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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v2 11/18] libxl: synchronise configuration when we hotplug a device
We update JSON version first, then write to xenstore, so that we
maintain the following invariant: any device which is present in
xenstore has a corresponding entry in JSON.
The locking pattern is as followed:
1. lock JSON domain config
2. write JSON entry
3. write xenstore entry for a device
4. unlock JSON domain config
And we ensure in code that JSON entry is always written before the
xenstore entry is written. That is, if 2 fails, 3 will not be executed.
As those routines are called both during domain creation and device
hotplug, we add a flag to indicate whether we need to update JSON
config. This flag is only set to true when we hotplug a device. We
cannot update JSON config during domain creation as JSON config is
committed to disk only when domain creation finishes.
Signed-off-by: Wei Liu <wei.liu2@xxxxxxxxxx>
---
tools/libxl/libxl.c | 64 ++++++++++++++++++
tools/libxl/libxl_internal.h | 151 ++++++++++++++++++++++++++++++++++++++++++
tools/libxl/libxl_pci.c | 20 ++++++
3 files changed, 235 insertions(+)
diff --git a/tools/libxl/libxl.c b/tools/libxl/libxl.c
index e6fe238..184e126 100644
--- a/tools/libxl/libxl.c
+++ b/tools/libxl/libxl.c
@@ -1888,6 +1888,11 @@ void libxl__device_vtpm_add(libxl__egc *egc, uint32_t
domid,
flexarray_t *back;
libxl__device *device;
int rc;
+ libxl_device_vtpm vtpm_saved;
+ libxl__carefd *lock = NULL;
+
+ libxl_device_vtpm_init(&vtpm_saved);
+ libxl_device_vtpm_copy(CTX, &vtpm_saved, vtpm);
rc = libxl__device_vtpm_setdefault(gc, vtpm);
if (rc) goto out;
@@ -1902,6 +1907,8 @@ void libxl__device_vtpm_add(libxl__egc *egc, uint32_t
domid,
}
}
+ libxl__update_config_vtpm(gc, &vtpm_saved, vtpm);
+
GCNEW(device);
rc = libxl__device_from_vtpm(gc, domid, vtpm, device);
if ( rc != 0 ) goto out;
@@ -1936,6 +1943,18 @@ void libxl__device_vtpm_add(libxl__egc *egc, uint32_t
domid,
flexarray_append(front, "handle");
flexarray_append(front, GCSPRINTF("%d", vtpm->devid));
+ if (aodev->update_json) {
+ lock = libxl__lock_domain_data(gc, domid);
+ if (!lock) {
+ rc = ERROR_LOCK_FAIL;
+ goto out;
+ }
+
+ rc = DEVICE_ADD_JSON(vtpm, vtpms, num_vtpms, domid, &vtpm_saved,
+ COMPARE_DEVID);
+ if (rc) goto out;
+ }
+
libxl__device_generic_add(gc, XBT_NULL, device,
libxl__xs_kvs_of_flexarray(gc, back,
back->count),
libxl__xs_kvs_of_flexarray(gc, front,
front->count),
@@ -1947,6 +1966,8 @@ void libxl__device_vtpm_add(libxl__egc *egc, uint32_t
domid,
rc = 0;
out:
+ if (lock) libxl__unlock_domain_data(lock);
+ libxl_device_vtpm_dispose(&vtpm_saved);
aodev->rc = rc;
if(rc) aodev->callback(egc, aodev);
return;
@@ -2186,6 +2207,10 @@ static void device_disk_add(libxl__egc *egc, uint32_t
domid,
int rc;
libxl_ctx *ctx = gc->owner;
xs_transaction_t t = XBT_NULL;
+ libxl_device_disk disk_saved;
+ libxl__carefd *lock = NULL;
+
+ libxl_device_disk_init(&disk_saved);
libxl_domain_type type = libxl__domain_type(gc, domid);
if (type == LIBXL_DOMAIN_TYPE_INVALID) {
@@ -2198,6 +2223,8 @@ static void device_disk_add(libxl__egc *egc, uint32_t
domid,
* we need to check if this device already exists in xenstore.
