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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * Virtio PCI driver - legacy device support4 *5 * This module allows virtio devices to be used over a virtual PCI device.6 * This can be used with QEMU based VMMs like KVM or Xen.7 *8 * Copyright IBM Corp. 20079 * Copyright Red Hat, Inc. 201410 *11 * Authors:12 * Anthony Liguori <aliguori@us.ibm.com>13 * Rusty Russell <rusty@rustcorp.com.au>14 * Michael S. Tsirkin <mst@redhat.com>15 */16 17#include "linux/virtio_pci_legacy.h"18#include "virtio_pci_common.h"19 20/* virtio config->get_features() implementation */21static u64 vp_get_features(struct virtio_device *vdev)22{23 struct virtio_pci_device *vp_dev = to_vp_device(vdev);24 25 /* When someone needs more than 32 feature bits, we'll need to26 * steal a bit to indicate that the rest are somewhere else. */27 return vp_legacy_get_features(&vp_dev->ldev);28}29 30/* virtio config->finalize_features() implementation */31static int vp_finalize_features(struct virtio_device *vdev)32{33 struct virtio_pci_device *vp_dev = to_vp_device(vdev);34 35 /* Give virtio_ring a chance to accept features. */36 vring_transport_features(vdev);37 38 /* Make sure we don't have any features > 32 bits! */39 BUG_ON((u32)vdev->features != vdev->features);40 41 /* We only support 32 feature bits. */42 vp_legacy_set_features(&vp_dev->ldev, vdev->features);43 44 return 0;45}46 47/* virtio config->get() implementation */48static void vp_get(struct virtio_device *vdev, unsigned int offset,49 void *buf, unsigned int len)50{51 struct virtio_pci_device *vp_dev = to_vp_device(vdev);52 void __iomem *ioaddr = vp_dev->ldev.ioaddr +53 VIRTIO_PCI_CONFIG_OFF(vp_dev->msix_enabled) +54 offset;55 u8 *ptr = buf;56 int i;57 58 for (i = 0; i < len; i++)59 ptr[i] = ioread8(ioaddr + i);60}61 62/* the config->set() implementation. it's symmetric to the config->get()63 * implementation */64static void vp_set(struct virtio_device *vdev, unsigned int offset,65 const void *buf, unsigned int len)66{67 struct virtio_pci_device *vp_dev = to_vp_device(vdev);68 void __iomem *ioaddr = vp_dev->ldev.ioaddr +69 VIRTIO_PCI_CONFIG_OFF(vp_dev->msix_enabled) +70 offset;71 const u8 *ptr = buf;72 int i;73 74 for (i = 0; i < len; i++)75 iowrite8(ptr[i], ioaddr + i);76}77 78/* config->{get,set}_status() implementations */79static u8 vp_get_status(struct virtio_device *vdev)80{81 struct virtio_pci_device *vp_dev = to_vp_device(vdev);82 return vp_legacy_get_status(&vp_dev->ldev);83}84 85static void vp_set_status(struct virtio_device *vdev, u8 status)86{87 struct virtio_pci_device *vp_dev = to_vp_device(vdev);88 /* We should never be setting status to 0. */89 BUG_ON(status == 0);90 vp_legacy_set_status(&vp_dev->ldev, status);91}92 93static void vp_reset(struct virtio_device *vdev)94{95 struct virtio_pci_device *vp_dev = to_vp_device(vdev);96 /* 0 status means a reset. */97 vp_legacy_set_status(&vp_dev->ldev, 0);98 /* Flush out the status write, and flush in device writes,99 * including MSi-X interrupts, if any. */100 vp_legacy_get_status(&vp_dev->ldev);101 /* Flush pending VQ/configuration callbacks. */102 vp_synchronize_vectors(vdev);103}104 105static u16 vp_config_vector(struct virtio_pci_device *vp_dev, u16 vector)106{107 return vp_legacy_config_vector(&vp_dev->ldev, vector);108}109 