[PATCH v5 18/19] iommufd: Add additional invariant assertions

Jason Gunthorpe
2022-11-16T21:01:05Z

These are on performance paths so we protect them using the
CONFIG_IOMMUFD_TEST to not take a hit during normal operation.

These are useful when running the test suite and syzkaller to find data
structure inconsistencies early.

Tested-by: Yi Liu <yi.l.liu@intel.com>
Tested-by: Matthew Rosato <mjrosato@linux.ibm.com> # s390
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
---
drivers/iommu/iommufd/device.c | 5 ++++
drivers/iommu/iommufd/io_pagetable.c | 22 +++++++++++++++
drivers/iommu/iommufd/io_pagetable.h | 3 ++
drivers/iommu/iommufd/pages.c | 42 ++++++++++++++++++++++++++--
4 files changed, 70 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c
index a9105237ec4131..07d4dcc0dbf5e1 100644
--- a/drivers/iommu/iommufd/device.c
+++ b/drivers/iommu/iommufd/device.c
@@ -621,6 +621,11 @@ int iommufd_access_pin_pages(struct iommufd_access *access, unsigned long iova,
struct iopt_area *area;
int rc;

+ /* Driver's ops don't support pin_pages */
+ if (IS_ENABLED(CONFIG_IOMMUFD_TEST) &&
+ WARN_ON(access->iova_alignment != PAGE_SIZE || !access->ops->unmap))
+ return -EINVAL;
+
if (!length)
return -EINVAL;
if (check_add_overflow(iova, length - 1, &last_iova))
diff --git a/drivers/iommu/iommufd/io_pagetable.c b/drivers/iommu/iommufd/io_pagetable.c
index 4f4a9d9aac570e..3467cea795684c 100644
--- a/drivers/iommu/iommufd/io_pagetable.c
+++ b/drivers/iommu/iommufd/io_pagetable.c
@@ -251,6 +251,11 @@ static int iopt_alloc_area_pages(struct io_pagetable *iopt,
(uintptr_t)elm->pages->uptr + elm->start_byte, length);
if (rc)
goto out_unlock;
+ if (IS_ENABLED(CONFIG_IOMMUFD_TEST) &&
+ WARN_ON(iopt_check_iova(iopt, *dst_iova, length))) {
+ rc = -EINVAL;
+ goto out_unlock;
+ }
} else {
rc = iopt_check_iova(iopt, *dst_iova, length);
if (rc)
@@ -277,6 +282,8 @@ static int iopt_alloc_area_pages(struct io_pagetable *iopt,

static void iopt_abort_area(struct iopt_area *area)
{
+ if (IS_ENABLED(CONFIG_IOMMUFD_TEST))
+ WARN_ON(area->pages);
if (area->iopt) {
down_write(&area->iopt->iova_rwsem);
interval_tree_remove(&area->node, &area->iopt->area_itree);
@@ -642,6 +649,9 @@ void iopt_destroy_table(struct io_pagetable *iopt)
{
struct interval_tree_node *node;

+ if (IS_ENABLED(CONFIG_IOMMUFD_TEST))
+ iopt_remove_reserved_iova(iopt, NULL);
+
while ((node = interval_tree_iter_first(&iopt->allowed_itree, 0,
ULONG_MAX))) {
interval_tree_remove(node, &iopt->allowed_itree);
@@ -688,6 +698,8 @@ static void iopt_unfill_domain(struct io_pagetable *iopt,
continue;

mutex_lock(&pages->mutex);
+ if (IS_ENABLED(CONFIG_IOMMUFD_TEST))
+ WARN_ON(!area->storage_domain);
if (area->storage_domain == domain)
area->storage_domain = storage_domain;
mutex_unlock(&pages->mutex);
@@ -792,6 +804,16 @@ static int iopt_check_iova_alignment(struct io_pagetable *iopt,
(iopt_area_length(area) & align_mask) ||
(area->page_offset & align_mask))
return -EADDRINUSE;
+
+ if (IS_ENABLED(CONFIG_IOMMUFD_TEST)) {
+ struct iommufd_access *access;
+ unsigned long index;
+
+ xa_for_each(&iopt->access_list, index, access)
+ if (WARN_ON(access->iova_alignment >
+ new_iova_alignment))
+ return -EADDRINUSE;
+ }
return 0;
}

diff --git a/drivers/iommu/iommufd/io_pagetable.h b/drivers/iommu/iommufd/io_pagetable.h
index 2ee6942c3ef4a5..83e7c175f2a277 100644
--- a/drivers/iommu/iommufd/io_pagetable.h
+++ b/drivers/iommu/iommufd/io_pagetable.h
@@ -101,6 +101,9 @@ static inline size_t iopt_area_length(struct iopt_area *area)
static inline unsigned long iopt_area_start_byte(struct iopt_area *area,
unsigned long iova)
{
+ if (IS_ENABLED(CONFIG_IOMMUFD_TEST))
+ WARN_ON(iova < iopt_area_iova(area) ||
+ iova > iopt_area_last_iova(area));
return (iova - iopt_area_iova(area)) + area->page_offset +
iopt_area_index(area) * PAGE_SIZE;
}
diff --git a/drivers/iommu/iommufd/pages.c b/drivers/iommu/iommufd/pages.c
index c5d2d9a8c56203..429fa3b0a239cd 100644
--- a/drivers/iommu/iommufd/pages.c
+++ b/drivers/iommu/iommufd/pages.c
@@ -162,12 +162,20 @@ void interval_tree_double_span_iter_next(

