On Fri, 2024-05-17 at 10:23 +1200, Huang, Kai wrote: > On 17/05/2024 9:46 am, Edgecombe, Rick P wrote: > > On Tue, 2024-05-14 at 17:59 -0700, Rick Edgecombe wrote: > > > > > > For lack of a better method currently, use kvm_gfn_shared_mask() to > > > determine if private memory cannot be zapped (as in TDX, the only VM type > > > that sets it). > > > > Trying to replace kvm_gfn_shared_mask() with something appropriate, I saw > > that > > SNP actually uses this function: > > https://lore.kernel.org/kvm/20240501085210.2213060-12-michael.roth@xxxxxxx/ > > > > So trying to have a helper that says "The VM can't zap and refault in memory > > at > > will" won't cut it. I guess there would have to be some more specific. I'm > > thinking to just drop this patch instead. > > Or KVM_BUG_ON() in the callers by explicitly checking VM type being TDX > as I mentioned before. > > Having such checking in a generic function like this is just dangerous > and not flexible. > > Just my 2 cents, though. As I said before, the point is to catch new callers. I see how it's a little wrong to assume the intentions of the callers, but I don't see how it's dangerous. Can you explain? But you just reminded me that, yes, we can probably just check the vm_type here: https://lore.kernel.org/kvm/f64c7da52a849cd9697b944769c200dfa3ee7db7.camel@xxxxxxxxx/
