[PATCH v3 07/10] vfio/ccw: Change pa_pfn list to pa_iova list

Nicolin Chen
2022-07-08T22:44:54Z

The vfio_ccw_cp code maintains both iova and its PFN list because the
vfio_pin/unpin_pages API wanted pfn list. Since vfio_pin/unpin_pages()
now accept "iova", change to maintain only pa_iova list and rename all
"pfn_array" strings to "page_array", so as to simplify the code.

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Eric Farman <farman@linux.ibm.com>
Tested-by: Eric Farman <farman@linux.ibm.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
---
drivers/s390/cio/vfio_ccw_cp.c | 135 ++++++++++++++++-----------------
1 file changed, 64 insertions(+), 71 deletions(-)

diff --git a/drivers/s390/cio/vfio_ccw_cp.c b/drivers/s390/cio/vfio_ccw_cp.c
index a739262f988d..3854c3d573f5 100644
--- a/drivers/s390/cio/vfio_ccw_cp.c
+++ b/drivers/s390/cio/vfio_ccw_cp.c
@@ -18,11 +18,9 @@
#include "vfio_ccw_cp.h"
#include "vfio_ccw_private.h"

-struct pfn_array {
- /* Starting guest physical I/O address. */
- unsigned long pa_iova;
- /* Array that stores PFNs of the pages need to pin. */
- unsigned long *pa_iova_pfn;
+struct page_array {
+ /* Array that stores pages need to pin. */
+ dma_addr_t *pa_iova;
/* Array that receives PFNs of the pages pinned. */
unsigned long *pa_pfn;
/* Number of pages pinned from @pa_iova. */
@@ -37,53 +35,50 @@ struct ccwchain {
/* Count of the valid ccws in chain. */
int ch_len;
/* Pinned PAGEs for the original data. */
- struct pfn_array *ch_pa;
+ struct page_array *ch_pa;
};

/*
- * pfn_array_alloc() - alloc memory for PFNs
- * @pa: pfn_array on which to perform the operation
+ * page_array_alloc() - alloc memory for page array
+ * @pa: page_array on which to perform the operation
* @iova: target guest physical address
* @len: number of bytes that should be pinned from @iova
*
- * Attempt to allocate memory for PFNs.
+ * Attempt to allocate memory for page array.
*
- * Usage of pfn_array:
- * We expect (pa_nr == 0) and (pa_iova_pfn == NULL), any field in
+ * Usage of page_array:
+ * We expect (pa_nr == 0) and (pa_iova == NULL), any field in
* this structure will be filled in by this function.
*
* Returns:
- * 0 if PFNs are allocated
- * -EINVAL if pa->pa_nr is not initially zero, or pa->pa_iova_pfn is not NULL
+ * 0 if page array is allocated
+ * -EINVAL if pa->pa_nr is not initially zero, or pa->pa_iova is not NULL
* -ENOMEM if alloc failed
*/
-static int pfn_array_alloc(struct pfn_array *pa, u64 iova, unsigned int len)
+static int page_array_alloc(struct page_array *pa, u64 iova, unsigned int len)
{
int i;

- if (pa->pa_nr || pa->pa_iova_pfn)
+ if (pa->pa_nr || pa->pa_iova)
return -EINVAL;

- pa->pa_iova = iova;
-
pa->pa_nr = ((iova & ~PAGE_MASK) + len + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
if (!pa->pa_nr)
return -EINVAL;

- pa->pa_iova_pfn = kcalloc(pa->pa_nr,
- sizeof(*pa->pa_iova_pfn) +
- sizeof(*pa->pa_pfn),
- GFP_KERNEL);
- if (unlikely(!pa->pa_iova_pfn)) {
+ pa->pa_iova = kcalloc(pa->pa_nr,
+ sizeof(*pa->pa_iova) + sizeof(*pa->pa_pfn),
+ GFP_KERNEL);
+ if (unlikely(!pa->pa_iova)) {
pa->pa_nr = 0;
return -ENOMEM;
}
- pa->pa_pfn = pa->pa_iova_pfn + pa->pa_nr;
+ pa->pa_pfn = (unsigned long *)&pa->pa_iova[pa->pa_nr];

- pa->pa_iova_pfn[0] = pa->pa_iova >> PAGE_SHIFT;
+ pa->pa_iova[0] = iova;
pa->pa_pfn[0] = -1ULL;
for (i = 1; i < pa->pa_nr; i++) {
- pa->pa_iova_pfn[i] = pa->pa_iova_pfn[i - 1] + 1;
+ pa->pa_iova[i] = pa->pa_iova[i - 1] + PAGE_SIZE;
pa->pa_pfn[i] = -1ULL;
}

@@ -91,30 +86,30 @@ static int pfn_array_alloc(struct pfn_array *pa, u64 iova, unsigned int len)
}

