Re: [PATCH v4 10/15] accel/mshv: implement cpu_thread_is_idle() hook

[Magnus Kulke <magnuskulke@linux.microsoft.com>]

On Wed, May 27, 2026 at 05:00:46AM +0000, Aastha Rawat wrote:
> From: Magnus Kulke <magnuskulke@linux.microsoft.com>
> 
> In MSHV the hypervisor APIC is always used, so we to implement this hook
> to make sure the AP's vcpu thread is not blocked waiting for an INIT SIPI
> by the BSP. Without this change soft reboots with -smp cpus>=2 will
> hang.
> 
> Signed-off-by: Magnus Kulke <magnuskulke@linux.microsoft.com>
> Reviewed-by: Mohamed Mediouni <mohamed@unpredictable.fr>
> Signed-off-by: Aastha Rawat <aastharawat@linux.microsoft.com>
> ---
>  accel/mshv/mshv-all.c | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/accel/mshv/mshv-all.c b/accel/mshv/mshv-all.c
> index 927e1b39bb..61a9d58546 100644
> --- a/accel/mshv/mshv-all.c
> +++ b/accel/mshv/mshv-all.c
> @@ -719,11 +719,23 @@ static const TypeInfo mshv_accel_type = {
>      .instance_size = sizeof(MshvState),
>  };
>  
> +/*
> + * Haulted vCPUs must still enter mshv_cpu_exec() so that MSHV_RUN_VP
> + * is called and the hypervisor can wake them (via SIPI on x86 or
> + * PSCI on ARM64).
> + */
> +
> +static bool mshv_vcpu_thread_is_idle(CPUState *cpu)
> +{
> +    return false;
> +}
> +
>  static void mshv_accel_ops_class_init(ObjectClass *oc, const void *data)
>  {
>      AccelOpsClass *ops = ACCEL_OPS_CLASS(oc);
>  
>      ops->create_vcpu_thread = mshv_start_vcpu_thread;
> +    ops->cpu_thread_is_idle = mshv_vcpu_thread_is_idle;
>      ops->synchronize_post_init = mshv_cpu_synchronize_post_init;
>      ops->synchronize_post_reset = mshv_cpu_synchronize_post_reset;
>      ops->synchronize_state = mshv_cpu_synchronize;
> 
> -- 
> 2.45.4

this has been merged independently since: dbfb680772d5184544f7c0a8bba96bec229c96e6

best,

magnus