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authorDong Jia Shi <bjsdjshi@linux.vnet.ibm.com>2017-10-11 05:38:22 +0300
committerCornelia Huck <cohuck@redhat.com>2017-10-16 12:14:48 +0300
commit4cebc5d6a6ff41c0266d235aa4854b062d34ad09 (patch)
tree41b1f670f9cefb1f8a0aa118f59bccb8983bf3dd /drivers/s390
parent688c29533ffc969773bc860d07d3a5f1995f5878 (diff)
downloadlinux-4cebc5d6a6ff41c0266d235aa4854b062d34ad09.tar.xz
vfio: ccw: validate the count field of a ccw before pinning
If the count field of a ccw is zero, there is no need to try to pin page(s) for it. Let's check the count value before starting pinning operations. Reviewed-by: Pierre Morel <pmorel@linux.vnet.ibm.com> Signed-off-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com> Message-Id: <20171011023822.42948-3-bjsdjshi@linux.vnet.ibm.com> Signed-off-by: Cornelia Huck <cohuck@redhat.com>
Diffstat (limited to 'drivers/s390')
-rw-r--r--drivers/s390/cio/vfio_ccw_cp.c18
1 files changed, 17 insertions, 1 deletions
diff --git a/drivers/s390/cio/vfio_ccw_cp.c b/drivers/s390/cio/vfio_ccw_cp.c
index 722f8b8c7273..d8f98ad9b029 100644
--- a/drivers/s390/cio/vfio_ccw_cp.c
+++ b/drivers/s390/cio/vfio_ccw_cp.c
@@ -105,7 +105,10 @@ static int pfn_array_alloc_pin(struct pfn_array *pa, struct device *mdev,
{
int ret = 0;
- if (!len || pa->pa_nr)
+ if (!len)
+ return 0;
+
+ if (pa->pa_nr)
return -EINVAL;
pa->pa_iova = iova;
@@ -501,6 +504,16 @@ static int ccwchain_fetch_direct(struct ccwchain *chain,
ccw = chain->ch_ccw + idx;
+ if (!ccw->count) {
+ /*
+ * We just want the translation result of any direct ccw
+ * to be an IDA ccw, so let's add the IDA flag for it.
+ * Although the flag will be ignored by firmware.
+ */
+ ccw->flags |= CCW_FLAG_IDA;
+ return 0;
+ }
+
/*
* Pin data page(s) in memory.
* The number of pages actually is the count of the idaws which will be
@@ -541,6 +554,9 @@ static int ccwchain_fetch_idal(struct ccwchain *chain,
ccw = chain->ch_ccw + idx;
+ if (!ccw->count)
+ return 0;
+
/* Calculate size of idaws. */
ret = copy_from_iova(cp->mdev, &idaw_iova, ccw->cda, sizeof(idaw_iova));
if (ret)