*/
if (!get_vdev) {
+ libxl_device_disk_copy(CTX, &disk_saved, disk);
+
/* Construct libxl__device from libxl_device_disk */
libxl__device_disk_setdefault(gc, disk);
GCNEW(device);
@@ -2216,6 +2243,18 @@ static void device_disk_add(libxl__egc *egc, uint32_t
domid,
rc = ERROR_DEVICE_EXISTS;
goto out;
}
+
+ if (aodev && aodev->update_json) {
+ lock = libxl__lock_domain_data(gc, domid);
+ if (!lock) {
+ rc = ERROR_LOCK_FAIL;
+ goto out;
+ }
+
+ rc = DEVICE_ADD_JSON(disk, disks, num_disks, domid,
+ &disk_saved, COMPARE_DISK);
+ if (rc) goto out;
+ }
}
for (;;) {
@@ -2378,6 +2417,8 @@ static void device_disk_add(libxl__egc *egc, uint32_t
domid,
rc = 0;
out:
+ if (lock) libxl__unlock_domain_data(lock);
+ libxl_device_disk_dispose(&disk_saved);
libxl__xs_transaction_abort(gc, &t);
aodev->rc = rc;
if (rc) aodev->callback(egc, aodev);
@@ -3034,6 +3075,11 @@ void libxl__device_nic_add(libxl__egc *egc, uint32_t
domid,
flexarray_t *back;
libxl__device *device;
int rc;
+ libxl_device_nic nic_saved;
+ libxl__carefd *lock = NULL;
+
+ libxl_device_nic_init(&nic_saved);
+ libxl_device_nic_copy(CTX, &nic_saved, nic);
rc = libxl__device_nic_setdefault(gc, nic, domid);
if (rc) goto out;
@@ -3048,6 +3094,8 @@ void libxl__device_nic_add(libxl__egc *egc, uint32_t
domid,
}
}
+ libxl__update_config_nic(gc, &nic_saved, nic);
+
GCNEW(device);
rc = libxl__device_from_nic(gc, domid, nic, device);
if ( rc != 0 ) goto out;
@@ -3113,6 +3161,19 @@ void libxl__device_nic_add(libxl__egc *egc, uint32_t
domid,
flexarray_append(front, "mac");
flexarray_append(front, libxl__sprintf(gc,
LIBXL_MAC_FMT, LIBXL_MAC_BYTES(nic->mac)));
+
+ if (aodev->update_json) {
+ lock = libxl__lock_domain_data(gc, domid);
+ if (!lock) {
+ rc = ERROR_LOCK_FAIL;
+ goto out;
+ }
+
+ rc = DEVICE_ADD_JSON(nic, nics, num_nics, domid, &nic_saved,
+ COMPARE_DEVID);
+ if (rc) goto out;
+ }
+
libxl__device_generic_add(gc, XBT_NULL, device,
libxl__xs_kvs_of_flexarray(gc, back,
back->count),
libxl__xs_kvs_of_flexarray(gc, front,
front->count),
@@ -3124,6 +3185,8 @@ void libxl__device_nic_add(libxl__egc *egc, uint32_t
domid,
rc = 0;
out:
+ if (lock) libxl__unlock_domain_data(lock);
+ libxl_device_nic_dispose(&nic_saved);
aodev->rc = rc;
if (rc) aodev->callback(egc, aodev);
return;
@@ -3702,6 +3765,7 @@ DEFINE_DEVICE_REMOVE(vtpm, destroy, 1)
\
GCNEW(aodev); \
libxl__prepare_ao_device(ao, aodev); \
+ aodev->update_json = true; \
aodev->callback = device_add_aocomplete; \
libxl__device_##type##_add(egc, domid, type, aodev); \
\
diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
index 1b44c2c..a5eb7d4 100644
--- a/tools/libxl/libxl_internal.h
+++ b/tools/libxl/libxl_internal.h
@@ -2144,6 +2144,8 @@ struct libxl__ao_device {
int num_exec;
/* for calling hotplug scripts */
libxl__async_exec_state aes;
+ /* If we need to udpate JSON config */
+ bool update_json;
};
/*
@@ -3271,6 +3273,155 @@ static inline void libxl__update_config_vtpm(libxl__gc
*gc,
libxl_uuid_copy(CTX, &dst->uuid, &src->uuid);
}
+/* Macros used to compare device identifier. Returns true if the two
+ * devices have same identifier. */
+#define COMPARE_DEVID(a, b) ((a)->devid == (b)->devid)
+#define COMPARE_DISK(a, b) (!strcmp((a)->vdev, (b)->vdev))
+#define COMPARE_PCI(a, b) ((a)->func == (b)->func && \
+ (a)->bus == (b)->bus && \
+ (a)->dev == (b)->dev)
+
+/* Expression int DEVICE_{ADD,REMOVE,UPDATE}_JSON
+ *
+ * Add / remove / update a device in JSON config file. Caller
+ * must hold data store lock before invoking these macros.
