libxl/xl: implement support for guest ioport and irq permissions.

This is useful for passing legacy ISA devices (e.g. com ports,
parallel ports) to guests.

Supported syntax is as described in
http://cmrg.fifthhorseman.net/wiki/xen#grantingaccesstoserialhardwaretoadomU

I tested this using Xen's 'q' key handler which prints out the I/O
port and IRQ ranges allowed for each domain. e.g.:

(XEN) Rangesets belonging to domain 31:
(XEN)     I/O Ports  { 2e8-2ef, 2f8-2ff }
(XEN)     Interrupts { 3, 5-6 }

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Tested-by: Dieter Bloms <dieter@bloms.de>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Committed-by: Ian Campbell <ian.campbell@citrix.com>

1 files changed, 24 insertions, 0 deletions

diff --git a/docs/man/xl.cfg.pod.5 b/docs/man/xl.cfg.pod.5
index 8aaff1fec9..e332661f73 100644
--- a/docs/man/xl.cfg.pod.5
+++ b/docs/man/xl.cfg.pod.5
@@ -402,6 +402,30 @@ for more information on the "permissive" flag.
 
 =back
 
+=item B<ioports=[ "IOPORT_RANGE", "IOPORT_RANGE", ... ]>
+
+=over 4
+
+Allow guest to access specific legacy I/O ports. Each B<IOPORT_RANGE>
+is given in hexadecimal and may either a span e.g. C<2f8-2ff>
+(inclusive) or a single I/O port C<2f8>.
+
+It is recommended to use this option only for trusted VMs under
+administrator control.
+
+=back
+
+=item B<irqs=[ NUMBER, NUMBER, ... ]>
+
+=over 4
+
+Allow a guest to access specific physical IRQs.
+
+It is recommended to use this option only for trusted VMs under
+administrator control.
+
+=back
+
 =head2 Paravirtualised (PV) Guest Specific Options
 
 The following options apply only to Paravirtual guests.