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authorDavid Gibson <david@gibson.dropbear.id.au>2012-08-07 16:41:51 +1000
committerAnthony Liguori <aliguori@us.ibm.com>2012-08-16 13:41:17 -0500
commitbe52202902d166e914d426c8e3d8976b25121b4d (patch)
treea641e84748f67bb291040d5b146d3357ebadee8a /vl.c
parent35139a590c4e2f3086d069028bda77f1de1d46b0 (diff)
Allow QEMUMachine to override reset sequencing
qemu_system_reset() function always performs the same basic actions on all machines. This includes running all the reset handler hooks, however the order in which these will run is not always easily predictable. This patch splits the core of qemu_system_reset() - the invocation of the reset handlers - out into a new qemu_devices_reset() function. qemu_system_reset() will usually call qemu_devices_reset(), but that can be now overriden by a new reset method in the QEMUMachine structure. Individual machines can use this reset method, if necessary, to perform any extra, machine specific initializations which have to occur before or after the bulk of the reset handlers. It's expected that the method will call qemu_devices_reset() at some point, but if the machine has really strange ordering requirements between devices resets it could even override that with it's own reset sequence (with great care, obviously). For a specific example of when this might be needed: a number of machines (but not PC) load images specified with -kernel or -initrd directly into the machine RAM before booting the guest. This mostly works at the moment, but to make this actually safe requires that this load occurs after peripheral devices are reset - otherwise they could have active DMAs in progress which would clobber the in memory images. Some machines (notably pseries) also have other entry conditions which need to be set up as the last thing before executing in guest space - some of this could be considered "emulated firmware" in the sense that the actions of the firmware are emulated directly by qemu rather than by executing a firmware image within the guest. When the platform's firmware to OS interface is sufficiently well specified, this saves time both in implementing the "firmware" and executing it. aliguori: don't unconditionally dereference current_machine Reviewed-by: Andreas Färber <afaerber@suse.de> Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Diffstat (limited to 'vl.c')
-rw-r--r--vl.c11
1 files changed, 10 insertions, 1 deletions
diff --git a/vl.c b/vl.c
index 124d30d3e7..67f5813e75 100644
--- a/vl.c
+++ b/vl.c
@@ -1464,7 +1464,7 @@ void qemu_unregister_reset(QEMUResetHandler *func, void *opaque)
}
}
-void qemu_system_reset(bool report)
+void qemu_devices_reset(void)
{
QEMUResetEntry *re, *nre;
@@ -1472,6 +1472,15 @@ void qemu_system_reset(bool report)
QTAILQ_FOREACH_SAFE(re, &reset_handlers, entry, nre) {
re->func(re->opaque);
}
+}
+
+void qemu_system_reset(bool report)
+{
+ if (current_machine && current_machine->reset) {
+ current_machine->reset();
+ } else {
+ qemu_devices_reset();
+ }
if (report) {
monitor_protocol_event(QEVENT_RESET, NULL);
}