[v4,10/14] none-machine: allow several cpus

Commit Message

Damien Hedde Feb. 23, 2022, 9:07 a.m. UTC

In order to dynamically create (cold-plugging) cpus, we need to
increase _maxcpus_. This value is indeed used to initialize the
accelerator during qemu startup.
Allowing 16 seems a good starting point.

Add a check to prevent a user to request more than 1 cpu if he
specifies the cpu type on the CLI so that the legacy use case
of the none machine is preserved.

This commit is needed to use the 'none' machine as a base, and
subsequently to dynamically populate it wth cpus usign qapi
commands.

Signed-off-by: Damien Hedde <[e-mail]>
---
 hw/core/null-machine.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

Patch

diff --git a/hw/core/null-machine.c b/hw/core/null-machine.c
index 702b56232d..64f9931857 100644
--- a/hw/core/null-machine.c
+++ b/hw/core/null-machine.c
@@ -34,6 +34,10 @@  static void machine_none_init(MachineState *mch)
 
     /* Initialize CPU (if user asked for it) */
     if (mch->cpu_type) {
+        if (mch->smp.cpus > 1) {
+            error_report("Cannot initialize more than 1 CPU");
+            exit(1);
+        }
         cpu = cpu_create(mch->cpu_type);
         if (!cpu) {
             error_report("Unable to initialize CPU");
@@ -79,7 +83,7 @@  static void machine_none_class_init(ObjectClass *oc, void *data)
 
     mc->desc = "empty machine";
     mc->init = machine_none_init;
-    mc->max_cpus = 1;
+    mc->max_cpus = 16;
     mc->default_ram_size = 0;
     mc->default_ram_id = "ram";
     mc->no_serial = 1;