Messages in this thread | | | Date | Fri, 16 Oct 2015 08:54:40 +0800 | From | Jian Zhou <> | Subject | Re: [PATCH] KVM: VMX: enable LBR virtualization |
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>>> 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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