+ *
+ * They take 6 parameters:
+ * type: the type of the device, say nic, vtpm, disk, pci etc
+ * ptr: the pointer to array inside libxl_domain_config
+ * cnt: the counter of array
+ * domid: domain id of target domain
+ * dev: the device that is to be added / removed / updated
+ * compare: the COMPARE_* macro used to compare @dev's identifier to
+ * those in the array pointed to by @ptr
+ *
+ * Return 0 if no error occurs, ERROR_* otherwise.
+ *
+ * For most device types (nic, vtpm), the array name @ptr and array
+ * counter @cnt can be derived from @type, pci device being the
+ * exception, hence we need to have @ptr and @cnt.
+ */
+
+/* Add a device to JSON config. If there is already device with the
+ * same identifier in JSON config, no action will be taken.
+ * Use the "update" macro to update JSON config of a device.
+ */
+#define DEVICE_ADD_JSON(type, ptr, cnt, domid, dev, compare) \
+ ({ \
+ int DAJ_x, DAJ_rc; \
+ libxl_domain_config DAJ_d_config; \
+ libxl_device_##type *DAJ_p; \
+ \
+ libxl_domain_config_init(&DAJ_d_config); \
+ \
+ DAJ_rc = libxl__get_domain_configuration(gc, (domid), \
+ &DAJ_d_config); \
+ if (DAJ_rc) \
+ goto DAJ_out; \
+ \
+ /* Check for duplicated device */ \
+ for (DAJ_x = 0; DAJ_x < DAJ_d_config.cnt; DAJ_x++) { \
+ if (compare(&DAJ_d_config.ptr[DAJ_x], (dev))) { \
+ DAJ_rc = 0; \
+ goto DAJ_out; \
+ } \
+ } \
+ \
+ DAJ_d_config.ptr = \
+ libxl__realloc(NOGC, DAJ_d_config.ptr, \
+ (DAJ_d_config.cnt + 1) * \
+ sizeof(libxl_device_##type)); \
+ DAJ_p = &DAJ_d_config.ptr[DAJ_d_config.cnt]; \
+ DAJ_d_config.cnt++; \
+ libxl_device_##type##_copy(CTX, DAJ_p, (dev)); \
+ \
+ DAJ_rc = libxl__set_domain_configuration(gc, (domid), \
+ &DAJ_d_config); \
+ \
+ DAJ_out: \
+ libxl_domain_config_dispose(&DAJ_d_config); \
+ DAJ_rc; \
+ })
+
+/* Remove a device from JSON config. */
+#define DEVICE_REMOVE_JSON(type, ptr, cnt, domid, dev, compare) \
+ ({ \
+ int DRJ_i, DRJ_j, DRJ_rc; \
+ libxl_device_##type *DRJ_p = dev; \
+ libxl_domain_config DRJ_d_config; \
+ \
+ libxl_domain_config_init(&DRJ_d_config); \
+ \
+ DRJ_rc = libxl__get_domain_configuration(gc, (domid), \
+ &DRJ_d_config); \
+ if (DRJ_rc) \
+ goto DRJ_out; \
+ \
+ /* This loop may shuffle down the array */ \
+ for (DRJ_i = DRJ_j = 0; DRJ_i < DRJ_d_config.cnt; DRJ_i++) { \
+ if (!compare(&DRJ_d_config.ptr[DRJ_i], DRJ_p)) { \
+ if (DRJ_i != DRJ_j) { \
+ libxl_device_##type DRJ_tmp; \
+ DRJ_tmp = DRJ_d_config.ptr[DRJ_j]; \
+ DRJ_d_config.ptr[DRJ_j] = DRJ_d_config.ptr[DRJ_i]; \
+ DRJ_d_config.ptr[DRJ_i] = DRJ_tmp; \
+ } \
+ DRJ_j++; \
+ } \
+ } \
+ \
+ if (DRJ_i == DRJ_j) /* no matching entry found */ \
+ goto DRJ_out; \
+ \
+ libxl_device_##type##_dispose(&DRJ_d_config.ptr[DRJ_j]); \
+ DRJ_d_config.ptr = \
+ libxl__realloc(NOGC, DRJ_d_config.ptr, \
+ DRJ_j * sizeof(libxl_device_##type)); \
+ DRJ_d_config.cnt = DRJ_j; \
+ \
+ DRJ_rc = libxl__set_domain_configuration(gc, (domid), \
+ &DRJ_d_config); \
+ \
+ DRJ_out: \
+ libxl_domain_config_dispose(&DRJ_d_config); \
+ DRJ_rc; \
+ })
+
+/* Search device list for device with the same identifier as "dev",
+ * update that device with the content pointed to by "dev".
