Re: [PATCH v3 00/28] KVM: x86: Introduce memory protection attributes

[Alex Turner]

A second user, with no guest cooperation: we run untrusted AI coding
agents in Cloud Hypervisor microVMs, and the host builds the guest
kernel. We would set NW on its text after boot, so that a ring-0 write
exits to the VMM as tamper evidence.

Two questions:
1. Does NX distinguish supervisor from user execution? Without that,
   ring 0 can copy its text to an unprotected GFN and repoint its page
   tables. Is MBEC/GMET-backed NX planned, or should the VMM
   write-protect guest page tables?
2. For the emulator EFAULT gap you noted in patch 26: will a write the
   emulator performs on an NW gfn always exit?

We can test the series from Cloud Hypervisor if that helps.