CVS commit: src/sys/arch

["Cherry G. Mathew" <cherry%netbsd.org@localhost>]

Module Name:    src
Committed By:   cherry
Date:           Sun Oct  7 05:23:01 UTC 2018

Modified Files:
        src/sys/arch/x86/x86: i8259.c intr.c
        src/sys/arch/xen/include: intr.h
        src/sys/arch/xen/x86: pintr.c

Log Message:
Switch over to a "GSI" concept for guest irqs.

On XEN there is a namespace called GSI which includes:

i) legacy_irq (0 - 16)
ii) "gsi" (16-nr_irqs_gsi)
iii) msi

We try to mirror this in guest space, but are mindful that legacy_irq
is 1:1 bound to actual hardware legacy_irq. Apart from this, XEN doesn't
really care what number scheme we use, as long as it doesn't encroach
on the MSI space, which is TBD for us.

Thus we trust the mpbios.c/mpacpi.c code to correctly map the pic,pin
tuples into the correct global gsi space, which we then register with
xen. As we now do, we allow for duplicate gsi registrations, in case
any hardware shares the same (pic,pin);

This enables us to now use the (pic,pin) tuple as the canonical reference
for device interrupt addresses, and leave any global mappings to specific
code. Thus xen_pic_to_gsi().

Note that this requires separate support for MSI, which I will get around to
once things stabilise - however the API change facilitates this nicely.

I note that the msi addroute() function does not use the "pin" parameter.
This can be made use of, to encode the gsi number, for XEN. This is however
TBD.

We further tweak the xen_vec_alloc() code to be uniform for the NIOAPICS
and other cases, and ensure that i8259.c DTRT wrt to route().

This will allow us to use pic->pic_addroute() without needing to worry about
pic specific issues.

The next step is to consolidate the pic_addroute() XEN related #ifdefs into
a -DXEN specific file, so that we don't clutter x86/ code with #ifdef XENs.

This change has functional implications, and there is likely breakage coming
especially on bespoke platforms that I haven't been able to test yet.

I am especially interested in bug reports from platforms with legacy (esp. i386)
and with multiple ioapics.


To generate a diff of this commit:
cvs rdiff -u -r1.17 -r1.18 src/sys/arch/x86/x86/i8259.c
cvs rdiff -u -r1.132 -r1.133 src/sys/arch/x86/x86/intr.c
cvs rdiff -u -r1.47 -r1.48 src/sys/arch/xen/include/intr.h
cvs rdiff -u -r1.6 -r1.7 src/sys/arch/xen/x86/pintr.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.