From ded563f31d0eb4de0bcb101b755cdf6f4ed805e4 Mon Sep 17 00:00:00 2001 From: Eric Farman Date: Tue, 18 Jun 2019 22:23:50 +0200 Subject: 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: Eric Farman Message-Id: <20190618202352.39702-4-farman@linux.ibm.com> Reviewed-by: Cornelia Huck Reviewed-by: Farhan Ali Signed-off-by: Cornelia Huck --- drivers/s390/cio/vfio_ccw_cp.c | 19 +++++++------------ 1 file changed, 7 insertions(+), 12 deletions(-) (limited to 'drivers/s390/cio') diff --git a/drivers/s390/cio/vfio_ccw_cp.c b/drivers/s390/cio/vfio_ccw_cp.c index 37d513e86530..a55f8d110920 100644 --- a/drivers/s390/cio/vfio_ccw_cp.c +++ b/drivers/s390/cio/vfio_ccw_cp.c @@ -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; -- cgit v1.2.3