Re: [Qemu-ppc] [Qemu-devel] [PATCH 72/77] ppc: A couple more dummy POWER8 Book4 regs

[Thomas Huth]

On 10.03.2016 23:27, Cédric Le Goater wrote:
> On 03/10/2016 07:01 PM, Thomas Huth wrote:
>> On 09.03.2016 22:17, Thomas Huth wrote:
>>> On 09.03.2016 21:04, Cédric Le Goater wrote:
>> ....
>>>> I have been maintaining a port of Ben's patchset on the latest qemu for 
>>>> other 
>>>> parts which should come after pnv is merged so I have a framework to test 
>>>> such 
>>>> sub-patchsets. I also have time to work on them but clearly not the 
>>>> expertise
>>>> in all areas !
>>>
>>> That would be great if you could take care of this!
>>>
>>>> What would be nice is to identify the most obvious ones, non controversial
>>>> that could be merged after a few iterations. I have a vague idea, the ones 
>>>> Reviewed-by David obviously being good candidates, the definition of new 
>>>> SPRs 
>>>> (even the dummy ones ?).
>>>
>>> I really like to see the KVM SPRs patches first - since they are fixing
>>> potential problems with migration of the _current_ KVM machines already!
>>> And being bug fixes, maybe these patches could even be included for QEMU
>>> 2.6 already? (i.e. before the hard freeze at the end of March)
>>>
>>> So my wish-list for a first small patch series looks like this:
>>>
>>> 5b287e66c7513209  ppc: Add macros to register hypervisor mode SPRs
>>> 34f1af75e75e7ba0  ppc: Add dummy CIABR SPR
>>> 48adf38e9cab4663  ppc: A couple more dummy POWER8 Book4 regs
>>> 730a9b4dc9414818  ppc: Add KVM numbers to some P8 SPRs
>>>
>>> There are a couple of other patches touching the SPRs initialization,
>>> but they are not important with regards to migration... so not sure
>>> whether it makes sense to include them now already...
>>
>> FWIW, I just saw today (by doing some more experiments with
>> kvm-unit-tests) that the IAMR register is also not migrated yet ... so
>> it would be nice if you could include the related patches for IAMR, too,
>> and wire the KVM part up with KVM_REG_PPC_IAMR...
> 
> OK. So we should be targeting something like :
> 
>       ppc: Update SPR definitions
>       ppc: Add macros to register hypervisor mode SPRs
>       ppc: Add a bunch of hypervisor SPRs to Book3s
> 
>       ppc: LPCR is a HV resource
>       ppc: SPURR & PURR are HV writeable and privileged
>       ppc: Add dummy SPR_IC for POWER8
>       ppc: Initialize AMOR in PAPR mode
>       ppc: Fix writing to AMR/UAMOR
>       ppc: Add POWER8 IAMR register
>       ppc: Add a few more P8 PMU SPRs
>       ppc: Add dummy write to VTB
>       ppc: Add dummy POWER8 MPPR register
>       ppc: Add dummy POWER8 PSPB SPR
>       ppc: Add dummy CIABR SPR
>       ppc: Add dummy ACOP SPR
>       ppc: A couple more dummy POWER8 Book4 regs
>       ppc: Add KVM numbers to some P8 SPRs

Sounds good - but you likely can drop the "Add a few more P8 PMU SPRs"
from your list since it has already been queued by David already (see
https://github.com/dgibson/qemu/commits/ppc-for-2.6), and the PSPB patch
is also not required anymore since I submitted a similar patch to David
already when I discovered that it is lost during migration.

> Also, there seem to be an issue with qemu's HEAD on ppc64el with the
> random device :
> 
>       -object rng-random,filename=/dev/urandom,id=gid0 -device 
> spapr-rng,rng=gid0
> 
> qemu "hangs". This is a vague description for a symptom ... Does that ring
> a bell or do I need to dig in to get more info ? 

Works for me™ ... could you supply more information? Where does it hang?
Which exact level of QEMU are you using? ... and please open a new mail
thread for this, since it's off-topic to this mail thread.

 Thomas