Re: [PULL 06/15] tests/qtest/migration: Don't use -cpu max for aarch64

[Peter Xu <peterx@redhat.com>]

On Fri, Jan 26, 2024 at 11:54:32AM -0300, Fabiano Rosas wrote:
> Peter Maydell <peter.maydell@linaro.org> writes:
> 
> > On Fri, 26 Jan 2024 at 14:36, Fabiano Rosas <farosas@suse.de> wrote:
> >>
> >> peterx@redhat.com writes:
> >>
> >> > From: Fabiano Rosas <farosas@suse.de>
> >> >
> >> > The 'max' cpu is not expected to be stable in terms of features across
> >> > QEMU versions, so it should not be expected to migrate.
> >> >
> >> > While the tests currently all pass with -cpu max, that is only because
> >> > we're not testing across QEMU versions, which is the more common
> >> > use-case for migration.
> >> >
> >> > We've recently introduced compatibility tests that use two different
> >> > QEMU versions and the tests are now failing for aarch64. The next
> >> > patch adds those tests to CI, so we cannot use the 'max' cpu
> >> > anymore. Replace it with the 'neoverse-n1', which has a fixed set of
> >> > features.
> >> >
> >> > Suggested-by: Peter Maydell <peter.maydell@linaro.org>
> >> > Signed-off-by: Fabiano Rosas <farosas@suse.de>
> >> > Link: https://lore.kernel.org/r/20240118164951.30350-2-farosas@suse.de
> >> > Signed-off-by: Peter Xu <peterx@redhat.com>
> >> > ---
> >> >  tests/qtest/migration-test.c | 2 +-
> >> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >> >
> >> > diff --git a/tests/qtest/migration-test.c b/tests/qtest/migration-test.c
> >> > index 7675519cfa..15713f3666 100644
> >> > --- a/tests/qtest/migration-test.c
> >> > +++ b/tests/qtest/migration-test.c
> >> > @@ -820,7 +820,7 @@ static int test_migrate_start(QTestState **from, QTestState **to,
> >> >          memory_size = "150M";
> >> >          machine_alias = "virt";
> >> >          machine_opts = "gic-version=max";
> >> > -        arch_opts = g_strdup_printf("-cpu max -kernel %s", bootpath);
> >> > +        arch_opts = g_strdup_printf("-cpu neoverse-n1 -kernel %s", bootpath);
> >> >          start_address = ARM_TEST_MEM_START;
> >> >          end_address = ARM_TEST_MEM_END;
> >> >      } else {
> >>
> >> This breaks the tests on an arm host with KVM support. We could drop
> >> this patch from the PR, it doesn't affect anything else.
> >>
> >> Or squash in:
> >>
> >> -->8--
> >> From b8aa5d8a2b33dcc28e4cd4ce2c4f4eacc3a3b845 Mon Sep 17 00:00:00 2001
> >> From: Fabiano Rosas <farosas@suse.de>
> >> Date: Fri, 26 Jan 2024 11:33:15 -0300
> >> Subject: [PATCH] fixup! tests/qtest/migration: Don't use -cpu max for aarch64
> >>
> >> Signed-off-by: Fabiano Rosas <farosas@suse.de>
> >> ---
> >>  tests/qtest/migration-test.c | 4 +++-
> >>  1 file changed, 3 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/tests/qtest/migration-test.c b/tests/qtest/migration-test.c
> >> index 15713f3666..2ba9cab684 100644
> >> --- a/tests/qtest/migration-test.c
> >> +++ b/tests/qtest/migration-test.c
> >> @@ -820,7 +820,9 @@ static int test_migrate_start(QTestState **from, QTestState **to,
> >>          memory_size = "150M";
> >>          machine_alias = "virt";
> >>          machine_opts = "gic-version=max";
> >> -        arch_opts = g_strdup_printf("-cpu neoverse-n1 -kernel %s", bootpath);
> >> +        arch_opts = g_strdup_printf("-cpu %s -kernel %s",
> >> +                                    qtest_has_accel("kvm") ?
> >> +                                    "host" : "neoverse-n1", bootpath);
> >>          start_address = ARM_TEST_MEM_START;
> >>          end_address = ARM_TEST_MEM_END;
> >>      } else {
> >
> > If you want to do that then a comment explaining why would be
> > helpful for future readers, I think.
> 
> Ok, let's drop this one then, I'll resend.

I'll drop this one for now then, thanks.

Just to double check: Fabiano, you meant that "-cpu host" won't hit the
same issue as what "-cpu max" would have for the new "n-1" CI test, right?

I can also wait to read your patch if that will contain the explanations.

-- 
Peter Xu