/*
- * pfn_array_unpin() - Unpin user pages in memory
- * @pa: pfn_array on which to perform the operation
+ * page_array_unpin() - Unpin user pages in memory
+ * @pa: page_array on which to perform the operation
* @vdev: the vfio device to perform the operation
* @pa_nr: number of user pages to unpin
*
* Only unpin if any pages were pinned to begin with, i.e. pa_nr > 0,
* otherwise only clear pa->pa_nr
*/
-static void pfn_array_unpin(struct pfn_array *pa,
- struct vfio_device *vdev, int pa_nr)
+static void page_array_unpin(struct page_array *pa,
+ struct vfio_device *vdev, int pa_nr)
{
int unpinned = 0, npage = 1;

while (unpinned < pa_nr) {
- unsigned long *first = &pa->pa_iova_pfn[unpinned];
- unsigned long *last = &first[npage];
+ dma_addr_t *first = &pa->pa_iova[unpinned];
+ dma_addr_t *last = &first[npage];

if (unpinned + npage < pa_nr &&
- *first + npage == *last) {
+ *first + npage * PAGE_SIZE == *last) {
npage++;
continue;
}

- vfio_unpin_pages(vdev, *first << PAGE_SHIFT, npage);
+ vfio_unpin_pages(vdev, *first, npage);
unpinned += npage;
npage = 1;
}
@@ -123,30 +118,30 @@ static void pfn_array_unpin(struct pfn_array *pa,
}

/*
- * pfn_array_pin() - Pin user pages in memory
- * @pa: pfn_array on which to perform the operation
+ * page_array_pin() - Pin user pages in memory
+ * @pa: page_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 vfio_device *vdev)
+static int page_array_pin(struct page_array *pa, struct vfio_device *vdev)
{
int pinned = 0, npage = 1;
int ret = 0;

while (pinned < pa->pa_nr) {
- unsigned long *first = &pa->pa_iova_pfn[pinned];
- unsigned long *last = &first[npage];
+ dma_addr_t *first = &pa->pa_iova[pinned];
+ dma_addr_t *last = &first[npage];

if (pinned + npage < pa->pa_nr &&
- *first + npage == *last) {
+ *first + npage * PAGE_SIZE == *last) {
npage++;
continue;
}

- ret = vfio_pin_pages(vdev, *first << PAGE_SHIFT, npage,
+ ret = vfio_pin_pages(vdev, *first, npage,
IOMMU_READ | IOMMU_WRITE,
&pa->pa_pfn[pinned]);
if (ret < 0) {
@@ -163,32 +158,30 @@ static int pfn_array_pin(struct pfn_array *pa, struct vfio_device *vdev)
return ret;

err_out:
- pfn_array_unpin(pa, vdev, pinned);
+ page_array_unpin(pa, vdev, pinned);
return ret;
}

/* Unpin the pages before releasing the memory. */
-static void pfn_array_unpin_free(struct pfn_array *pa, struct vfio_device *vdev)
+static void page_array_unpin_free(struct page_array *pa, struct vfio_device *vdev)
{
- pfn_array_unpin(pa, vdev, pa->pa_nr);
- kfree(pa->pa_iova_pfn);
+ page_array_unpin(pa, vdev, pa->pa_nr);
+ kfree(pa->pa_iova);
}

-static bool pfn_array_iova_pinned(struct pfn_array *pa, unsigned long iova)
+static bool page_array_iova_pinned(struct page_array *pa, unsigned long iova)
{
- unsigned long iova_pfn = iova >> PAGE_SHIFT;
int i;

for (i = 0; i < pa->pa_nr; i++)
- if (pa->pa_iova_pfn[i] == iova_pfn)
+ if (pa->pa_iova[i] == iova)
return true;

return false;
}
-/* Create the list of IDAL words for a pfn_array. */
-static inline void pfn_array_idal_create_words(
- struct pfn_array *pa,
- unsigned long *idaws)
+/* Create the list of IDAL words for a page_array. */
+static inline void page_array_idal_create_words(struct page_array *pa,
+ unsigned long *idaws)
{
int i;

@@ -204,7 +197,7 @@ static inline void pfn_array_idal_create_words(
idaws[i] = pa->pa_pfn[i] << PAGE_SHIFT;

/* Adjust the first IDAW, since it may not start on a page boundary */
- idaws[0] += pa->pa_iova & (PAGE_SIZE - 1);
+ idaws[0] += pa->pa_iova[0] & (PAGE_SIZE - 1);
}

static void convert_ccw0_to_ccw1(struct ccw1 *source, unsigned long len)
@@ -236,18 +229,18 @@ static void convert_ccw0_to_ccw1(struct ccw1 *source, unsigned long len)
static long copy_from_iova(struct vfio_device *vdev, void *to, u64 iova,
unsigned long n)
{
- struct pfn_array pa = {0};
+ struct page_array pa = {0};
u64 from;
int i, ret;
unsigned long l, m;

