From: Joerg Roedel <[email protected]> This patch prevents that emulation failures which result from emulating an instruction for an L2-Guest results in being reported to userspace. Without this patch a malicious L2-Guest would be able to kill the L1 by triggering a race-condition between an vmexit and the instruction emulator. With this patch the L2 will most likely only kill itself in this situation.
Signed-off-by: Joerg Roedel <[email protected]> Signed-off-by: Marcelo Tosatti <[email protected]> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 495db8e..ed373ba 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4319,13 +4319,19 @@ EXPORT_SYMBOL_GPL(kvm_inject_realmode_interrupt); static int handle_emulation_failure(struct kvm_vcpu *vcpu) { + int r = EMULATE_DONE; + ++vcpu->stat.insn_emulation_fail; trace_kvm_emulate_insn_failed(vcpu); - vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR; - vcpu->run->internal.suberror = KVM_INTERNAL_ERROR_EMULATION; - vcpu->run->internal.ndata = 0; + if (!is_guest_mode(vcpu)) { + vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR; + vcpu->run->internal.suberror = KVM_INTERNAL_ERROR_EMULATION; + vcpu->run->internal.ndata = 0; + r = EMULATE_FAIL; + } kvm_queue_exception(vcpu, UD_VECTOR); - return EMULATE_FAIL; + + return r; } static bool reexecute_instruction(struct kvm_vcpu *vcpu, gva_t gva) -- To unsubscribe from this list: send the line "unsubscribe kvm-commits" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
