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

From: Lin Ming
Date: Tue Apr 10 2012 - 11:17:48 EST


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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