blob: 8549cb111627f0b4bc64956df7c2b1e945bbfdc2 [file] [log] [blame]
/*
* VFIO: IOMMU DMA mapping support for Type1 IOMMU
*
* Copyright (C) 2012 Red Hat, Inc. All rights reserved.
* Author: Alex Williamson <alex.williamson@redhat.com>
*
* 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, pugs@cisco.com
*
* We arbitrarily define a Type1 IOMMU as one matching the below code.
* It could be called the x86 IOMMU as it's designed for AMD-Vi & Intel
* VT-d, but that makes it harder to re-use as theoretically anyone
* implementing a similar IOMMU could make use of this. We expect the
* IOMMU to support the IOMMU API and have few to no restrictions around
* the IOVA range that can be mapped. The Type1 IOMMU is currently
* optimized for relatively static mappings of a userspace process with
* userpsace pages pinned into memory. We also assume devices and IOMMU
* domains are PCI based as the IOMMU API is still centered around a
* device/bus interface rather than a group interface.
*/
#include <linux/compat.h>
#include <linux/device.h>
#include <linux/fs.h>
#include <linux/iommu.h>
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/rbtree.h>
#include <linux/sched/signal.h>
#include <linux/sched/mm.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/vfio.h>
#include <linux/workqueue.h>
#include <linux/mdev.h>
#include <linux/notifier.h>
#include <linux/dma-iommu.h>
#include <linux/irqdomain.h>
#define DRIVER_VERSION "0.2"
#define DRIVER_AUTHOR "Alex Williamson <alex.williamson@redhat.com>"
#define DRIVER_DESC "Type1 IOMMU driver for VFIO"
static bool allow_unsafe_interrupts;
module_param_named(allow_unsafe_interrupts,
allow_unsafe_interrupts, bool, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(allow_unsafe_interrupts,
"Enable VFIO IOMMU support for on platforms without interrupt remapping support.");
static bool disable_hugepages;
module_param_named(disable_hugepages,
disable_hugepages, bool, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(disable_hugepages,
"Disable VFIO IOMMU support for IOMMU hugepages.");
struct vfio_iommu {
struct list_head domain_list;
struct vfio_domain *external_domain; /* domain for external user */
struct mutex lock;
struct rb_root dma_list;
struct blocking_notifier_head notifier;
bool v2;
bool nesting;
};
struct vfio_domain {
struct iommu_domain *domain;
struct list_head next;
struct list_head group_list;
int prot; /* IOMMU_CACHE */
bool fgsp; /* Fine-grained super pages */
};
struct vfio_dma {
struct rb_node node;
dma_addr_t iova; /* Device address */
unsigned long vaddr; /* Process virtual addr */
size_t size; /* Map size (bytes) */
int prot; /* IOMMU_READ/WRITE */
bool iommu_mapped;
struct task_struct *task;
struct rb_root pfn_list; /* Ex-user pinned pfn list */
};
struct vfio_group {
struct iommu_group *iommu_group;
struct list_head next;
};
/*
* Guest RAM pinning working set or DMA target
*/
struct vfio_pfn {
struct rb_node node;
dma_addr_t iova; /* Device address */
unsigned long pfn; /* Host pfn */
atomic_t ref_count;
};
#define IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu) \
(!list_empty(&iommu->domain_list))
static int put_pfn(unsigned long pfn, int prot);
/*
* This code handles mapping and unmapping of user data buffers
* into DMA'ble space using the IOMMU
*/
static struct vfio_dma *vfio_find_dma(struct vfio_iommu *iommu,
dma_addr_t start, size_t size)
{
struct rb_node *node = iommu->dma_list.rb_node;
while (node) {
struct vfio_dma *dma = rb_entry(node, struct vfio_dma, node);
if (start + size <= dma->iova)
node = node->rb_left;
else if (start >= dma->iova + dma->size)
node = node->rb_right;
else
return dma;
}
return NULL;
}
static void vfio_link_dma(struct vfio_iommu *iommu, struct vfio_dma *new)
{
struct rb_node **link = &iommu->dma_list.rb_node, *parent = NULL;
struct vfio_dma *dma;
while (*link) {
parent = *link;
dma = rb_entry(parent, struct vfio_dma, node);
if (new->iova + new->size <= dma->iova)
link = &(*link)->rb_left;
else
link = &(*link)->rb_right;
}
rb_link_node(&new->node, parent, link);
rb_insert_color(&new->node, &iommu->dma_list);
}
static void vfio_unlink_dma(struct vfio_iommu *iommu, struct vfio_dma *old)
{
rb_erase(&old->node, &iommu->dma_list);
}
/*
* Helper Functions for host iova-pfn list
*/
static struct vfio_pfn *vfio_find_vpfn(struct vfio_dma *dma, dma_addr_t iova)
{
struct vfio_pfn *vpfn;
struct rb_node *node = dma->pfn_list.rb_node;
while (node) {
vpfn = rb_entry(node, struct vfio_pfn, node);
if (iova < vpfn->iova)
node = node->rb_left;
else if (iova > vpfn->iova)
node = node->rb_right;
else
return vpfn;
}
return NULL;
}
static void vfio_link_pfn(struct vfio_dma *dma,
