Commit 7f8e89a8 authored by Eric Farman's avatar Eric Farman Committed by Cornelia Huck
Browse files

vfio-ccw: Factor out the ccw0-to-ccw1 transition 



This is a really useful function, but it's buried in the
copy_ccw_from_iova() routine so that ccwchain_calc_length()
can just work with Format-1 CCWs while doing its counting.
But it means we're translating a full 2K of "CCWs" to Format-1,
when in reality there's probably far fewer in that space.

Let's factor it out, so maybe we can do something with it later.

Signed-off-by: default avatarEric Farman <farman@linux.ibm.com>
Message-Id: <20190618202352.39702-5-farman@linux.ibm.com>
Reviewed-by: default avatarCornelia Huck <cohuck@redhat.com>
Reviewed-by: default avatarFarhan Ali <alifm@linux.ibm.com>
Signed-off-by: default avatarCornelia Huck <cohuck@redhat.com>
parent ded563f3

drivers/s390/cio/vfio_ccw_cp.c

+25 −23
Original line number Diff line number Diff line
@@ -161,6 +161,27 @@ static inline void pfn_array_idal_create_words( 
	idaws[0] += pa->pa_iova & (PAGE_SIZE - 1);

}



void convert_ccw0_to_ccw1(struct ccw1 *source, unsigned long len)

{

	struct ccw0 ccw0;

	struct ccw1 *pccw1 = source;

	int i;



	for (i = 0; i < len; i++) {

		ccw0 = *(struct ccw0 *)pccw1;

		if ((pccw1->cmd_code & 0x0f) == CCW_CMD_TIC) {

			pccw1->cmd_code = CCW_CMD_TIC;

			pccw1->flags = 0;

			pccw1->count = 0;

		} else {

			pccw1->cmd_code = ccw0.cmd_code;

			pccw1->flags = ccw0.flags;

			pccw1->count = ccw0.count;

		}

		pccw1->cda = ccw0.cda;

		pccw1++;

	}

}



/*

 * Within the domain (@mdev), copy @n bytes from a guest physical
@@ -211,32 +232,9 @@ static long copy_ccw_from_iova(struct channel_program *cp, 
			       struct ccw1 *to, u64 iova,

			       unsigned long len)

{

	struct ccw0 ccw0;

	struct ccw1 *pccw1;

	int ret;

	int i;



	ret = copy_from_iova(cp->mdev, to, iova, len * sizeof(struct ccw1));

	if (ret)

		return ret;



	if (!cp->orb.cmd.fmt) {

		pccw1 = to;

		for (i = 0; i < len; i++) {

			ccw0 = *(struct ccw0 *)pccw1;

			if ((pccw1->cmd_code & 0x0f) == CCW_CMD_TIC) {

				pccw1->cmd_code = CCW_CMD_TIC;

				pccw1->flags = 0;

				pccw1->count = 0;

			} else {

				pccw1->cmd_code = ccw0.cmd_code;

				pccw1->flags = ccw0.flags;

				pccw1->count = ccw0.count;

			}

			pccw1->cda = ccw0.cda;

			pccw1++;

		}

	}



	return ret;

}
@@ -441,6 +439,10 @@ static int ccwchain_handle_ccw(u32 cda, struct channel_program *cp) 
	if (len)

		return len;



	/* Convert any Format-0 CCWs to Format-1 */

	if (!cp->orb.cmd.fmt)

		convert_ccw0_to_ccw1(cp->guest_cp, len);



	/* Count the CCWs in the current chain */

	len = ccwchain_calc_length(cda, cp);

	if (len < 0)

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