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| author |   Eric Farman <farman@linux.ibm.com> | 2019-06-18 22:23:50 +0200 |
|---|---|---|
| committer |   Cornelia Huck <cohuck@redhat.com> | 2019-06-21 14:12:45 +0200 |
| commit | ded563f31d0eb4de0bcb101b755cdf6f4ed805e4 (patch) | |
| tree | d77b09c8f75f602fed50ba1f61efb6200bdfb509 /drivers/s390/cio | |
| parent | vfio-ccw: Skip second copy of guest cp to host (diff) | |
| download | linux-dev-ded563f31d0eb4de0bcb101b755cdf6f4ed805e4.tar.xz linux-dev-ded563f31d0eb4de0bcb101b755cdf6f4ed805e4.zip | |
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 <farman@linux.ibm.com>
Message-Id: <20190618202352.39702-4-farman@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Farhan Ali <alifm@linux.ibm.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
Diffstat (limited to '')
| -rw-r--r-- | drivers/s390/cio/vfio_ccw_cp.c | 19 |
1 files changed, 7 insertions, 12 deletions
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; |