struct vfio_pfn *new)
{
struct rb_node **link, *parent = NULL;
struct vfio_pfn *vpfn;
link = &dma->pfn_list.rb_node;
while (*link) {
parent = *link;
vpfn = rb_entry(parent, struct vfio_pfn, node);
if (new->iova < vpfn->iova)
link = &(*link)->rb_left;
else
link = &(*link)->rb_right;
}
rb_link_node(&new->node, parent, link);
rb_insert_color(&new->node, &dma->pfn_list);
}
static void vfio_unlink_pfn(struct vfio_dma *dma, struct vfio_pfn *old)
{
rb_erase(&old->node, &dma->pfn_list);
}
static int vfio_add_to_pfn_list(struct vfio_dma *dma, dma_addr_t iova,
unsigned long pfn)
{
struct vfio_pfn *vpfn;
vpfn = kzalloc(sizeof(*vpfn), GFP_KERNEL);
if (!vpfn)
return -ENOMEM;
vpfn->iova = iova;
vpfn->pfn = pfn;
atomic_set(&vpfn->ref_count, 1);
vfio_link_pfn(dma, vpfn);
return 0;
}
static void vfio_remove_from_pfn_list(struct vfio_dma *dma,
struct vfio_pfn *vpfn)
{
vfio_unlink_pfn(dma, vpfn);
kfree(vpfn);
}
static struct vfio_pfn *vfio_iova_get_vfio_pfn(struct vfio_dma *dma,
unsigned long iova)
{
struct vfio_pfn *vpfn = vfio_find_vpfn(dma, iova);
if (vpfn)
atomic_inc(&vpfn->ref_count);
return vpfn;
}
static int vfio_iova_put_vfio_pfn(struct vfio_dma *dma, struct vfio_pfn *vpfn)
{
int ret = 0;
if (atomic_dec_and_test(&vpfn->ref_count)) {
ret = put_pfn(vpfn->pfn, dma->prot);
vfio_remove_from_pfn_list(dma, vpfn);
}
return ret;
}
static int vfio_lock_acct(struct task_struct *task, long npage, bool *lock_cap)
{
struct mm_struct *mm;
bool is_current;
int ret;
if (!npage)
return 0;
is_current = (task->mm == current->mm);
mm = is_current ? task->mm : get_task_mm(task);
if (!mm)
return -ESRCH; /* process exited */
ret = down_write_killable(&mm->mmap_sem);
if (!ret) {
if (npage > 0) {
if (lock_cap ? !*lock_cap :
!has_capability(task, CAP_IPC_LOCK)) {
unsigned long limit;
limit = task_rlimit(task,
RLIMIT_MEMLOCK) >> PAGE_SHIFT;
if (mm->locked_vm + npage > limit)
ret = -ENOMEM;
}
}
if (!ret)
mm->locked_vm += npage;
up_write(&mm->mmap_sem);
}
if (!is_current)
mmput(mm);
return ret;
}
/*
* Some mappings aren't backed by a struct page, for example an mmap'd
* MMIO range for our own or another device. These use a different
* pfn conversion and shouldn't be tracked as locked pages.
*/
static bool is_invalid_reserved_pfn(unsigned long pfn)
{
if (pfn_valid(pfn)) {
bool reserved;
struct page *tail = pfn_to_page(pfn);
struct page *head = compound_head(tail);
reserved = !!(PageReserved(head));
if (head != tail) {
/*
* "head" is not a dangling pointer
* (compound_head takes care of that)
* but the hugepage may have been split
* from under us (and we may not hold a
* reference count on the head page so it can
* be reused before we run PageReferenced), so
* we've to check PageTail before returning
* what we just read.
*/
smp_rmb();
if (PageTail(tail))
return reserved;
}
return PageReserved(tail);
}
return true;
}
static int put_pfn(unsigned long pfn, int prot)
{
if (!is_invalid_reserved_pfn(pfn)) {
struct page *page = pfn_to_page(pfn);
if (prot & IOMMU_WRITE)
SetPageDirty(page);
put_page(page);
return 1;
}
return 0;
}
static int vaddr_get_pfn(struct mm_struct *mm, unsigned long vaddr,
int prot, unsigned long *pfn)
{
struct page *page[1];
struct vm_area_struct *vma;
int ret;
if (mm == current->mm) {
ret = get_user_pages_fast(vaddr, 1, !!(prot & IOMMU_WRITE),
page);
} else {
unsigned int flags = 0;
if (prot & IOMMU_WRITE)
flags |= FOLL_WRITE;
down_read(&mm->mmap_sem);
ret = get_user_pages_remote(NULL, mm, vaddr, 1, flags, page,
NULL, NULL);
up_read(&mm->mmap_sem);
}
if (ret == 1) {
*pfn = page_to_pfn(page[0]);
return 0;
}
down_read(&mm->mmap_sem);
vma = find_vma_intersection(mm, vaddr, vaddr + 1);
if (vma && vma->vm_flags & VM_PFNMAP) {
*pfn = ((vaddr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
if (is_invalid_reserved_pfn(*pfn))
ret = 0;
}
up_read(&mm->mmap_sem);
return ret;
}
/*
* Attempt to pin pages. We really don't want to track all the pfns and
* the iommu can only map chunks of consecutive pfns anyway, so get the
* first page and all consecutive pages with the same locking.
*/
static long vfio_pin_pages_remote(struct vfio_dma *dma, unsigned long vaddr,
long npage, unsigned long *pfn_base,
bool lock_cap, unsigned long limit)
{
unsigned long pfn = 0;
long ret, pinned = 0, lock_acct = 0;
bool rsvd;
dma_addr_t iova = vaddr - dma->vaddr + dma->iova;
/* This code path is only user initiated */
if (!current->mm)
return -ENODEV;
ret = vaddr_get_pfn(current->mm, vaddr, dma->prot, pfn_base);
if (ret)
return ret;
pinned++;
rsvd = is_invalid_reserved_pfn(*pfn_base);
/*
* Reserved pages aren't counted against the user, externally pinned
* pages are already counted against the user.
*/
if (!rsvd && !vfio_find_vpfn(dma, iova)) {
if (!lock_cap && current->mm->locked_vm + 1 > limit) {
put_pfn(*pfn_base, dma->prot);
pr_warn("%s: RLIMIT_MEMLOCK (%ld) exceeded\n", __func__,
limit << PAGE_SHIFT);
return -ENOMEM;
}
lock_acct++;
}
if (unlikely(disable_hugepages))
goto out;
/* Lock all the consecutive pages from pfn_base */
for (vaddr += PAGE_SIZE, iova += PAGE_SIZE; pinned < npage;
pinned++, vaddr += PAGE_SIZE, iova += PAGE_SIZE) {
ret = vaddr_get_pfn(current->mm, vaddr, dma->prot, &pfn);
if (ret)
break;
if (pfn != *pfn_base + pinned ||
rsvd != is_invalid_reserved_pfn(pfn)) {
put_pfn(pfn, dma->prot);
break;
}
if (!rsvd && !vfio_find_vpfn(dma, iova)) {
if (!lock_cap &&
current->mm->locked_vm + lock_acct + 1 > limit) {
put_pfn(pfn, dma->prot);
pr_warn("%s: RLIMIT_MEMLOCK (%ld) exceeded\n",
__func__, limit << PAGE_SHIFT);
ret = -ENOMEM;
goto unpin_out;
}
lock_acct++;
}
}
out:
ret = vfio_lock_acct(current, lock_acct, &lock_cap);
unpin_out:
if (ret) {
if (!rsvd) {
for (pfn = *pfn_base ; pinned ; pfn++, pinned--)
put_pfn(pfn, dma->prot);
}
return ret;
}
return pinned;
}
static long vfio_unpin_pages_remote(struct vfio_dma *dma, dma_addr_t iova,
unsigned long pfn, long npage,
bool do_accounting)
{
long unlocked = 0, locked = 0;
long i;
for (i = 0; i < npage; i++, iova += PAGE_SIZE) {
if (put_pfn(pfn++, dma->prot)) {
unlocked++;
if (vfio_find_vpfn(dma, iova))
locked++;
}
}
if (do_accounting)
vfio_lock_acct(dma->task, locked - unlocked, NULL);
return unlocked;
}
static int vfio_pin_page_external(struct vfio_dma *dma, unsigned long vaddr,
unsigned long *pfn_base, bool do_accounting)
{
struct mm_struct *mm;
int ret;
mm = get_task_mm(dma->task);
if (!mm)
return -ENODEV;
ret = vaddr_get_pfn(mm, vaddr, dma->prot, pfn_base);
if (!ret && do_accounting && !is_invalid_reserved_pfn(*pfn_base)) {
ret = vfio_lock_acct(dma->task, 1, NULL);
if (ret) {
put_pfn(*pfn_base, dma->prot);
if (ret == -ENOMEM)
pr_warn("%s: Task %s (%d) RLIMIT_MEMLOCK "
"(%ld) exceeded\n", __func__,
dma->task->comm, task_pid_nr(dma->task),
task_rlimit(dma->task, RLIMIT_MEMLOCK));
}
}
mmput(mm);
return ret;
}
static int vfio_unpin_page_external(struct vfio_dma *dma, dma_addr_t iova,
bool do_accounting)
{
int unlocked;
struct vfio_pfn *vpfn = vfio_find_vpfn(dma, iova);
if (!vpfn)
return 0;
unlocked = vfio_iova_put_vfio_pfn(dma, vpfn);
if (do_accounting)
vfio_lock_acct(dma->task, -unlocked, NULL);
return unlocked;
}
static int vfio_iommu_type1_pin_pages(void *iommu_data,
unsigned long *user_pfn,
int npage, int prot,
unsigned long *phys_pfn)
{
struct vfio_iommu *iommu = iommu_data;
int i, j, ret;
unsigned long remote_vaddr;
struct vfio_dma *dma;
bool do_accounting;
if (!iommu || !user_pfn || !phys_pfn)
return -EINVAL;
/* Supported for v2 version only */
if (!iommu->v2)
return -EACCES;
mutex_lock(&iommu->lock);
/* Fail if notifier list is empty */
if ((!iommu->external_domain) || (!iommu->notifier.head)) {
ret = -EINVAL;
goto pin_done;
}
/*
* If iommu capable domain exist in the container then all pages are
* already pinned and accounted. Accouting should be done if there is no
* iommu capable domain in the container.
*/
do_accounting = !IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu);
for (i = 0; i < npage; i++) {
dma_addr_t iova;
struct vfio_pfn *vpfn;
iova = user_pfn[i] << PAGE_SHIFT;
dma = vfio_find_dma(iommu, iova, PAGE_SIZE);
if (!dma) {
ret = -EINVAL;
goto pin_unwind;
}
if ((dma->prot & prot) != prot) {
ret = -EPERM;
goto pin_unwind;
}
vpfn = vfio_iova_get_vfio_pfn(dma, iova);
if (vpfn) {
phys_pfn[i] = vpfn->pfn;
continue;
}
remote_vaddr = dma->vaddr + iova - dma->iova;
ret = vfio_pin_page_external(dma, remote_vaddr, &phys_pfn[i],
do_accounting);
if (ret)
goto pin_unwind;
ret = vfio_add_to_pfn_list(dma, iova, phys_pfn[i]);
if (ret) {
vfio_unpin_page_external(dma, iova, do_accounting);
goto pin_unwind;
}
}
ret = i;
goto pin_done;
pin_unwind:
phys_pfn[i] = 0;
for (j = 0; j < i; j++) {
dma_addr_t iova;
iova = user_pfn[j] << PAGE_SHIFT;
dma = vfio_find_dma(iommu, iova, PAGE_SIZE);
vfio_unpin_page_external(dma, iova, do_accounting);
phys_pfn[j] = 0;
}
pin_done:
mutex_unlock(&iommu->lock);
return ret;
}
static int vfio_iommu_type1_unpin_pages(void *iommu_data,
unsigned long *user_pfn,
int npage)
{
struct vfio_iommu *iommu = iommu_data;
bool do_accounting;
int i;
if (!iommu || !user_pfn)
return -EINVAL;
/* Supported for v2 version only */
if (!iommu->v2)
return -EACCES;
mutex_lock(&iommu->lock);
if (!iommu->external_domain) {
mutex_unlock(&iommu->lock);
return -EINVAL;
}
do_accounting = !IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu);
for (i = 0; i < npage; i++) {
struct vfio_dma *dma;
dma_addr_t iova;
iova = user_pfn[i] << PAGE_SHIFT;
dma = vfio_find_dma(iommu, iova, PAGE_SIZE);
if (!dma)
goto unpin_exit;
vfio_unpin_page_external(dma, iova, do_accounting);
}
unpin_exit:
mutex_unlock(&iommu->lock);
return i > npage ? npage : (i > 0 ? i : -EINVAL);
}
static long vfio_unmap_unpin(struct vfio_iommu *iommu, struct vfio_dma *dma,
bool do_accounting)
{
dma_addr_t iova = dma->iova, end = dma->iova + dma->size;
struct vfio_domain *domain, *d;
long unlocked = 0;
if (!dma->size)
return 0;
if (!IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu))
return 0;
/*
* We use the IOMMU to track the physical addresses, otherwise we'd
* need a much more complicated tracking system. Unfortunately that
* means we need to use one of the iommu domains to figure out the
* pfns to unpin. The rest need to be unmapped in advance so we have
* no iommu translations remaining when the pages are unpinned.
