Re: [Xen-devel] [RFC PATCH] xen: get correct nr_irqs_gsi value from hypervisor

[Lin Ming <mlin@xxxxxxxxxxxxx>]

On Tue, 2012-04-10 at 22:57 +0800, Lin Ming wrote:
> nr_irqs_gsi is set in probe_nr_irqs_gsi()
>       nr_irqs_gsi = gsi_top + NR_IRQS_LEGACY;
> 
> gsi_top is set in mp_register_ioapic()
>       gsi_top = gsi_cfg->gsi_end + 1;
> 
> mp_register_ioapic() calls io_apic_read, which don't have a Xen specific
> version. Actually, io_apic_read() always return -1 on Xen Dom0 kernel.
> 
> So currently, nr_irqs_gsi is always wrong on Xen Dom0 kernel.
> 
> This patch gets the correct nr_irqs_gsi value from Xen hypervisor with a
> hypercall.
> 
> Signed-off-by: Lin Ming <mlin@xxxxxxxxxxxxx>
> --
>  arch/x86/include/asm/io_apic.h  |    2 ++
>  arch/x86/kernel/apic/io_apic.c  |    2 +-
>  arch/x86/xen/setup.c            |    9 +++++++++
>  include/xen/interface/physdev.h |    6 ++++++
>  4 files changed, 18 insertions(+), 1 deletions(-)
> 
> (I will send xen hypervisor patch in another mail)\

Here is xen hypervisor side patch:

[RFC PATCH] x86: Add a new physdev_op PHYSDEVOP_nr_irqs_gsi
http://marc.info/?l=xen-devel&m=133407101003891&w=2

Regards,
Lin Ming


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