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34 lines
1.7 KiB
34 lines
1.7 KiB
7 months ago
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Demonstrations of kvm_hypercall.py, showing eBPF/bcc based hypercall analysis
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This example demonstrates how we can statefully save static tracepoint
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events based on conditions being met for other events with which they are
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associated. Here, we wish to record kvm_exit and kvm_entry events which are
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linked to the kvm_hypercall event. We are interested in kvm_exit with exit
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reason as VMCALL (18). This may be useful to analyze latency caused by a
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hypercall itself.
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To test this, while the python script is run, induce a hypercall from a
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guest based on the following example:
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https://gist.github.com/abenbachir/344822b5ba9fc5ac384cdec3f087e018
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# ./kvm_hypercall.py
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TIME(s) COMM PID MESSAGE
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2445.577087000 CPU 0/KVM 8896 KVM_EXIT exit_reason : 18
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2445.577122000 CPU 0/KVM 8896 HYPERCALL nr : 0
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2445.577129000 CPU 0/KVM 8896 KVM_ENTRY vcpu_id : 0
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2445.577136000 CPU 0/KVM 8896 KVM_EXIT exit_reason : 18
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2445.577145000 CPU 0/KVM 8896 HYPERCALL nr : 1
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2445.577149000 CPU 0/KVM 8896 KVM_ENTRY vcpu_id : 0
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2445.577155000 CPU 0/KVM 8896 KVM_EXIT exit_reason : 18
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2445.577160000 CPU 0/KVM 8896 HYPERCALL nr : 2
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2445.577164000 CPU 0/KVM 8896 KVM_ENTRY vcpu_id : 0
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2445.577170000 CPU 0/KVM 8896 KVM_EXIT exit_reason : 18
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2445.577175000 CPU 0/KVM 8896 HYPERCALL nr : 3
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2445.577179000 CPU 0/KVM 8896 KVM_ENTRY vcpu_id : 0
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2445.577185000 CPU 0/KVM 8896 KVM_EXIT exit_reason : 18
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2445.577190000 CPU 0/KVM 8896 HYPERCALL nr : 4
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2445.577194000 CPU 0/KVM 8896 KVM_ENTRY vcpu_id : 0
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This output shows a sequence of exit -> hypercall -> entry where the
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exit_reason was VMCALL.
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