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    SubjectRe: [RFC] /dev/ioasid uAPI proposal
    On Mon, Jun 07, 2021 at 08:51:42AM +0200, Paolo Bonzini wrote:
    > 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.

    Yes, exactly.

    You cannot write a correct VFIO application for hardware that uses the
    no-snoop bit without access to wbinvd.

    KVM or not does not matter.

    Jason

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