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- // SPDX-License-Identifier: GPL-2.0-only
- /*
- * VFIO-KVM bridge pseudo device
- *
- * Copyright (C) 2013 Red Hat, Inc. All rights reserved.
- * Author: Alex Williamson <[email protected]>
- */
- #include <linux/errno.h>
- #include <linux/file.h>
- #include <linux/kvm_host.h>
- #include <linux/list.h>
- #include <linux/module.h>
- #include <linux/mutex.h>
- #include <linux/slab.h>
- #include <linux/uaccess.h>
- #include <linux/vfio.h>
- #include "vfio.h"
- #ifdef CONFIG_SPAPR_TCE_IOMMU
- #include <asm/kvm_ppc.h>
- #endif
- struct kvm_vfio_file {
- struct list_head node;
- struct file *file;
- #ifdef CONFIG_SPAPR_TCE_IOMMU
- struct iommu_group *iommu_group;
- #endif
- };
- struct kvm_vfio {
- struct list_head file_list;
- struct mutex lock;
- bool noncoherent;
- };
- static void kvm_vfio_file_set_kvm(struct file *file, struct kvm *kvm)
- {
- void (*fn)(struct file *file, struct kvm *kvm);
- fn = symbol_get(vfio_file_set_kvm);
- if (!fn)
- return;
- fn(file, kvm);
- symbol_put(vfio_file_set_kvm);
- }
- static bool kvm_vfio_file_enforced_coherent(struct file *file)
- {
- bool (*fn)(struct file *file);
- bool ret;
- fn = symbol_get(vfio_file_enforced_coherent);
- if (!fn)
- return false;
- ret = fn(file);
- symbol_put(vfio_file_enforced_coherent);
- return ret;
- }
- static bool kvm_vfio_file_is_group(struct file *file)
- {
- bool (*fn)(struct file *file);
- bool ret;
- fn = symbol_get(vfio_file_is_group);
- if (!fn)
- return false;
- ret = fn(file);
- symbol_put(vfio_file_is_group);
- return ret;
- }
- #ifdef CONFIG_SPAPR_TCE_IOMMU
- static struct iommu_group *kvm_vfio_file_iommu_group(struct file *file)
- {
- struct iommu_group *(*fn)(struct file *file);
- struct iommu_group *ret;
- fn = symbol_get(vfio_file_iommu_group);
- if (!fn)
- return NULL;
- ret = fn(file);
- symbol_put(vfio_file_iommu_group);
- return ret;
- }
- static void kvm_spapr_tce_release_vfio_group(struct kvm *kvm,
- struct kvm_vfio_file *kvf)
- {
- if (WARN_ON_ONCE(!kvf->iommu_group))
- return;
- kvm_spapr_tce_release_iommu_group(kvm, kvf->iommu_group);
- iommu_group_put(kvf->iommu_group);
- kvf->iommu_group = NULL;
- }
- #endif
- /*
- * Groups/devices can use the same or different IOMMU domains. If the same
- * then adding a new group/device may change the coherency of groups/devices
- * we've previously been told about. We don't want to care about any of
- * that so we retest each group/device and bail as soon as we find one that's
- * noncoherent. This means we only ever [un]register_noncoherent_dma once
- * for the whole device.
- */
- static void kvm_vfio_update_coherency(struct kvm_device *dev)
- {
- struct kvm_vfio *kv = dev->private;
- bool noncoherent = false;
- struct kvm_vfio_file *kvf;
- mutex_lock(&kv->lock);
- list_for_each_entry(kvf, &kv->file_list, node) {
- if (!kvm_vfio_file_enforced_coherent(kvf->file)) {
- noncoherent = true;
- break;
- }
- }
- if (noncoherent != kv->noncoherent) {
- kv->noncoherent = noncoherent;
- if (kv->noncoherent)
- kvm_arch_register_noncoherent_dma(dev->kvm);
- else
- kvm_arch_unregister_noncoherent_dma(dev->kvm);
- }
- mutex_unlock(&kv->lock);
- }
- static int kvm_vfio_file_add(struct kvm_device *dev, unsigned int fd)
- {
- struct kvm_vfio *kv = dev->private;
- struct kvm_vfio_file *kvf;
- struct file *filp;
- int ret;
- filp = fget(fd);
- if (!filp)
- return -EBADF;
- /* Ensure the FD is a vfio group FD.*/
- if (!kvm_vfio_file_is_group(filp)) {
- ret = -EINVAL;
- goto err_fput;
- }
- mutex_lock(&kv->lock);
- list_for_each_entry(kvf, &kv->file_list, node) {
- if (kvf->file == filp) {
- ret = -EEXIST;
- goto err_unlock;
- }
- }
- kvf = kzalloc(sizeof(*kvf), GFP_KERNEL_ACCOUNT);
- if (!kvf) {
- ret = -ENOMEM;
- goto err_unlock;
- }
- kvf->file = filp;
- list_add_tail(&kvf->node, &kv->file_list);
- kvm_arch_start_assignment(dev->kvm);
- kvm_vfio_file_set_kvm(kvf->file, dev->kvm);
- mutex_unlock(&kv->lock);
- kvm_vfio_update_coherency(dev);
- return 0;
- err_unlock:
- mutex_unlock(&kv->lock);
- err_fput:
- fput(filp);
- return ret;
- }
- static int kvm_vfio_file_del(struct kvm_device *dev, unsigned int fd)