*/
domain = d = list_first_entry(&iommu->domain_list,
struct vfio_domain, next);
list_for_each_entry_continue(d, &iommu->domain_list, next) {
iommu_unmap(d->domain, dma->iova, dma->size);
cond_resched();
}
while (iova < end) {
size_t unmapped, len;
phys_addr_t phys, next;
phys = iommu_iova_to_phys(domain->domain, iova);
if (WARN_ON(!phys)) {
iova += PAGE_SIZE;
continue;
}
/*
* To optimize for fewer iommu_unmap() calls, each of which
* may require hardware cache flushing, try to find the
* largest contiguous physical memory chunk to unmap.
*/
for (len = PAGE_SIZE;
!domain->fgsp && iova + len < end; len += PAGE_SIZE) {
next = iommu_iova_to_phys(domain->domain, iova + len);
if (next != phys + len)
break;
}
unmapped = iommu_unmap(domain->domain, iova, len);
if (WARN_ON(!unmapped))
break;
unlocked += vfio_unpin_pages_remote(dma, iova,
phys >> PAGE_SHIFT,
unmapped >> PAGE_SHIFT,
false);
iova += unmapped;
cond_resched();
}
dma->iommu_mapped = false;
if (do_accounting) {
vfio_lock_acct(dma->task, -unlocked, NULL);
return 0;
}
return unlocked;
}
static void vfio_remove_dma(struct vfio_iommu *iommu, struct vfio_dma *dma)
{
vfio_unmap_unpin(iommu, dma, true);
vfio_unlink_dma(iommu, dma);
put_task_struct(dma->task);
kfree(dma);
}
static unsigned long vfio_pgsize_bitmap(struct vfio_iommu *iommu)
{
struct vfio_domain *domain;
unsigned long bitmap = ULONG_MAX;
mutex_lock(&iommu->lock);
list_for_each_entry(domain, &iommu->domain_list, next)
bitmap &= domain->domain->pgsize_bitmap;
mutex_unlock(&iommu->lock);
/*
* In case the IOMMU supports page sizes smaller than PAGE_SIZE
* we pretend PAGE_SIZE is supported and hide sub-PAGE_SIZE sizes.
* That way the user will be able to map/unmap buffers whose size/
* start address is aligned with PAGE_SIZE. Pinning code uses that
* granularity while iommu driver can use the sub-PAGE_SIZE size
* to map the buffer.
*/
if (bitmap & ~PAGE_MASK) {
bitmap &= PAGE_MASK;
bitmap |= PAGE_SIZE;
}
return bitmap;
}
static int vfio_dma_do_unmap(struct vfio_iommu *iommu,
struct vfio_iommu_type1_dma_unmap *unmap)
{
uint64_t mask;
struct vfio_dma *dma, *dma_last = NULL;
size_t unmapped = 0;
int ret = 0, retries = 0;
mask = ((uint64_t)1 << __ffs(vfio_pgsize_bitmap(iommu))) - 1;
if (unmap->iova & mask)
return -EINVAL;
if (!unmap->size || unmap->size & mask)
return -EINVAL;
WARN_ON(mask & PAGE_MASK);
again:
mutex_lock(&iommu->lock);
/*
* vfio-iommu-type1 (v1) - User mappings were coalesced together to
* avoid tracking individual mappings. This means that the granularity
* of the original mapping was lost and the user was allowed to attempt
* to unmap any range. Depending on the contiguousness of physical
* memory and page sizes supported by the IOMMU, arbitrary unmaps may
* or may not have worked. We only guaranteed unmap granularity
* matching the original mapping; even though it was untracked here,
* the original mappings are reflected in IOMMU mappings. This
* resulted in a couple unusual behaviors. First, if a range is not
* able to be unmapped, ex. a set of 4k pages that was mapped as a
* 2M hugepage into the IOMMU, the unmap ioctl returns success but with
* a zero sized unmap. Also, if an unmap request overlaps the first
* address of a hugepage, the IOMMU will unmap the entire hugepage.
* This also returns success and the returned unmap size reflects the
* actual size unmapped.
*
* We attempt to maintain compatibility with this "v1" interface, but
* we take control out of the hands of the IOMMU. Therefore, an unmap
* request offset from the beginning of the original mapping will
* return success with zero sized unmap. And an unmap request covering
* the first iova of mapping will unmap the entire range.
*
* The v2 version of this interface intends to be more deterministic.
* Unmap requests must fully cover previous mappings. Multiple
* mappings may still be unmaped by specifying large ranges, but there
* must not be any previous mappings bisected by the range. An error
* will be returned if these conditions are not met. The v2 interface
* will only return success and a size of zero if there were no
* mappings within the range.
*/
if (iommu->v2) {
dma = vfio_find_dma(iommu, unmap->iova, 1);
if (dma && dma->iova != unmap->iova) {
ret = -EINVAL;
goto unlock;
}
dma = vfio_find_dma(iommu, unmap->iova + unmap->size - 1, 0);
if (dma && dma->iova + dma->size != unmap->iova + unmap->size) {
ret = -EINVAL;
goto unlock;
}
}
while ((dma = vfio_find_dma(iommu, unmap->iova, unmap->size))) {
if (!iommu->v2 && unmap->iova > dma->iova)
break;
/*
* Task with same address space who mapped this iova range is
* allowed to unmap the iova range.
