On Wed, Aug 9, 2023 at 10:56 AM Yang, Weijiang <weijiang.yang@xxxxxxxxx> wrote: > > I'm pretty sure I've advocated for the exact opposite in the past, i.e. argued > > that KVM's ABI is to not enforce ordering between KVM_SET_CPUID2 and KVM_SET_MSR. > > But this is becoming untenable, juggling the dependencies in KVM is complex and > > is going to result in a nasty bug at some point. > > > > For this series, lets just tighten the rules for XSS, i.e. drop the host_initated > > exemption. And in a parallel/separate series, try to do a wholesale cleanup of > > all the cases that essentially allow userspace to do KVM_SET_MSR before KVM_SET_CPUID2. > OK, will do it for this series and investigate for other MSRs. > Thanks! Remember that, while the ordering between KVM_SET_CPUID2 and KVM_SET_MSR must be enforced(*), the host_initiated path must allow the default (generally 0) value. Paolo (*) this means that you should check guest_cpuid_has even if host_initiated == true.