- ret = pfn_array_alloc(&pa, iova, n);
+ ret = page_array_alloc(&pa, iova, n);
if (ret < 0)
return ret;

- ret = pfn_array_pin(&pa, vdev);
+ ret = page_array_pin(&pa, vdev);
if (ret < 0) {
- pfn_array_unpin_free(&pa, vdev);
+ page_array_unpin_free(&pa, vdev);
return ret;
}

@@ -268,7 +261,7 @@ static long copy_from_iova(struct vfio_device *vdev, void *to, u64 iova,
break;
}

- pfn_array_unpin_free(&pa, vdev);
+ page_array_unpin_free(&pa, vdev);

return l;
}
@@ -371,7 +364,7 @@ static struct ccwchain *ccwchain_alloc(struct channel_program *cp, int len)
chain->ch_ccw = (struct ccw1 *)data;

data = (u8 *)(chain->ch_ccw) + sizeof(*chain->ch_ccw) * len;
- chain->ch_pa = (struct pfn_array *)data;
+ chain->ch_pa = (struct page_array *)data;

chain->ch_len = len;

@@ -555,7 +548,7 @@ static int ccwchain_fetch_direct(struct ccwchain *chain,
struct vfio_device *vdev =
&container_of(cp, struct vfio_ccw_private, cp)->vdev;
struct ccw1 *ccw;
- struct pfn_array *pa;
+ struct page_array *pa;
u64 iova;
unsigned long *idaws;
int ret;
@@ -589,13 +582,13 @@ static int ccwchain_fetch_direct(struct ccwchain *chain,
}

/*
- * Allocate an array of pfn's for pages to pin/translate.
+ * Allocate an array of pages to pin/translate.
* The number of pages is actually the count of the idaws
* required for the data transfer, since we only only support
* 4K IDAWs today.
*/
pa = chain->ch_pa + idx;
- ret = pfn_array_alloc(pa, iova, bytes);
+ ret = page_array_alloc(pa, iova, bytes);
if (ret < 0)
goto out_free_idaws;

@@ -606,21 +599,21 @@ static int ccwchain_fetch_direct(struct ccwchain *chain,
goto out_unpin;

/*
- * Copy guest IDAWs into pfn_array, in case the memory they
+ * Copy guest IDAWs into page_array, in case the memory they
* occupy is not contiguous.
*/
for (i = 0; i < idaw_nr; i++)
- pa->pa_iova_pfn[i] = idaws[i] >> PAGE_SHIFT;
+ pa->pa_iova[i] = idaws[i];
} else {
/*
- * No action is required here; the iova addresses in pfn_array
- * were initialized sequentially in pfn_array_alloc() beginning
+ * No action is required here; the iova addresses in page_array
+ * were initialized sequentially in page_array_alloc() beginning
* with the contents of ccw->cda.
*/
}

if (ccw_does_data_transfer(ccw)) {
- ret = pfn_array_pin(pa, vdev);
+ ret = page_array_pin(pa, vdev);
if (ret < 0)
goto out_unpin;
} else {
@@ -630,13 +623,13 @@ static int ccwchain_fetch_direct(struct ccwchain *chain,
ccw->cda = (__u32) virt_to_phys(idaws);
ccw->flags |= CCW_FLAG_IDA;

- /* Populate the IDAL with pinned/translated addresses from pfn */
- pfn_array_idal_create_words(pa, idaws);
+ /* Populate the IDAL with pinned/translated addresses from page */
+ page_array_idal_create_words(pa, idaws);

return 0;

out_unpin:
- pfn_array_unpin_free(pa, vdev);
+ page_array_unpin_free(pa, vdev);
out_free_idaws:
kfree(idaws);
out_init:
@@ -742,7 +735,7 @@ void cp_free(struct channel_program *cp)
cp->initialized = false;
list_for_each_entry_safe(chain, temp, &cp->ccwchain_list, next) {
for (i = 0; i < chain->ch_len; i++) {
- pfn_array_unpin_free(chain->ch_pa + i, vdev);
+ page_array_unpin_free(chain->ch_pa + i, vdev);
ccwchain_cda_free(chain, i);
}
ccwchain_free(chain);
@@ -918,7 +911,7 @@ bool cp_iova_pinned(struct channel_program *cp, u64 iova)

list_for_each_entry(chain, &cp->ccwchain_list, next) {
for (i = 0; i < chain->ch_len; i++)
- if (pfn_array_iova_pinned(chain->ch_pa + i, iova))
+ if (page_array_iova_pinned(chain->ch_pa + i, iova))
return true;
}

--
2.17.1