]> git.baikalelectronics.ru Git - kernel.git/commit
KVM: s390: vsie: Fix delivery of addressing exceptions
authorDavid Hildenbrand <david@redhat.com>
Fri, 3 Apr 2020 15:30:47 +0000 (17:30 +0200)
committerChristian Borntraeger <borntraeger@de.ibm.com>
Tue, 7 Apr 2020 11:12:34 +0000 (13:12 +0200)
commit4d4cee96fb7a3cc53702a9be8299bf525be4ee98
tree0b08caaf0900541290acc03a4655ecbb84065d90
parenta1d032a49522cb5368e5dfb945a85899b4c74f65
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: <stable@vger.kernel.org> # v4.8+
Signed-off-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/20200403153050.20569-3-david@redhat.com
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
[borntraeger@de.ibm.com: fix patch description]
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
arch/s390/kvm/vsie.c