+ */
+#define DEVICE_UPDATE_JSON(type, ptr, cnt, domid, dev, compare) \
+ ({ \
+ int DUJ_x, DUJ_rc; \
+ libxl_domain_config DUJ_d_config; \
+ bool DUJ_updated = false; \
+ \
+ libxl_domain_config_init(&DUJ_d_config); \
+ \
+ DUJ_rc = libxl__get_domain_configuration(gc, domid, \
+ &DUJ_d_config); \
+ if (DUJ_rc) \
+ goto DUJ_out; \
+ \
+ for (DUJ_x = 0; DUJ_x < DUJ_d_config.cnt; DUJ_x++) { \
+ if (compare(&DUJ_d_config.ptr[DUJ_x], (dev))) { \
+ libxl_device_##type##_dispose( \
+ &DUJ_d_config.ptr[DUJ_x]); \
+ libxl_device_##type##_copy(CTX, \
+ &DUJ_d_config.ptr[DUJ_x], \
+ (dev)); \
+ DUJ_updated = true; \
+ } \
+ } \
+ if (DUJ_updated) \
+ DUJ_rc = libxl__set_domain_configuration(gc, domid, \
+ &DUJ_d_config); \
+ \
+ DUJ_out: \
+ libxl_domain_config_dispose(&DUJ_d_config); \
+ DUJ_rc; \
+ })
+
#endif
/*
diff --git a/tools/libxl/libxl_pci.c b/tools/libxl/libxl_pci.c
index e05f047..357e274 100644
--- a/tools/libxl/libxl_pci.c
+++ b/tools/libxl/libxl_pci.c
@@ -1044,6 +1044,10 @@ int libxl__device_pci_add(libxl__gc *gc, uint32_t domid,
libxl_device_pci *pcide
int num_assigned, i, rc;
libxl__device device;
int stubdomid = 0;
+ libxl_device_pci pcidev_saved;
+ libxl__carefd *lock = NULL;
+
+ libxl_device_pci_init(&pcidev_saved);
if (libxl__domain_type(gc, domid) == LIBXL_DOMAIN_TYPE_HVM) {
rc = xc_test_assign_device(ctx->xch, domid, pcidev_encode_bdf(pcidev));
@@ -1057,6 +1061,8 @@ int libxl__device_pci_add(libxl__gc *gc, uint32_t domid,
libxl_device_pci *pcide
}
}
+ libxl_device_pci_copy(CTX, &pcidev_saved, pcidev);
+
rc = libxl__device_pci_setdefault(gc, pcidev);
if (rc) goto out;
@@ -1125,6 +1131,18 @@ int libxl__device_pci_add(libxl__gc *gc, uint32_t domid,
libxl_device_pci *pcide
pfunc_mask = (1 << pcidev->func);
}
+ if (!starting) {
+ lock = libxl__lock_domain_data(gc, domid);
+ if (!lock) {
+ rc = ERROR_LOCK_FAIL;
+ goto out;
+ }
+
+ rc = DEVICE_ADD_JSON(pci, pcidevs, num_pcidevs, domid, pcidev,
+ COMPARE_PCI);
+ if (rc) goto out;
+ }
+
for(rc = 0, i = 7; i >= 0; --i) {
if ( (1 << i) & pfunc_mask ) {
if ( pcidev->vfunc_mask == pfunc_mask ) {
@@ -1143,6 +1161,8 @@ int libxl__device_pci_add(libxl__gc *gc, uint32_t domid,
libxl_device_pci *pcide
}
out:
+ if (lock) libxl__unlock_domain_data(lock);
+ libxl_device_pci_dispose(&pcidev_saved);
return rc;
}
--
1.7.10.4
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