*/
if (dma->task->mm != current->mm)
break;
if (!RB_EMPTY_ROOT(&dma->pfn_list)) {
struct vfio_iommu_type1_dma_unmap nb_unmap;
if (dma_last == dma) {
BUG_ON(++retries > 10);
} else {
dma_last = dma;
retries = 0;
}
nb_unmap.iova = dma->iova;
nb_unmap.size = dma->size;
/*
* Notify anyone (mdev vendor drivers) to invalidate and
* unmap iovas within the range we're about to unmap.
* Vendor drivers MUST unpin pages in response to an
* invalidation.
*/
mutex_unlock(&iommu->lock);
blocking_notifier_call_chain(&iommu->notifier,
VFIO_IOMMU_NOTIFY_DMA_UNMAP,
&nb_unmap);
goto again;
}
unmapped += dma->size;
vfio_remove_dma(iommu, dma);
}
unlock:
mutex_unlock(&iommu->lock);
/* Report how much was unmapped */
unmap->size = unmapped;
return ret;
}
/*
* Turns out AMD IOMMU has a page table bug where it won't map large pages
* to a region that previously mapped smaller pages. This should be fixed
* soon, so this is just a temporary workaround to break mappings down into
* PAGE_SIZE. Better to map smaller pages than nothing.
*/
static int map_try_harder(struct vfio_domain *domain, dma_addr_t iova,
unsigned long pfn, long npage, int prot)
{
long i;
int ret = 0;
for (i = 0; i < npage; i++, pfn++, iova += PAGE_SIZE) {
ret = iommu_map(domain->domain, iova,
(phys_addr_t)pfn << PAGE_SHIFT,
PAGE_SIZE, prot | domain->prot);
if (ret)
break;
}
for (; i < npage && i > 0; i--, iova -= PAGE_SIZE)
iommu_unmap(domain->domain, iova, PAGE_SIZE);
return ret;
}
static int vfio_iommu_map(struct vfio_iommu *iommu, dma_addr_t iova,
unsigned long pfn, long npage, int prot)
{
struct vfio_domain *d;
int ret;
list_for_each_entry(d, &iommu->domain_list, next) {
ret = iommu_map(d->domain, iova, (phys_addr_t)pfn << PAGE_SHIFT,
npage << PAGE_SHIFT, prot | d->prot);
if (ret) {
if (ret != -EBUSY ||
map_try_harder(d, iova, pfn, npage, prot))
goto unwind;
}
cond_resched();
}
return 0;
unwind:
list_for_each_entry_continue_reverse(d, &iommu->domain_list, next)
iommu_unmap(d->domain, iova, npage << PAGE_SHIFT);
return ret;
}
static int vfio_pin_map_dma(struct vfio_iommu *iommu, struct vfio_dma *dma,
size_t map_size)
{
dma_addr_t iova = dma->iova;
unsigned long vaddr = dma->vaddr;
size_t size = map_size;
long npage;
unsigned long pfn, limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
bool lock_cap = capable(CAP_IPC_LOCK);
int ret = 0;
while (size) {
/* Pin a contiguous chunk of memory */
npage = vfio_pin_pages_remote(dma, vaddr + dma->size,
size >> PAGE_SHIFT, &pfn,
lock_cap, limit);
if (npage <= 0) {
WARN_ON(!npage);
ret = (int)npage;
break;
}
/* Map it! */
ret = vfio_iommu_map(iommu, iova + dma->size, pfn, npage,
dma->prot);
if (ret) {
vfio_unpin_pages_remote(dma, iova + dma->size, pfn,
npage, true);
break;
}
size -= npage << PAGE_SHIFT;
dma->size += npage << PAGE_SHIFT;
}
dma->iommu_mapped = true;
if (ret)
vfio_remove_dma(iommu, dma);
return ret;
}
static int vfio_dma_do_map(struct vfio_iommu *iommu,
struct vfio_iommu_type1_dma_map *map)
{
dma_addr_t iova = map->iova;
unsigned long vaddr = map->vaddr;
size_t size = map->size;
int ret = 0, prot = 0;
uint64_t mask;
struct vfio_dma *dma;
/* Verify that none of our __u64 fields overflow */
if (map->size != size || map->vaddr != vaddr || map->iova != iova)
return -EINVAL;
mask = ((uint64_t)1 << __ffs(vfio_pgsize_bitmap(iommu))) - 1;
WARN_ON(mask & PAGE_MASK);
/* READ/WRITE from device perspective */
if (map->flags & VFIO_DMA_MAP_FLAG_WRITE)
prot |= IOMMU_WRITE;
if (map->flags & VFIO_DMA_MAP_FLAG_READ)
prot |= IOMMU_READ;
if (!prot || !size || (size | iova | vaddr) & mask)
return -EINVAL;
/* Don't allow IOVA or virtual address wrap */
if (iova + size - 1 < iova || vaddr + size - 1 < vaddr)
return -EINVAL;
mutex_lock(&iommu->lock);
if (vfio_find_dma(iommu, iova, size)) {
ret = -EEXIST;
goto out_unlock;
}
dma = kzalloc(sizeof(*dma), GFP_KERNEL);
if (!dma) {
ret = -ENOMEM;
goto out_unlock;
}
dma->iova = iova;
dma->vaddr = vaddr;
dma->prot = prot;
get_task_struct(current);
dma->task = current;
dma->pfn_list = RB_ROOT;
/* Insert zero-sized and grow as we map chunks of it */
vfio_link_dma(iommu, dma);
/* Don't pin and map if container doesn't contain IOMMU capable domain*/
if (!IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu))
dma->size = size;
else
ret = vfio_pin_map_dma(iommu, dma, size);
out_unlock:
mutex_unlock(&iommu->lock);
return ret;
}
static int vfio_bus_type(struct device *dev, void *data)
{
struct bus_type **bus = data;
if (*bus && *bus != dev->bus)
return -EINVAL;
*bus = dev->bus;
return 0;
}
static int vfio_iommu_replay(struct vfio_iommu *iommu,
struct vfio_domain *domain)
{
struct vfio_domain *d;
struct rb_node *n;
unsigned long limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
bool lock_cap = capable(CAP_IPC_LOCK);
int ret;
/* Arbitrarily pick the first domain in the list for lookups */
d = list_first_entry(&iommu->domain_list, struct vfio_domain, next);
n = rb_first(&iommu->dma_list);
for (; n; n = rb_next(n)) {
struct vfio_dma *dma;
dma_addr_t iova;
dma = rb_entry(n, struct vfio_dma, node);
iova = dma->iova;
while (iova < dma->iova + dma->size) {
phys_addr_t phys;
size_t size;
if (dma->iommu_mapped) {
