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[Qemu-devel] [PATCH 3/5] vfio: VFIO core group interface
|
From: |
Alex Williamson |
|
Subject: |
[Qemu-devel] [PATCH 3/5] vfio: VFIO core group interface |
|
Date: |
Wed, 21 Dec 2011 14:42:26 -0700 |
|
User-agent: |
StGIT/0.14.3 |
This provides the base group management with conduits to the
IOMMU driver and VFIO bus drivers.
Signed-off-by: Alex Williamson <address@hidden>
---
drivers/vfio/vfio_main.c | 1201 +++++++++++++++++++++++++++++++++++++++++++
drivers/vfio/vfio_private.h | 36 +
2 files changed, 1237 insertions(+), 0 deletions(-)
create mode 100644 drivers/vfio/vfio_main.c
create mode 100644 drivers/vfio/vfio_private.h
diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c
new file mode 100644
index 0000000..e4f0f92
--- /dev/null
+++ b/drivers/vfio/vfio_main.c
@@ -0,0 +1,1201 @@
+/*
+ * VFIO framework
+ *
+ * Copyright (C) 2011 Red Hat, Inc. All rights reserved.
+ * Author: Alex Williamson <address@hidden>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * Derived from original vfio:
+ * Copyright 2010 Cisco Systems, Inc. All rights reserved.
+ * Author: Tom Lyon, address@hidden
+ */
+
+#include <linux/cdev.h>
+#include <linux/compat.h>
+#include <linux/device.h>
+#include <linux/file.h>
+#include <linux/anon_inodes.h>
+#include <linux/fs.h>
+#include <linux/idr.h>
+#include <linux/iommu.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/uaccess.h>
+#include <linux/vfio.h>
+#include <linux/wait.h>
+
+#include "vfio_private.h"
+
+#define DRIVER_VERSION "0.2"
+#define DRIVER_AUTHOR "Alex Williamson <address@hidden>"
+#define DRIVER_DESC "VFIO - User Level meta-driver"
+
+static struct vfio {
+ dev_t devt;
+ struct cdev cdev;
+ struct list_head group_list;
+ struct mutex lock;
+ struct kref kref;
+ struct class *class;
+ struct idr idr;
+ wait_queue_head_t release_q;
+} vfio;
+
+static const struct file_operations vfio_group_fops;
+
+struct vfio_group {
+ dev_t devt;
+ unsigned int groupid;
+ struct bus_type *bus;
+ struct vfio_iommu *iommu;
+ struct list_head device_list;
+ struct list_head iommu_next;
+ struct list_head group_next;
+ struct device *dev;
+ struct kobject *devices_kobj;
+ int refcnt;
+ bool tainted;
+};
+
+struct vfio_device {
+ struct device *dev;
+ const struct vfio_device_ops *ops;
+ struct vfio_group *group;
+ struct list_head device_next;
+ bool attached;
+ bool deleteme;
+ int refcnt;
+ void *device_data;
+};
+
+/*
+ * Helper functions called under vfio.lock
+ */
+
+/* Return true if any devices within a group are opened */
+static bool __vfio_group_devs_inuse(struct vfio_group *group)
+{
+ struct list_head *pos;
+
+ list_for_each(pos, &group->device_list) {
+ struct vfio_device *device;
+
+ device = list_entry(pos, struct vfio_device, device_next);
+ if (device->refcnt)
+ return true;
+ }
+ return false;
+}
+
+/* Return true if any of the groups attached to an iommu are opened.
