From: Alex Turner <alex@turntrout.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
nsaenz@amazon.com, vkuznets@redhat.com,
snambakam@linux.microsoft.com
Subject: Re: [PATCH v3 00/28] KVM: x86: Introduce memory protection attributes
Date: Mon, 12 Oct 2026 00:31:21 +0000 [thread overview]
Message-ID: <20261012003036.61996-1-alex@turntrout.com> (raw)
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.
next reply other threads:[~2026-10-12 0:31 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-12 0:31 Alex Turner [this message]
-- strict thread matches above, loose matches on Subject: below --
2026-09-18 13:49 Paolo Bonzini
2026-09-18 15:20 ` Paolo Bonzini
2026-09-21 16:56 ` Vitaly Kuznetsov
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