phys_addr_t p;
dma_addr_t i;
phys = iommu_iova_to_phys(d->domain, iova);
if (WARN_ON(!phys)) {
iova += PAGE_SIZE;
continue;
}
size = PAGE_SIZE;
p = phys + size;
i = iova + size;
while (i < dma->iova + dma->size &&
p == iommu_iova_to_phys(d->domain, i)) {
size += PAGE_SIZE;
p += PAGE_SIZE;
i += PAGE_SIZE;
}
} else {
unsigned long pfn;
unsigned long vaddr = dma->vaddr +
(iova - dma->iova);
size_t n = dma->iova + dma->size - iova;
long npage;
npage = vfio_pin_pages_remote(dma, vaddr,
n >> PAGE_SHIFT,
&pfn, lock_cap,
limit);
if (npage <= 0) {
WARN_ON(!npage);
ret = (int)npage;
return ret;
}
phys = pfn << PAGE_SHIFT;
size = npage << PAGE_SHIFT;
}
ret = iommu_map(domain->domain, iova, phys,
size, dma->prot | domain->prot);
if (ret)
return ret;
iova += size;
}
dma->iommu_mapped = true;
}
return 0;
}
/*
* We change our unmap behavior slightly depending on whether the IOMMU
* supports fine-grained superpages. IOMMUs like AMD-Vi will use a superpage
* for practically any contiguous power-of-two mapping we give it. This means
* we don't need to look for contiguous chunks ourselves to make unmapping
* more efficient. On IOMMUs with coarse-grained super pages, like Intel VT-d
* with discrete 2M/1G/512G/1T superpages, identifying contiguous chunks
* significantly boosts non-hugetlbfs mappings and doesn't seem to hurt when
* hugetlbfs is in use.
*/
static void vfio_test_domain_fgsp(struct vfio_domain *domain)
{
struct page *pages;
int ret, order = get_order(PAGE_SIZE * 2);
pages = alloc_pages(GFP_KERNEL | __GFP_ZERO, order);
if (!pages)
return;
ret = iommu_map(domain->domain, 0, page_to_phys(pages), PAGE_SIZE * 2,
IOMMU_READ | IOMMU_WRITE | domain->prot);
if (!ret) {
size_t unmapped = iommu_unmap(domain->domain, 0, PAGE_SIZE);
if (unmapped == PAGE_SIZE)
iommu_unmap(domain->domain, PAGE_SIZE, PAGE_SIZE);
else
domain->fgsp = true;
}
__free_pages(pages, order);
}
static struct vfio_group *find_iommu_group(struct vfio_domain *domain,
struct iommu_group *iommu_group)
{
struct vfio_group *g;
list_for_each_entry(g, &domain->group_list, next) {
if (g->iommu_group == iommu_group)
return g;
}
return NULL;
}
static bool vfio_iommu_has_sw_msi(struct iommu_group *group, phys_addr_t *base)
{
struct list_head group_resv_regions;
struct iommu_resv_region *region, *next;
bool ret = false;
INIT_LIST_HEAD(&group_resv_regions);
iommu_get_group_resv_regions(group, &group_resv_regions);
list_for_each_entry(region, &group_resv_regions, list) {
if (region->type == IOMMU_RESV_SW_MSI) {
*base = region->start;
ret = true;
goto out;
}
}
out:
list_for_each_entry_safe(region, next, &group_resv_regions, list)
kfree(region);
return ret;
}
static int vfio_iommu_type1_attach_group(void *iommu_data,
struct iommu_group *iommu_group)
{
struct vfio_iommu *iommu = iommu_data;
struct vfio_group *group;
struct vfio_domain *domain, *d;
struct bus_type *bus = NULL, *mdev_bus;
int ret;
bool resv_msi, msi_remap;
phys_addr_t resv_msi_base;
mutex_lock(&iommu->lock);
list_for_each_entry(d, &iommu->domain_list, next) {
if (find_iommu_group(d, iommu_group)) {
mutex_unlock(&iommu->lock);
return -EINVAL;
}
}
if (iommu->external_domain) {
if (find_iommu_group(iommu->external_domain, iommu_group)) {
mutex_unlock(&iommu->lock);
return -EINVAL;
}
}
group = kzalloc(sizeof(*group), GFP_KERNEL);
domain = kzalloc(sizeof(*domain), GFP_KERNEL);
if (!group || !domain) {
ret = -ENOMEM;
goto out_free;
}
group->iommu_group = iommu_group;
/* Determine bus_type in order to allocate a domain */
ret = iommu_group_for_each_dev(iommu_group, &bus, vfio_bus_type);
if (ret)
goto out_free;
mdev_bus = symbol_get(mdev_bus_type);
if (mdev_bus) {
if ((bus == mdev_bus) && !iommu_present(bus)) {
symbol_put(mdev_bus_type);
if (!iommu->external_domain) {
INIT_LIST_HEAD(&domain->group_list);
iommu->external_domain = domain;
} else
kfree(domain);
list_add(&group->next,
&iommu->external_domain->group_list);
mutex_unlock(&iommu->lock);
return 0;
}
symbol_put(mdev_bus_type);
}
domain->domain = iommu_domain_alloc(bus);
if (!domain->domain) {
ret = -EIO;
goto out_free;
}
if (iommu->nesting) {
int attr = 1;
ret = iommu_domain_set_attr(domain->domain, DOMAIN_ATTR_NESTING,
&attr);
if (ret)
goto out_domain;
}
ret = iommu_attach_group(domain->domain, iommu_group);
if (ret)
goto out_domain;
resv_msi = vfio_iommu_has_sw_msi(iommu_group, &resv_msi_base);
INIT_LIST_HEAD(&domain->group_list);
list_add(&group->next, &domain->group_list);
msi_remap = resv_msi ? irq_domain_check_msi_remap() :
iommu_capable(bus, IOMMU_CAP_INTR_REMAP);
if (!allow_unsafe_interrupts && !msi_remap) {
pr_warn("%s: No interrupt remapping support. Use the module param \"allow_unsafe_interrupts\" to enable VFIO IOMMU support on this platform\n",
__func__);
ret = -EPERM;
goto out_detach;
}
if (iommu_capable(bus, IOMMU_CAP_CACHE_COHERENCY))
domain->prot |= IOMMU_CACHE;
/*
* Try to match an existing compatible domain. We don't want to
* preclude an IOMMU driver supporting multiple bus_types and being
* able to include different bus_types in the same IOMMU domain, so
* we test whether the domains use the same iommu_ops rather than
* testing if they're on the same bus_type.
