[Qemu-devel] [PATCH v5] vl: exit if maxcpus is negative

[Seeteena Thoufeek <s1seetee@linux.vnet.ibm.com>]

---Steps to Reproduce---

When passed a negative number to 'maxcpus' parameter, Qemu aborts
with a core dump.

Run the following command with maxcpus argument as negative number

ppc64-softmmu/qemu-system-ppc64 --nographic -vga none -machine
pseries,accel=kvm,kvm-type=HV -m size=200g -device virtio-blk-pci,
drive=rootdisk -drive file=/home/images/pegas-1.0-ppc64le.qcow2,
if=none,cache=none,id=rootdisk,format=qcow2 -monitor telnet
:127.0.0.1:1234,server,nowait -net nic,model=virtio -net
user -redir tcp:2000::22 -device nec-usb-xhci -smp 8,cores=1,
threads=1,maxcpus=-12

(process:12149): GLib-ERROR **: gmem.c:130: failed to allocate
 18446744073709550568 bytes

Trace/breakpoint trap

Reported-by: R.Nageswara Sastry <rnsastry@linux.vnet.ibm.com>
Signed-off-by: Seeteena Thoufeek <s1seetee@linux.vnet.ibm.com>
---
v1 -> v2:
  - Fix the error check in vl.c to make it generic.
v2 -> v3:
  - Fix coding style pointed out by patchew.
  - Fix check for "<= 0" instead of just "< 0".
v3 -> v4:
  - Fix subject line.
  - Removed space before ":" from vl.c:1248
  - Removed Reviewed-by: flag
v4-> v5:
  - Code rework to declare max_cpus as unsigned int in sysemu.h
  - Remove the error check in vl.c referred in v2.
  - declare max_cpus as unsigned int in vl.c
---
 include/sysemu/sysemu.h | 2 +-
 vl.c                    | 6 +++---
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/include/sysemu/sysemu.h b/include/sysemu/sysemu.h
index b213696..c083869 100644
--- a/include/sysemu/sysemu.h
+++ b/include/sysemu/sysemu.h
@@ -113,7 +113,7 @@ extern int win2k_install_hack;
 extern int alt_grab;
 extern int ctrl_grab;
 extern int smp_cpus;
-extern int max_cpus;
+extern unsigned int max_cpus;
 extern int cursor_hide;
 extern int graphic_rotate;
 extern int no_quit;
diff --git a/vl.c b/vl.c
index 8e247cc..1470c21 100644
--- a/vl.c
+++ b/vl.c
@@ -164,7 +164,7 @@ Chardev *sclp_hds[MAX_SCLP_CONSOLES];
 int win2k_install_hack = 0;
 int singlestep = 0;
 int smp_cpus = 1;
-int max_cpus = 1;
+unsigned int max_cpus = 1;
 int smp_cores = 1;
 int smp_threads = 1;
 int acpi_enabled = 1;
@@ -4233,8 +4233,8 @@ int main(int argc, char **argv, char **envp)
 
     machine_class->max_cpus = machine_class->max_cpus ?: 1; /* Default to UP */
     if (max_cpus > machine_class->max_cpus) {
-        error_report("Number of SMP CPUs requested (%d) exceeds max CPUs "
-                     "supported by machine '%s' (%d)", max_cpus,
+        error_report("Invalid SMP CPUs %d. The max CPUs "
+                     "supported by machine '%s' is %d", max_cpus,
                      machine_class->name, machine_class->max_cpus);
         exit(1);
     }
-- 
1.8.3.1