULE_DESCRIPTION("vp-vdpa");
+MODULE_LICENSE("GPL");
+MODULE_VERSION("1");
Isn't there something we can do to reduce the amount of code
duplication? virtio, ifcvf and now this share a ton of code ...
Let's make a library?

I do think about this since IFCVF driver is posted.

It depends on what level we want to share. Do we have to have a common
parent structure for modern pci device? If yes, it probably requires
non-trivial refactoring on the existed modern virtio-pci driver. If we just
want to share some helpers, it would be easy.
Share some helpers I'd say.


Ok, I can do that.



I think we can do those stuffs on top.
Well with a 3rd copy in-tree I'm inclined to say no, let's refactor first.


Yes.

Thanks



Thanks


--
2.20.1

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