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vfio-ccw: Fix the conversion of Format-0 CCWs to Format-1

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When processing Format-0 CCWs, we use the "len" variable as the
number of CCWs to convert to Format-1.  But that variable
contains zero here, and is not a meaningful CCW count until
ccwchain_calc_length() returns.  Since that routine requires and
expects Format-1 CCWs to identify the chaining behavior, the
format conversion must be done first.

Convert the 2KB we copied even if it's more than we need.

Fixes: 7f8e89a8f2 ("vfio-ccw: Factor out the ccw0-to-ccw1 transition")
Reported-by: Farhan Ali <alifm@linux.ibm.com>
Signed-off-by: Eric Farman <farman@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Message-Id: <20190702180928.18113-1-farman@linux.ibm.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
This commit is contained in:
Eric Farman 2019-07-02 20:09:28 +02:00 committed by Cornelia Huck
parent 05f31e3bf6
commit c382cbc6db
1 changed files with 1 additions and 1 deletions
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2
drivers/s390/cio/vfio_ccw_cp.c
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@ -431,7 +431,7 @@ static int ccwchain_handle_ccw(u32 cda, struct channel_program *cp)
/* Convert any Format-0 CCWs to Format-1 */
if (!cp->orb.cmd.fmt)
convert_ccw0_to_ccw1(cp->guest_cp, len);
convert_ccw0_to_ccw1(cp->guest_cp, CCWCHAIN_LEN_MAX);
/* Count the CCWs in the current chain */
len = ccwchain_calc_length(cda, cp);