diff options
Diffstat (limited to '')
| -rw-r--r-- | virt/kvm/vfio.c | 425 |
1 files changed, 425 insertions, 0 deletions
diff --git a/virt/kvm/vfio.c b/virt/kvm/vfio.c new file mode 100644 index 000000000..8fcbc5022 --- /dev/null +++ b/virt/kvm/vfio.c @@ -0,0 +1,425 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * VFIO-KVM bridge pseudo device + * + * Copyright (C) 2013 Red Hat, Inc. All rights reserved. + * Author: Alex Williamson <alex.williamson@redhat.com> + */ + +#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_group { + struct list_head node; + struct vfio_group *vfio_group; +}; + +struct kvm_vfio { + struct list_head group_list; + struct mutex lock; + bool noncoherent; +}; + +static struct vfio_group *kvm_vfio_group_get_external_user(struct file *filep) +{ + struct vfio_group *vfio_group; + struct vfio_group *(*fn)(struct file *); + + fn = symbol_get(vfio_group_get_external_user); + if (!fn) + return ERR_PTR(-EINVAL); + + vfio_group = fn(filep); + + symbol_put(vfio_group_get_external_user); + + return vfio_group; +} + +static bool kvm_vfio_external_group_match_file(struct vfio_group *group, + struct file *filep) +{ + bool ret, (*fn)(struct vfio_group *, struct file *); + + fn = symbol_get(vfio_external_group_match_file); + if (!fn) + return false; + + ret = fn(group, filep); + + symbol_put(vfio_external_group_match_file); + + return ret; +} + +static void kvm_vfio_group_put_external_user(struct vfio_group *vfio_group) +{ + void (*fn)(struct vfio_group *); + + fn = symbol_get(vfio_group_put_external_user); + if (!fn) + return; + + fn(vfio_group); + + symbol_put(vfio_group_put_external_user); +} + +static void kvm_vfio_group_set_kvm(struct vfio_group *group, struct kvm *kvm) +{ + void (*fn)(struct vfio_group *, struct kvm *); + + fn = symbol_get(vfio_group_set_kvm); + if (!fn) + return; + + fn(group, kvm); + + symbol_put(vfio_group_set_kvm); +} + +static bool kvm_vfio_group_is_coherent(struct vfio_group *vfio_group) +{ + long (*fn)(struct vfio_group *, unsigned long); + long ret; + + fn = symbol_get(vfio_external_check_extension); + if (!fn) + return false; + + ret = fn(vfio_group, VFIO_DMA_CC_IOMMU); + + symbol_put(vfio_external_check_extension); + + return ret > 0; +} + +#ifdef CONFIG_SPAPR_TCE_IOMMU +static int kvm_vfio_external_user_iommu_id(struct vfio_group *vfio_group) +{ + int (*fn)(struct vfio_group *); + int ret = -EINVAL; + + fn = symbol_get(vfio_external_user_iommu_id); + if (!fn) + return ret; + + ret = fn(vfio_group); + + symbol_put(vfio_external_user_iommu_id); + + return ret; +} + +static struct iommu_group *kvm_vfio_group_get_iommu_group( + struct vfio_group *group) +{ + int group_id = kvm_vfio_external_user_iommu_id(group); + + if (group_id < 0) + return NULL; + + return iommu_group_get_by_id(group_id); +} + +static void kvm_spapr_tce_release_vfio_group(struct kvm *kvm, + struct vfio_group *vfio_group) +{ + struct iommu_group *grp = kvm_vfio_group_get_iommu_group(vfio_group); + + if (WARN_ON_ONCE(!grp)) + return; + + kvm_spapr_tce_release_iommu_group(kvm, grp); + iommu_group_put(grp); +} +#endif + +/* + * Groups can use the same or different IOMMU domains. If the same then + * adding a new group may change the coherency of groups we've previously + * been told about. We don't want to care about any of that so we retest + * each group 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_group *kvg; + + mutex_lock(&kv->lock); + + list_for_each_entry(kvg, &kv->group_list, node) { + if (!kvm_vfio_group_is_coherent(kvg->vfio_group)) { + 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_set_group(struct kvm_device *dev, long attr, u64 arg) +{ + struct kvm_vfio *kv = dev->private; + struct vfio_group *vfio_group; + struct kvm_vfio_group *kvg; + int32_t __user *argp = (int32_t __user *)(unsigned long)arg; + struct fd f; + int32_t fd; + int ret; + + switch (attr) { + case KVM_DEV_VFIO_GROUP_ADD: + if (get_user(fd, argp)) + return -EFAULT; + + f = fdget(fd); + if (!f.file) + return -EBADF; + + vfio_group = kvm_vfio_group_get_external_user(f.file); + fdput(f); + + if (IS_ERR(vfio_group)) + return PTR_ERR(vfio_group); + + mutex_lock(&kv->lock); + + list_for_each_entry(kvg, &kv->group_list, node) { + if (kvg->vfio_group == vfio_group) { + mutex_unlock(&kv->lock); + kvm_vfio_group_put_external_user(vfio_group); + return -EEXIST; + } + } + + kvg = kzalloc(sizeof(*kvg), GFP_KERNEL_ACCOUNT); + if (!kvg) { + mutex_unlock(&kv->lock); + kvm_vfio_group_put_external_user(vfio_group); + return -ENOMEM; + } + + list_add_tail(&kvg->node, &kv->group_list); + kvg->vfio_group = vfio_group; + + kvm_arch_start_assignment(dev->kvm); + + mutex_unlock(&kv->lock); + + kvm_vfio_group_set_kvm(vfio_group, dev->kvm); + + kvm_vfio_update_coherency(dev); + + return 0; + + case KVM_DEV_VFIO_GROUP_DEL: + if (get_user(fd, argp)) + return -EFAULT; + + f = fdget(fd); + if (!f.file) + return -EBADF; + + ret = -ENOENT; + + mutex_lock(&kv->lock); + + list_for_each_entry(kvg, &kv->group_list, node) { + if (!kvm_vfio_external_group_match_file(kvg->vfio_group, + f.file)) + continue; + + list_del(&kvg->node); + kvm_arch_end_assignment(dev->kvm); +#ifdef CONFIG_SPAPR_TCE_IOMMU + kvm_spapr_tce_release_vfio_group(dev->kvm, + kvg->vfio_group); +#endif + kvm_vfio_group_set_kvm(kvg->vfio_group, NULL); + kvm_vfio_group_put_external_user(kvg->vfio_group); + kfree(kvg); + ret = 0; + break; + } + + mutex_unlock(&kv->lock); + + fdput(f); + + kvm_vfio_update_coherency(dev); + + return ret; + +#ifdef CONFIG_SPAPR_TCE_IOMMU + case KVM_DEV_VFIO_GROUP_SET_SPAPR_TCE: { + struct kvm_vfio_spapr_tce param; + struct kvm_vfio *kv = dev->private; + struct vfio_group *vfio_group; + struct kvm_vfio_group *kvg; + struct fd f; + struct iommu_group *grp; + + if (copy_from_user(¶m, (void __user *)arg, + sizeof(struct kvm_vfio_spapr_tce))) + return -EFAULT; + + f = fdget(param.groupfd); + if (!f.file) + return -EBADF; + + vfio_group = kvm_vfio_group_get_external_user(f.file); + fdput(f); + + if (IS_ERR(vfio_group)) + return PTR_ERR(vfio_group); + + grp = kvm_vfio_group_get_iommu_group(vfio_group); + if (WARN_ON_ONCE(!grp)) { + kvm_vfio_group_put_external_user(vfio_group); + return -EIO; + } + + ret = -ENOENT; + + mutex_lock(&kv->lock); + + list_for_each_entry(kvg, &kv->group_list, node) { + if (kvg->vfio_group != vfio_group) + continue; + + ret = kvm_spapr_tce_attach_iommu_group(dev->kvm, + param.tablefd, grp); + break; + } + + mutex_unlock(&kv->lock); + + iommu_group_put(grp); + kvm_vfio_group_put_external_user(vfio_group); + + return ret; + } +#endif /* CONFIG_SPAPR_TCE_IOMMU */ + } + + 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_group(dev, attr->attr, 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_destroy(struct kvm_device *dev) +{ + struct kvm_vfio *kv = dev->private; + struct kvm_vfio_group *kvg, *tmp; + + list_for_each_entry_safe(kvg, tmp, &kv->group_list, node) { +#ifdef CONFIG_SPAPR_TCE_IOMMU + kvm_spapr_tce_release_vfio_group(dev->kvm, kvg->vfio_group); +#endif + kvm_vfio_group_set_kvm(kvg->vfio_group, NULL); + kvm_vfio_group_put_external_user(kvg->vfio_group); + list_del(&kvg->node); + kfree(kvg); + kvm_arch_end_assignment(dev->kvm); + } + + kvm_vfio_update_coherency(dev); + + kfree(kv); + kfree(dev); /* alloc by kvm_ioctl_create_device, free by .destroy */ +} + +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, + .destroy = kvm_vfio_destroy, + .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->group_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); +} |