Re: [Qemu-devel] [PULL 57/60] target/ppc: add HV support for POWER9

[David Gibson <david@gibson.dropbear.id.au>]

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On Fri, Jun 28, 2019 at 03:20:32PM +0200, Philippe Mathieu-Daudé wrote:
> Hi,
> 
> On 3/12/19 8:58 PM, Cédric Le Goater wrote:
> > On 3/12/19 8:30 PM, Cleber Rosa wrote:
> >>> From: "Cleber Rosa" <crosa@redhat.com>
> >>> Sent: Tuesday, March 12, 2019 3:14:09 PM
> >>> Subject: Re: [Qemu-devel] [PULL 57/60] target/ppc: add HV support for POWER9
> >>>
> >>> On Tue, Mar 12, 2019 at 07:34:04PM +0100, Cédric Le Goater wrote:
> >>>> On 3/12/19 4:01 PM, Cleber Rosa wrote:
> >>>>> On Sun, Mar 10, 2019 at 07:27:00PM +1100, David Gibson wrote:
> >>>>>> From: Cédric Le Goater <clg@kaod.org>
> >>>>>>
> >>>>>> We now have enough support to boot a PowerNV machine with a POWER9
> >>>>>> processor. Allow HV mode on POWER9.
> >>>>>>
> >>>>>> Signed-off-by: Cédric Le Goater <clg@kaod.org>
> >>>>>> Message-Id: <20190307223548.20516-16-clg@kaod.org>
> >>>>>> Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
> >>>>>> ---
> >>>>>>  target/ppc/translate_init.inc.c | 3 ++-
> >>>>>>  1 file changed, 2 insertions(+), 1 deletion(-)
> >>>>>>
> >>>>>> diff --git a/target/ppc/translate_init.inc.c
> >>>>>> b/target/ppc/translate_init.inc.c
> >>>>>> index af70a3b78c..0bd555eb19 100644
> >>>>>> --- a/target/ppc/translate_init.inc.c
> >>>>>> +++ b/target/ppc/translate_init.inc.c
> >>>>>> @@ -8895,7 +8895,7 @@ POWERPC_FAMILY(POWER9)(ObjectClass *oc, void
> >>>>>> *data)
> >>>>>>                         PPC_CACHE | PPC_CACHE_ICBI | PPC_CACHE_DCBZ |
> >>>>>>                         PPC_MEM_SYNC | PPC_MEM_EIEIO |
> >>>>>>                         PPC_MEM_TLBSYNC |
> >>>>>> -                       PPC_64B | PPC_64BX | PPC_ALTIVEC |
> >>>>>> +                       PPC_64B | PPC_64H | PPC_64BX | PPC_ALTIVEC |
> >>>>>>                         PPC_SEGMENT_64B | PPC_SLBI |
> >>>>>>                         PPC_POPCNTB | PPC_POPCNTWD |
> >>>>>>                         PPC_CILDST;
> >>>>>> @@ -8907,6 +8907,7 @@ POWERPC_FAMILY(POWER9)(ObjectClass *oc, void
> >>>>>> *data)
> >>>>>>                          PPC2_ISA205 | PPC2_ISA207S | PPC2_FP_CVT_S64 |
> >>>>>>                          PPC2_TM | PPC2_ISA300 | PPC2_PRCNTL;
> >>>>>>      pcc->msr_mask = (1ull << MSR_SF) |
> >>>>>> +                    (1ull << MSR_SHV) |
> >>>>>>                      (1ull << MSR_TM) |
> >>>>>>                      (1ull << MSR_VR) |
> >>>>>>                      (1ull << MSR_VSX) |
> >>>>>>
> >>>>>>
> >>>>>
> >>>>> This change prevents a Fedora 29 kernel[1] from booting... is this
> >>>>> intended or a known limitation of the Fedora 29 kernel?
> >>>>
> >>>> The default CPU is still power8_v2.0. This is curious.
> >>>>
> >>>
> >>> Are you sure?  I'm getting:
> >>>
> >>>  $ git rev-parse HEAD
> >>>  cfc3fef6b4e493bf1a7ee16790ad584e20dfbbd1
> >>>  $ ./ppc64-softmmu/qemu-system-ppc64 -qmp unix:/tmp/qmp-sock,server
> >>>  $ ./scripts/qmp/qom-get -s /tmp/qmp-sock /machine/unattached/device[0].type
> >>>  power9_v2.0-spapr-cpu-core
> > 
> > That's a pseries machine, not a powernv machine. pseries should use P9
> > processor by default but the patch above should not impact f29 on pseries. 
> > If it does, then we have a bug. 
> >  
> >> Looks like the overall default is "power9_v2.0", and then on pseries-3.1 and
> >> lower, it's "power8_v2.0", as per 34a6b015a98.
> > 
> > I was looking at pnv_machine_class_init() which sets the default CPU :
> > 
> >     mc->default_cpu_type = POWERPC_CPU_TYPE_NAME("power8_v2.0");
> 
> I found this thread while trying auto-bisection for LP#1834613:
> https://bugs.launchpad.net/bugs/1834613
> 
> When trying the options suggested by Laurent here:
> https://lists.gnu.org/archive/html/qemu-devel/2019-06/msg06209.html
> 
> this one hangs:
> 
> $ qemu-system-ppc64 \
>  -kernel vmlinuz-vanilla \
>  -nographic -append "console=hvc0" \
>  -M cap-cfpc=broken,cap-sbbc=broken,cap-ibs=broken
> 
> but this one works:
> 
> $ qemu-system-ppc64 \
>  -kernel vmlinuz-vanilla \
>  -nographic -append "console=hvc0" \
>  -M pseries-3.1

Sorry, I missed most of this thread while on holidays.  What's the
actual bug here?

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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