The pfn_array_alloc_pin routine is doing too much. Today, it does the
alloc of the pfn_array struct and its member arrays, builds the iova
address lists out of a contiguous piece of guest memory, and asks vfio
to pin the resulting pages. While the input iova variable points to a
contiguous piece of memory, the pfn_array, uh, array would permit a
non-contiguous range of addresses such as those provided by an IDA List.
By breaking pfn_array_alloc_pin into its component pieces, we will be in
a good place to share this code regardless of what pfn_array contains.
Signed-off-by: Eric Farman <farman@xxxxxxxxxxxxx>
---
drivers/s390/cio/vfio_ccw_cp.c | 96 +++++++++++++++++++-----------------------
1 file changed, 44 insertions(+), 52 deletions(-)
diff --git a/drivers/s390/cio/vfio_ccw_cp.c b/drivers/s390/cio/vfio_ccw_cp.c
index 5f16aa88c629..d01e146289fb 100644
--- a/drivers/s390/cio/vfio_ccw_cp.c
+++ b/drivers/s390/cio/vfio_ccw_cp.c
@@ -49,37 +49,32 @@ struct ccwchain {
struct pfn_array_table *ch_pat;
};
-/*
- * pfn_array_alloc_pin() - alloc memory for PFNs, then pin user pages in memory
- * @pa: pfn_array on which to perform the operation
- * @mdev: the mediated device to perform pin/unpin operations
- * @iova: target guest physical address
- * @len: number of pages that should be pinned from @iova
- *
- * Attempt to allocate memory for PFNs, and pin user pages in memory.
- *
- * Usage of pfn_array:
- * We expect (pa_nr == 0) and (pa_iova_pfn == NULL), any field in
- * this structure will be filled in by this function.
- *
- * Returns:
- * Number of pages pinned on success.
- * If @pa->pa_nr is not 0, or @pa->pa_iova_pfn is not NULL initially,
- * returns -EINVAL.
- * If no pages were pinned, returns -errno.
- */
-static int pfn_array_alloc_pin(struct pfn_array *pa, struct device *mdev,
- u64 iova, unsigned int len)
+static int pfn_array_pin(struct pfn_array *pa, struct device *mdev)
{
- int i, ret = 0;
+ int ret = 0;
+
+ ret = vfio_pin_pages(mdev, pa->pa_iova_pfn, pa->pa_nr,
+ IOMMU_READ | IOMMU_WRITE, pa->pa_pfn);
+
+ if (ret > 0 && ret != pa->pa_nr) {
+ vfio_unpin_pages(mdev, pa->pa_iova_pfn, ret);
+ ret = -EINVAL;
+ }
+ if (ret < 0)
+ pa->pa_iova = 0;
+
+ return ret;
+}
+
+static int pfn_array_alloc(struct pfn_array *pa, unsigned int len)
+{
if (!len)
return 0;
if (pa->pa_nr || pa->pa_iova_pfn)
return -EINVAL;
- pa->pa_iova = iova;
pa->pa_nr = len;
pa->pa_iova_pfn = kcalloc(pa->pa_nr,
@@ -90,35 +85,14 @@ static int pfn_array_alloc_pin(struct pfn_array *pa, struct device *mdev,
return -ENOMEM;
pa->pa_pfn = pa->pa_iova_pfn + pa->pa_nr;
- pa->pa_iova_pfn[0] = pa->pa_iova >> PAGE_SHIFT;
- for (i = 1; i < pa->pa_nr; i++)
- pa->pa_iova_pfn[i] = pa->pa_iova_pfn[i - 1] + 1;
-
- ret = vfio_pin_pages(mdev, pa->pa_iova_pfn, pa->pa_nr,
- IOMMU_READ | IOMMU_WRITE, pa->pa_pfn);
-
- if (ret < 0) {
- goto err_out;
- } else if (ret > 0 && ret != pa->pa_nr) {
- vfio_unpin_pages(mdev, pa->pa_iova_pfn, ret);
- ret = -EINVAL;
- goto err_out;
- }
-
- return ret;
-
-err_out:
- pa->pa_nr = 0;
- kfree(pa->pa_iova_pfn);
- pa->pa_iova_pfn = NULL;
-
- return ret;
+ return 0;
}
/* Unpin the pages before releasing the memory. */
static void pfn_array_unpin_free(struct pfn_array *pa, struct device *mdev)
{
- vfio_unpin_pages(mdev, pa->pa_iova_pfn, pa->pa_nr);
+ if (pa->pa_iova)
+ vfio_unpin_pages(mdev, pa->pa_iova_pfn, pa->pa_nr);
pa->pa_nr = 0;
kfree(pa->pa_iova_pfn);
}
@@ -206,11 +180,21 @@ static long copy_from_iova(struct device *mdev,
int i, ret;
unsigned long l, m;
- ret = pfn_array_alloc_pin(&pa, mdev, iova,
- idal_nr_words((void *)(iova), n));
- if (ret <= 0)
+ ret = pfn_array_alloc(&pa, idal_nr_words((void *)(iova), n));
+ if (ret < 0)
return ret;
+ pa.pa_iova = iova;
+ pa.pa_iova_pfn[0] = pa.pa_iova >> PAGE_SHIFT;
+ for (i = 1; i < pa.pa_nr; i++)
+ pa.pa_iova_pfn[i] = pa.pa_iova_pfn[i - 1] + 1;
+
+ ret = pfn_array_pin(&pa, mdev);
+ if (ret <= 0) {
+ pfn_array_unpin_free(&pa, mdev);
+ return ret;
+ }
+
l = n;
for (i = 0; i < pa.pa_nr; i++) {
from = pa.pa_pfn[i] << PAGE_SHIFT;
@@ -454,6 +438,7 @@ static int ccwchain_fetch_ccw(struct ccwchain *chain,
{
struct ccw1 *ccw;
struct pfn_array_table *pat;
+ struct pfn_array *pa;
unsigned long *idaws;
u64 idaw_iova;
unsigned int idaw_nr, idaw_len;
@@ -515,11 +500,18 @@ static int ccwchain_fetch_ccw(struct ccwchain *chain,
for (i = 0; i < idaw_nr; i++) {
idaw_iova = *(idaws + i);
+ pa = pat->pat_pa + i;
- ret = pfn_array_alloc_pin(pat->pat_pa + i, cp->mdev,
- idaw_iova, 1);
+ ret = pfn_array_alloc(pa, 1);
if (ret < 0)
goto out_free_idaws;
+
+ pa->pa_iova = idaws[0];
+ pa->pa_iova_pfn[0] = idaws[i] >> PAGE_SHIFT;
+
+ ret = pfn_array_pin(pa, cp->mdev);
+ if (ret <= 0)
+ goto out_free_idaws;
}
ccw->cda = virt_to_phys(idaws);
--
2.16.4