+ * We can only tear apart merged groups when nothing is left open. */
+static bool __vfio_iommu_groups_inuse(struct vfio_iommu *iommu)
+{
+ struct list_head *pos;
+
+ list_for_each(pos, &iommu->group_list) {
+ struct vfio_group *group;
+
+ group = list_entry(pos, struct vfio_group, iommu_next);
+ if (group->refcnt)
+ return true;
+ }
+ return false;
+}
+
+/* An iommu is "in use" if it has a file descriptor open or if any of
+ * the groups assigned to the iommu have devices open. */
+static bool __vfio_iommu_inuse(struct vfio_iommu *iommu)
+{
+ struct list_head *pos;
+
+ if (iommu->refcnt)
+ return true;
+
+ list_for_each(pos, &iommu->group_list) {
+ struct vfio_group *group;
+
+ group = list_entry(pos, struct vfio_group, iommu_next);
+
+ if (__vfio_group_devs_inuse(group))
+ return true;
+ }
+ return false;
+}
+
+static void __vfio_group_set_iommu(struct vfio_group *group,
+ struct vfio_iommu *iommu)
+{
+ if (group->iommu)
+ list_del(&group->iommu_next);
+ if (iommu)
+ list_add(&group->iommu_next, &iommu->group_list);
+
+ group->iommu = iommu;
+}
+
+static void __vfio_iommu_detach_dev(struct vfio_iommu *iommu,
+ struct vfio_device *device)
+{
+ if (WARN_ON(!iommu->domain && device->attached))
+ return;
+
+ if (!device->attached)
+ return;
+
+ iommu_detach_device(iommu->domain, device->dev);
+ device->attached = false;
+}
+
+static void __vfio_iommu_detach_group(struct vfio_iommu *iommu,
+ struct vfio_group *group)
+{
+ struct list_head *pos;
+
+ list_for_each(pos, &group->device_list) {
+ struct vfio_device *device;
+
+ device = list_entry(pos, struct vfio_device, device_next);
+ __vfio_iommu_detach_dev(iommu, device);
+ }
+}
+
+static int __vfio_iommu_attach_dev(struct vfio_iommu *iommu,
+ struct vfio_device *device)
+{
+ int ret;
+
+ if (WARN_ON(device->attached || !iommu || !iommu->domain))
+ return -EINVAL;
+
+ ret = iommu_attach_device(iommu->domain, device->dev);
+ if (!ret)
+ device->attached = true;
+
+ return ret;
+}
+
+static int __vfio_iommu_attach_group(struct vfio_iommu *iommu,
+ struct vfio_group *group)
+{
+ struct list_head *pos;
+
+ list_for_each(pos, &group->device_list) {
+ struct vfio_device *device;
+ int ret;
+
+ device = list_entry(pos, struct vfio_device, device_next);
+ ret = __vfio_iommu_attach_dev(iommu, device);
+ if (ret) {
+ __vfio_iommu_detach_group(iommu, group);
+ return ret;
+ }
+ }
+ return 0;
+}
+
+/* The iommu is viable, ie. ready to be configured, when all the devices
+ * for all the groups attached to the iommu are bound to their vfio device
+ * drivers (ex. vfio-pci). This sets the device_data private data pointer. */
+static bool __vfio_iommu_viable(struct vfio_iommu *iommu)
+{
+ struct list_head *gpos, *dpos;
+
+ list_for_each(gpos, &iommu->group_list) {
+ struct vfio_group *group;
+ group = list_entry(gpos, struct vfio_group, iommu_next);
+
+ if (group->tainted)
+ return false;
+
+ list_for_each(dpos, &group->device_list) {
+ struct vfio_device *device;
+ device = list_entry(dpos,
+ struct vfio_device, device_next);
+
+ if (!device->device_data)
+ return false;
+ }
+ }
+ return true;
+}
+
+static void __vfio_iommu_close(struct vfio_iommu *iommu)
+{
+ struct list_head *pos;
+
+ if (!iommu->domain)
+ return;
+
+ list_for_each(pos, &iommu->group_list) {
+ struct vfio_group *group;
+ group = list_entry(pos, struct vfio_group, iommu_next);
+
+ __vfio_iommu_detach_group(iommu, group);
+ }
+
+ vfio_iommu_unmapall(iommu);
+
+ iommu_domain_free(iommu->domain);
+ iommu->domain = NULL;
+ iommu->mm = NULL;
+}
+
+/* Open the IOMMU. This gates all access to the iommu or device file
+ * descriptors and sets current->mm as the exclusive user. */
+static int __vfio_iommu_open(struct vfio_iommu *iommu)
+{
+ struct list_head *pos;
+ int ret;
+
+ if (!__vfio_iommu_viable(iommu))
+ return -EBUSY;
+
+ if (iommu->domain)
+ return -EINVAL;
+
+ iommu->domain = iommu_domain_alloc(iommu->bus);
+ if (!iommu->domain)
+ return -ENOMEM;
+
+ list_for_each(pos, &iommu->group_list) {
+ struct vfio_group *group;
+ group = list_entry(pos, struct vfio_group, iommu_next);
+
+ ret = __vfio_iommu_attach_group(iommu, group);
+ if (ret) {
+ __vfio_iommu_close(iommu);
+ return ret;
+ }
+ }
+
