[v11,8/8] xen: introduce ERRP_AUTO_PROPAGATE
diff mbox series

Message ID 20200703090816.3295-9-vsementsov@virtuozzo.com
State New
Headers show
Series
  • error: auto propagated local_err part I
Related show

Commit Message

Vladimir Sementsov-Ogievskiy July 3, 2020, 9:08 a.m. UTC
If we want to add some info to errp (by error_prepend() or
error_append_hint()), we must use the ERRP_AUTO_PROPAGATE macro.
Otherwise, this info will not be added when errp == &error_fatal
(the program will exit prior to the error_append_hint() or
error_prepend() call).  Fix such cases.

If we want to check error after errp-function call, we need to
introduce local_err and then propagate it to errp. Instead, use
ERRP_AUTO_PROPAGATE macro, benefits are:
1. No need of explicit error_propagate call
2. No need of explicit local_err variable: use errp directly
3. ERRP_AUTO_PROPAGATE leaves errp as is if it's not NULL or
   &error_fatal, this means that we don't break error_abort
   (we'll abort on error_set, not on error_propagate)

This commit is generated by command

    sed -n '/^X86 Xen CPUs$/,/^$/{s/^F: //p}' MAINTAINERS | \
    xargs git ls-files | grep '\.[hc]$' | \
    xargs spatch \
        --sp-file scripts/coccinelle/auto-propagated-errp.cocci \
        --macro-file scripts/cocci-macro-file.h \
        --in-place --no-show-diff --max-width 80

Reported-by: Kevin Wolf <kwolf@redhat.com>
Reported-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 hw/block/dataplane/xen-block.c |  17 +++---
 hw/block/xen-block.c           | 102 ++++++++++++++-------------------
 hw/pci-host/xen_igd_pt.c       |   7 +--
 hw/xen/xen-backend.c           |   7 +--
 hw/xen/xen-bus.c               |  92 +++++++++++++----------------
 hw/xen/xen-host-pci-device.c   |  27 +++++----
 hw/xen/xen_pt.c                |  25 ++++----
 hw/xen/xen_pt_config_init.c    |  17 +++---
 8 files changed, 128 insertions(+), 166 deletions(-)

Comments

Philippe Mathieu-Daudé July 4, 2020, 4:36 p.m. UTC | #1
On 7/3/20 11:08 AM, Vladimir Sementsov-Ogievskiy wrote:
> If we want to add some info to errp (by error_prepend() or
> error_append_hint()), we must use the ERRP_AUTO_PROPAGATE macro.
> Otherwise, this info will not be added when errp == &error_fatal
> (the program will exit prior to the error_append_hint() or
> error_prepend() call).  Fix such cases.
> 
> If we want to check error after errp-function call, we need to
> introduce local_err and then propagate it to errp. Instead, use
> ERRP_AUTO_PROPAGATE macro, benefits are:
> 1. No need of explicit error_propagate call
> 2. No need of explicit local_err variable: use errp directly
> 3. ERRP_AUTO_PROPAGATE leaves errp as is if it's not NULL or
>    &error_fatal, this means that we don't break error_abort
>    (we'll abort on error_set, not on error_propagate)
> 
> This commit is generated by command
> 
>     sed -n '/^X86 Xen CPUs$/,/^$/{s/^F: //p}' MAINTAINERS | \
>     xargs git ls-files | grep '\.[hc]$' | \
>     xargs spatch \
>         --sp-file scripts/coccinelle/auto-propagated-errp.cocci \
>         --macro-file scripts/cocci-macro-file.h \
>         --in-place --no-show-diff --max-width 80
> 
> Reported-by: Kevin Wolf <kwolf@redhat.com>
> Reported-by: Greg Kurz <groug@kaod.org>
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> ---
>  hw/block/dataplane/xen-block.c |  17 +++---
>  hw/block/xen-block.c           | 102 ++++++++++++++-------------------
>  hw/pci-host/xen_igd_pt.c       |   7 +--
>  hw/xen/xen-backend.c           |   7 +--
>  hw/xen/xen-bus.c               |  92 +++++++++++++----------------
>  hw/xen/xen-host-pci-device.c   |  27 +++++----
>  hw/xen/xen_pt.c                |  25 ++++----
>  hw/xen/xen_pt_config_init.c    |  17 +++---
>  8 files changed, 128 insertions(+), 166 deletions(-)

Without the description, this patch has 800 lines of diff...
It killed me, I don't have the energy to review patch #7 of this
series after that, sorry.
Consider splitting such mechanical patches next time. Here it
could have been hw/block, hw/pci-host, hw/xen.