*/
list_for_each_entry(d, &iommu->domain_list, next) {
if (d->domain->ops == domain->domain->ops &&
d->prot == domain->prot) {
iommu_detach_group(domain->domain, iommu_group);
if (!iommu_attach_group(d->domain, iommu_group)) {
list_add(&group->next, &d->group_list);
iommu_domain_free(domain->domain);
kfree(domain);
mutex_unlock(&iommu->lock);
return 0;
}
ret = iommu_attach_group(domain->domain, iommu_group);
if (ret)
goto out_domain;
}
}
vfio_test_domain_fgsp(domain);
/* replay mappings on new domains */
ret = vfio_iommu_replay(iommu, domain);
if (ret)
goto out_detach;
if (resv_msi) {
ret = iommu_get_msi_cookie(domain->domain, resv_msi_base);
if (ret)
goto out_detach;
}
list_add(&domain->next, &iommu->domain_list);
mutex_unlock(&iommu->lock);
return 0;
out_detach:
iommu_detach_group(domain->domain, iommu_group);
out_domain:
iommu_domain_free(domain->domain);
out_free:
kfree(domain);
kfree(group);
mutex_unlock(&iommu->lock);
return ret;
}
static void vfio_iommu_unmap_unpin_all(struct vfio_iommu *iommu)
{
struct rb_node *node;
while ((node = rb_first(&iommu->dma_list)))
vfio_remove_dma(iommu, rb_entry(node, struct vfio_dma, node));
}
static void vfio_iommu_unmap_unpin_reaccount(struct vfio_iommu *iommu)
{
struct rb_node *n, *p;
n = rb_first(&iommu->dma_list);
for (; n; n = rb_next(n)) {
struct vfio_dma *dma;
long locked = 0, unlocked = 0;
dma = rb_entry(n, struct vfio_dma, node);
unlocked += vfio_unmap_unpin(iommu, dma, false);
p = rb_first(&dma->pfn_list);
for (; p; p = rb_next(p)) {
struct vfio_pfn *vpfn = rb_entry(p, struct vfio_pfn,
node);
if (!is_invalid_reserved_pfn(vpfn->pfn))
locked++;
}
vfio_lock_acct(dma->task, locked - unlocked, NULL);
}
}
static void vfio_sanity_check_pfn_list(struct vfio_iommu *iommu)
{
struct rb_node *n;
n = rb_first(&iommu->dma_list);
for (; n; n = rb_next(n)) {
struct vfio_dma *dma;
dma = rb_entry(n, struct vfio_dma, node);
if (WARN_ON(!RB_EMPTY_ROOT(&dma->pfn_list)))
break;
}
/* mdev vendor driver must unregister notifier */
WARN_ON(iommu->notifier.head);
}
static void vfio_iommu_type1_detach_group(void *iommu_data,
struct iommu_group *iommu_group)
{
struct vfio_iommu *iommu = iommu_data;
struct vfio_domain *domain;
struct vfio_group *group;
mutex_lock(&iommu->lock);
if (iommu->external_domain) {
group = find_iommu_group(iommu->external_domain, iommu_group);
if (group) {
list_del(&group->next);
kfree(group);
if (list_empty(&iommu->external_domain->group_list)) {
vfio_sanity_check_pfn_list(iommu);
if (!IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu))
vfio_iommu_unmap_unpin_all(iommu);
kfree(iommu->external_domain);
iommu->external_domain = NULL;
}
goto detach_group_done;
}
}
list_for_each_entry(domain, &iommu->domain_list, next) {
group = find_iommu_group(domain, iommu_group);
if (!group)
continue;
iommu_detach_group(domain->domain, iommu_group);
list_del(&group->next);
kfree(group);
/*
* Group ownership provides privilege, if the group list is
* empty, the domain goes away. If it's the last domain with
* iommu and external domain doesn't exist, then all the
* mappings go away too. If it's the last domain with iommu and
* external domain exist, update accounting
*/
if (list_empty(&domain->group_list)) {
if (list_is_singular(&iommu->domain_list)) {
if (!iommu->external_domain)
vfio_iommu_unmap_unpin_all(iommu);
else
vfio_iommu_unmap_unpin_reaccount(iommu);
}
iommu_domain_free(domain->domain);
list_del(&domain->next);
kfree(domain);
}
break;
}
detach_group_done:
mutex_unlock(&iommu->lock);
}
static void *vfio_iommu_type1_open(unsigned long arg)
{
struct vfio_iommu *iommu;
iommu = kzalloc(sizeof(*iommu), GFP_KERNEL);
if (!iommu)
return ERR_PTR(-ENOMEM);
switch (arg) {
case VFIO_TYPE1_IOMMU:
break;
case VFIO_TYPE1_NESTING_IOMMU:
iommu->nesting = true;
case VFIO_TYPE1v2_IOMMU:
iommu->v2 = true;
break;
default:
kfree(iommu);
return ERR_PTR(-EINVAL);
}
INIT_LIST_HEAD(&iommu->domain_list);
iommu->dma_list = RB_ROOT;
mutex_init(&iommu->lock);
BLOCKING_INIT_NOTIFIER_HEAD(&iommu->notifier);
return iommu;
}
static void vfio_release_domain(struct vfio_domain *domain, bool external)
{
struct vfio_group *group, *group_tmp;
