[libvirt] [PATCHv2] Device{Attach, Detach}: Document S4 limitations
https://bugzilla.redhat.com/show_bug.cgi?id=808463
Well, libvirt doesn't distinguish between domain poweroff and
hibernation (S4). It's hard to differentiate these two on a real
machine anyway. As a result, any device that is hot(un-)plugged is
lost (appears again) when domain is started again as from our POV
it is a fresh cold boot. Instead of doing anything wise here, we
should just document this as known limitation.
Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com>
---
src/libvirt.c | 16 ++++++++++++++++
1 file changed, 16 insertions(+)
diff --git a/src/libvirt.c b/src/libvirt.c
index b6c99c5..79071db 100644
--- a/src/libvirt.c
+++ b/src/libvirt.c
@@ -10319,6 +10319,10 @@ virNodeGetSecurityModel(virConnectPtr conn, virSecurityModelPtr
secmodel)
* in an existing CDROM/Floppy device, however, applications are
* recommended to use the virDomainUpdateDeviceFlag method instead.
*
+ * Be aware that hotplug changes might not persist across a domain going
+ * into S4 state (also known as hibernation) unless you also modify the
+ * persistent domain definition.
+ *
* Returns 0 in case of success, -1 in case of failure.
*/
int
@@ -10374,6 +10378,10 @@ virDomainAttachDevice(virDomainPtr domain, const char *xml)
* in an existing CDROM/Floppy device, however, applications are
* recommended to use the virDomainUpdateDeviceFlag method instead.
*
+ * Be aware that hotplug changes might not persist across a domain going
+ * into S4 state (also known as hibernation) unless you also modify the
+ * persistent domain definition.
+ *
* Returns 0 in case of success, -1 in case of failure.
*/
int
@@ -10416,6 +10424,10 @@ virDomainAttachDeviceFlags(virDomainPtr domain,
* Destroy a virtual device attachment to backend. This function,
* having hot-unplug semantics, is only allowed on an active domain.
*
+ * Be aware that hotplug changes might not persist across a domain going
+ * into S4 state (also known as hibernation) unless you also modify the
+ * persistent domain definition.
+ *
* Returns 0 in case of success, -1 in case of failure.
*/
int
@@ -10487,6 +10499,10 @@ virDomainDetachDevice(virDomainPtr domain, const char *xml)
* a synchronous removal. In other words, this API may wait a bit for the
* removal to complete in case it was not synchronous.
*
+ * Be aware that hotplug changes might not persist across a domain going
+ * into S4 state (also known as hibernation) unless you also modify the
+ * persistent domain definition.
+ *
* Returns 0 in case of success, -1 in case of failure.
*/
int
--
1.9.0