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Markus Armbruster July 6, 2020, 7:41 a.m. UTC | #2
Philippe Mathieu-Daudé <philmd@redhat.com> writes:

> On 7/3/20 11:08 AM, Vladimir Sementsov-Ogievskiy wrote:
>> If we want to add some info to errp (by error_prepend() or
>> error_append_hint()), we must use the ERRP_AUTO_PROPAGATE macro.
>> Otherwise, this info will not be added when errp == &error_fatal
>> (the program will exit prior to the error_append_hint() or
>> error_prepend() call).  Fix such cases.
>> 
>> If we want to check error after errp-function call, we need to
>> introduce local_err and then propagate it to errp. Instead, use
>> ERRP_AUTO_PROPAGATE macro, benefits are:
>> 1. No need of explicit error_propagate call
>> 2. No need of explicit local_err variable: use errp directly
>> 3. ERRP_AUTO_PROPAGATE leaves errp as is if it's not NULL or
>>    &error_fatal, this means that we don't break error_abort
>>    (we'll abort on error_set, not on error_propagate)
>> 
>> This commit is generated by command
>> 
>>     sed -n '/^X86 Xen CPUs$/,/^$/{s/^F: //p}' MAINTAINERS | \
>>     xargs git ls-files | grep '\.[hc]$' | \
>>     xargs spatch \
>>         --sp-file scripts/coccinelle/auto-propagated-errp.cocci \
>>         --macro-file scripts/cocci-macro-file.h \
>>         --in-place --no-show-diff --max-width 80
>> 
>> Reported-by: Kevin Wolf <kwolf@redhat.com>
>> Reported-by: Greg Kurz <groug@kaod.org>
>> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
>> ---
>>  hw/block/dataplane/xen-block.c |  17 +++---
>>  hw/block/xen-block.c           | 102 ++++++++++++++-------------------
>>  hw/pci-host/xen_igd_pt.c       |   7 +--
>>  hw/xen/xen-backend.c           |   7 +--
>>  hw/xen/xen-bus.c               |  92 +++++++++++++----------------
>>  hw/xen/xen-host-pci-device.c   |  27 +++++----
>>  hw/xen/xen_pt.c                |  25 ++++----
>>  hw/xen/xen_pt_config_init.c    |  17 +++---
>>  8 files changed, 128 insertions(+), 166 deletions(-)
>
> Without the description, this patch has 800 lines of diff...
> It killed me, I don't have the energy to review patch #7 of this
> series after that, sorry.
> Consider splitting such mechanical patches next time. Here it
> could have been hw/block, hw/pci-host, hw/xen.

Probably my fault; I asked for less fine-grained splitting.

Finding a split of a tree-wide transformation that pleases everyone is
basically impossible.

The conversion to ERRP_AUTO_PROPAGATE() could be one patch per function,
but that would be excessive.

Vladimir chose to split along maintenance boundaries, so he can cc: the
right people on the right code.  I agree with the idea.  The difficulty
is which boundaries.  Our code is not partitioned into maintenance
domains.  Instead, we have overlapping sets.  Makes sense, because it
mirrors how we actually maintain it.

Because of that, a blind split guided by MAINTAINERS won't work well.  A
split that makes sense needs a bit of human judgement, too.

This part makes perfect sense to me from the cc: point of view: it's
Xen, the whole of Xen, and nothing but Xen.

I acknowledge that its size made it exhausting for you to review.  I
didn't expect that, probably because after having spent hours on
reviewing and improving the macro and the Coccinelle script, I know
exactly what to look for, and also consider the script trustworthy[*].

> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>

Thank you, much appreciated!


[*] I've learned not to trust Coccinelle 100%, ever.
Vladimir Sementsov-Ogievskiy July 6, 2020, 7:55 a.m. UTC | #3
04.07.2020 19:36, Philippe Mathieu-Daudé wrote:
> On 7/3/20 11:08 AM, Vladimir Sementsov-Ogievskiy wrote:
>> If we want to add some info to errp (by error_prepend() or
>> error_append_hint()), we must use the ERRP_AUTO_PROPAGATE macro.
>> Otherwise, this info will not be added when errp == &error_fatal
>> (the program will exit prior to the error_append_hint() or
>> error_prepend() call).  Fix such cases.
>>
>> If we want to check error after errp-function call, we need to
>> introduce local_err and then propagate it to errp. Instead, use
>> ERRP_AUTO_PROPAGATE macro, benefits are:
>> 1. No need of explicit error_propagate call
>> 2. No need of explicit local_err variable: use errp directly
>> 3. ERRP_AUTO_PROPAGATE leaves errp as is if it's not NULL or
>>     &error_fatal, this means that we don't break error_abort
>>     (we'll abort on error_set, not on error_propagate)
>>
>> This commit is generated by command
>>
>>      sed -n '/^X86 Xen CPUs$/,/^$/{s/^F: //p}' MAINTAINERS | \
>>      xargs git ls-files | grep '\.[hc]$' | \
>>      xargs spatch \
>>          --sp-file scripts/coccinelle/auto-propagated-errp.cocci \
>>          --macro-file scripts/cocci-macro-file.h \
>>          --in-place --no-show-diff --max-width 80
>>
>> Reported-by: Kevin Wolf <kwolf@redhat.com>
>> Reported-by: Greg Kurz <groug@kaod.org>
>> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
>> ---
>>   hw/block/dataplane/xen-block.c |  17 +++---
>>   hw/block/xen-block.c           | 102 ++++++++++++++-------------------
>>   hw/pci-host/xen_igd_pt.c       |   7 +--
>>   hw/xen/xen-backend.c           |   7 +--
>>   hw/xen/xen-bus.c               |  92 +++++++++++++----------------
>>   hw/xen/xen-host-pci-device.c   |  27 +++++----
>>   hw/xen/xen_pt.c                |  25 ++++----
>>   hw/xen/xen_pt_config_init.c    |  17 +++---
>>   8 files changed, 128 insertions(+), 166 deletions(-)
> 
> Without the description, this patch has 800 lines of diff...
> It killed me, I don't have the energy to review patch #7 of this
> series after that, sorry.

