Re: [Qemu-devel] Recording I/O activity after KVM does a VMEXIT

[Stefan Hajnoczi <stefanha@gmail.com>]

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On Wed, May 30, 2018 at 11:19:13PM -0400, Arnabjyoti Kalita wrote:
> I am trying to implement a 'minimal' record-replay mechanism for KVM, which
> is similar to the one existing for TCG via -icount. I am trying to record
> I/O events only (specifically disk and network events) when KVM does a
> VMEXIT. This has led me to the function kvm_cpu_exec where I can clearly
> see the different ways of handling all of the possible VMExit cases (like
> PIO, MMIO etc.). To record network packets, I am working with the e1000
> hardware device.
> 
> Can I make sure that all of the network I/O, atleast for the e1000 device
> happens through the KVM_EXIT_MMIO case and subsequent use of the
> address_space_rw() function ? Do I also need to look at other functions as
> well ? Also for recording disk activity, can I make sure that looking out
> for the KVM_EXIT_MMIO and/or KVM_EXIT_PIO cases in the vmexit mechanism,
> will be enough ?
> 
> Let me know if there are other details that I need to take care of. I am
> using QEMU 2.11 on a x86-64 CPU and the guest runs a Linux Kernel 4.4 with
> Ubuntu 16.04.

I have CCed Pavel Dovgalyuk, the record/replay maintainer.

Stefan

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