Re: QEMU Clock record and replay

[Lukas Straub]

On Thu, 25 Feb 2021 20:39:20 +0530
Arnabjyoti Kalita <akalita@cs.stonybrook.edu> wrote:

> Hello all,
>
> [...]
> 
> - Let's say we record the clock values when the guest starts in KVM mode,
> and we replay the clock values when the guest starts in TCG mode. Does the
> record-replay functionality change a lot?

Record-replay only works in TCG mode, as one needs to intercept rdtsc/wrtsc
instructions (among others) and KVM doesn't support that.

Regards,
Lukas Straub

> - Also, I couldn't understand the specific purpose of replaying the
> 'virtual real time clock' ? Do I still need to record and replay the
> 'virtual real time clock' if we record the clock values in KVM mode, and
> replay the clock values in TCG mode?
> 
> Thank you very much.
> 
> Best Regards,
> Arnab



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