Sorry for that! I really understand you, take a look at Markus's
"[PATCH v2 00/44] Less clumsy error checking", which I'm trying to review
currently..

Still, the patch exists in such form since
"[RFC v5 000/126] error: auto propagated local_err", where it was reviewed
by Anthony, and I suggested to split it, but it was not needed.
Unfortunately, I've dropped r-bs due to changes..

> Consider splitting such mechanical patches next time. Here it
> could have been hw/block, hw/pci-host, hw/xen.
> 
> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
> 

Thanks a lot!

Patch
diff mbox series

diff --git a/hw/block/dataplane/xen-block.c b/hw/block/dataplane/xen-block.c
index 5f8f15778b..1a077cc05f 100644
--- a/hw/block/dataplane/xen-block.c
+++ b/hw/block/dataplane/xen-block.c
@@ -723,8 +723,8 @@  void xen_block_dataplane_start(XenBlockDataPlane *dataplane,
                                unsigned int protocol,
                                Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     XenDevice *xendev = dataplane->xendev;
-    Error *local_err = NULL;
     unsigned int ring_size;
     unsigned int i;
 
@@ -760,9 +760,8 @@  void xen_block_dataplane_start(XenBlockDataPlane *dataplane,
     }
 
     xen_device_set_max_grant_refs(xendev, dataplane->nr_ring_ref,
-                                  &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
+                                  errp);
+    if (*errp) {
         goto stop;
     }
 
@@ -770,9 +769,8 @@  void xen_block_dataplane_start(XenBlockDataPlane *dataplane,
                                               dataplane->ring_ref,
                                               dataplane->nr_ring_ref,
                                               PROT_READ | PROT_WRITE,
-                                              &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
+                                              errp);
+    if (*errp) {
         goto stop;
     }
 
@@ -805,9 +803,8 @@  void xen_block_dataplane_start(XenBlockDataPlane *dataplane,
     dataplane->event_channel =
         xen_device_bind_event_channel(xendev, event_channel,
                                       xen_block_dataplane_event, dataplane,
-                                      &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
+                                      errp);
+    if (*errp) {
         goto stop;
     }
 
diff --git a/hw/block/xen-block.c b/hw/block/xen-block.c
index a775fba7c0..623ae5b8e0 100644
--- a/hw/block/xen-block.c
+++ b/hw/block/xen-block.c
@@ -195,6 +195,7 @@  static const BlockDevOps xen_block_dev_ops = {
 
 static void xen_block_realize(XenDevice *xendev, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     XenBlockDevice *blockdev = XEN_BLOCK_DEVICE(xendev);
     XenBlockDeviceClass *blockdev_class =
         XEN_BLOCK_DEVICE_GET_CLASS(xendev);
@@ -202,7 +203,6 @@  static void xen_block_realize(XenDevice *xendev, Error **errp)
     XenBlockVdev *vdev = &blockdev->props.vdev;
     BlockConf *conf = &blockdev->props.conf;
     BlockBackend *blk = conf->blk;
-    Error *local_err = NULL;
 
     if (vdev->type == XEN_BLOCK_VDEV_TYPE_INVALID) {
         error_setg(errp, "vdev property not set");
@@ -212,9 +212,8 @@  static void xen_block_realize(XenDevice *xendev, Error **errp)
     trace_xen_block_realize(type, vdev->disk, vdev->partition);
 
     if (blockdev_class->realize) {
-        blockdev_class->realize(blockdev, &local_err);
-        if (local_err) {
-            error_propagate(errp, local_err);
+        blockdev_class->realize(blockdev, errp);
+        if (*errp) {
             return;
         }
     }
@@ -280,8 +279,8 @@  static void xen_block_frontend_changed(XenDevice *xendev,
                                        enum xenbus_state frontend_state,
                                        Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     enum xenbus_state backend_state = xen_device_backend_get_state(xendev);
-    Error *local_err = NULL;
 
     switch (frontend_state) {
     case XenbusStateInitialised:
@@ -290,15 +289,13 @@  static void xen_block_frontend_changed(XenDevice *xendev,
             break;
         }
 
-        xen_block_disconnect(xendev, &local_err);
-        if (local_err) {
-            error_propagate(errp, local_err);
+        xen_block_disconnect(xendev, errp);
+        if (*errp) {
             break;
         }
 
-        xen_block_connect(xendev, &local_err);
-        if (local_err) {
-            error_propagate(errp, local_err);
+        xen_block_connect(xendev, errp);
+        if (*errp) {
             break;
         }
 
