Re: [RFC PATCH kvm-unit-tests 0/4] add generic stress test

[Sean Christopherson <seanjc@google.com>]

On Wed, Dec 23, 2020, Paolo Bonzini wrote:
> This short series adds a generic stress test to KVM unit tests that runs a
> series of

Unintentional cliffhanger?

> The test could grow a lot more features, including:
> 
> - wrapping the stress test with a VMX or SVM veneer which would forward
>   or inject interrupts periodically
> 
> - test perf events
> 
> - do some work in the MSI handler, so that they have a chance
>   of overlapping
> 
> - use PV EOI
> 
> - play with TPR and self IPIs, similar to Windows DPCs.
> 
> The configuration of the test is set individually for each VCPU on
> the command line, for example:
> 
>    ./x86/run x86/chaos.flat -smp 2 \
>       -append 'invtlb=1,mem=12,hz=100  hz=250,edu=1,edu_hz=53,hlt' -device edu
> 
> runs a continuous INVLPG+write test on 1<<12 pages on CPU 0, interrupted
> by a 100 Hz timer tick; and keeps CPU 1 mostly idle except for 250 timer
> ticks and 53 edu device interrupts per second.

Maybe take the target cpu as part of the command line instead of implicitly
defining it via group position?  The "duplicate" hz=??? is confusing.  E.g.

    ./x86/run x86/chaos.flat -smp 2 \
      -append 'cpu=0,invtlb=1,mem=12,hz=100 cpu=1,hz=250,edu=1,edu_hz=53,hlt' -device edu

> For now, the test runs for an infinite time so it's not included in
> unittests.cfg.  Do you think this is worth including in kvm-unit-tests,

What's the motivation for this type of test?  What class of bugs can it find
that won't be found by existing kvm-unit-tests or simple boot tests?

> and if so are you interested in non-x86 versions of it?  Or should the
> code be as pluggable as possible to make it easier to port it?