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

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Laurent Vivier (lvivier@redhat.com) wrote:
> 
> 
> On 26/07/2016 11:39, Laurent Vivier wrote:
> > 
> > 
> > On 26/07/2016 11:28, Thomas Huth wrote:
> >> On 26.07.2016 11:23, Laurent Vivier wrote:
> >>>
> >>>
> >>> 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.
> >>
> >> Would it work if you'd added some magic with "#ifdef CONFIG_KVM" here?
> > 
> > I think it needs to be dynamic as the same binary test is used on x86 to
> > test x86 and ppc64, and vice-versa. I'm going to check if we have
> > something like "qtest_get_accel()"...
> 
> Something like that should work:
> 
> --- a/tests/postcopy-test.c
> +++ b/tests/postcopy-test.c
> @@ -380,12 +380,17 @@ static void test_migrate(void)
>                                    tmpfs, bootpath, uri);
>      } else if (strcmp(arch, "ppc64") == 0) {
>          init_bootfile_ppc(bootpath);
> -        cmd_src = g_strdup_printf("-machine accel=kvm:tcg -m 256M"
> +#ifdef _ARCH_PPC64
> +#define QEMU_CMD_ACCEL            "-machine accel=kvm:tcg"
> +#else
> +#define QEMU_CMD_ACCEL            "-machine accel=tcg"
> +#endif
> +        cmd_src = g_strdup_printf(QEMU_CMD_ACCEL " -m 256M"
>                                    " -name pcsource,debug-threads=on"
>                                    " -serial file:%s/src_serial"
>                                    " -drive file=%s,if=pflash,format=raw",
>                                    tmpfs, bootpath);
> -        cmd_dst = g_strdup_printf("-machine accel=kvm:tcg -m 256M"
> +        cmd_dst = g_strdup_printf(QEMU_CMD_ACCEL " -m 256M"
>                                    " -name pcdest,debug-threads=on"
>                                    " -serial file:%s/dest_serial"
>                                    " -incoming %s",
> 
> Laurent

Is it worth the hastle to just get rid of the two warnings?

Dave

--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK