Re: [Xen-devel] [PATCH v2 07/10] xen/arm: Release maintenance interrupt when CPU is hot-unplugged

[Julien Grall <julien.grall@xxxxxxx>]

Hi Mirela,

On 20/04/18 13:25, Mirela Simonovic wrote:
> When a CPU is hot-unplugged the maintenance interrupt has to be
> released in order to free the memory that was allocated when the CPU
> was hotplugged and interrupt requested. The interrupt was requested
> using request_irq() which is called from start_secondary->
> init_maintenance_interrupt.
>
> Signed-off-by: Mirela Simonovic <mirela.simonovic@xxxxxxxxxx>
>
> ---
> CC: Stefano Stabellini <sstabellini@xxxxxxxxxx>
> CC: Julien Grall <julien.grall@xxxxxxx>
> ---
>   xen/arch/arm/gic.c        | 5 +++++
>   xen/arch/arm/smpboot.c    | 7 +++++++
>   xen/include/asm-arm/gic.h | 1 +
>   3 files changed, 13 insertions(+)
>
> diff --git a/xen/arch/arm/gic.c b/xen/arch/arm/gic.c
> index 653a815127..e536b99e84 100644
> --- a/xen/arch/arm/gic.c
> +++ b/xen/arch/arm/gic.c
> @@ -431,6 +431,11 @@ void init_maintenance_interrupt(void)
>                   "irq-maintenance", NULL);
>   }
>   
> +void deinit_maintenance_interrupt(void)
> +{
> +    release_irq(gic_hw_ops->info->maintenance_irq, NULL);
> +}
> +
>   int gic_make_hwdom_dt_node(const struct domain *d,
>                              const struct dt_device_node *gic,
>                              void *fdt)
> diff --git a/xen/arch/arm/smpboot.c b/xen/arch/arm/smpboot.c
> index abc642804f..449fefc77d 100644
> --- a/xen/arch/arm/smpboot.c
> +++ b/xen/arch/arm/smpboot.c
> @@ -375,11 +375,18 @@ void __cpu_disable(void)
>   
>       local_irq_disable();
>       gic_disable_cpu();
> +
Spurious change.

>       /* Allow any queued timer interrupts to get serviced */
>       local_irq_enable();
>       mdelay(1);
>       local_irq_disable();
>   
> +    /*
> +     * Deinitialize interrupts (this will free the memory that was allocated
> +     * in respective init interrupt functions called from start_secondary)
> +     */
> +    deinit_maintenance_interrupt();
Can you have a look at using a notifier (see CPU_DIYING)? This would 
avoid exporting too much new function.
> +
>       /* It's now safe to remove this processor from the online map */
>       cpumask_clear_cpu(cpu, &cpu_online_map);
>   
> diff --git a/xen/include/asm-arm/gic.h b/xen/include/asm-arm/gic.h
> index 58b910fe6a..0db42e6cce 100644
> --- a/xen/include/asm-arm/gic.h
> +++ b/xen/include/asm-arm/gic.h
> @@ -254,6 +254,7 @@ extern void gic_clear_pending_irqs(struct vcpu *v);
>   extern int vgic_vcpu_pending_irq(struct vcpu *v);
>   
>   extern void init_maintenance_interrupt(void);
> +extern void deinit_maintenance_interrupt(void);
>   extern void gic_raise_guest_irq(struct vcpu *v, unsigned int irq,
>           unsigned int priority);
>   extern void gic_raise_inflight_irq(struct vcpu *v, unsigned int virtual_irq);
Cheers,

--
Julien Grall

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