@@ -311,9 +308,8 @@  static void xen_block_frontend_changed(XenDevice *xendev,
 
     case XenbusStateClosed:
     case XenbusStateUnknown:
-        xen_block_disconnect(xendev, &local_err);
-        if (local_err) {
-            error_propagate(errp, local_err);
+        xen_block_disconnect(xendev, errp);
+        if (*errp) {
             break;
         }
 
@@ -665,9 +661,9 @@  static void xen_block_blockdev_del(const char *node_name, Error **errp)
 static char *xen_block_blockdev_add(const char *id, QDict *qdict,
                                     Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     const char *driver = qdict_get_try_str(qdict, "driver");
     BlockdevOptions *options = NULL;
-    Error *local_err = NULL;
     char *node_name;
     Visitor *v;
 
@@ -688,10 +684,9 @@  static char *xen_block_blockdev_add(const char *id, QDict *qdict,
         goto fail;
     }
 
-    qmp_blockdev_add(options, &local_err);
+    qmp_blockdev_add(options, errp);
 
-    if (local_err) {
-        error_propagate(errp, local_err);
+    if (*errp) {
         goto fail;
     }
 
@@ -710,14 +705,12 @@  fail:
 
 static void xen_block_drive_destroy(XenBlockDrive *drive, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     char *node_name = drive->node_name;
 
     if (node_name) {
-        Error *local_err = NULL;
-
-        xen_block_blockdev_del(node_name, &local_err);
-        if (local_err) {
-            error_propagate(errp, local_err);
+        xen_block_blockdev_del(node_name, errp);
+        if (*errp) {
             return;
         }
         g_free(node_name);
@@ -731,6 +724,7 @@  static XenBlockDrive *xen_block_drive_create(const char *id,
                                              const char *device_type,
                                              QDict *opts, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     const char *params = qdict_get_try_str(opts, "params");
     const char *mode = qdict_get_try_str(opts, "mode");
     const char *direct_io_safe = qdict_get_try_str(opts, "direct-io-safe");
@@ -738,7 +732,6 @@  static XenBlockDrive *xen_block_drive_create(const char *id,
     char *driver = NULL;
     char *filename = NULL;
     XenBlockDrive *drive = NULL;
-    Error *local_err = NULL;
     QDict *file_layer;
     QDict *driver_layer;
 
@@ -817,13 +810,12 @@  static XenBlockDrive *xen_block_drive_create(const char *id,
 
     g_assert(!drive->node_name);
     drive->node_name = xen_block_blockdev_add(drive->id, driver_layer,
-                                              &local_err);
+                                              errp);
 
     qobject_unref(driver_layer);
 
 done:
-    if (local_err) {
-        error_propagate(errp, local_err);
+    if (*errp) {
         xen_block_drive_destroy(drive, NULL);
         return NULL;
     }
@@ -848,8 +840,8 @@  static void xen_block_iothread_destroy(XenBlockIOThread *iothread,
 static XenBlockIOThread *xen_block_iothread_create(const char *id,
                                                    Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     XenBlockIOThread *iothread = g_new(XenBlockIOThread, 1);
-    Error *local_err = NULL;
     QDict *opts;
     QObject *ret_data = NULL;
 
@@ -858,13 +850,11 @@  static XenBlockIOThread *xen_block_iothread_create(const char *id,
     opts = qdict_new();
     qdict_put_str(opts, "qom-type", TYPE_IOTHREAD);
     qdict_put_str(opts, "id", id);
-    qmp_object_add(opts, &ret_data, &local_err);
+    qmp_object_add(opts, &ret_data, errp);
     qobject_unref(opts);
     qobject_unref(ret_data);
 
-    if (local_err) {
-        error_propagate(errp, local_err);
-
+    if (*errp) {
         g_free(iothread->id);
         g_free(iothread);
         return NULL;
@@ -876,6 +866,7 @@  static XenBlockIOThread *xen_block_iothread_create(const char *id,
 static void xen_block_device_create(XenBackendInstance *backend,
                                     QDict *opts, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     XenBus *xenbus = xen_backend_get_bus(backend);
     const char *name = xen_backend_get_name(backend);
     unsigned long number;
@@ -883,7 +874,6 @@  static void xen_block_device_create(XenBackendInstance *backend,
     XenBlockDrive *drive = NULL;
     XenBlockIOThread *iothread = NULL;
     XenDevice *xendev = NULL;
-    Error *local_err = NULL;
     const char *type;
     XenBlockDevice *blockdev;
 
@@ -915,16 +905,15 @@  static void xen_block_device_create(XenBackendInstance *backend,
         goto fail;
     }
 
-    drive = xen_block_drive_create(vdev, device_type, opts, &local_err);
+    drive = xen_block_drive_create(vdev, device_type, opts, errp);
     if (!drive) {
-        error_propagate_prepend(errp, local_err, "failed to create drive: ");
+        error_prepend(errp, "failed to create drive: ");
         goto fail;
     }
 
