tree 2d453cdd9c9f6e83caf404c2982701fb1a91c994
parent 0096369daa9eaaef1a309e5d8167b023af3f998d
author Christian Borntraeger <borntraeger@de.ibm.com> 1216993914 +0200
committer Avi Kivity <avi@qumranet.com> 1217147765 +0300

KVM: s390: Fix program check on interrupt delivery handling

The current interrupt handling on s390 misbehaves on an error case. On s390
each cpu has the prefix area (lowcore) for interrupt delivery. This memory
must always be available. If we fail to access the prefix area for a guest
on interrupt delivery the configuration is completely unusable. There is no
point in sending another program interrupt to an inaccessible lowcore.
Furthermore, we should not bug the host kernel, because this can be triggered
by userspace. I think the guest kernel itself can not trigger the problem, as
SET PREFIX and SIGNAL PROCESSOR SET PREFIX both check that the memory is
available and sane. As this is a userspace bug (e.g. setting the wrong guest
offset, unmapping guest memory) we should kill the userspace process instead
of BUGing the host kernel.
In the long term we probably should notify the userspace process about this
problem.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>