static void iopt_pages_add_npinned(struct iopt_pages *pages, size_t npages)
{
- pages->npinned += npages;
+ int rc;
+
+ rc = check_add_overflow(pages->npinned, npages, &pages->npinned);
+ if (IS_ENABLED(CONFIG_IOMMUFD_TEST))
+ WARN_ON(rc || pages->npinned > pages->npages);
}

static void iopt_pages_sub_npinned(struct iopt_pages *pages, size_t npages)
{
- pages->npinned -= npages;
+ int rc;
+
+ rc = check_sub_overflow(pages->npinned, npages, &pages->npinned);
+ if (IS_ENABLED(CONFIG_IOMMUFD_TEST))
+ WARN_ON(rc || pages->npinned > pages->npages);
}

static void iopt_pages_err_unpin(struct iopt_pages *pages,
@@ -189,6 +197,9 @@ static void iopt_pages_err_unpin(struct iopt_pages *pages,
static unsigned long iopt_area_index_to_iova(struct iopt_area *area,
unsigned long index)
{
+ if (IS_ENABLED(CONFIG_IOMMUFD_TEST))
+ WARN_ON(index < iopt_area_index(area) ||
+ index > iopt_area_last_index(area));
index -= iopt_area_index(area);
if (index == 0)
return iopt_area_iova(area);
@@ -198,6 +209,9 @@ static unsigned long iopt_area_index_to_iova(struct iopt_area *area,
static unsigned long iopt_area_index_to_iova_last(struct iopt_area *area,
unsigned long index)
{
+ if (IS_ENABLED(CONFIG_IOMMUFD_TEST))
+ WARN_ON(index < iopt_area_index(area) ||
+ index > iopt_area_last_index(area));
if (index == iopt_area_last_index(area))
return iopt_area_last_iova(area);
return iopt_area_iova(area) - area->page_offset +
@@ -286,6 +300,8 @@ static void batch_skip_carry(struct pfn_batch *batch, unsigned int skip_pfns)
{
if (!batch->total_pfns)
return;
+ if (IS_ENABLED(CONFIG_IOMMUFD_TEST))
+ WARN_ON(batch->total_pfns != batch->npfns[0]);
skip_pfns = min(batch->total_pfns, skip_pfns);
batch->pfns[0] += skip_pfns;
batch->npfns[0] -= skip_pfns;
@@ -301,6 +317,8 @@ static int __batch_init(struct pfn_batch *batch, size_t max_pages, void *backup,
batch->pfns = temp_kmalloc(&size, backup, backup_len);
if (!batch->pfns)
return -ENOMEM;
+ if (IS_ENABLED(CONFIG_IOMMUFD_TEST) && WARN_ON(size < elmsz))
+ return -EINVAL;
batch->array_size = size / elmsz;
batch->npfns = (u32 *)(batch->pfns + batch->array_size);
batch_clear(batch);
@@ -429,6 +447,10 @@ static int batch_iommu_map_small(struct iommu_domain *domain,
unsigned long start_iova = iova;
int rc;

+ if (IS_ENABLED(CONFIG_IOMMUFD_TEST))
+ WARN_ON(paddr % PAGE_SIZE || iova % PAGE_SIZE ||
+ size % PAGE_SIZE);
+
while (size) {
rc = iommu_map(domain, iova, paddr, PAGE_SIZE, prot);
if (rc)
@@ -718,6 +740,10 @@ static int pfn_reader_user_pin(struct pfn_reader_user *user,
uintptr_t uptr;
long rc;

+ if (IS_ENABLED(CONFIG_IOMMUFD_TEST) &&
+ WARN_ON(last_index < start_index))
+ return -EINVAL;
+
if (!user->upages) {
/* All undone in pfn_reader_destroy() */
user->upages_len =
@@ -956,6 +982,10 @@ static int pfn_reader_fill_span(struct pfn_reader *pfns)
struct iopt_area *area;
int rc;

+ if (IS_ENABLED(CONFIG_IOMMUFD_TEST) &&
+ WARN_ON(span->last_used < start_index))
+ return -EINVAL;
+
if (span->is_used == 1) {
batch_from_xarray(&pfns->batch, &pfns->pages->pinned_pfns,
start_index, span->last_used);
@@ -1008,6 +1038,10 @@ static int pfn_reader_next(struct pfn_reader *pfns)
while (pfns->batch_end_index != pfns->last_index + 1) {
unsigned int npfns = pfns->batch.total_pfns;

+ if (IS_ENABLED(CONFIG_IOMMUFD_TEST) &&
+ WARN_ON(interval_tree_double_span_iter_done(&pfns->span)))
+ return -EINVAL;
+
rc = pfn_reader_fill_span(pfns);
if (rc)
return rc;
@@ -1091,6 +1125,10 @@ static int pfn_reader_first(struct pfn_reader *pfns, struct iopt_pages *pages,
{
int rc;

+ if (IS_ENABLED(CONFIG_IOMMUFD_TEST) &&
+ WARN_ON(last_index < start_index))
+ return -EINVAL;
+
rc = pfn_reader_init(pfns, pages, start_index, last_index);
if (rc)
return rc;
--
2.38.1