On Mon, Oct 07, 2013 at 06:29:30PM +0530, Kashyap Chamarthy wrote:
> Gleb, so I just did a trace of KVM MMU to try to understand why L2 is
> stuck with shadow on EPT
>
> Ensure, EPT is enabled on L0 & disabled on L1
>
> On L0:
> ---------
> $ cat /sys/module/kvm_intel/parameters/ept
> Y
>
> On L1
> ---------
> $ cat /sys/module/kvm_intel/parameters/ept
> N
>
> Build and install trace-cmd on L1:
>
> $ git clone
> git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/trace-cmd.git
> trace-cmd
> $ make && sudo make-install
>
> Run trace command (on L1) to capture kvmmmu event:
>
> $ trace-cmd record -b 2000 -e kvmmmu
You need to trace kvm events too and make buffer bigger
trace-cmd record -b 100000 -e kvmmmu -e kvm.
> /sys/kernel/debug/tracing/events/kvmmmu/filter
> /sys/kernel/debug/tracing/events/*/kvmmmu/filter
> Hit Ctrl^C to stop recording
>
> Boot L2 guest:
>
> $ virsh start nguest-01 --console
>
> After a minute or two, ctl-C the trace-cmd, generate the report:
>
> $ trace-cmd report
> version = 6
> trace-cmd: No such file or directory
> function is_writable_pte not defined
> CPU 1 is empty
> CPU 2 is empty
> CPU 3 is empty
> cpus=4
> qemu-system-x86-2554 [000] 90667.995345:
> kvm_mmu_invalidate_zap_all_pages: kvm-mmu-valid-gen 0 used_pages 0
> qemu-system-x86-2557 [000] 90668.078978: kvm_mmu_get_page: new
> sp gfn 0 0/2 q0 direct --- !pge !nxe root 0 sync
> qemu-system-x86-2557 [000] 90668.078980: kvm_mmu_get_page: new
> sp gfn 40000 0/2 q0 direct --- !pge !nxe root 0 sync
> qemu-system-x86-2557 [000] 90668.078980: kvm_mmu_get_page: new
> sp gfn 80000 0/2 q0 direct --- !pge !nxe root 0 sync
> qemu-system-x86-2557 [000] 90668.078981: kvm_mmu_get_page: new
> sp gfn c0000 0/2 q0 direct --- !pge !nxe root 0 sync
> qemu-system-x86-2557 [000] 90668.079025: kvm_mmu_get_page: new
> sp gfn 0 0/1 q0 direct --- !pge !nxe root 0 sync
Is this all?
>
> Side question: I wonder why would trace-cmd say "trace-cmd: No such
> file or directory"?
>
Ignore it.
--
Gleb.
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