Messages in this thread | | | Date | Fri, 30 Jun 2023 08:15:24 -0700 | Subject | Re: [PATCH v3 10/21] KVM:x86: Add #CP support in guest exception classification | From | Sean Christopherson <> |
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On Fri, Jun 30, 2023, Gil Neiger wrote: > Intel will not produce any CPU with CET that does not enumerate IA32_VMX_BASIC[56] as 1. > > One can check that bit before injecting a #CP with error code, but it should > not be necessary if CET is enumerated. > > Of course, if the KVM may run as a guest of another VMM/hypervisor, it may be > that the virtual CPU in which KVM operates may enumerate CET but clear the > bit in IA32_VMX_BASIC.
Yeah, I think KVM should be paranoid and expose CET to the guest if and only if IA32_VMX_BASIC[56] is 1. That'll also help validate nested support, e.g. will make it more obvious if userspace+KVM provides a "bad" model to L1.
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