On 11/09/20 18:04, Sean Christopherson wrote: > This doesn't actually verify that @data == 0. kvm_pv_async_pf_enabled() > returns true iff KVM_ASYNC_PF_ENABLED and KVM_ASYNC_PF_DELIVERY_AS_INT are > set, e.g. this would allow setting one and not the other. This also allows > userspace to set vcpu->arch.apf.msr_en_val to an unsupported value, i.e. > @data has already been propagated to the vcpu and isn't unwound. > > Why not just pivot on @data when lapic_in_kernel() is false? vcpu->arch.apic > is immutable so there's no need to update apf.msr_en_val in either direction. > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index 539ea1cd6020..36969d5ec291 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -2735,7 +2735,7 @@ static int kvm_pv_enable_async_pf(struct kvm_vcpu *vcpu, u64 data) > return 1; > > if (!lapic_in_kernel(vcpu)) > - return 1; > + return data ? 1 : 0; > > vcpu->arch.apf.msr_en_val = data; > > >> + return 1; >> + >> if (kvm_gfn_to_hva_cache_init(vcpu->kvm, &vcpu->arch.apf.data, gpa, >> sizeof(u64))) >> return 1; >> -- >> 2.25.4 >> > Committed this instead, though. Paolo
