Commit 03ee51d3 authored by Jose Ricardo Ziviani's avatar Jose Ricardo Ziviani Committed by David Gibson
Browse files

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: default avatarJose Ricardo Ziviani <joserz@linux.vnet.ibm.com>
[dwg: Added an explanatory comment]
Signed-off-by: default avatarDavid Gibson <david@gibson.dropbear.id.au>
parent 895d5cd6

target/ppc/compat.c

+8 −1
Original line number Diff line number Diff line
@@ -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,

    },

};