+ iommu->cache = (iommu_domain_has_cap(iommu->domain,
+ IOMMU_CAP_CACHE_COHERENCY) != 0);
+ iommu->mm = current->mm;
+
+ return 0;
+}
+
+/* Actively try to tear down the iommu and merged groups. If there are no
+ * open iommu or device fds, we close the iommu. If we close the iommu and
+ * there are also no open group fds, we can further dissolve the group to
+ * iommu association and free the iommu data structure. */
+static int __vfio_try_dissolve_iommu(struct vfio_iommu *iommu)
+{
+
+ if (__vfio_iommu_inuse(iommu))
+ return -EBUSY;
+
+ __vfio_iommu_close(iommu);
+
+ if (!__vfio_iommu_groups_inuse(iommu)) {
+ struct list_head *pos, *ppos;
+
+ list_for_each_safe(pos, ppos, &iommu->group_list) {
+ struct vfio_group *group;
+
+ group = list_entry(pos, struct vfio_group, iommu_next);
+ __vfio_group_set_iommu(group, NULL);
+ }
+
+ kfree(iommu);
+ }
+
+ return 0;
+}
+
+static struct vfio_device *__vfio_lookup_dev(struct device *dev)
+{
+ struct list_head *gpos;
+ unsigned int groupid;
+
+ if (iommu_device_group(dev, &groupid))
+ return NULL;
+
+ list_for_each(gpos, &vfio.group_list) {
+ struct vfio_group *group;
+ struct list_head *dpos;
+
+ group = list_entry(gpos, struct vfio_group, group_next);
+
+ if (group->groupid != groupid || group->bus != dev->bus)
+ continue;
+
+ list_for_each(dpos, &group->device_list) {
+ struct vfio_device *device;
+
+ device = list_entry(dpos,
+ struct vfio_device, device_next);
+
+ if (device->dev == dev)
+ return device;
+ }
+ }
+ return NULL;
+}
+
+static struct vfio_group *__vfio_dev_to_group(struct device *dev,
+ unsigned int groupid)
+{
+ struct list_head *pos;
+ struct vfio_group *group;
+
+ list_for_each(pos, &vfio.group_list) {
+ group = list_entry(pos, struct vfio_group, group_next);
+ if (group->groupid == groupid && group->bus == dev->bus)
+ return group;
+ }
+
+ return NULL;
+}
+
+struct vfio_device *__vfio_group_find_device(struct vfio_group *group,
+ struct device *dev)
+{
+ struct list_head *pos;
+ struct vfio_device *device;
+
+ list_for_each(pos, &group->device_list) {
+ device = list_entry(pos, struct vfio_device, device_next);
+ if (device->dev == dev)
+ return device;
+ }
+
+ return NULL;
+}
+
+static struct vfio_group *__vfio_create_group(struct device *dev,
+ unsigned int groupid)
+{
+ struct vfio_group *group;
+ int ret, minor;
+
+ group = kzalloc(sizeof(*group), GFP_KERNEL);
+
+ /* We can't recover from this. If we can't even get memory for
+ * the group, we can't track the device and we don't have a place
+ * to mark the groupid tainted. Failures below should at least
+ * return a tainted group. */
+ BUG_ON(!group);
+
+ group->groupid = groupid;
+ group->bus = dev->bus;
+ INIT_LIST_HEAD(&group->device_list);
+
+ group->tainted = true;
+ list_add(&group->group_next, &vfio.group_list);
+
+again:
+ if (unlikely(idr_pre_get(&vfio.idr, GFP_KERNEL) == 0))
+ goto out;
+
+ ret = idr_get_new(&vfio.idr, group, &minor);
+ if (ret == -EAGAIN)
+ goto again;
+ if (ret || minor > MINORMASK) {
+ if (minor > MINORMASK)
+ idr_remove(&vfio.idr, minor);
+ goto out;
+ }
+
+ group->devt = MKDEV(MAJOR(vfio.devt), minor);
+ group->dev = device_create(vfio.class, NULL, group->devt, group,
+ "%s:%u", dev->bus->name, groupid);
+ if (IS_ERR(group->dev))
+ goto out_device;
+
+ /* Create a place to link individual devices in sysfs */
+ group->devices_kobj = kobject_create_and_add("devices",
+ &group->dev->kobj);
+ if (!group->devices_kobj)
+ goto out_kobj;
+
+ group->tainted = false;
+
+ return group;
+
+out_kobj:
+ device_destroy(vfio.class, group->devt);
+out_device:
+ group->dev = NULL;
+ group->devt = 0;
+ idr_remove(&vfio.idr, minor);
+out:
+ printk(KERN_WARNING "vfio: Failed to complete setup on group %u, "
+ "marking as unusable\n", groupid);
+
+ return group;
+}
+
+static struct vfio_iommu *vfio_create_iommu(struct vfio_group *group)
+{
+ struct vfio_iommu *iommu;
+
+ iommu = kzalloc(sizeof(*iommu), GFP_KERNEL);
+ if (!iommu)
+ return ERR_PTR(-ENOMEM);
+
+ INIT_LIST_HEAD(&iommu->group_list);
+ INIT_LIST_HEAD(&iommu->dma_list);
+ mutex_init(&iommu->lock);
+ iommu->bus = group->bus;
+
+ return iommu;
+}
+
+/* All release paths simply decrement the refcnt, attempt to teardown
