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Commit 4cebc5d6 authored by Dong Jia Shi's avatar Dong Jia Shi Committed by Cornelia Huck
Browse files

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: default avatarPierre Morel <pmorel@linux.vnet.ibm.com>
Signed-off-by: default avatarDong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
Message-Id: <20171011023822.42948-3-bjsdjshi@linux.vnet.ibm.com>
Signed-off-by: default avatarCornelia Huck <cohuck@redhat.com>
parent 688c2953

drivers/s390/cio/vfio_ccw_cp.c

+17 −1
Original line number Diff line number Diff line
@@ -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)