-    iothread = xen_block_iothread_create(vdev, &local_err);
-    if (local_err) {
-        error_propagate_prepend(errp, local_err,
-                                "failed to create iothread: ");
+    iothread = xen_block_iothread_create(vdev, errp);
+    if (*errp) {
+        error_prepend(errp, "failed to create iothread: ");
         goto fail;
     }
 
@@ -932,32 +921,29 @@  static void xen_block_device_create(XenBackendInstance *backend,
     blockdev = XEN_BLOCK_DEVICE(xendev);
 
     if (!object_property_set_str(OBJECT(xendev), "vdev", vdev,
-                                 &local_err)) {
-        error_propagate_prepend(errp, local_err, "failed to set 'vdev': ");
+                                 errp)) {
+        error_prepend(errp, "failed to set 'vdev': ");
         goto fail;
     }
 
     if (!object_property_set_str(OBJECT(xendev), "drive",
                                  xen_block_drive_get_node_name(drive),
-                                 &local_err)) {
-        error_propagate_prepend(errp, local_err, "failed to set 'drive': ");
+                                 errp)) {
+        error_prepend(errp, "failed to set 'drive': ");
         goto fail;
     }
 
     if (!object_property_set_str(OBJECT(xendev), "iothread", iothread->id,
-                                 &local_err)) {
-        error_propagate_prepend(errp, local_err,
-                                "failed to set 'iothread': ");
+                                 errp)) {
+        error_prepend(errp, "failed to set 'iothread': ");
         goto fail;
     }
 
     blockdev->iothread = iothread;
     blockdev->drive = drive;
 
-    if (!qdev_realize_and_unref(DEVICE(xendev), BUS(xenbus), &local_err)) {
-        error_propagate_prepend(errp, local_err,
-                                "realization of device %s failed: ",
-                                type);
+    if (!qdev_realize_and_unref(DEVICE(xendev), BUS(xenbus), errp)) {
+        error_prepend(errp, "realization of device %s failed: ", type);
         goto fail;
     }
 
@@ -981,31 +967,29 @@  fail:
 static void xen_block_device_destroy(XenBackendInstance *backend,
                                      Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     XenDevice *xendev = xen_backend_get_device(backend);
     XenBlockDevice *blockdev = XEN_BLOCK_DEVICE(xendev);
     XenBlockVdev *vdev = &blockdev->props.vdev;
     XenBlockDrive *drive = blockdev->drive;
     XenBlockIOThread *iothread = blockdev->iothread;
-    Error *local_err = NULL;
 
     trace_xen_block_device_destroy(vdev->number);
 
     object_unparent(OBJECT(xendev));
 
     if (iothread) {
-        xen_block_iothread_destroy(iothread, &local_err);
-        if (local_err) {
-            error_propagate_prepend(errp, local_err,
-                                    "failed to destroy iothread: ");
+        xen_block_iothread_destroy(iothread, errp);
+        if (*errp) {
+            error_prepend(errp, "failed to destroy iothread: ");
             return;
         }
     }
 
     if (drive) {
-        xen_block_drive_destroy(drive, &local_err);
-        if (local_err) {
-            error_propagate_prepend(errp, local_err,
-                                    "failed to destroy drive: ");
+        xen_block_drive_destroy(drive, errp);
+        if (*errp) {
+            error_prepend(errp, "failed to destroy drive: ");
             return;
         }
     }
diff --git a/hw/pci-host/xen_igd_pt.c b/hw/pci-host/xen_igd_pt.c
index efcc9347ff..29ade9ca25 100644
--- a/hw/pci-host/xen_igd_pt.c
+++ b/hw/pci-host/xen_igd_pt.c
@@ -79,17 +79,16 @@  static void host_pci_config_read(int pos, int len, uint32_t *val, Error **errp)
 
 static void igd_pt_i440fx_realize(PCIDevice *pci_dev, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     uint32_t val = 0;
     size_t i;
     int pos, len;
-    Error *local_err = NULL;
 
     for (i = 0; i < ARRAY_SIZE(igd_host_bridge_infos); i++) {
         pos = igd_host_bridge_infos[i].offset;
         len = igd_host_bridge_infos[i].len;
-        host_pci_config_read(pos, len, &val, &local_err);
-        if (local_err) {
-            error_propagate(errp, local_err);
+        host_pci_config_read(pos, len, &val, errp);
+        if (*errp) {
             return;
         }
         pci_default_write_config(pci_dev, pos, val, len);
diff --git a/hw/xen/xen-backend.c b/hw/xen/xen-backend.c
index da065f81b7..1cc0694053 100644
--- a/hw/xen/xen-backend.c
+++ b/hw/xen/xen-backend.c
@@ -98,9 +98,9 @@  static void xen_backend_list_remove(XenBackendInstance *backend)
 void xen_backend_device_create(XenBus *xenbus, const char *type,
                                const char *name, QDict *opts, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     const XenBackendImpl *impl = xen_backend_table_lookup(type);
     XenBackendInstance *backend;
-    Error *local_error = NULL;
 
     if (!impl) {
         return;
@@ -110,9 +110,8 @@  void xen_backend_device_create(XenBus *xenbus, const char *type,
     backend->xenbus = xenbus;
     backend->name = g_strdup(name);
 