list_for_each_entry_safe(group, group_tmp,
&domain->group_list, next) {
if (!external)
iommu_detach_group(domain->domain, group->iommu_group);
list_del(&group->next);
kfree(group);
}
if (!external)
iommu_domain_free(domain->domain);
}
static void vfio_iommu_type1_release(void *iommu_data)
{
struct vfio_iommu *iommu = iommu_data;
struct vfio_domain *domain, *domain_tmp;
if (iommu->external_domain) {
vfio_release_domain(iommu->external_domain, true);
vfio_sanity_check_pfn_list(iommu);
kfree(iommu->external_domain);
}
vfio_iommu_unmap_unpin_all(iommu);
list_for_each_entry_safe(domain, domain_tmp,
&iommu->domain_list, next) {
vfio_release_domain(domain, false);
list_del(&domain->next);
kfree(domain);
}
kfree(iommu);
}
static int vfio_domains_have_iommu_cache(struct vfio_iommu *iommu)
{
struct vfio_domain *domain;
int ret = 1;
mutex_lock(&iommu->lock);
list_for_each_entry(domain, &iommu->domain_list, next) {
if (!(domain->prot & IOMMU_CACHE)) {
ret = 0;
break;
}
}
mutex_unlock(&iommu->lock);
return ret;
}
static long vfio_iommu_type1_ioctl(void *iommu_data,
unsigned int cmd, unsigned long arg)
{
struct vfio_iommu *iommu = iommu_data;
unsigned long minsz;
if (cmd == VFIO_CHECK_EXTENSION) {
switch (arg) {
case VFIO_TYPE1_IOMMU:
case VFIO_TYPE1v2_IOMMU:
case VFIO_TYPE1_NESTING_IOMMU:
return 1;
case VFIO_DMA_CC_IOMMU:
if (!iommu)
return 0;
return vfio_domains_have_iommu_cache(iommu);
default:
return 0;
}
} else if (cmd == VFIO_IOMMU_GET_INFO) {
struct vfio_iommu_type1_info info;
minsz = offsetofend(struct vfio_iommu_type1_info, iova_pgsizes);
if (copy_from_user(&info, (void __user *)arg, minsz))
return -EFAULT;
if (info.argsz < minsz)
return -EINVAL;
info.flags = VFIO_IOMMU_INFO_PGSIZES;
info.iova_pgsizes = vfio_pgsize_bitmap(iommu);
return copy_to_user((void __user *)arg, &info, minsz) ?
-EFAULT : 0;
} else if (cmd == VFIO_IOMMU_MAP_DMA) {
struct vfio_iommu_type1_dma_map map;
uint32_t mask = VFIO_DMA_MAP_FLAG_READ |
VFIO_DMA_MAP_FLAG_WRITE;
minsz = offsetofend(struct vfio_iommu_type1_dma_map, size);
if (copy_from_user(&map, (void __user *)arg, minsz))
return -EFAULT;
if (map.argsz < minsz || map.flags & ~mask)
return -EINVAL;
return vfio_dma_do_map(iommu, &map);
} else if (cmd == VFIO_IOMMU_UNMAP_DMA) {
struct vfio_iommu_type1_dma_unmap unmap;
long ret;
minsz = offsetofend(struct vfio_iommu_type1_dma_unmap, size);
if (copy_from_user(&unmap, (void __user *)arg, minsz))
return -EFAULT;
if (unmap.argsz < minsz || unmap.flags)
return -EINVAL;
ret = vfio_dma_do_unmap(iommu, &unmap);
if (ret)
return ret;
return copy_to_user((void __user *)arg, &unmap, minsz) ?
-EFAULT : 0;
}
return -ENOTTY;
}
static int vfio_iommu_type1_register_notifier(void *iommu_data,
unsigned long *events,
struct notifier_block *nb)
{
struct vfio_iommu *iommu = iommu_data;
/* clear known events */
*events &= ~VFIO_IOMMU_NOTIFY_DMA_UNMAP;
/* refuse to register if still events remaining */
if (*events)
return -EINVAL;
return blocking_notifier_chain_register(&iommu->notifier, nb);
}
static int vfio_iommu_type1_unregister_notifier(void *iommu_data,
struct notifier_block *nb)
{
struct vfio_iommu *iommu = iommu_data;
return blocking_notifier_chain_unregister(&iommu->notifier, nb);
}
static const struct vfio_iommu_driver_ops vfio_iommu_driver_ops_type1 = {
.name = "vfio-iommu-type1",
.owner = THIS_MODULE,
.open = vfio_iommu_type1_open,
.release = vfio_iommu_type1_release,
.ioctl = vfio_iommu_type1_ioctl,
.attach_group = vfio_iommu_type1_attach_group,
.detach_group = vfio_iommu_type1_detach_group,
.pin_pages = vfio_iommu_type1_pin_pages,
.unpin_pages = vfio_iommu_type1_unpin_pages,
.register_notifier = vfio_iommu_type1_register_notifier,
.unregister_notifier = vfio_iommu_type1_unregister_notifier,
};
static int __init vfio_iommu_type1_init(void)
{
return vfio_register_iommu_driver(&vfio_iommu_driver_ops_type1);
}
static void __exit vfio_iommu_type1_cleanup(void)
{
vfio_unregister_iommu_driver(&vfio_iommu_driver_ops_type1);
}
module_init(vfio_iommu_type1_init);
module_exit(vfio_iommu_type1_cleanup);
MODULE_VERSION(DRIVER_VERSION);
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);