Re: [PATCH 1/3] msi vector targeting abstractions

[Grant Grundler <iod00d@hp.com>]

On Thu, Dec 22, 2005 at 02:15:49PM -0600, Mark Maule wrote:
> Abstract portions of the MSI core for platforms that do not use standard
> APIC interrupt controllers.  This is implemented through a new arch-specific
> msi setup routine, and a set of msi ops which can be set on a per platform
> basis.

...
> +
> +		msi_ops->target(vector, dest_cpu, &address_hi, &address_lo);
> +
> +		pci_write_config_dword(entry->dev, msi_upper_address_reg(pos),
> +			address_hi);
>  		pci_write_config_dword(entry->dev, msi_lower_address_reg(pos),
> -			address.lo_address.value);
> +			address_lo);
>  		set_native_irq_info(irq, cpu_mask);
>  		break;
>  	}
...
> --- /dev/null	1970-01-01 00:00:00.000000000 +0000
> +++ msi/drivers/pci/msi-apic.c	2005-12-22 11:09:37.022232088 -0600
...
> +struct msi_ops msi_apic_ops = {
> +	.setup = msi_setup_apic,
> +	.teardown = msi_teardown_apic,
> +#ifdef CONFIG_SMP
> +	.target = msi_target_apic,
> +#endif

Mark,
msi_target_apic() initializes address_lo parameter.
Even on a UP machine, we need inialize this value.

If target is called unconditionally, wouldn't it be better
for msi_target_apic() always be called?

It would also be good for msi_target_apic to validate the 'dest_cpu' is online.
Maybe a BUG_ON or something like that.

grant

ps. not done looking through this...and still curious to see where
    other discussion about generic vector assignment leads.