+ * the iommu and merged groups, and wakeup anything that might be
+ * waiting if we successfully dissolve anything. */
+static int vfio_do_release(int *refcnt, struct vfio_iommu *iommu)
+{
+ bool wake;
+
+ mutex_lock(&vfio.lock);
+
+ (*refcnt)--;
+ wake = (__vfio_try_dissolve_iommu(iommu) == 0);
+
+ mutex_unlock(&vfio.lock);
+
+ if (wake)
+ wake_up(&vfio.release_q);
+
+ return 0;
+}
+
+/*
+ * Device fops - passthrough to vfio device driver w/ device_data
+ */
+static int vfio_device_release(struct inode *inode, struct file *filep)
+{
+ struct vfio_device *device = filep->private_data;
+
+ vfio_do_release(&device->refcnt, device->group->iommu);
+
+ device->ops->release(device->device_data);
+
+ return 0;
+}
+
+static long vfio_device_unl_ioctl(struct file *filep,
+ unsigned int cmd, unsigned long arg)
+{
+ struct vfio_device *device = filep->private_data;
+
+ return device->ops->ioctl(device->device_data, cmd, arg);
+}
+
+static ssize_t vfio_device_read(struct file *filep, char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ struct vfio_device *device = filep->private_data;
+
+ return device->ops->read(device->device_data, buf, count, ppos);
+}
+
+static ssize_t vfio_device_write(struct file *filep, const char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ struct vfio_device *device = filep->private_data;
+
+ return device->ops->write(device->device_data, buf, count, ppos);
+}
+
+static int vfio_device_mmap(struct file *filep, struct vm_area_struct *vma)
+{
+ struct vfio_device *device = filep->private_data;
+
+ return device->ops->mmap(device->device_data, vma);
+}
+
+#ifdef CONFIG_COMPAT
+static long vfio_device_compat_ioctl(struct file *filep,
+ unsigned int cmd, unsigned long arg)
+{
+ arg = (unsigned long)compat_ptr(arg);
+ return vfio_device_unl_ioctl(filep, cmd, arg);
+}
+#endif /* CONFIG_COMPAT */
+
+const struct file_operations vfio_device_fops = {
+ .owner = THIS_MODULE,
+ .release = vfio_device_release,
+ .read = vfio_device_read,
+ .write = vfio_device_write,
+ .unlocked_ioctl = vfio_device_unl_ioctl,
+#ifdef CONFIG_COMPAT
+ .compat_ioctl = vfio_device_compat_ioctl,
+#endif
+ .mmap = vfio_device_mmap,
+};
+
+/*
+ * Group fops
+ */
+static int vfio_group_open(struct inode *inode, struct file *filep)
+{
+ struct vfio_group *group;
+ int ret = 0;
+
+ mutex_lock(&vfio.lock);
+
+ group = idr_find(&vfio.idr, iminor(inode));
+
+ if (!group) {
+ ret = -ENODEV;
+ goto out;
+ }
+
+ filep->private_data = group;
+
+ if (!group->iommu) {
+ struct vfio_iommu *iommu;
+
+ iommu = vfio_create_iommu(group);
+ if (IS_ERR(iommu)) {
+ ret = PTR_ERR(iommu);
+ goto out;
+ }
+ __vfio_group_set_iommu(group, iommu);
+ }
+ group->refcnt++;
+
+out:
+ mutex_unlock(&vfio.lock);
+
+ return ret;
+}
+
+static int vfio_group_release(struct inode *inode, struct file *filep)
+{
+ struct vfio_group *group = filep->private_data;
+
+ return vfio_do_release(&group->refcnt, group->iommu);
+}
+
+/* Attempt to merge the group pointed to by fd into group. The merge-ee
+ * group must not have an iommu or any devices open because we cannot
+ * maintain that context across the merge. The merge-er group can be
+ * in use. */
+static int vfio_group_merge(struct vfio_group *group, int fd)
+{
+ struct vfio_group *new;
+ struct vfio_iommu *old_iommu;
+ struct file *file;
+ int ret = 0;
+ bool opened = false;
+
+ mutex_lock(&vfio.lock);
+
+ file = fget(fd);
+ if (!file) {
+ ret = -EBADF;
+ goto out_noput;
+ }
+
+ /* Sanity check, is this really our fd? */
+ if (file->f_op != &vfio_group_fops) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ new = file->private_data;
+
+ if (!new || new == group || !new->iommu ||
+ new->iommu->domain || new->bus != group->bus) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ /* We need to attach all the devices to each domain separately
+ * in order to validate that the capabilities match for both. */
+ ret = __vfio_iommu_open(new->iommu);
+ if (ret)
+ goto out;
+
+ if (!group->iommu->domain) {
+ ret = __vfio_iommu_open(group->iommu);
+ if (ret)
+ goto out;
+ opened = true;
+ }
+
+ /* If cache coherency doesn't match we'd potentially need to
+ * remap existing iommu mappings in the merge-er domain.
