tree 23c82057ddea6d47e74b3db6619e6098b81651b2
parent b90c062c65cc8839edfac39778a37a55ca9bda36
author Jan Kiszka <jan.kiszka@siemens.com> 1249317808 +0200
committer Avi Kivity <avi@redhat.com> 1252560800 +0300

KVM: x86: Disallow hypercalls for guest callers in rings > 0

So far unprivileged guest callers running in ring 3 can issue, e.g., MMU
hypercalls. Normally, such callers cannot provide any hand-crafted MMU
command structure as it has to be passed by its physical address, but
they can still crash the guest kernel by passing random addresses.

To close the hole, this patch considers hypercalls valid only if issued
from guest ring 0. This may still be relaxed on a per-hypercall base in
the future once required.

Cc: stable@kernel.org
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>