1 files changed, 394 insertions, 0 deletions
diff --git a/virt/kvm/vfio.c b/virt/kvm/vfio.c
new file mode 100644
index 0000000000..ca24ce1209
--- /dev/null
+++ b/virt/kvm/vfio.c
@@ -0,0 +1,394 @@
+// 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;
+
+	/* 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);
+}