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Commit ded563f3 authored by Eric Farman's avatar Eric Farman Committed by Cornelia Huck
Browse files

vfio-ccw: Copy CCW data outside length calculation 



It doesn't make much sense to "hide" the copy to the channel_program
struct inside a routine that calculates the length of the chain.

Let's move it to the calling routine, which will later copy from
channel_program to the memory it allocated itself.

Signed-off-by: default avatarEric Farman <farman@linux.ibm.com>
Message-Id: <20190618202352.39702-4-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 62465902

drivers/s390/cio/vfio_ccw_cp.c

+7 −12
Original line number Diff line number Diff line
@@ -381,18 +381,8 @@ static void ccwchain_cda_free(struct ccwchain *chain, int idx) 
static int ccwchain_calc_length(u64 iova, struct channel_program *cp)

{

	struct ccw1 *ccw = cp->guest_cp;

	int cnt;

	int cnt = 0;



	/*

	 * Copy current chain from guest to host kernel.

	 * Currently the chain length is limited to CCWCHAIN_LEN_MAX (256).

	 * So copying 2K is enough (safe).

	 */

	cnt = copy_ccw_from_iova(cp, ccw, iova, CCWCHAIN_LEN_MAX);

	if (cnt)

		return cnt;



	cnt = 0;

	do {

		cnt++;
@@ -446,7 +436,12 @@ static int ccwchain_handle_ccw(u32 cda, struct channel_program *cp) 
	struct ccwchain *chain;

	int len;



	/* Copy the chain from cda to cp, and count the CCWs in it */

	/* Copy 2K (the most we support today) of possible CCWs */

	len = copy_ccw_from_iova(cp, cp->guest_cp, cda, CCWCHAIN_LEN_MAX);

	if (len)

		return len;



	/* Count the CCWs in the current chain */

	len = ccwchain_calc_length(cda, cp);

	if (len < 0)

		return len;