Re: [PATCH v3 0/8] KVM: VMX: Harden against interpreting TDX vCPU as vcpu_vmx

From: Sean Christopherson

Date: Mon Sep 21 2026 - 12:56:30 EST


On Mon, Sep 21, 2026, Sean Christopherson wrote:
> On Thu, 03 Sep 2026 18:03:45 -0700, Sean Christopherson wrote:
> > Move and rename "all" (read: everything I could find) common helpers out of
> > vmx.c and/or replace their vmx_ prefix with vt_, and then poison to_vmx() for
> > all common .c files to harden KVM against misinterpreting a TDX vCPU as a VMX
> > vCPU, i.e. consuming to_vmx() on a TDX vCPU. Spotted when working through
> > the bus lock series.
> >
> > v3:
> > - Collect tags. [Kai, Xiaoyao, Binbin]
> > - Move the poisoning to patch 1. [Xiaoyao]
> > - s/Disallowing/Disallow. [Binbin, Kai]
> > - s/vmx_needs_pi_wakeup/vt_needs_pi_wakeup. [Xiaoyao]
> >
> > [...]
>
> Applied to kvm-x86 vmx, thanks!
>
> [1/8] KVM: VMX: Disallow using to_vmx() in common VT code
> https://github.com/kvm-x86/linux/commit/05a0c1e2a525
> [2/8] KVM: VMX: Move the shared "IRQs off" exit handler(s) to common code
> https://github.com/kvm-x86/linux/commit/903420c26086
> [3/8] KVM: VMX: Move the shared NMI handler/trampoline to common code
> https://github.com/kvm-x86/linux/commit/81fbafddf6e5
> [4/8] KVM: VMX: Rename posted interrupt prefixes from "vmx" to "vt"
> https://github.com/kvm-x86/linux/commit/09c6f74ecb86
> [5/8] KVM: VMX: Rename EPT violation handler prefix from "vmx" to "vt"
> https://github.com/kvm-x86/linux/commit/96a113536fa0
> [6/8] KVM: VMX: Use dummy pseudo-overlay struct for to_vt() and vt_to_vcpu()
> https://github.com/kvm-x86/linux/commit/881455777a02
> [7/8] KVM: VMX: Move common VT getters/converters to common.h
> https://github.com/kvm-x86/linux/commit/d238df58b1e1
> [8/8] KVM: VMX: Rename common exit info getters prefixes from "vmx" to "vt"
> https://github.com/kvm-x86/linux/commit/decbd448b05e

FYI, I'm going to rebase these on top of the TDX bus-lock series[*], i.e. these
hashes are going to change. I forgot that series needs to got to stable@.

[*] https://lore.kernel.org/all/20260819094903.3060020-1-xiaoyao.li@xxxxxxxxx