Messages in this thread |  | | Date | Fri, 22 Nov 2019 10:46:35 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH v10 4/6] x86/split_lock: Enumerate split lock detection if the IA32_CORE_CAPABILITIES MSR is not supported |
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On Thu, Nov 21, 2019 at 06:13:18PM -0800, Andy Lutomirski wrote:
> You seem to be assuming that certain model CPUs have this feature even > if not enumerated. You need to make sure you don’t try to use it in a > VM without the hypervisor giving you an indication that it’s available > and permitted. My suggestion is to disable model-based enumeration if > HYPERVISOR is set. You should also consider probing the MSR to double > check even if you don’t think you have a hypervisor.
Yep, in patch 6 this results in an unconditinoal WRMSR, which, when ran under a HV, will explode most mighty.
He doesn't double check, doesn't use wrmsrl_safe()...
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