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

[Philippe Mathieu-Daudé]

On 10/23/20 9:34 AM, Pavel Dovgalyuk 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) {
> +        fprintf(stderr, "Machine definition error: trying to create too many 
> CPUs\n");
> +        exit(1);

Shouldn't this be an assert()?

> +    }
> +
>       cpu->nr_cores = ms->smp.cores;
>       cpu->nr_threads =  ms->smp.threads;
>       cpu->stopped = true;