[Qemu-devel] [PULL 0/1] ppc-for-2.9 queue 20170403

[Qemu-devel] [PULL 0/1] ppc-for-2.9 queue 20170403

[David Gibson]

The following changes since commit 95b31d709ba343ad237c3630047ee7438bac4065:

  Merge remote-tracking branch 'remotes/awilliam/tags/vfio-updates-20170331.0' into staging (2017-03-31 18:06:13 +0100)

are available in the git repository at:

  git://github.com/dgibson/qemu.git tags/ppc-for-2.9-20170403

for you to fetch changes up to 8149e2992f7811355cc34721b79d69d1a3a667dd:

  pseries: Enforce homogeneous threads-per-core (2017-04-03 13:46:18 +1000)

----------------------------------------------------------------
ppc patch queue 2017-04-03

A single bugfix in this pull request, for an ugly assert() failure, if
the user ignores the information in query-hotpluggable-cpus and tries
to hot add CPUs to pseries with bad parameters.

----------------------------------------------------------------
David Gibson (1):
      pseries: Enforce homogeneous threads-per-core

 hw/ppc/spapr.c | 6 ++++++
 1 file changed, 6 insertions(+)

[Qemu-devel] [PULL 1/1] pseries: Enforce homogeneous threads-per-core

[David Gibson]

For reasons that may be useful in future, CPU core objects, as used on the
pseries machine type have their own nr-threads property, potentially
allowing cores with different numbers of threads in the same system.

If the user/management uses the values specified in query-hotpluggable-cpus
as they're expected to do, this will never matter in pratice.  But that's
not actually enforced - it's possible to manually specify a core with
a different number of threads from that in -smp.  That will confuse the
platform - most immediately, this can be used to create a CPU thread with
index above max_cpus which leads to an assertion failure in
spapr_cpu_core_realize().

For now, enforce that all cores must have the same, standard, number of
threads.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
---
 hw/ppc/spapr.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 44c26e4..35db949 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -2790,6 +2790,12 @@ static void spapr_core_pre_plug(HotplugHandler *hotplug_dev, DeviceState *dev,
         goto out;
     }
 
+    if (cc->nr_threads != smp_threads) {
+        error_setg(errp, "invalid nr-threads %d, must be %d",
+                   cc->nr_threads, smp_threads);
+        return;
+    }
+
     core_slot = spapr_find_cpu_slot(MACHINE(hotplug_dev), cc->core_id, &index);
     if (!core_slot) {
         error_setg(&local_err, "core id %d out of range", cc->core_id);
-- 
2.9.3

Re: [Qemu-devel] [PULL 0/1] ppc-for-2.9 queue 20170403

[Peter Maydell]

On 3 April 2017 at 11:08, David Gibson <david@gibson.dropbear.id.au> wrote:
> The following changes since commit 95b31d709ba343ad237c3630047ee7438bac4065:
>
>   Merge remote-tracking branch 'remotes/awilliam/tags/vfio-updates-20170331.0' into staging (2017-03-31 18:06:13 +0100)
>
> are available in the git repository at:
>
>   git://github.com/dgibson/qemu.git tags/ppc-for-2.9-20170403
>
> for you to fetch changes up to 8149e2992f7811355cc34721b79d69d1a3a667dd:
>
>   pseries: Enforce homogeneous threads-per-core (2017-04-03 13:46:18 +1000)
>
> ----------------------------------------------------------------
> ppc patch queue 2017-04-03
>
> A single bugfix in this pull request, for an ugly assert() failure, if
> the user ignores the information in query-hotpluggable-cpus and tries
> to hot add CPUs to pseries with bad parameters.
>
> ----------------------------------------------------------------
> David Gibson (1):
>       pseries: Enforce homogeneous threads-per-core

Applied, thanks.

-- PMM