On Tue, Jul 16, 2024 at 04:49:00PM -0700, Isaku Yamahata <isaku.yamahata@xxxxxxxxx> wrote: > > > - For non-TDX case (DEFAULT_VM, SW_PROTECTED_VM, or SEV): > > > When the host supports 5-level TDP, KVM decides to use 4-level TDP if > > > cpuid_maxphyaddr() <= 48. cpuid_maxhyaddr() check prevents > > > KVM_PRE_FAULT_MEMORY from passing GFN beyond mappable GFN. > > > > Hardening against cpuid_maxphyaddr() should be out of scope. We don't enforce > > it for guest faults, e.g. KVM doesn't kill the guest if allow_smaller_maxphyaddr > > is false and the GPA is supposed to be illegal. And trying to enforce it here is > > a fool's errand since userspace can simply do KVM_SET_CPUID2 to circumvent the > > restriction. > > Ok, I'll drop maxphys addr check. Now Rick added a patch to check aliased GFN. This patch and per-VM mmu_max_gfn become unnecessarily. Now I come up with update to pre_fault to test no memslot case. https://lore.kernel.org/kvm/20240718211230.1492011-19-rick.p.edgecombe@xxxxxxxxx/ For non-x86 case, I'm not sure if we can expect what error.
