[PATCH v4 3/3] xl: add 'disable_evtchn_fifo' boolean option into xl.cfg(5) ...

[Paul Durrant <paul@xxxxxxx>]

From: Paul Durrant <pdurrant@xxxxxxxxxx>

...to set the value of the 'disable_evtchn_fifo' flag in
libxl_domain_build_info.

Signed-off-by: Paul Durrant <pdurrant@xxxxxxxxxx>
Signed-off-by: Eslam Elnikety <elnikety@xxxxxxxxxx>
---
Cc: Ian Jackson <iwj@xxxxxxxxxxxxxx>
Cc: Wei Liu <wl@xxxxxxx>
Cc: Anthony PERARD <anthony.perard@xxxxxxxxxx>

v4:
 - New in v4
---
 docs/man/xl.cfg.5.pod.in | 8 ++++++++
 tools/xl/xl_parse.c      | 3 +++
 2 files changed, 11 insertions(+)

diff --git a/docs/man/xl.cfg.5.pod.in b/docs/man/xl.cfg.5.pod.in
index 0532739c1fff..80d5e7aaf38f 100644
--- a/docs/man/xl.cfg.5.pod.in
+++ b/docs/man/xl.cfg.5.pod.in
@@ -1338,6 +1338,14 @@ FIFO-based event channel ABI support up to 131,071 event 
channels.
 Other guests are limited to 4095 (64-bit x86 and ARM) or 1023 (32-bit
 x86).
 
+=item B<disable_evtchn_fifo=BOOLEAN>
+
+Indicates if support for FIFO event channel operations (EVTCHNOP_init_control,
+EVTCHNOP_expand_array and EVTCHNOP_set_priority) are disabled. This can be
+used to work around issues with guests hibernated on a version of Xen
+prior to 4.4 and resumed on a version of Xen from 4.4. onwards. The default
+value is false.
+
 =item B<vdispl=[ "VDISPL_SPEC_STRING", "VDISPL_SPEC_STRING", ...]>
 
 Specifies the virtual display devices to be provided to the guest.
diff --git a/tools/xl/xl_parse.c b/tools/xl/xl_parse.c
index cae8eb679c5a..f79f644c4c2e 100644
--- a/tools/xl/xl_parse.c
+++ b/tools/xl/xl_parse.c
@@ -1569,6 +1569,9 @@ void parse_config_data(const char *config_source,
     if (!xlu_cfg_get_long(config, "max_event_channels", &l, 0))
         b_info->event_channels = l;
 
+    xlu_cfg_get_defbool(config, "disable_evtchn_fifo",
+                        &b_info->disable_evtchn_fifo, 0);
+
     xlu_cfg_replace_string (config, "kernel", &b_info->kernel, 0);
     xlu_cfg_replace_string (config, "ramdisk", &b_info->ramdisk, 0);
     xlu_cfg_replace_string (config, "device_tree", &b_info->device_tree, 0);
-- 
2.20.1