On 18/05/20 18:01, Peter Maydell wrote: > The "right" answer is that the kernel should enhance the KVM_EXIT_MMIO > API to allow userspace to say "sorry, you got a bus error on that > memory access the guest just tried" (which the kernel then has to > turn into an appropriate guest exception, or ignore, depending on > what the architecture requires.) You don't want to set ret to > non-zero here, because that will cause us to VM_STOP, and I > suspect that x86 at least is relying on the implict RAZ/WI > behaviour it currently gets. Yes, it is. It may even be already possible to inject the right exception (on ARM) through KVM_SET_VCPU_EVENTS or something like that, too. Paolo