-    impl->create(backend, opts, &local_error);
-    if (local_error) {
-        error_propagate(errp, local_error);
+    impl->create(backend, opts, errp);
+    if (*errp) {
         g_free(backend->name);
         g_free(backend);
         return;
diff --git a/hw/xen/xen-bus.c b/hw/xen/xen-bus.c
index c4e2162ae9..2ea5144ef0 100644
--- a/hw/xen/xen-bus.c
+++ b/hw/xen/xen-bus.c
@@ -53,9 +53,9 @@  static char *xen_device_get_frontend_path(XenDevice *xendev)
 
 static void xen_device_unplug(XenDevice *xendev, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev)));
     const char *type = object_get_typename(OBJECT(xendev));
-    Error *local_err = NULL;
     xs_transaction_t tid;
 
     trace_xen_device_unplug(type, xendev->name);
@@ -69,14 +69,14 @@  again:
     }
 
     xs_node_printf(xenbus->xsh, tid, xendev->backend_path, "online",
-                   &local_err, "%u", 0);
-    if (local_err) {
+                   errp, "%u", 0);
+    if (*errp) {
         goto abort;
     }
 
     xs_node_printf(xenbus->xsh, tid, xendev->backend_path, "state",
-                   &local_err, "%u", XenbusStateClosing);
-    if (local_err) {
+                   errp, "%u", XenbusStateClosing);
+    if (*errp) {
         goto abort;
     }
 
@@ -96,7 +96,6 @@  abort:
      * from ending the transaction.
      */
     xs_transaction_end(xenbus->xsh, tid, true);
-    error_propagate(errp, local_err);
 }
 
 static void xen_bus_print_dev(Monitor *mon, DeviceState *dev, int indent)
@@ -205,15 +204,13 @@  static XenWatch *watch_list_add(XenWatchList *watch_list, const char *node,
                                 const char *key, XenWatchHandler handler,
                                 void *opaque, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     XenWatch *watch = new_watch(node, key, handler, opaque);
-    Error *local_err = NULL;
 
     notifier_list_add(&watch_list->notifiers, &watch->notifier);
 
-    xs_node_watch(watch_list->xsh, node, key, watch->token, &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
-
+    xs_node_watch(watch_list->xsh, node, key, watch->token, errp);
+    if (*errp) {
         notifier_remove(&watch->notifier);
         free_watch(watch);
 
@@ -255,11 +252,11 @@  static void xen_bus_backend_create(XenBus *xenbus, const char *type,
                                    const char *name, char *path,
                                    Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     xs_transaction_t tid;
     char **key;
     QDict *opts;
     unsigned int i, n;
-    Error *local_err = NULL;
 
     trace_xen_bus_backend_create(type, path);
 
@@ -314,13 +311,11 @@  again:
         return;
     }
 
-    xen_backend_device_create(xenbus, type, name, opts, &local_err);
+    xen_backend_device_create(xenbus, type, name, opts, errp);
     qobject_unref(opts);
 
-    if (local_err) {
-        error_propagate_prepend(errp, local_err,
-                                "failed to create '%s' device '%s': ",
-                                type, name);
+    if (*errp) {
+        error_prepend(errp, "failed to create '%s' device '%s': ", type, name);
     }
 }
 
@@ -692,9 +687,9 @@  static void xen_device_remove_watch(XenDevice *xendev, XenWatch *watch,
 
 static void xen_device_backend_create(XenDevice *xendev, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev)));
     struct xs_permissions perms[2];
-    Error *local_err = NULL;
 
     xendev->backend_path = xen_device_get_backend_path(xendev);
 
@@ -706,30 +701,27 @@  static void xen_device_backend_create(XenDevice *xendev, Error **errp)
     g_assert(xenbus->xsh);
 
     xs_node_create(xenbus->xsh, XBT_NULL, xendev->backend_path, perms,
-                   ARRAY_SIZE(perms), &local_err);
-    if (local_err) {
-        error_propagate_prepend(errp, local_err,
-                                "failed to create backend: ");
+                   ARRAY_SIZE(perms), errp);
+    if (*errp) {
+        error_prepend(errp, "failed to create backend: ");
         return;
     }
 
     xendev->backend_state_watch =
         xen_device_add_watch(xendev, xendev->backend_path,
                              "state", xen_device_backend_changed,
-                             &local_err);
-    if (local_err) {
-        error_propagate_prepend(errp, local_err,
-                                "failed to watch backend state: ");
+                             errp);
+    if (*errp) {
+        error_prepend(errp, "failed to watch backend state: ");
         return;
     }
 
     xendev->backend_online_watch =
         xen_device_add_watch(xendev, xendev->backend_path,
                              "online", xen_device_backend_changed,
-                             &local_err);
-    if (local_err) {
-        error_propagate_prepend(errp, local_err,
-                                "failed to watch backend online: ");
+                             errp);
+    if (*errp) {
+        error_prepend(errp, "failed to watch backend online: ");
         return;
     }
 }
@@ -866,9 +858,9 @@  static bool xen_device_frontend_exists(XenDevice *xendev)
 
 static void xen_device_frontend_create(XenDevice *xendev, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev)));
     struct xs_permissions perms[2];
-    Error *local_err = NULL;
 
     xendev->frontend_path = xen_device_get_frontend_path(xendev);
 
