Re: [Xen-devel] [PATCH v10 03/10] xen/arm: inflight irqs during migration

[Julien Grall <julien.grall@xxxxxxxxxx>]

Hi Stefano,

On 08/05/2014 12:26 PM, Stefano Stabellini wrote:
> We need to take special care when migrating irqs that are already
> inflight from one vcpu to another. See "The effect of changes to an
> GICD_ITARGETSR", part of chapter 4.3.12 of the ARM Generic Interrupt
> Controller Architecture Specification.

NIT: Can you give the reference of the book? ie: IHI 0048B

[..]

> +        i = 0;
> +        while ( (i = find_next_bit(&target, 32, i)) < 32 )
> +        {
> +            unsigned int irq, new_target, old_target;
> +            unsigned long old_target_mask;
> +            struct vcpu *v_target, *v_old;
> +
> +            new_target = i % 8;
> +            old_target_mask = 
> vgic_byte_read(rank->itargets[REG_RANK_INDEX(8, gicd_reg - GICD_ITARGETSR, 
> DABT_WORD)], 0, i/8);

Can you try to split this line?

> +            old_target = find_first_bit(&old_target_mask, 8);
> +
> +            if ( new_target != old_target )
> +            {
> +                irq = gicd_reg + (i / 8);

gicd_reg contains the register offset (i.e GICD_ITARGETSR + off). How
can you get the correct IRQ number here?

I think this should be

irq = gicd_reg - GICD_ITARGETSR + (i / 8);

-- 
Julien Grall

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