Re: [PATCH] cpus: verify that number of created cpus do not exceed smp params

[Igor Mammedov <imammedo@redhat.com>]

On Fri, 23 Oct 2020 10:34:41 +0300
Pavel Dovgalyuk <pavel.dovgalyuk@ispras.ru> wrote:

> Machine definitions may miss some vCPU-related parameters.
> E.g., xlnx-versal-virt missed min_cpus and it was set to 1 by default.
> This allowed using -smp 1 command line argument. But the machine
> still created 2 vCPUs and passed all checks.
> This patch adds one more check that does not allow creating
> extra cpus that exceed the values specified in machine/smp.
> 
> Signed-off-by: Pavel Dovgalyuk <pavel.dovgalyuk@ispras.ru>
> ---
>  0 files changed
> 
> diff --git a/softmmu/cpus.c b/softmmu/cpus.c
> index 47cceddd80..da74794e09 100644
> --- a/softmmu/cpus.c
> +++ b/softmmu/cpus.c
> @@ -603,6 +603,11 @@ void qemu_init_vcpu(CPUState *cpu)
>  {
>      MachineState *ms = MACHINE(qdev_get_machine());
>  
> +    if (cpu->cpu_index >= ms->smp.cpus) {
looks like for such machines we need MachineClass:min_cpus + setting it in affected machines
and corresponding check in smp_parse(), instead of terminating from qemu_init_vcpu();


> +        fprintf(stderr, "Machine definition error: trying to create too many CPUs\n");
> +        exit(1);
> +    }
> +
>      cpu->nr_cores = ms->smp.cores;
>      cpu->nr_threads =  ms->smp.threads;
>      cpu->stopped = true;
> 
>