110static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,111 struct virtio_pci_vq_info *info,112 unsigned int index,113 void (*callback)(struct virtqueue *vq),114 const char *name,115 bool ctx,116 u16 msix_vec)117{118 struct virtqueue *vq;119 u16 num;120 int err;121 u64 q_pfn;122 123 /* Check if queue is either not available or already active. */124 num = vp_legacy_get_queue_size(&vp_dev->ldev, index);125 if (!num || vp_legacy_get_queue_enable(&vp_dev->ldev, index))126 return ERR_PTR(-ENOENT);127 128 info->msix_vector = msix_vec;129 130 /* create the vring */131 vq = vring_create_virtqueue(index, num,132 VIRTIO_PCI_VRING_ALIGN, &vp_dev->vdev,133 true, false, ctx,134 vp_notify, callback, name);135 if (!vq)136 return ERR_PTR(-ENOMEM);137 138 vq->num_max = num;139 140 q_pfn = virtqueue_get_desc_addr(vq) >> VIRTIO_PCI_QUEUE_ADDR_SHIFT;141 if (q_pfn >> 32) {142 dev_err(&vp_dev->pci_dev->dev,143 "platform bug: legacy virtio-pci must not be used with RAM above 0x%llxGB\n",144 0x1ULL << (32 + PAGE_SHIFT - 30));145 err = -E2BIG;146 goto out_del_vq;147 }148 149 /* activate the queue */150 vp_legacy_set_queue_address(&vp_dev->ldev, index, q_pfn);151 152 vq->priv = (void __force *)vp_dev->ldev.ioaddr + VIRTIO_PCI_QUEUE_NOTIFY;153 154 if (msix_vec != VIRTIO_MSI_NO_VECTOR) {155 msix_vec = vp_legacy_queue_vector(&vp_dev->ldev, index, msix_vec);156 if (msix_vec == VIRTIO_MSI_NO_VECTOR) {157 err = -EBUSY;158 goto out_deactivate;159 }160 }161 162 return vq;163 164out_deactivate:165 vp_legacy_set_queue_address(&vp_dev->ldev, index, 0);166out_del_vq:167 vring_del_virtqueue(vq);168 return ERR_PTR(err);169}170 171static void del_vq(struct virtio_pci_vq_info *info)172{173 struct virtqueue *vq = info->vq;174 struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev);175 176 if (vp_dev->msix_enabled) {177 vp_legacy_queue_vector(&vp_dev->ldev, vq->index,178 VIRTIO_MSI_NO_VECTOR);179 /* Flush the write out to device */180 ioread8(vp_dev->ldev.ioaddr + VIRTIO_PCI_ISR);181 }182 183 /* Select and deactivate the queue */184 vp_legacy_set_queue_address(&vp_dev->ldev, vq->index, 0);185 186 vring_del_virtqueue(vq);187}188 189static const struct virtio_config_ops virtio_pci_config_ops = {190 .get = vp_get,191 .set = vp_set,192 .get_status = vp_get_status,193 .set_status = vp_set_status,194 .reset = vp_reset,195 .find_vqs = vp_find_vqs,196 .del_vqs = vp_del_vqs,197 .synchronize_cbs = vp_synchronize_vectors,198 .get_features = vp_get_features,199 .finalize_features = vp_finalize_features,200 .bus_name = vp_bus_name,201 .set_vq_affinity = vp_set_vq_affinity,202 .get_vq_affinity = vp_get_vq_affinity,203};204 205/* the PCI probing function */206int virtio_pci_legacy_probe(struct virtio_pci_device *vp_dev)207{208 struct virtio_pci_legacy_device *ldev = &vp_dev->ldev;209 struct pci_dev *pci_dev = vp_dev->pci_dev;210 int rc;211 212 ldev->pci_dev = pci_dev;213 214 rc = vp_legacy_probe(ldev);215 if (rc)216 return rc;217 218 vp_dev->isr = ldev->isr;219 vp_dev->vdev.id = ldev->id;220 221 vp_dev->vdev.config = &virtio_pci_config_ops;222 223 vp_dev->config_vector = vp_config_vector;224 vp_dev->setup_vq = setup_vq;225 vp_dev->del_vq = del_vq;226 vp_dev->is_legacy = true;227 228 return 0;229}230 231void virtio_pci_legacy_remove(struct virtio_pci_device *vp_dev)232{233 struct virtio_pci_legacy_device *ldev = &vp_dev->ldev;234 235 vp_legacy_remove(ldev);236}237