Messages in this thread | | | Subject | Re: [PATCH v2 2/3] KVM: nVMX: add kvm_nested_vmlaunch_resume tracepoint | From | Paolo Bonzini <> | Date | Fri, 15 Jan 2021 14:48:38 +0100 |
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On 15/01/21 01:14, Sean Christopherson wrote: >> + trace_kvm_nested_vmlaunch_resume(kvm_rip_read(vcpu), > Hmm, won't this RIP be wrong for the migration case? I.e. it'll be L2, not L1 > as is the case for the "true" nested VM-Enter path.
It will be the previous RIP---might as well be 0xfffffff0 depending on what userspace does. I don't think you can do much better than that, using vmcs12->host_rip would be confusing in the SMM case.
>> + vmx->nested.current_vmptr, >> + vmcs12->guest_rip, >> + vmcs12->vm_entry_intr_info_field); > The placement is a bit funky. I assume you put it here so that calls from > vmx_set_nested_state() also get traced. But, that also means > vmx_pre_leave_smm() will get traced, and it also creates some weirdness where > some nested VM-Enters that VM-Fail will get traced, but others will not. > > Tracing vmx_pre_leave_smm() isn't necessarily bad, but it could be confusing, > especially if the debugger looks up the RIP and sees RSM. Ditto for the > migration case.
Actually tracing vmx_pre_leave_smm() is good, and pointing to RSM makes sense so I'm not worried about that.
Paolo
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