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    SubjectRe: [PATCH] KVM: VMX: enable LBR virtualization
    >>> Does it depend on vPMU _for Linux guests_ or in general?  My impression
    >>> is that LBR can be used by the guest independent of the PMU.
    >>
    >> I think only for Linux guests.
    >>
    >> I googled how to enable LBR on other guests(except Linux guests),
    >> e.g. Windows, and got no developer manuals about it.
    >>
    >> Here is an article about it:
    >> http://www.codeproject.com/Articles/517466/Last-branch-records-
    >> and-branch-tracing
    >> it says:
    >> "bit 8 of DR7 represents bit 0 of DebugCtl. This is the LBR bit."
    >
    > Don't worry about the operating system in the guest: you are just
    > emulating a processor feature, you do not care about anything except
    > what is written in the Intel SDM.
    >
    > You can use kvm-unit-tests
    > (https://git.kernel.org/cgit/virt/kvm/kvm-unit-tests.git/) to write a
    > test for your feature. There are existing tests for debugging features.

    ok.

    Regards,

    Jian

    >
    >
    >



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