+ * Poor return to bother trying to allow this currently. */
+ if (iommu_domain_has_cap(group->iommu->domain,
+ IOMMU_CAP_CACHE_COHERENCY) !=
+ iommu_domain_has_cap(new->iommu->domain,
+ IOMMU_CAP_CACHE_COHERENCY)) {
+ __vfio_iommu_close(new->iommu);
+ if (opened)
+ __vfio_iommu_close(group->iommu);
+ ret = -EINVAL;
+ goto out;
+ }
+
+ /* Close the iommu for the merge-ee and attach all its devices
+ * to the merge-er iommu. */
+ __vfio_iommu_close(new->iommu);
+
+ ret = __vfio_iommu_attach_group(group->iommu, new);
+ if (ret)
+ goto out;
+
+ /* set_iommu unlinks new from the iommu, so save a pointer to it */
+ old_iommu = new->iommu;
+ __vfio_group_set_iommu(new, group->iommu);
+ kfree(old_iommu);
+
+out:
+ fput(file);
+out_noput:
+ mutex_unlock(&vfio.lock);
+ return ret;
+}
+
+/* Unmerge a group */
+static int vfio_group_unmerge(struct vfio_group *group)
+{
+ struct vfio_iommu *iommu;
+ int ret = 0;
+
+ /* Since the merge-out group is already opened, it needs to
+ * have an iommu struct associated with it. */
+ iommu = vfio_create_iommu(group);
+ if (IS_ERR(iommu))
+ return PTR_ERR(iommu);
+
+ mutex_lock(&vfio.lock);
+
+ if (list_is_singular(&group->iommu->group_list)) {
+ ret = -EINVAL; /* Not merged group */
+ goto out;
+ }
+
+ /* We can't merge-out a group with devices still in use. */
+ if (__vfio_group_devs_inuse(group)) {
+ ret = -EBUSY;
+ goto out;
+ }
+
+ __vfio_iommu_detach_group(group->iommu, group);
+ __vfio_group_set_iommu(group, iommu);
+
+out:
+ if (ret)
+ kfree(iommu);
+ mutex_unlock(&vfio.lock);
+ return ret;
+}
+
+/* Get a new iommu file descriptor. This will open the iommu, setting
+ * the current->mm ownership if it's not already set. */
+static int vfio_group_get_iommu_fd(struct vfio_group *group)
+{
+ int ret = 0;
+
+ mutex_lock(&vfio.lock);
+
+ if (!group->iommu->domain) {
+ ret = __vfio_iommu_open(group->iommu);
+ if (ret)
+ goto out;
+ }
+
+ ret = anon_inode_getfd("[vfio-iommu]", &vfio_iommu_fops,
+ group->iommu, O_RDWR);
+ if (ret < 0)
+ goto out;
+
+ group->iommu->refcnt++;
+out:
+ mutex_unlock(&vfio.lock);
+ return ret;
+}
+
+/* Get a new device file descriptor. This will open the iommu, setting
+ * the current->mm ownership if it's not already set. It's difficult to
+ * specify the requirements for matching a user supplied buffer to a
+ * device, so we use a vfio driver callback to test for a match. For
+ * PCI, dev_name(dev) is unique, but other drivers may require including
+ * a parent device string. */
+static int vfio_group_get_device_fd(struct vfio_group *group, char *buf)
+{
+ struct vfio_iommu *iommu = group->iommu;
+ struct list_head *gpos;
+ int ret = -ENODEV;
+
+ mutex_lock(&vfio.lock);
+
+ if (!iommu->domain) {
+ ret = __vfio_iommu_open(iommu);
+ if (ret)
+ goto out;
+ }
+
+ list_for_each(gpos, &iommu->group_list) {
+ struct list_head *dpos;
+
+ group = list_entry(gpos, struct vfio_group, iommu_next);
+
+ list_for_each(dpos, &group->device_list) {
+ struct vfio_device *device;
+ struct file *file;
+
+ device = list_entry(dpos,
+ struct vfio_device, device_next);
+
+ if (!device->ops->match(device->dev, buf))
+ continue;
+
+ ret = device->ops->open(device->device_data);
+ if (ret)
+ goto out;
+
+ /* We can't use anon_inode_getfd(), like above
+ * because we need to modify the f_mode flags
+ * directly to allow more than just ioctls */
+ ret = get_unused_fd();
+ if (ret < 0) {
+ device->ops->release(device->device_data);
+ goto out;
+ }
+
+ file = anon_inode_getfile("[vfio-device]",
+ &vfio_device_fops,
+ device, O_RDWR);
+ if (IS_ERR(file)) {
+ put_unused_fd(ret);
+ ret = PTR_ERR(file);
+ device->ops->release(device->device_data);
+ goto out;
+ }
+
+ /* Todo: add an anon_inode interface to do
+ * this. Appears to be missing by lack of
+ * need rather than explicitly prevented.
