Re: HPET and IRQs


Yan, Like
 

I thought we have a document talking about the VM type definitions and constraints.
Let me check first, we will add one if it's not there.

-----Original Message-----
From: acrn-users@... <acrn-users@...> On
Behalf Of Geoffroy Van Cutsem
Sent: Thursday, April 30, 2020 4:36 PM
To: acrn-users@...
Subject: Re: [acrn-users] HPET and IRQs



-----Original Message-----
From: acrn-users@...
<acrn-users@...>
On Behalf Of Yan, Like
Sent: Wednesday, April 29, 2020 5:24 PM
To: acrn-users@...
Subject: Re: [acrn-users] HPET and IRQs

Hi Tomasz,

If you launched VM with --lapic_pt, then it's a RT VM.
An RT VM is only allowed to be powered-off/reset when initiated inside
the RT VM. The design principle here is that the other VMs (even the
SOS VM) should not interfere RT VM to guarantee the RT performance.
And there are some limitations as to RT VM, legacy devices are not
supported, such as vHPET.
Here are 2 documents for RT VM:
https://projectacrn.github.io/latest/tutorials/rtvm_workload_design_gu
ideli
ne.html
https://projectacrn.github.io/latest/tutorials/rtvm_performance_tips.h
tml
Thanks for the information Like. I was suspecting this but couldn't find a
good reference about this in our documentation. The couple of documents
you referenced above provide some good background information and
useful tips on how to run RTVMs on ACRN. It does not really talk about what
this limitation for example. It would be great to have some High-Level Design
Guide that talk more extensively about the different types of User VMs: i.e.
pre-launched, post-launched and RTVM vs. "normal" User VMs.

Is this something we can plan to add?

Thanks,
Geoffroy



Thanks,
Like

-----Original Message-----
From: acrn-users@...
<acrn-users@...> On Behalf Of Tomasz Bursztyka
Sent: Wednesday, April 29, 2020 2:37 PM
To: acrn-users@...
Subject: Re: [acrn-users] HPET and IRQs

Hi Like,

VM or RT VM, I don't know. It did not occur to me there was an
actual difference, I just used the launcher script for zephyr. I'll check.

I could get LAPIC (which we indeed call LOAPIC) to work using --
lapic_pt option to acrn-dm. But then I am unable to
stop/reset/delete the VM for some reason (even with --force on stop, it
always returns -1).

I'll still investigate about HPET. It "should" work, and if Zephyr
is missing some support - runtime calibration that is - then it will
be worth
adding it.

Thanks for the inputs,

Tomasz





Join acrn-users@lists.projectacrn.org to automatically receive all group messages.