Re: [Qemu-devel] [PATCH v5 06/10] xics_kvm: Add cpu_destroy method to XICS

[David Gibson <david@gibson.dropbear.id.au>]

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On Fri, Nov 20, 2015 at 06:24:35PM +0530, Bharata B Rao wrote:
> XICS is setup for each CPU during initialization. Provide a routine
> to undo the same when CPU is unplugged.
> 
> This allows reboot of a VM that has undergone CPU hotplug and unplug
> to work correctly.
> 
> Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
> Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
> ---
>  hw/intc/xics.c        | 12 ++++++++++++
>  hw/intc/xics_kvm.c    | 13 +++++++++++--
>  include/hw/ppc/xics.h |  2 ++
>  3 files changed, 25 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/intc/xics.c b/hw/intc/xics.c
> index 9ff5796..e1161b2 100644
> --- a/hw/intc/xics.c
> +++ b/hw/intc/xics.c
> @@ -44,6 +44,18 @@ static int get_cpu_index_by_dt_id(int cpu_dt_id)
>      return -1;
>  }
>  
> +void xics_cpu_destroy(XICSState *icp, PowerPCCPU *cpu)
> +{
> +    CPUState *cs = CPU(cpu);
> +    XICSStateClass *info = XICS_COMMON_GET_CLASS(icp);
> +
> +    assert(cs->cpu_index < icp->nr_servers);
> +
> +    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..cb96f69 100644
> --- a/hw/intc/xics_kvm.c
> +++ b/hw/intc/xics_kvm.c
> @@ -331,6 +331,8 @@ static void xics_kvm_cpu_setup(XICSState *icp, PowerPCCPU *cpu)
>          abort();
>      }
>  
> +    ss->cs = cs;
> +

Actually, it probably makes more sense to move the management of
ss->cs to the base xics code.  There's nothing really kvm specific
about it.

>      /*
>       * If we are reusing a parked vCPU fd corresponding to the CPU
>       * which was hot-removed earlier we don't have to renable
> @@ -343,8 +345,6 @@ static void xics_kvm_cpu_setup(XICSState *icp, PowerPCCPU *cpu)
>      if (icpkvm->kernel_xics_fd != -1) {
>          int ret;
>  
> -        ss->cs = cs;
> -
>          ret = kvm_vcpu_enable_cap(cs, KVM_CAP_IRQ_XICS, 0,
>                                    icpkvm->kernel_xics_fd, kvm_arch_vcpu_id(cs));
>          if (ret < 0) {
> @@ -356,6 +356,14 @@ 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 +494,7 @@ 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__ */

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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