@@ -885,20 +877,18 @@  static void xen_device_frontend_create(XenDevice *xendev, Error **errp)
         g_assert(xenbus->xsh);
 
         xs_node_create(xenbus->xsh, XBT_NULL, xendev->frontend_path, perms,
-                       ARRAY_SIZE(perms), &local_err);
-        if (local_err) {
-            error_propagate_prepend(errp, local_err,
-                                    "failed to create frontend: ");
+                       ARRAY_SIZE(perms), errp);
+        if (*errp) {
+            error_prepend(errp, "failed to create frontend: ");
             return;
         }
     }
 
     xendev->frontend_state_watch =
         xen_device_add_watch(xendev, xendev->frontend_path, "state",
-                             xen_device_frontend_changed, &local_err);
-    if (local_err) {
-        error_propagate_prepend(errp, local_err,
-                                "failed to watch frontend state: ");
+                             xen_device_frontend_changed, errp);
+    if (*errp) {
+        error_prepend(errp, "failed to watch frontend state: ");
     }
 }
 
@@ -1247,11 +1237,11 @@  static void xen_device_exit(Notifier *n, void *data)
 
 static void xen_device_realize(DeviceState *dev, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     XenDevice *xendev = XEN_DEVICE(dev);
     XenDeviceClass *xendev_class = XEN_DEVICE_GET_CLASS(xendev);
     XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev)));
     const char *type = object_get_typename(OBJECT(xendev));
-    Error *local_err = NULL;
 
     if (xendev->frontend_id == DOMID_INVALID) {
         xendev->frontend_id = xen_domid;
@@ -1267,10 +1257,9 @@  static void xen_device_realize(DeviceState *dev, Error **errp)
         goto unrealize;
     }
 
-    xendev->name = xendev_class->get_name(xendev, &local_err);
-    if (local_err) {
-        error_propagate_prepend(errp, local_err,
-                                "failed to get device name: ");
+    xendev->name = xendev_class->get_name(xendev, errp);
+    if (*errp) {
+        error_prepend(errp, "failed to get device name: ");
         goto unrealize;
     }
 
@@ -1293,22 +1282,19 @@  static void xen_device_realize(DeviceState *dev, Error **errp)
     xendev->feature_grant_copy =
         (xengnttab_grant_copy(xendev->xgth, 0, NULL) == 0);
 
-    xen_device_backend_create(xendev, &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
+    xen_device_backend_create(xendev, errp);
+    if (*errp) {
         goto unrealize;
     }
 
-    xen_device_frontend_create(xendev, &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
+    xen_device_frontend_create(xendev, errp);
+    if (*errp) {
         goto unrealize;
     }
 
     if (xendev_class->realize) {
-        xendev_class->realize(xendev, &local_err);
-        if (local_err) {
-            error_propagate(errp, local_err);
+        xendev_class->realize(xendev, errp);
+        if (*errp) {
             goto unrealize;
         }
     }
diff --git a/hw/xen/xen-host-pci-device.c b/hw/xen/xen-host-pci-device.c
index 1b44dcafaf..02379c341c 100644
--- a/hw/xen/xen-host-pci-device.c
+++ b/hw/xen/xen-host-pci-device.c
@@ -333,8 +333,8 @@  void xen_host_pci_device_get(XenHostPCIDevice *d, uint16_t domain,
                              uint8_t bus, uint8_t dev, uint8_t func,
                              Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     unsigned int v;
-    Error *err = NULL;
 
     d->config_fd = -1;
     d->domain = domain;
@@ -342,36 +342,36 @@  void xen_host_pci_device_get(XenHostPCIDevice *d, uint16_t domain,
     d->dev = dev;
     d->func = func;
 
-    xen_host_pci_config_open(d, &err);
-    if (err) {
+    xen_host_pci_config_open(d, errp);
+    if (*errp) {
         goto error;
     }
 
-    xen_host_pci_get_resource(d, &err);
-    if (err) {
+    xen_host_pci_get_resource(d, errp);
+    if (*errp) {
         goto error;
     }
 
-    xen_host_pci_get_hex_value(d, "vendor", &v, &err);
-    if (err) {
+    xen_host_pci_get_hex_value(d, "vendor", &v, errp);
+    if (*errp) {
         goto error;
     }
     d->vendor_id = v;
 
-    xen_host_pci_get_hex_value(d, "device", &v, &err);
-    if (err) {
+    xen_host_pci_get_hex_value(d, "device", &v, errp);
+    if (*errp) {
         goto error;
     }
     d->device_id = v;
 
