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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v2] libxl: fix migration of PV and PVH domUs with and without qemu
If a domU has a qemu-xen instance attached, it is required to call qemus
"xen-save-devices-state" method. Without it, the receiving side of a PV or
PVH migration may be unable to lock the image:
xen be: qdisk-51712: xen be: qdisk-51712: error: Failed to get "write" lock
error: Failed to get "write" lock
xen be: qdisk-51712: xen be: qdisk-51712: initialise() failed
initialise() failed
To fix this bug, libxl__domain_suspend_device_model() and
libxl__domain_resume_device_model() have to be called not only for HVM,
but also if the active device_model is QEMU_XEN.
Unfortunately, libxl__domain_build_info_setdefault() hardcodes
b_info->device_model_version to QEMU_XEN if it does not know it any
better. This breaks domUs without a device_model. libxl__qmp_stop() would
wait 10 seconds in qmp_open() for a qemu that will never appear. During
this long timeframe the domU remains in state paused on the sending side.
As a result network connections may be dropped. Once this bug is fixed as
well, by just removing that assumption, there is no code to actually
initialise b_info->device_model_version.
There is a helper function libxl__need_xenpv_qemu(), which is used in
various places to decide if any device_model has to be spawned. This
function can not be used as is, just to fill b_info->device_model_version,
because store_libxl_entry() was already called earlier. Update this
function to receive a domid to work with, instead of reading xenstore.
Rearrange the code and initialize b_info->device_model_version in
libxl__domain_build_info_setdefault() per DOMAIN_TYPE.
Update initiate_domain_create() to set b_info->device_model_version if it
was not set earlier, using the updated libxl__need_xenpv_qemu().
Introduce LIBXL_DEVICE_MODEL_VERSION_NONE_REQUIRED for PV and PVH that
have no need for a device_model.
Update existing users of libxl__need_xenpv_qemu() to use
b_info->device_model_version for their check if a device_model is needed.
v02:
- update wording in a comment
- remove stale goto in domcreate_launch_dm
- initialize ret in libxl__need_xenpv_qemu
Signed-off-by: Olaf Hering <olaf@xxxxxxxxx>
Cc: Roger Pau Monné <roger.pau@xxxxxxxxxx>
Cc: Anthony PERARD <anthony.perard@xxxxxxxxxx>
---
tools/libxl/libxl_create.c | 39 +++++++++++++++++++++++++++++++--------
tools/libxl/libxl_dm.c | 40 +++++++++++++++++++++++-----------------
tools/libxl/libxl_dom_suspend.c | 8 ++++++--
tools/libxl/libxl_internal.h | 3 ++-
tools/libxl/libxl_types.idl | 1 +
5 files changed, 63 insertions(+), 28 deletions(-)
diff --git a/tools/libxl/libxl_create.c b/tools/libxl/libxl_create.c
index 89fe80fc9c..150ab02354 100644
--- a/tools/libxl/libxl_create.c
+++ b/tools/libxl/libxl_create.c
@@ -87,16 +87,20 @@ int libxl__domain_build_info_setdefault(libxl__gc *gc,
b_info->device_model_ssidref = SECINITSID_DOMDM;
if (!b_info->device_model_version) {
- if (b_info->type == LIBXL_DOMAIN_TYPE_HVM) {
+ switch (b_info->type) {
+ case LIBXL_DOMAIN_TYPE_HVM:
if (libxl_defbool_val(b_info->device_model_stubdomain)) {
b_info->device_model_version =
LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN_TRADITIONAL;
} else {
b_info->device_model_version = libxl__default_device_model(gc);
}
- } else {
- b_info->device_model_version =
- LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN;
+ break;
+ case LIBXL_DOMAIN_TYPE_PV:
+ case LIBXL_DOMAIN_TYPE_PVH:
+ default:
+ /* may be set later */
+ break;
}
if (b_info->device_model_version
== LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN) {
@@ -978,6 +982,17 @@ static void initiate_domain_create(libxl__egc *egc,
goto error_out;
}
+ if (d_config->b_info.device_model_version
+ == LIBXL_DEVICE_MODEL_VERSION_UNKNOWN) {
+ ret = libxl__need_xenpv_qemu(gc, d_config, domid);
+ if (ret)
+ d_config->b_info.device_model_version =
+ LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN;
+ else
+ d_config->b_info.device_model_version =
+ LIBXL_DEVICE_MODEL_VERSION_NONE_REQUIRED;
+ }
+
dcs->guest_domid = domid;
dcs->sdss.dm.guest_domid = 0; /* means we haven't spawned */
@@ -1312,6 +1327,7 @@ static void domcreate_launch_dm(libxl__egc *egc,
libxl__multidev *multidev,
libxl__domain_create_state *dcs = CONTAINER_OF(multidev, *dcs, multidev);
STATE_AO_GC(dcs->ao);
int i;
+ bool need_qemu;
/* convenience aliases */
const uint32_t domid = dcs->guest_domid;
@@ -1464,10 +1480,17 @@ static void domcreate_launch_dm(libxl__egc *egc,
libxl__multidev *multidev,
libxl__device_console_add(gc, domid, &console, state, &device);
libxl__device_console_dispose(&console);
- ret = libxl__need_xenpv_qemu(gc, d_config);
- if (ret < 0)
- goto error_out;
- if (ret) {
+ switch (d_config->b_info.device_model_version) {
