Re: [PATCH] xen/pv: Add PV specific legacy_pic struct to expose legacy IRQs.

[Boris Ostrovsky]

On 3/19/19 4:02 PM, Jennifer Herbert wrote:
> The ACPI tables doesn't always contain all IRQs for legacy devices
> such as RTC.  Since no PIC controller is visible for a PV linux guest,
> under Xen, legacy_pic currently defaults to the null_legacy_pic - with
> reports no legacy IRQs.  Since the commit "rtc: cmos: Do not assume
> irq 8 for rtc when there are no legacy irqs" by Hans de Goede
> (commit id: a1e23a42f1bdc00e32fc4869caef12e4e6272f26), the rtc now
> incorrectly decides it has no irq it can use, for some hardware.
>
> This patch rectifies the problem by providing a xen legacy_pic
> struct, which is much like the null_legacy_pic except that it
> reports NR_IRQS_LEGACY irqs.

I assume this is for dom0?

Could there be the same problem with PVH dom0? (and if yes then this
should probably go into arch/x86/xen/enlighten.c).

-boris