+ * Now there's need. */
+ file->f_mode |= (FMODE_LSEEK |
+ FMODE_PREAD |
+ FMODE_PWRITE);
+
+ fd_install(ret, file);
+
+ device->refcnt++;
+ goto out;
+ }
+ }
+out:
+ mutex_unlock(&vfio.lock);
+ return ret;
+}
+
+static long vfio_group_unl_ioctl(struct file *filep,
+ unsigned int cmd, unsigned long arg)
+{
+ struct vfio_group *group = filep->private_data;
+
+ if (cmd == VFIO_GROUP_GET_INFO) {
+ struct vfio_group_info info;
+ unsigned long minsz;
+
+ minsz = offsetofend(struct vfio_group_info, flags);
+
+ if (copy_from_user(&info, (void __user *)arg, minsz))
+ return -EFAULT;
+
+ if (info.argsz < minsz)
+ return -EINVAL;
+
+ mutex_lock(&vfio.lock);
+ if (__vfio_iommu_viable(group->iommu))
+ info.flags |= VFIO_GROUP_FLAGS_VIABLE;
+ mutex_unlock(&vfio.lock);
+
+ if (group->iommu->mm)
+ info.flags |= VFIO_GROUP_FLAGS_MM_LOCKED;
+
+ return copy_to_user((void __user *)arg, &info, minsz);
+ }
+
+ /* Below commands are restricted once the mm is set */
+ if (group->iommu->mm && group->iommu->mm != current->mm)
+ return -EPERM;
+
+ if (cmd == VFIO_GROUP_MERGE) {
+ int fd;
+
+ if (get_user(fd, (int __user *)arg))
+ return -EFAULT;
+ if (fd < 0)
+ return -EINVAL;
+
+ return vfio_group_merge(group, fd);
+
+ } else if (cmd == VFIO_GROUP_UNMERGE) {
+
+ return vfio_group_unmerge(group);
+
+ } else if (cmd == VFIO_GROUP_GET_IOMMU_FD) {
+
+ return vfio_group_get_iommu_fd(group);
+
+ } else if (cmd == VFIO_GROUP_GET_DEVICE_FD) {
+ char *buf;
+ int ret;
+
+ buf = strndup_user((const char __user *)arg, PAGE_SIZE);
+ if (IS_ERR(buf))
+ return PTR_ERR(buf);
+
+ ret = vfio_group_get_device_fd(group, buf);
+ kfree(buf);
+ return ret;
+ }
+
+ return -ENOTTY;
+}
+
+#ifdef CONFIG_COMPAT
+static long vfio_group_compat_ioctl(struct file *filep,
+ unsigned int cmd, unsigned long arg)
+{
+ arg = (unsigned long)compat_ptr(arg);
+ return vfio_group_unl_ioctl(filep, cmd, arg);
+}
+#endif /* CONFIG_COMPAT */
+
+static const struct file_operations vfio_group_fops = {
+ .owner = THIS_MODULE,
+ .open = vfio_group_open,
+ .release = vfio_group_release,
+ .unlocked_ioctl = vfio_group_unl_ioctl,
+#ifdef CONFIG_COMPAT
+ .compat_ioctl = vfio_group_compat_ioctl,
+#endif
+};
+
+/* iommu fd release hook */
+int vfio_release_iommu(struct vfio_iommu *iommu)
+{
+ return vfio_do_release(&iommu->refcnt, iommu);
+}
+
+/*
+ * VFIO driver API
+ */
+
+/* Add a new device to the vfio framework with associated vfio driver
+ * callbacks. This is the entry point for vfio drivers to register devices. */
+int vfio_group_add_dev(struct device *dev, const struct vfio_device_ops *ops)
+{
+ struct vfio_group *group;
+ struct vfio_device *device;
+ unsigned int groupid;
+ int ret = 0;
+
+ if (iommu_device_group(dev, &groupid))
+ return -ENODEV;
+
+ if (WARN_ON(!ops))
+ return -EINVAL;
+
+ mutex_lock(&vfio.lock);
+
+ group = __vfio_dev_to_group(dev, groupid);
+ if (!group)
+ group = __vfio_create_group(dev, groupid); /* No fail */
+
+ device = __vfio_group_find_device(group, dev);
+ if (!device) {
+ device = kzalloc(sizeof(*device), GFP_KERNEL);
+ if (WARN_ON(!device)) {
+ /* We created the group, but can't add this device,
+ * taint the group to prevent it being used. If
+ * it's already in use, we have to BUG_ON.
