[PULL 1/2] vfio: ccw: bypass bad idaw address when fetching IDAL ccws

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



From: Dong Jia Shi <bjsdjshi@xxxxxxxxxxxxxxxxxx>

We currently return the same error code (-EFAULT) to indicate two
different error cases:
1. a bug in vfio-ccw implementation has been found.
2. a buggy channel program has been detected.

This brings difficulty for userland program (specifically Qemu) to
handle.

Let's use -EFAULT to only indicate the first case. For the second
case, we simply hand over the ccws to lower level for further
handling.

Notice:
Once a bad idaw address is detected, the current behavior is to
suppress the ssch. With this fix, the channel program will be
accepted, and part of the channel program (the part ahead of
the bad idaw) could possibly be executed by the device before
I/O conclusion.

Suggested-by: Halil Pasic <pasic@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Pierre Morel <pmorel@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Dong Jia Shi <bjsdjshi@xxxxxxxxxxxxxxxxxx>
Message-Id: <20171011023822.42948-2-bjsdjshi@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Cornelia Huck <cohuck@xxxxxxxxxx>
---
 drivers/s390/cio/vfio_ccw_cp.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/drivers/s390/cio/vfio_ccw_cp.c b/drivers/s390/cio/vfio_ccw_cp.c
index 5ccfdc80d0ec..722f8b8c7273 100644
--- a/drivers/s390/cio/vfio_ccw_cp.c
+++ b/drivers/s390/cio/vfio_ccw_cp.c
@@ -569,10 +569,6 @@ static int ccwchain_fetch_idal(struct ccwchain *chain,
 
 	for (i = 0; i < idaw_nr; i++) {
 		idaw_iova = *(idaws + i);
-		if (IS_ERR_VALUE(idaw_iova)) {
-			ret = -EFAULT;
-			goto out_free_idaws;
-		}
 
 		ret = pfn_array_alloc_pin(pat->pat_pa + i, cp->mdev,
 					  idaw_iova, 1);
-- 
2.13.6

--
To unsubscribe from this list: send the line "unsubscribe linux-s390" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html



[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Index of Archives]     [Kernel Development]     [Kernel Newbies]     [IDE]     [Security]     [Git]     [Netfilter]     [Bugtraq]     [Yosemite Info]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Linux ATA RAID]     [Samba]     [Linux Media]     [Device Mapper]

  Powered by Linux