s390x/css: handle format-0 TIC CCW correctly

For TIC CCW, bit positions 8-32 of the format-1 CCW must contain zeros;
otherwise, a program-check condition is generated. For format-0 TIC CCWs,
bits 32-63 are ignored.

To convert TIC from format-0 CCW to format-1 CCW correctly, let's clear
bits 8-32 to guarantee compatibility.

Reviewed-by: Pierre Morel <pmorel@linux.vnet.ibm.com>
Signed-off-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>

1 files changed, 9 insertions, 6 deletions

diff --git a/hw/s390x/css.c b/hw/s390x/css.c
index 0f2580d644..e32b2a4d42 100644
--- a/hw/s390x/css.c
+++ b/hw/s390x/css.c
@@ -368,13 +368,16 @@ static CCW1 copy_ccw_from_guest(hwaddr addr, bool fmt1)
         ret.cda = be32_to_cpu(tmp1.cda);
     } else {
         cpu_physical_memory_read(addr, &tmp0, sizeof(tmp0));
-        ret.cmd_code = tmp0.cmd_code;
-        ret.flags = tmp0.flags;
-        ret.count = be16_to_cpu(tmp0.count);
-        ret.cda = be16_to_cpu(tmp0.cda1) | (tmp0.cda0 << 16);
-        if ((ret.cmd_code & 0x0f) == CCW_CMD_TIC) {
-            ret.cmd_code &= 0x0f;
+        if ((tmp0.cmd_code & 0x0f) == CCW_CMD_TIC) {
+            ret.cmd_code = CCW_CMD_TIC;
+            ret.flags = 0;
+            ret.count = 0;
+        } else {
+            ret.cmd_code = tmp0.cmd_code;
+            ret.flags = tmp0.flags;
+            ret.count = be16_to_cpu(tmp0.count);
         }
+        ret.cda = be16_to_cpu(tmp0.cda1) | (tmp0.cda0 << 16);
     }
     return ret;
 }