On Mon, 2026-09-14 at 15:04 +0800, Binbin Wu wrote: > > Note, an equivalent TDX side implementation is missing. No TDX module > > with FRED support exists yet so this would be an issue for future > > platforms. A generic discussion regarding this is ongoing at: > > https://lore.kernel.org/kvm/[email protected]/ > > For old KVM versions, we want to defer the opt-in design or backport decision. > ( > https://lore.kernel.org/kvm/[email protected] > m/) > > We may finally choose to backport the TDX CPUID filtering patch series to > stable kernels. If this patch series lands first, should we add FRED in the > deny list for TDX as a temporary solution to avoid having some version(s) that > allow FRED for TDX without FRED support in KVM?
The specific FRED problem starts with FRED host usage + TDX, so I don't think there is a reason to tie and temporary fixups to VMX FRED support, in any case. Or were you thinking to blame userspace for not respecting KVM_GET_SUPPORTED_CPUID, which would change after this series? Since there are plenty of released kernels with FRED host support already, I'd think to wait until we settle the opt-in question. Which doesn't seem like it should be too much longer. It will be less thrash.