+ * XXX - Kill the user process? */
+ group->tainted = true;
+ BUG_ON(group->iommu && group->iommu->domain);
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ list_add(&device->device_next, &group->device_list);
+ device->dev = dev;
+ device->ops = ops;
+ device->group = group;
+
+ if (!group->devices_kobj ||
+ sysfs_create_link(group->devices_kobj,
+ &dev->kobj, dev_name(dev)))
+ printk(KERN_WARNING
+ "vfio: Unable to create sysfs link to %s\n",
+ dev_name(dev));
+
+ if (group->iommu && group->iommu->domain) {
+ printk(KERN_WARNING "Adding device %s to group %s:%u "
+ "while group is already in use!!\n",
+ dev_name(dev), group->bus->name, group->groupid);
+
+ mutex_unlock(&vfio.lock);
+
+ ret = ops->claim(dev);
+
+ BUG_ON(ret);
+
+ goto out_unlocked;
+ }
+
+ }
+out:
+ mutex_unlock(&vfio.lock);
+out_unlocked:
+ return ret;
+}
+EXPORT_SYMBOL_GPL(vfio_group_add_dev);
+
+/* Remove a device from the vfio framework */
+void vfio_group_del_dev(struct device *dev)
+{
+ struct vfio_group *group;
+ struct vfio_device *device;
+ unsigned int groupid;
+
+ if (iommu_device_group(dev, &groupid))
+ return;
+
+ mutex_lock(&vfio.lock);
+
+ group = __vfio_dev_to_group(dev, groupid);
+
+ if (WARN_ON(!group))
+ goto out;
+
+ device = __vfio_group_find_device(group, dev);
+
+ if (WARN_ON(!device))
+ goto out;
+
+ /* If device is bound to a bus driver, we'll get a chance to
+ * unbind it first. Just mark it to be removed after unbind. */
+ if (device->device_data) {
+ device->deleteme = true;
+ goto out;
+ }
+
+ if (device->attached)
+ __vfio_iommu_detach_dev(group->iommu, device);
+
+ list_del(&device->device_next);
+
+ if (group->devices_kobj)
+ sysfs_remove_link(group->devices_kobj, dev_name(dev));
+
+ kfree(device);
+
+ /* If this was the only device in the group, remove the group.
+ * Note that we intentionally unmerge empty groups here if the
+ * group fd isn't opened. */
+ if (list_empty(&group->device_list) && group->refcnt == 0) {
+ struct vfio_iommu *iommu = group->iommu;
+
+ if (iommu) {
+ __vfio_group_set_iommu(group, NULL);
+ __vfio_try_dissolve_iommu(iommu);
+ }
+
+ /* Groups can be mostly placeholders if setup isn't
+ * completed, remove them carefully. */
+ if (group->devices_kobj)
+ kobject_put(group->devices_kobj);
+ if (group->dev) {
+ device_destroy(vfio.class, group->devt);
+ idr_remove(&vfio.idr, MINOR(group->devt));
+ }
+ list_del(&group->group_next);
+ kfree(group);
+ }
+
+out:
+ mutex_unlock(&vfio.lock);
+}
+EXPORT_SYMBOL_GPL(vfio_group_del_dev);
+
+/* When a device is bound to a vfio device driver (ex. vfio-pci), this
+ * entry point is used to mark the device usable (viable). The vfio
+ * device driver associates a private device_data struct with the device
+ * here, which will later be return for vfio_device_fops callbacks. */
+int vfio_bind_dev(struct device *dev, void *device_data)
+{
+ struct vfio_device *device;
+ int ret;
+
+ if (WARN_ON(!device_data))
+ return -EINVAL;
+
+ mutex_lock(&vfio.lock);
+
+ device = __vfio_lookup_dev(dev);
+
+ if (WARN_ON(!device)) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ ret = dev_set_drvdata(dev, device);
+ if (!ret)
+ device->device_data = device_data;
+
+out:
+ mutex_unlock(&vfio.lock);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(vfio_bind_dev);
+
+/* A device is only removable if the iommu for the group is not in use. */
+static bool vfio_device_removeable(struct vfio_device *device)
+{
+ bool ret = true;
+
+ mutex_lock(&vfio.lock);
+
+ if (device->group->iommu && __vfio_iommu_inuse(device->group->iommu))
+ ret = false;
+
+ mutex_unlock(&vfio.lock);
+ return ret;
+}
+
+/* Notify vfio that a device is being unbound from the vfio device driver
+ * and return the device private device_data pointer. If the group is
+ * in use, we need to block or take other measures to make it safe for
+ * the device to be removed from the iommu. */
+void *vfio_unbind_dev(struct device *dev)
+{
+ struct vfio_device *device = dev_get_drvdata(dev);
+ void *device_data;
+
+ if (WARN_ON(!device))
+ return NULL;
+again:
+ if (!vfio_device_removeable(device)) {
+ /* XXX signal for all devices in group to be removed or
+ * resort to killing the process holding the device fds.
