virt/kvm/vfio.c - linux - Git at Google

 // 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_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_valid(struct file *file)
 {
 	bool (*fn)(struct file *file);
 	bool ret;

 	fn = symbol_get(vfio_file_is_valid);
 	if (!fn)
 		return false;

 	ret = fn(file);

 	symbol_put(vfio_file_is_valid);

 	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;

 	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);
 	}
 }

 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 = 0;

 	filp = fget(fd);
 	if (!filp)
 		return -EBADF;

 	/* Ensure the FD is a vfio FD. */
 	if (!kvm_vfio_file_is_valid(filp)) {
 		ret = -EINVAL;
 		goto out_fput;
 	}

 	mutex_lock(&kv->lock);

 	list_for_each_entry(kvf, &kv->file_list, node) {
 		if (kvf->file == filp) {
 			ret = -EEXIST;
 			goto out_unlock;
 		}
 	}

 	kvf = kzalloc(sizeof(*kvf), GFP_KERNEL_ACCOUNT);
 	if (!kvf) {
 		ret = -ENOMEM;
 		goto out_unlock;
 	}

 	kvf->file = get_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);
 	kvm_vfio_update_coherency(dev);

 out_unlock:
 	mutex_unlock(&kv->lock);
 out_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;
 	}

 	kvm_vfio_update_coherency(dev);

 	mutex_unlock(&kv->lock);

 	fdput(f);

 	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(&param, 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_FILE_ADD:
 		if (get_user(fd, argp))
 			return -EFAULT;
 		return kvm_vfio_file_add(dev, fd);

 	case KVM_DEV_VFIO_FILE_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_FILE:
 		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_FILE:
 		switch (attr->attr) {
 		case KVM_DEV_VFIO_FILE_ADD:
 		case KVM_DEV_VFIO_FILE_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;

 	lockdep_assert_held(&dev->kvm->lock);

 	/* 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);
 }
	// 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_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_valid(struct file *file)
	{
	bool (fn)(struct file file);
	bool ret;

	fn = symbol_get(vfio_file_is_valid);
	if (!fn)
	return false;

	ret = fn(file);

	symbol_put(vfio_file_is_valid);

	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;

	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);
	}
	}

	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 = 0;

	filp = fget(fd);
	if (!filp)
	return -EBADF;

	/* Ensure the FD is a vfio FD. */
	if (!kvm_vfio_file_is_valid(filp)) {
	ret = -EINVAL;
	goto out_fput;
	}

	mutex_lock(&kv->lock);

	list_for_each_entry(kvf, &kv->file_list, node) {
	if (kvf->file == filp) {
	ret = -EEXIST;
	goto out_unlock;
	}
	}

	kvf = kzalloc(sizeof(*kvf), GFP_KERNEL_ACCOUNT);
	if (!kvf) {
	ret = -ENOMEM;
	goto out_unlock;
	}

	kvf->file = get_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);
	kvm_vfio_update_coherency(dev);

	out_unlock:
	mutex_unlock(&kv->lock);
	out_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;
	}

	kvm_vfio_update_coherency(dev);

	mutex_unlock(&kv->lock);

	fdput(f);

	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(&param, 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_FILE_ADD:
	if (get_user(fd, argp))
	return -EFAULT;
	return kvm_vfio_file_add(dev, fd);

	case KVM_DEV_VFIO_FILE_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_FILE:
	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_FILE:
	switch (attr->attr) {
	case KVM_DEV_VFIO_FILE_ADD:
	case KVM_DEV_VFIO_FILE_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;

	lockdep_assert_held(&dev->kvm->lock);

	/* 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);
	}