- {
- struct kvm_vfio *kv = dev->private;
- struct kvm_vfio_file *kvf;
- struct fd f;
- int ret;
- f = fdget(fd);
- if (!f.file)
- return -EBADF;
- ret = -ENOENT;
- mutex_lock(&kv->lock);
- list_for_each_entry(kvf, &kv->file_list, node) {
- if (kvf->file != f.file)
- continue;
- list_del(&kvf->node);
- kvm_arch_end_assignment(dev->kvm);
- #ifdef CONFIG_SPAPR_TCE_IOMMU
- kvm_spapr_tce_release_vfio_group(dev->kvm, kvf);
- #endif
- kvm_vfio_file_set_kvm(kvf->file, NULL);
- fput(kvf->file);
- kfree(kvf);
- ret = 0;
- break;
- }
- mutex_unlock(&kv->lock);
- fdput(f);
- kvm_vfio_update_coherency(dev);
- return ret;
- }
- #ifdef CONFIG_SPAPR_TCE_IOMMU
- static int kvm_vfio_file_set_spapr_tce(struct kvm_device *dev,
- void __user *arg)
- {
- struct kvm_vfio_spapr_tce param;
- struct kvm_vfio *kv = dev->private;
- struct kvm_vfio_file *kvf;
- struct fd f;
- int ret;
- if (copy_from_user(¶m, arg, sizeof(struct kvm_vfio_spapr_tce)))
- return -EFAULT;
- f = fdget(param.groupfd);
- if (!f.file)
- return -EBADF;
- ret = -ENOENT;
- mutex_lock(&kv->lock);
- list_for_each_entry(kvf, &kv->file_list, node) {
- if (kvf->file != f.file)
- continue;
- if (!kvf->iommu_group) {
- kvf->iommu_group = kvm_vfio_file_iommu_group(kvf->file);
- if (WARN_ON_ONCE(!kvf->iommu_group)) {
- ret = -EIO;
- goto err_fdput;
- }
- }
- ret = kvm_spapr_tce_attach_iommu_group(dev->kvm, param.tablefd,
- kvf->iommu_group);
- break;
- }
- err_fdput:
- mutex_unlock(&kv->lock);
- fdput(f);
- return ret;
- }
- #endif
- static int kvm_vfio_set_file(struct kvm_device *dev, long attr,
- void __user *arg)
- {
- int32_t __user *argp = arg;
- int32_t fd;
- switch (attr) {
- case KVM_DEV_VFIO_GROUP_ADD:
- if (get_user(fd, argp))
- return -EFAULT;
- return kvm_vfio_file_add(dev, fd);
- case KVM_DEV_VFIO_GROUP_DEL:
- if (get_user(fd, argp))
- return -EFAULT;
- return kvm_vfio_file_del(dev, fd);
- #ifdef CONFIG_SPAPR_TCE_IOMMU
- case KVM_DEV_VFIO_GROUP_SET_SPAPR_TCE:
- return kvm_vfio_file_set_spapr_tce(dev, arg);
- #endif
- }
- return -ENXIO;
- }
- static int kvm_vfio_set_attr(struct kvm_device *dev,
- struct kvm_device_attr *attr)
- {
- switch (attr->group) {
- case KVM_DEV_VFIO_GROUP:
- return kvm_vfio_set_file(dev, attr->attr,
- u64_to_user_ptr(attr->addr));
- }
- return -ENXIO;
- }
- static int kvm_vfio_has_attr(struct kvm_device *dev,
- struct kvm_device_attr *attr)
- {
- switch (attr->group) {
- case KVM_DEV_VFIO_GROUP:
- switch (attr->attr) {
- case KVM_DEV_VFIO_GROUP_ADD:
- case KVM_DEV_VFIO_GROUP_DEL:
- #ifdef CONFIG_SPAPR_TCE_IOMMU
- case KVM_DEV_VFIO_GROUP_SET_SPAPR_TCE:
- #endif
- return 0;
- }
- break;
- }
- return -ENXIO;
- }
- static void kvm_vfio_release(struct kvm_device *dev)
- {
- struct kvm_vfio *kv = dev->private;
- struct kvm_vfio_file *kvf, *tmp;
- list_for_each_entry_safe(kvf, tmp, &kv->file_list, node) {
- #ifdef CONFIG_SPAPR_TCE_IOMMU
- kvm_spapr_tce_release_vfio_group(dev->kvm, kvf);
- #endif
- kvm_vfio_file_set_kvm(kvf->file, NULL);
- fput(kvf->file);
- list_del(&kvf->node);
- kfree(kvf);
- kvm_arch_end_assignment(dev->kvm);
- }
- kvm_vfio_update_coherency(dev);
- kfree(kv);
- kfree(dev); /* alloc by kvm_ioctl_create_device, free by .release */
- }
- static int kvm_vfio_create(struct kvm_device *dev, u32 type);
- static struct kvm_device_ops kvm_vfio_ops = {
- .name = "kvm-vfio",
- .create = kvm_vfio_create,
- .release = kvm_vfio_release,
- .set_attr = kvm_vfio_set_attr,
- .has_attr = kvm_vfio_has_attr,
- };
- static int kvm_vfio_create(struct kvm_device *dev, u32 type)
- {
- struct kvm_device *tmp;
- struct kvm_vfio *kv;
- /* Only one VFIO "device" per VM */
- list_for_each_entry(tmp, &dev->kvm->devices, vm_node)
- if (tmp->ops == &kvm_vfio_ops)
- return -EBUSY;
- kv = kzalloc(sizeof(*kv), GFP_KERNEL_ACCOUNT);
- if (!kv)
- return -ENOMEM;
- INIT_LIST_HEAD(&kv->file_list);
- mutex_init(&kv->lock);
- dev->private = kv;
- return 0;
- }
- int kvm_vfio_ops_init(void)
- {
- return kvm_register_device_ops(&kvm_vfio_ops, KVM_DEV_TYPE_VFIO);
- }
- void kvm_vfio_ops_exit(void)
- {
- kvm_unregister_device_ops(KVM_DEV_TYPE_VFIO);
- }
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