+ case LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN_TRADITIONAL:
+ case LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN:
+ need_qemu = true;
+ break;
+ default:
+ need_qemu = false;
+ break;
+ }
+
+ if (need_qemu) {
dcs->sdss.dm.guest_domid = domid;
libxl__spawn_local_dm(egc, &dcs->sdss.dm);
return;
diff --git a/tools/libxl/libxl_dm.c b/tools/libxl/libxl_dm.c
index 2f19786bdd..bab04ab196 100644
--- a/tools/libxl/libxl_dm.c
+++ b/tools/libxl/libxl_dm.c
@@ -2268,7 +2268,7 @@ static void spawn_stub_launch_dm(libxl__egc *egc,
libxl__domain_build_state *const d_state = sdss->dm.build_state;
libxl__domain_build_state *const stubdom_state = &sdss->dm_state;
uint32_t dm_domid = sdss->pvqemu.guest_domid;
- int need_qemu;
+ bool need_qemu;
if (ret) {
LOGD(ERROR, guest_domid, "error connecting disk devices");
@@ -2337,7 +2337,15 @@ static void spawn_stub_launch_dm(libxl__egc *egc,
}
}
- need_qemu = libxl__need_xenpv_qemu(gc, dm_config);
+ switch (dm_config->b_info.device_model_version) {
+ case LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN_TRADITIONAL:
+ case LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN:
+ need_qemu = true;
+ break;
+ default:
+ need_qemu = false;
+ break;
+ }
for (i = 0; i < num_console; i++) {
libxl__device device;
@@ -3175,18 +3183,11 @@ static void kill_device_model_uid_cb(libxl__egc *egc,
}
/* Return 0 if no dm needed, 1 if needed and <0 if error. */
-int libxl__need_xenpv_qemu(libxl__gc *gc, libxl_domain_config *d_config)
+int libxl__need_xenpv_qemu(libxl__gc *gc, libxl_domain_config *d_config,
uint32_t domid)
{
- int idx, i, ret, num;
- uint32_t domid;
+ int idx, i, ret = 0, num;
const struct libxl_device_type *dt;
- ret = libxl__get_domid(gc, &domid);
- if (ret) {
- LOG(ERROR, "unable to get domain id");
- goto out;
- }
-
if (d_config->num_vfbs > 0 || d_config->num_p9s > 0) {
ret = 1;
goto out;
@@ -3238,21 +3239,26 @@ int libxl__dm_check_start(libxl__gc *gc,
libxl_domain_config *d_config,
uint32_t domid)
{
int rc;
+ bool need_qemu;
if (libxl__dm_active(gc, domid))
return 0;
- rc = libxl__need_xenpv_qemu(gc, d_config);
- if (rc < 0)
- goto out;
-
- if (!rc)
+ switch (d_config->b_info.device_model_version) {
+ case LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN_TRADITIONAL:
+ case LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN:
+ need_qemu = true;
+ break;
+ default:
+ need_qemu = false;
+ break;
+ }
+ if (need_qemu == false)
return 0;
LOGD(ERROR, domid, "device model required but not running");
rc = ERROR_FAIL;
-out:
return rc;
}
diff --git a/tools/libxl/libxl_dom_suspend.c b/tools/libxl/libxl_dom_suspend.c
index d1af3a6573..c492fe5dd1 100644
--- a/tools/libxl/libxl_dom_suspend.c
+++ b/tools/libxl/libxl_dom_suspend.c
@@ -379,7 +379,9 @@ static void
domain_suspend_common_guest_suspended(libxl__egc *egc,
libxl__ev_xswatch_deregister(gc, &dsps->guest_watch);
libxl__ev_time_deregister(gc, &dsps->guest_timeout);
- if (dsps->type == LIBXL_DOMAIN_TYPE_HVM) {
+ if (dsps->type == LIBXL_DOMAIN_TYPE_HVM ||
+ libxl__device_model_version_running(gc, dsps->domid) ==
+ LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN) {
dsps->callback_device_model_done = domain_suspend_common_done;
libxl__domain_suspend_device_model(egc, dsps); /* must be last */
return;
@@ -459,7 +461,9 @@ int libxl__domain_resume(libxl__gc *gc, uint32_t domid, int
suspend_cancel)
goto out;
}
- if (type == LIBXL_DOMAIN_TYPE_HVM) {
+ if (type == LIBXL_DOMAIN_TYPE_HVM ||
+ libxl__device_model_version_running(gc, domid) ==
+ LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN) {
rc = libxl__domain_resume_device_model(gc, domid);
if (rc) {
LOGD(ERROR, domid, "failed to resume device model:%d", rc);
diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
index 44e0221284..9eb4211d85 100644
--- a/tools/libxl/libxl_internal.h
+++ b/tools/libxl/libxl_internal.h
@@ -1817,7 +1817,8 @@ _hidden int libxl__domain_build(libxl__gc *gc,
_hidden const char *libxl__domain_device_model(libxl__gc *gc,
const libxl_domain_build_info *info);
_hidden int libxl__need_xenpv_qemu(libxl__gc *gc,
- libxl_domain_config *d_config);
+ libxl_domain_config *d_config,
+ uint32_t domid);
_hidden bool libxl__query_qemu_backend(libxl__gc *gc,
uint32_t domid,
uint32_t backend_id,
diff --git a/tools/libxl/libxl_types.idl b/tools/libxl/libxl_types.idl
index cb4702fd7a..7d75bd3850 100644
--- a/tools/libxl/libxl_types.idl
+++ b/tools/libxl/libxl_types.idl
@@ -106,6 +106,7 @@ libxl_device_model_version =
Enumeration("device_model_version", [
(0, "UNKNOWN"),
(1, "QEMU_XEN_TRADITIONAL"), # Historical qemu-xen device model (qemu-dm)
(2, "QEMU_XEN"), # Upstream based qemu-xen device model
+ (3, "NONE_REQUIRED"),
])
libxl_console_type = Enumeration("console_type", [
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