In a KVM-only scenario that does not support nested KVM, a well written guest would never try to call nested KVM hypercalls. However, if a buggy or malicious guest calls the nested KVM API even without nested KVM support, the L0 would redirect the hypercalls into QEMU. Previously this would have caused an H_FUNCTION return for every call, but now that QEMU knows about the nested KVM API, it tries to service the calls. This is incorrect because the spapr virtual hypervisor implementation of the nested KVM API depends on the first level guest to be emulated by TCG.
So add guards against that and move the whole code under CONFIG_TCG. Fabiano Rosas (3): spapr: Ignore nested KVM hypercalls when not running TCG spapr: Move hypercall_register_softmmu spapr: Move nested KVM hypercalls under a TCG only config. hw/ppc/spapr_hcall.c | 76 ++++++++++++++++++++++++++------------------ 1 file changed, 45 insertions(+), 31 deletions(-) -- 2.34.1
