Re: [PATCH 6 of 7] IOMMU: add crash_shutdown iommu_op

[Andrew Cooper <andrew.cooper3@citrix.com>]

On 14/06/11 23:15, Kay, Allen M wrote:
> +static void vtd_crash_shutdown(void)
> +{
> +    struct acpi_drhd_unit *drhd;
> +    struct iommu *iommu;
> +
> +    if ( !iommu_enabled )
> +        return;
> +
> +    iommu_flush_all();
> +
> +    for_each_drhd_unit ( drhd )
> +    {
> +        iommu = drhd->iommu;
> +        iommu_disable_translation(iommu);
> +    }
> +
> +    iommu_disable_x2apic_IR();
> +}
> +
>
> Iommu_disable_x2apic_IR() check for iommu_supports_eim() before entering.  What happens when x2apic is not enabled but interrupt remapping is enabled?
>
> Maybe you should just create disable_intremap() and disable_qi() functions and call from vtd_crash_shutdown() and iommu_disable_x2apic_IR().
>
> Allen 
Well spotted - I missed that.  My suggestion would be to remove the
check for eim and deal with it in the relevant disable_intremap and
disable_qi functions.  My feeling is that a call to "iommu_disable_IR"
should be able to deal whether or not you have eim.

If there are no objections, I will go ahead and try this and integrate
it into the patch 5 of the series which is already dealing with eim, and
needs some refactoring following my chat with Ian Campbell this morning.

-- 
Andrew Cooper - Dom0 Kernel Engineer, Citrix XenServer
T: +44 (0)1223 225 900, http://www.citrix.com