Re: [Xen-devel] [PATCH V3 17/29] x86/vvtd: add a helper function to decide the interrupt format

[Roger Pau Monné <roger.pau@xxxxxxxxxx>]

On Thu, Sep 21, 2017 at 11:01:58PM -0400, Lan Tianyu wrote:
> From: Chao Gao <chao.gao@xxxxxxxxx>
> 
> Different platform may use different method to distinguish
> remapping format interrupt and normal format interrupt.
> 
> Intel uses one bit in IOAPIC RTE or MSI address register to
> indicate the interrupt is remapping format. vvtd will handle
> all the interrupts when .check_irq_remapping() return true.
> 
> Signed-off-by: Chao Gao <chao.gao@xxxxxxxxx>
> Signed-off-by: Lan Tianyu <tianyu.lan@xxxxxxxxx>
> ---
>  xen/drivers/passthrough/vtd/vvtd.c | 25 ++++++++++++++++++++++++-
>  1 file changed, 24 insertions(+), 1 deletion(-)
> 
> diff --git a/xen/drivers/passthrough/vtd/vvtd.c 
> b/xen/drivers/passthrough/vtd/vvtd.c
> index 5e22ace..bd1cadd 100644
> --- a/xen/drivers/passthrough/vtd/vvtd.c
> +++ b/xen/drivers/passthrough/vtd/vvtd.c
> @@ -536,6 +536,28 @@ static int vvtd_get_irq_info(struct domain *d,
>      return 0;
>  }
>  
> +/* Probe whether the interrupt request is an remapping format */
> +static bool vvtd_is_remapping(struct domain *d,
> +                              struct arch_irq_remapping_request *irq)
> +{
> +    if ( irq->type == VIOMMU_REQUEST_IRQ_APIC )
> +    {
> +        struct IO_APIC_route_remap_entry rte = { .val = irq->msg.rte };
> +
> +        return rte.format;
> +    }
> +    else if ( irq->type == VIOMMU_REQUEST_IRQ_MSI )
> +    {
> +        struct msi_msg_remap_entry msi_msg =
> +        { .address_lo = { .val = irq->msg.msi.addr } };
> +
> +        return msi_msg.address_lo.format;
> +    }
> +    ASSERT_UNREACHABLE();

Switch please.

Also there's a bunch of temporary IO_APIC_route_remap_entry and
msi_msg_remap_entry local structures. Why don't you just create some
kind of union in arch_irq_remapping_request so that you don't need to
do this each time?

Thanks, Roger.

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