Commit e4f3f18b authored by Eric Farman's avatar Eric Farman Committed by Cornelia Huck

s390/cio: Split pfn_array_alloc_pin into pieces

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.

Let's effectively revert a significant portion of commit 5c1cfb1c
("vfio: ccw: refactor and improve pfn_array_alloc_pin()") such that we
break pfn_array_alloc_pin() into its component pieces, and have one
routine that allocates/populates the pfn_array structs, and another
that actually pins the memory.  In the future, we will be able to
handle scenarios where pinning memory isn't actually appropriate.
Signed-off-by: default avatarEric Farman <farman@linux.ibm.com>
Message-Id: <20190514234248.36203-4-farman@linux.ibm.com>
Reviewed-by: default avatarFarhan Ali <alifm@linux.ibm.com>
Signed-off-by: default avatarCornelia Huck <cohuck@redhat.com>
parent 4e31d6ae
......@@ -50,28 +50,25 @@ struct ccwchain {
};
/*
* pfn_array_alloc_pin() - alloc memory for PFNs, then pin user pages in memory
* pfn_array_alloc() - alloc memory for PFNs
* @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 bytes that should be pinned from @iova
*
* Attempt to allocate memory for PFNs, and pin user pages in memory.
* Attempt to allocate memory for PFNs.
*
* 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.
* 0 if PFNs are allocated
* -EINVAL if pa->pa_nr is not initially zero, or pa->pa_iova_pfn is not NULL
* -ENOMEM if alloc failed
*/
static int pfn_array_alloc_pin(struct pfn_array *pa, struct device *mdev,
u64 iova, unsigned int len)
static int pfn_array_alloc(struct pfn_array *pa, u64 iova, unsigned int len)
{
int i, ret = 0;
int i;
if (!len)
return 0;
......@@ -97,6 +94,22 @@ static int pfn_array_alloc_pin(struct pfn_array *pa, struct device *mdev,
for (i = 1; i < pa->pa_nr; i++)
pa->pa_iova_pfn[i] = pa->pa_iova_pfn[i - 1] + 1;
return 0;
}
/*
* pfn_array_pin() - Pin user pages in memory
* @pa: pfn_array on which to perform the operation
* @mdev: the mediated device to perform pin operations
*
* Returns number of pages pinned upon success.
* If the pin request partially succeeds, or fails completely,
* all pages are left unpinned and a negative error value is returned.
*/
static int pfn_array_pin(struct pfn_array *pa, struct device *mdev)
{
int ret = 0;
ret = vfio_pin_pages(mdev, pa->pa_iova_pfn, pa->pa_nr,
IOMMU_READ | IOMMU_WRITE, pa->pa_pfn);
......@@ -112,8 +125,6 @@ static int pfn_array_alloc_pin(struct pfn_array *pa, struct device *mdev,
err_out:
pa->pa_nr = 0;
kfree(pa->pa_iova_pfn);
pa->pa_iova_pfn = NULL;
return ret;
}
......@@ -121,7 +132,9 @@ static int pfn_array_alloc_pin(struct pfn_array *pa, struct device *mdev,
/* 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);
/* Only unpin if any pages were pinned to begin with */
if (pa->pa_nr)
vfio_unpin_pages(mdev, pa->pa_iova_pfn, pa->pa_nr);
pa->pa_nr = 0;
kfree(pa->pa_iova_pfn);
}
......@@ -209,10 +222,16 @@ static long copy_from_iova(struct device *mdev,
int i, ret;
unsigned long l, m;
ret = pfn_array_alloc_pin(&pa, mdev, iova, n);
if (ret <= 0)
ret = pfn_array_alloc(&pa, iova, n);
if (ret < 0)
return ret;
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;
......@@ -560,7 +579,11 @@ static int ccwchain_fetch_direct(struct ccwchain *chain,
if (ret)
goto out_init;
ret = pfn_array_alloc_pin(pat->pat_pa, cp->mdev, ccw->cda, ccw->count);
ret = pfn_array_alloc(pat->pat_pa, ccw->cda, ccw->count);
if (ret < 0)
goto out_unpin;
ret = pfn_array_pin(pat->pat_pa, cp->mdev);
if (ret < 0)
goto out_unpin;
......@@ -590,6 +613,7 @@ static int ccwchain_fetch_idal(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;
......@@ -628,9 +652,13 @@ static int ccwchain_fetch_idal(struct ccwchain *chain,
for (i = 0; i < idaw_nr; i++) {
idaw_iova = *(idaws + i);
pa = pat->pat_pa + i;
ret = pfn_array_alloc(pa, idaw_iova, 1);
if (ret < 0)
goto out_free_idaws;
ret = pfn_array_alloc_pin(pat->pat_pa + i, cp->mdev,
idaw_iova, 1);
ret = pfn_array_pin(pa, cp->mdev);
if (ret < 0)
goto out_free_idaws;
}
......
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