Re: [Qemu-devel] [PATCH v2] test: port postcopy test to ppc64

[Laurent Vivier <lvivier@redhat.com>]

On 23/07/2016 08:30, David Gibson wrote:
> On Fri, Jul 22, 2016 at 09:28:58AM +0200, Laurent Vivier wrote:
>>
>>
>> On 22/07/2016 08:43, David Gibson wrote:
>>> On Thu, Jul 21, 2016 at 06:47:56PM +0200, Laurent Vivier wrote:
>>>> As userfaultfd syscall is available on powerpc, migration
>>>> postcopy can be used.
>>>>
>>>> This patch adds the support needed to test this on powerpc,
>>>> instead of using a bootsector to run code to modify memory,
>>>> we use a FORTH script in "boot-command" property.
>>>>
>>>> As spapr machine doesn't support "-prom-env" argument
>>>> (the nvram is initialized by SLOF and not by QEMU),
>>>> "boot-command" is provided to SLOF via a file mapped nvram
>>>> (with "-drive file=...,if=pflash")
>>>>
>>>> Signed-off-by: Laurent Vivier <lvivier@redhat.com>
>>>> ---
>>>> v2: move FORTH script directly in sprintf()
>>>>     use openbios_firmware_abi.h
>>>>     remove useless "default" case
>>>>
>>>>  tests/Makefile.include |   1 +
>>>>  tests/postcopy-test.c  | 116 +++++++++++++++++++++++++++++++++++++++++--------
>>>>  2 files changed, 98 insertions(+), 19 deletions(-)
>>>
>>> There's a mostly cosmetic problem with this.  If you run make check
>>> for a ppc64 target on an x86 machine, you get:
>>>
>>> GTESTER check-qtest-ppc64
>>> "kvm" accelerator not found.
>>> "kvm" accelerator not found.
>>
>> I think this is because of "-machine accel=kvm:tcg", it tries to use kvm
>> and fall back to tcg.
>>
>> accel.c:
>>
>>      80 void configure_accelerator(MachineState *ms)
>>      81 {
>> ...
>>     100         acc = accel_find(buf);
>>     101         if (!acc) {
>>     102             fprintf(stderr, "\"%s\" accelerator not found.\n", buf);
>>     103             continue;
>>     104         }
>>
>> We can remove the "-machine" argument to use the default instead (tcg or
>> kvm).
> 
> That sounds like a good option for a general test.
> 

In fact, we can't: we need to add a "-machine accel=XXXX" to our command
line to override the "-machine accel=qtest" provided by the qtest
framework. If we don't override it, the machine doesn't start.

Laurent