vfio/ccw: allocate/populate the guest idal

Today, we allocate memory for a list of IDAWs, and if the CCW
being processed contains an IDAL we read that data from the guest
into that space. We then copy each IDAW into the pa_iova array,
or fabricate that pa_iova array with a list of addresses based
on a direct-addressed CCW.

Combine the reading of the guest IDAL with the creation of a
pseudo-IDAL for direct-addressed CCWs, so that both CCW types
have a "guest" IDAL that can be populated straight into the
pa_iova array.

Signed-off-by: Eric Farman <farman@linux.ibm.com>
Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

diff --git a/drivers/s390/cio/vfio_ccw_cp.c b/drivers/s390/cio/vfio_ccw_cp.c
index 6a2c6ee..5252777 100644 (file)
--- a/drivers/s390/cio/vfio_ccw_cp.c
+++ b/drivers/s390/cio/vfio_ccw_cp.c
@@ -192,11 +192,12 @@ static inline void page_array_idal_create_words(struct page_array *pa,
         * idaw.
         */
 
-       for (i = 0; i < pa->pa_nr; i++)
+       for (i = 0; i < pa->pa_nr; i++) {
                idaws[i] = page_to_phys(pa->pa_page[i]);
 
-       /* Adjust the first IDAW, since it may not start on a page boundary */
-       idaws[0] += pa->pa_iova[0] & (PAGE_SIZE - 1);
+               /* Incorporate any offset from each starting address */
+               idaws[i] += pa->pa_iova[i] & (PAGE_SIZE - 1);
+       }
 }
 
 static void convert_ccw0_to_ccw1(struct ccw1 *source, unsigned long len)
@@ -496,6 +497,44 @@ static int ccwchain_fetch_tic(struct ccw1 *ccw,
        return -EFAULT;
 }
 
+static unsigned long *get_guest_idal(struct ccw1 *ccw,
+                                    struct channel_program *cp,
+                                    int idaw_nr)
+{
+       struct vfio_device *vdev =
+               &container_of(cp, struct vfio_ccw_private, cp)->vdev;
+       unsigned long *idaws;
+       int idal_len = idaw_nr * sizeof(*idaws);
+       int idaw_size = PAGE_SIZE;
+       int idaw_mask = ~(idaw_size - 1);
+       int i, ret;
+
+       idaws = kcalloc(idaw_nr, sizeof(*idaws), GFP_DMA | GFP_KERNEL);
+       if (!idaws)
+               return ERR_PTR(-ENOMEM);
+
+       if (ccw_is_idal(ccw)) {
+               /* Copy IDAL from guest */
+               ret = vfio_dma_rw(vdev, ccw->cda, idaws, idal_len, false);
+               if (ret) {
+                       kfree(idaws);
+                       return ERR_PTR(ret);
+               }
+       } else {
+               /* Fabricate an IDAL based off CCW data address */
+               if (cp->orb.cmd.c64) {
+                       idaws[0] = ccw->cda;
+                       for (i = 1; i < idaw_nr; i++)
+                               idaws[i] = (idaws[i - 1] + idaw_size) & idaw_mask;
+               } else {
+                       kfree(idaws);
+                       return ERR_PTR(-EOPNOTSUPP);
+               }
+       }
+
+       return idaws;
+}
+
 /*
  * ccw_count_idaws() - Calculate the number of IDAWs needed to transfer
  * a specified amount of data
@@ -560,7 +599,7 @@ static int ccwchain_fetch_ccw(struct ccw1 *ccw,
                &container_of(cp, struct vfio_ccw_private, cp)->vdev;
        unsigned long *idaws;
        int ret;
-       int idaw_nr, idal_len;
+       int idaw_nr;
        int i;
 
        /* Calculate size of IDAL */
@@ -568,12 +607,10 @@ static int ccwchain_fetch_ccw(struct ccw1 *ccw,
        if (idaw_nr < 0)
                return idaw_nr;
 
-       idal_len = idaw_nr * sizeof(*idaws);
-
        /* Allocate an IDAL from host storage */
-       idaws = kcalloc(idaw_nr, sizeof(*idaws), GFP_DMA | GFP_KERNEL);
-       if (!idaws) {
-               ret = -ENOMEM;
+       idaws = get_guest_idal(ccw, cp, idaw_nr);
+       if (IS_ERR(idaws)) {
+               ret = PTR_ERR(idaws);
                goto out_init;
        }
 
@@ -587,22 +624,13 @@ static int ccwchain_fetch_ccw(struct ccw1 *ccw,
        if (ret < 0)
                goto out_free_idaws;
 
-       if (ccw_is_idal(ccw)) {
-               /* Copy guest IDAL into host IDAL */
-               ret = vfio_dma_rw(vdev, ccw->cda, idaws, idal_len, false);
-               if (ret)
-                       goto out_unpin;
-
-               /*
-                * Copy guest IDAWs into page_array, in case the memory they
-                * occupy is not contiguous.
-                */
-               for (i = 0; i < idaw_nr; i++)
+       /*
+        * Copy guest IDAWs into page_array, in case the memory they
+        * occupy is not contiguous.
+        */
+       for (i = 0; i < idaw_nr; i++) {
+               if (cp->orb.cmd.c64)
                        pa->pa_iova[i] = idaws[i];
-       } else {
-               pa->pa_iova[0] = ccw->cda;
-               for (i = 1; i < pa->pa_nr; i++)
-                       pa->pa_iova[i] = pa->pa_iova[i - 1] + PAGE_SIZE;
        }
 
        if (ccw_does_data_transfer(ccw)) {