KVM: s390: Fixes and features for 4.11 (via kvm/next)
- enable some simd extensions for guests
- enable nx for guests
- debug log for cpu model
- PER fixes
- remove bitwise annotation from ar_t
- detect guests in operation exception program check loops
- fix potential null-pointer dereference for ucontrol guests
- also contains merge for fix that went into 4.10 to avoid conflicts
KVM: s390: detect some program check loops
Sometimes (e.g. early boot) a guest is broken in such ways that it loops
100% delivering operation exceptions (illegal operation) but the pgm new
PSW is not set properly. This will result in code being read from
address zero, which usually contains another illegal op. Let's detect
this case and return to userspace. Instead of only detecting
this for address zero apply a heuristic that will work for any program
check new psw.
We do not want guest problem state to be able to trigger a guest panic,
e.g. by faulting on an address that is the same as the program check
new PSW, so we check for the problem state bit being off.
With proper handling in userspace we
a: get rid of CPU consumption of such broken guests
b: keep the program old PSW. This allows to find out the original illegal
operation - making debugging such early boot issues much easier than
with single stepping
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
1 file changed
