diff options
| author | Jose Ricardo Ziviani <joserz@linux.vnet.ibm.com> | 2018-01-14 17:23:48 -0200 |
|---|---|---|
| committer | Michael Roth <mdroth@linux.vnet.ibm.com> | 2018-02-05 18:55:26 -0600 |
| commit | a1f33a5b93f75abfdbaf4023cf9b7935285a705f (patch) | |
| tree | c4899a02828fea03395d71d1e006be32702b28cb /target | |
| parent | 6a47136799c942bc8bc6eda0c39a2fe19b418864 (diff) | |
ppc: Change Power9 compat table to support at most 8 threads/core
Increases the max smt mode to 8 for Power9. That's because KVM supports
smt emulation in this platform so QEMU should allow users to use it as
well.
Today if we try to pass -smp ...,threads=8, QEMU will silently truncate
it to smt4 mode and may cause a crash if we try to perform a cpu
hotplug.
Signed-off-by: Jose Ricardo Ziviani <joserz@linux.vnet.ibm.com>
[dwg: Added an explanatory comment]
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
(cherry picked from commit 03ee51d3548f5f553a3089f466483c1c6d5c666b)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Diffstat (limited to 'target')
| -rw-r--r-- | target/ppc/compat.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/target/ppc/compat.c b/target/ppc/compat.c index ad8f93c064..276b5b52c2 100644 --- a/target/ppc/compat.c +++ b/target/ppc/compat.c @@ -73,7 +73,14 @@ static const CompatInfo compat_table[] = { .pvr = CPU_POWERPC_LOGICAL_3_00, .pcr = PCR_COMPAT_3_00, .pcr_level = PCR_COMPAT_3_00, - .max_threads = 4, + /* + * POWER9 hardware only supports 4 threads / core, but this + * limit is for guests. We need to support 8 vthreads/vcore + * on POWER9 for POWER8 compatibility guests, and it's very + * confusing if half of the threads disappear from the guest + * if it announces it's POWER9 aware at CAS time. + */ + .max_threads = 8, }, }; |