+ * For now just block waiting for releases to wake us. */
+ wait_event(vfio.release_q, vfio_device_removeable(device));
+ }
+
+ mutex_lock(&vfio.lock);
+
+ /* Need to re-check that the device is still removable under lock. */
+ if (device->group->iommu && __vfio_iommu_inuse(device->group->iommu)) {
+ mutex_unlock(&vfio.lock);
+ goto again;
+ }
+
+ device_data = device->device_data;
+
+ device->device_data = NULL;
+ dev_set_drvdata(dev, NULL);
+
+ mutex_unlock(&vfio.lock);
+
+ if (device->deleteme)
+ vfio_group_del_dev(dev);
+
+ return device_data;
+}
+EXPORT_SYMBOL_GPL(vfio_unbind_dev);
+
+/*
+ * Module/class support
+ */
+static void vfio_class_release(struct kref *kref)
+{
+ class_destroy(vfio.class);
+ vfio.class = NULL;
+}
+
+static char *vfio_devnode(struct device *dev, mode_t *mode)
+{
+ return kasprintf(GFP_KERNEL, "vfio/%s", dev_name(dev));
+}
+
+static int __init vfio_init(void)
+{
+ int ret;
+
+ idr_init(&vfio.idr);
+ mutex_init(&vfio.lock);
+ INIT_LIST_HEAD(&vfio.group_list);
+ init_waitqueue_head(&vfio.release_q);
+
+ kref_init(&vfio.kref);
+ vfio.class = class_create(THIS_MODULE, "vfio");
+ if (IS_ERR(vfio.class)) {
+ ret = PTR_ERR(vfio.class);
+ goto err_class;
+ }
+
+ vfio.class->devnode = vfio_devnode;
+
+ /* FIXME - how many minors to allocate... all of them! */
+ ret = alloc_chrdev_region(&vfio.devt, 0, MINORMASK, "vfio");
+ if (ret)
+ goto err_chrdev;
+
+ cdev_init(&vfio.cdev, &vfio_group_fops);
+ ret = cdev_add(&vfio.cdev, vfio.devt, MINORMASK);
+ if (ret)
+ goto err_cdev;
+
+ pr_info(DRIVER_DESC " version: " DRIVER_VERSION "\n");
+
+ return 0;
+
+err_cdev:
+ unregister_chrdev_region(vfio.devt, MINORMASK);
+err_chrdev:
+ kref_put(&vfio.kref, vfio_class_release);
+err_class:
+ return ret;
+}
+
+static void __exit vfio_cleanup(void)
+{
+ struct list_head *gpos, *gppos;
+
+ list_for_each_safe(gpos, gppos, &vfio.group_list) {
+ struct vfio_group *group;
+ struct list_head *dpos, *dppos;
+
+ group = list_entry(gpos, struct vfio_group, group_next);
+
+ list_for_each_safe(dpos, dppos, &group->device_list) {
+ struct vfio_device *device;
+
+ device = list_entry(dpos,
+ struct vfio_device, device_next);
+ vfio_group_del_dev(device->dev);
+ }
+ }
+
+ idr_destroy(&vfio.idr);
+ cdev_del(&vfio.cdev);
+ unregister_chrdev_region(vfio.devt, MINORMASK);
+ kref_put(&vfio.kref, vfio_class_release);
+}
+
+module_init(vfio_init);
+module_exit(vfio_cleanup);
+
+MODULE_VERSION(DRIVER_VERSION);
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR(DRIVER_AUTHOR);
+MODULE_DESCRIPTION(DRIVER_DESC);
diff --git a/drivers/vfio/vfio_private.h b/drivers/vfio/vfio_private.h
new file mode 100644
index 0000000..db99e75
--- /dev/null
+++ b/drivers/vfio/vfio_private.h
@@ -0,0 +1,36 @@
+/*
+ * Copyright (C) 2011 Red Hat, Inc. All rights reserved.
+ * Author: Alex Williamson <address@hidden>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * Derived from original vfio:
+ * Copyright 2010 Cisco Systems, Inc. All rights reserved.
+ * Author: Tom Lyon, address@hidden
+ */
+
+#include <linux/list.h>
+#include <linux/mutex.h>
+
+#ifndef VFIO_PRIVATE_H
+#define VFIO_PRIVATE_H
+
+struct vfio_iommu {
+ struct iommu_domain *domain;
+ struct bus_type *bus;
+ struct mutex lock;
+ struct list_head dma_list;
+ struct mm_struct *mm;
+ struct list_head group_list;
+ int refcnt;
+ bool cache;
+};
+
+extern const struct file_operations vfio_iommu_fops;
+
+extern int vfio_release_iommu(struct vfio_iommu *iommu);
+extern void vfio_iommu_unmapall(struct vfio_iommu *iommu);
+
+#endif /* VFIO_PRIVATE_H */