Re: [Qemu-devel] [PATCH v4 8/8] xics_kvm: Add cpu_destroy method to XICS

[Alexey Kardashevskiy]

On 06/05/2015 02:25 PM, Bharata B Rao wrote:
> XICS is setup for each CPU during initialization. Provide a routine
> to undo the same when CPU is unplugged. Also ensure xics reset doesn't set
> irq for CPUs that are already unplugged.
>
> This allows reboot of a VM that has undergone CPU hotplug and unplug
> to work correctly.
>
> Signed-off-by: Bharata B Rao <address@hidden>
> ---
>   hw/intc/xics.c        | 14 ++++++++++++++
>   hw/intc/xics_kvm.c    | 15 +++++++++++++--
>   include/hw/ppc/xics.h |  2 ++
>   3 files changed, 29 insertions(+), 2 deletions(-)
>
> diff --git a/hw/intc/xics.c b/hw/intc/xics.c
> index 924b1ae..3f87f82 100644
> --- a/hw/intc/xics.c
> +++ b/hw/intc/xics.c
> @@ -44,6 +44,20 @@ static int get_cpu_index_by_dt_id(int cpu_dt_id)
>       return -1;
>   }
>
> +void xics_cpu_destroy(XICSState *icp, PowerPCCPU *cpu)


xics_cpu_destroy() is not used by anything, may be push it later with the 
stuff which needs it?


> +{
> +    CPUState *cs = CPU(cpu);
> +    XICSStateClass *info = XICS_COMMON_GET_CLASS(icp);
> +    ICPState *ss = &icp->ss[cs->cpu_index];
> +
> +    assert(cs->cpu_index < icp->nr_servers);
> +
> +    ss->output = NULL;
> +    if (info->cpu_destroy) {
> +        info->cpu_destroy(icp, cpu);
> +    }
> +}
> +
>   void xics_cpu_setup(XICSState *icp, PowerPCCPU *cpu)
>   {
>       CPUState *cs = CPU(cpu);
> diff --git a/hw/intc/xics_kvm.c b/hw/intc/xics_kvm.c
> index d58729c..e35f319 100644
> --- a/hw/intc/xics_kvm.c
> +++ b/hw/intc/xics_kvm.c
> @@ -109,8 +109,10 @@ static void icp_kvm_reset(DeviceState *dev)
>       icp->pending_priority = 0xff;
>       icp->mfrr = 0xff;
>
> -    /* Make all outputs are deasserted */
> -    qemu_set_irq(icp->output, 0);
> +    /* Make all outputs are deasserted only if the CPU thread is in use */
> +    if (icp->output) {
> +        qemu_set_irq(icp->output, 0);
> +    }


This feels unrelated to what the patch claims that it does. Or 
xics_cpu_destroy() somehow indirectly calls icp_kvm_reset()?


>       icp_set_kvm_state(icp, 1);
>   }
> @@ -356,6 +358,14 @@ static void xics_kvm_cpu_setup(XICSState *icp, PowerPCCPU 
> *cpu)
>       }
>   }
>
> +static void xics_kvm_cpu_destroy(XICSState *icp, PowerPCCPU *cpu)
> +{
> +    CPUState *cs = CPU(cpu);
> +    ICPState *ss = &icp->ss[cs->cpu_index];
> +
> +    ss->cs = NULL;
> +}
> +
>   static void xics_kvm_set_nr_irqs(XICSState *icp, uint32_t nr_irqs, Error 
> **errp)
>   {
>       icp->nr_irqs = icp->ics->nr_irqs = nr_irqs;
> @@ -486,6 +496,7 @@ static void xics_kvm_class_init(ObjectClass *oc, void *data)
>
>       dc->realize = xics_kvm_realize;
>       xsc->cpu_setup = xics_kvm_cpu_setup;
> +    xsc->cpu_destroy = xics_kvm_cpu_destroy;
>       xsc->set_nr_irqs = xics_kvm_set_nr_irqs;
>       xsc->set_nr_servers = xics_kvm_set_nr_servers;
>   }
> diff --git a/include/hw/ppc/xics.h b/include/hw/ppc/xics.h
> index 355a966..2faad48 100644
> --- a/include/hw/ppc/xics.h
> +++ b/include/hw/ppc/xics.h
> @@ -68,6 +68,7 @@ struct XICSStateClass {
>       DeviceClass parent_class;
>
>       void (*cpu_setup)(XICSState *icp, PowerPCCPU *cpu);
> +    void (*cpu_destroy)(XICSState *icp, PowerPCCPU *cpu);
>       void (*set_nr_irqs)(XICSState *icp, uint32_t nr_irqs, Error **errp);
>       void (*set_nr_servers)(XICSState *icp, uint32_t nr_servers, Error **errp);
>   };
> @@ -166,5 +167,6 @@ int xics_alloc_block(XICSState *icp, int src, int num, bool 
> lsi, bool align);
>   void xics_free(XICSState *icp, int irq, int num);
>
>   void xics_cpu_setup(XICSState *icp, PowerPCCPU *cpu);
> +void xics_cpu_destroy(XICSState *icp, PowerPCCPU *cpu);
>
>   #endif /* __XICS_H__ */


--
Alexey