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Subject: Re: [RFC] /dev/ioasid uAPI proposal
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From:   Paolo Bonzini <pbonzini@redhat.com>
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Date:   Mon, 7 Jun 2021 08:51:42 +0200
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On 07/06/21 05:25, Tian, Kevin wrote:
> Per Intel SDM wbinvd is a privileged instruction. A process on the
> host has no privilege to execute it.

(Half of) the point of the kernel is to do privileged tasks on the 
processes' behalf.  There are good reasons why a process that uses VFIO 
(without KVM) could want to use wbinvd, so VFIO lets them do it with a 
ioctl and adequate checks around the operation.

Paolo