KVM: s390: vsie: Fix delivery of addressing exceptions

Whenever we get an -EFAULT, we failed to read in guest 2 physical
address space. Such addressing exceptions are reported via a program
intercept to the nested hypervisor.

We faked the intercept, we have to return to guest 2. Instead, right
now we would be returning -EFAULT from the intercept handler, eventually
crashing the VM.
the correct thing to do is to return 1 as rc == 1 is the internal
representation of "we have to go back into g2".

Addressing exceptions can only happen if the g2->g3 page tables
reference invalid g2 addresses (say, either a table or the final page is
not accessible - so something that basically never happens in sane
environments.

Identified by manual code inspection.

Fixes: a3508fbe9dc6 ("KVM: s390: vsie: initial support for nested virtualization")
Cc: <[email protected]> # v4.8+
Signed-off-by: David Hildenbrand <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: Claudio Imbrenda <[email protected]>
Reviewed-by: Christian Borntraeger <[email protected]>
[[email protected]: fix patch description]
Signed-off-by: Christian Borntraeger <[email protected]>

0 files changed, 0 insertions, 0 deletions