-    xen_host_pci_get_dec_value(d, "irq", &v, &err);
-    if (err) {
+    xen_host_pci_get_dec_value(d, "irq", &v, errp);
+    if (*errp) {
         goto error;
     }
     d->irq = v;
 
-    xen_host_pci_get_hex_value(d, "class", &v, &err);
-    if (err) {
+    xen_host_pci_get_hex_value(d, "class", &v, errp);
+    if (*errp) {
         goto error;
     }
     d->class_code = v;
@@ -381,7 +381,6 @@  void xen_host_pci_device_get(XenHostPCIDevice *d, uint16_t domain,
     return;
 
 error:
-    error_propagate(errp, err);
 
     if (d->config_fd >= 0) {
         close(d->config_fd);
diff --git a/hw/xen/xen_pt.c b/hw/xen/xen_pt.c
index ab84443d5e..baa25eb91a 100644
--- a/hw/xen/xen_pt.c
+++ b/hw/xen/xen_pt.c
@@ -777,12 +777,12 @@  static void xen_pt_destroy(PCIDevice *d) {
 
 static void xen_pt_realize(PCIDevice *d, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     XenPCIPassthroughState *s = XEN_PT_DEVICE(d);
     int i, rc = 0;
     uint8_t machine_irq = 0, scratch;
     uint16_t cmd = 0;
     int pirq = XEN_PT_UNASSIGNED_PIRQ;
-    Error *err = NULL;
 
     /* register real device */
     XEN_PT_LOG(d, "Assigning real physical device %02x:%02x.%d"
@@ -793,10 +793,9 @@  static void xen_pt_realize(PCIDevice *d, Error **errp)
     xen_host_pci_device_get(&s->real_device,
                             s->hostaddr.domain, s->hostaddr.bus,
                             s->hostaddr.slot, s->hostaddr.function,
-                            &err);
-    if (err) {
-        error_append_hint(&err, "Failed to \"open\" the real pci device");
-        error_propagate(errp, err);
+                            errp);
+    if (*errp) {
+        error_append_hint(errp, "Failed to \"open\" the real pci device");
         return;
     }
 
@@ -823,11 +822,10 @@  static void xen_pt_realize(PCIDevice *d, Error **errp)
             return;
         }
 
-        xen_pt_setup_vga(s, &s->real_device, &err);
-        if (err) {
-            error_append_hint(&err, "Setup VGA BIOS of passthrough"
-                    " GFX failed");
-            error_propagate(errp, err);
+        xen_pt_setup_vga(s, &s->real_device, errp);
+        if (*errp) {
+            error_append_hint(errp, "Setup VGA BIOS of passthrough"
+                              " GFX failed");
             xen_host_pci_device_put(&s->real_device);
             return;
         }
@@ -840,10 +838,9 @@  static void xen_pt_realize(PCIDevice *d, Error **errp)
     xen_pt_register_regions(s, &cmd);
 
     /* reinitialize each config register to be emulated */
-    xen_pt_config_init(s, &err);
-    if (err) {
-        error_append_hint(&err, "PCI Config space initialisation failed");
-        error_propagate(errp, err);
+    xen_pt_config_init(s, errp);
+    if (*errp) {
+        error_append_hint(errp, "PCI Config space initialisation failed");
         rc = -1;
         goto err_out;
     }
diff --git a/hw/xen/xen_pt_config_init.c b/hw/xen/xen_pt_config_init.c
index d0d7c720a6..af3fbd1bfb 100644
--- a/hw/xen/xen_pt_config_init.c
+++ b/hw/xen/xen_pt_config_init.c
@@ -2008,8 +2008,8 @@  static void xen_pt_config_reg_init(XenPCIPassthroughState *s,
 
 void xen_pt_config_init(XenPCIPassthroughState *s, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     int i, rc;
-    Error *err = NULL;
 
     QLIST_INIT(&s->reg_grps);
 
@@ -2067,13 +2067,14 @@  void xen_pt_config_init(XenPCIPassthroughState *s, Error **errp)
 
                 /* initialize capability register */
                 for (j = 0; regs->size != 0; j++, regs++) {
-                    xen_pt_config_reg_init(s, reg_grp_entry, regs, &err);
-                    if (err) {
-                        error_append_hint(&err, "Failed to init register %d"
-                                " offsets 0x%x in grp_type = 0x%x (%d/%zu)", j,
-                                regs->offset, xen_pt_emu_reg_grps[i].grp_type,
-                                i, ARRAY_SIZE(xen_pt_emu_reg_grps));
-                        error_propagate(errp, err);
+                    xen_pt_config_reg_init(s, reg_grp_entry, regs, errp);
+                    if (*errp) {
+                        error_append_hint(errp, "Failed to init register %d"
+                                          " offsets 0x%x in grp_type = 0x%x (%d/%zu)",
+                                          j,
+                                          regs->offset,
+                                          xen_pt_emu_reg_grps[i].grp_type,
+                                          i, ARRAY_SIZE(xen_pt_emu_reg_grps));
                         xen_pt_config_delete(s);
                         return;
                     }