[PATCH v4 2/3] spapr: use DEVICE_UNPLUG_ERROR to report unplug errors

[Daniel Henrique Barboza <danielhb413@gmail.com>]

Linux Kernel 5.12 is now unisolating CPU DRCs in the device_removal
error path, signalling that the hotunplug process wasn't successful.
This allow us to send a DEVICE_UNPLUG_ERROR in drc_unisolate_logical()
to signal this error to the management layer.

We also have another error path in spapr_memory_unplug_rollback() for
configured LMB DRCs. Kernels older than 5.13 will not unisolate the LMBs
in the hotunplug error path, but it will reconfigure them. Let's send
the DEVICE_UNPLUG_ERROR event in that code path as well to cover the
case of older kernels.

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
---
 hw/ppc/spapr.c     |  8 ++++++++
 hw/ppc/spapr_drc.c | 15 +++++++++------
 2 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 4dd90b75cc..fc071a1767 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -29,6 +29,7 @@
 #include "qemu/datadir.h"
 #include "qapi/error.h"
 #include "qapi/qapi-events-machine.h"
+#include "qapi/qapi-events-qdev.h"
 #include "qapi/visitor.h"
 #include "sysemu/sysemu.h"
 #include "sysemu/hostmem.h"
@@ -3641,7 +3642,14 @@ void spapr_memory_unplug_rollback(SpaprMachineState *spapr, DeviceState *dev)
      */
     qapi_error = g_strdup_printf("Memory hotunplug rejected by the guest "
                                  "for device %s", dev->id);
+
+    /*
+     * Send both MEM_UNPLUG_ERROR and DEVICE_UNPLUG_ERROR
+     * while the deprecation of MEM_UNPLUG_ERROR is
+     * pending.
+     */
     qapi_event_send_mem_unplug_error(dev->id, qapi_error);
+    qapi_event_send_device_unplug_error(dev->id, qapi_error);
 }
 
 /* Callback to be called during DRC release. */
diff --git a/hw/ppc/spapr_drc.c b/hw/ppc/spapr_drc.c
index a2f2634601..45a7b1aa16 100644
--- a/hw/ppc/spapr_drc.c
+++ b/hw/ppc/spapr_drc.c
@@ -17,6 +17,8 @@
 #include "hw/ppc/spapr_drc.h"
 #include "qom/object.h"
 #include "migration/vmstate.h"
+#include "qapi/error.h"
+#include "qapi/qapi-events-qdev.h"
 #include "qapi/visitor.h"
 #include "qemu/error-report.h"
 #include "hw/ppc/spapr.h" /* for RTAS return codes */
@@ -160,6 +162,10 @@ static uint32_t drc_unisolate_logical(SpaprDrc *drc)
          * means that the kernel is refusing the removal.
          */
         if (drc->unplug_requested && drc->dev) {
+            const char qapi_error_fmt[] = "Device hotunplug rejected by the "
+                                          "guest for device %s";
+            g_autofree char *qapi_error = NULL;
+
             if (spapr_drc_type(drc) == SPAPR_DR_CONNECTOR_TYPE_LMB) {
                 spapr = SPAPR_MACHINE(qdev_get_machine());
 
@@ -167,13 +173,10 @@ static uint32_t drc_unisolate_logical(SpaprDrc *drc)
             }
 
             drc->unplug_requested = false;
-            error_report("Device hotunplug rejected by the guest "
-                         "for device %s", drc->dev->id);
+            error_report(qapi_error_fmt, drc->dev->id);
 
-            /*
-             * TODO: send a QAPI DEVICE_UNPLUG_ERROR event when
-             * it is implemented.
-             */
+            qapi_error = g_strdup_printf(qapi_error_fmt, drc->dev->id);
+            qapi_event_send_device_unplug_error(drc->dev->id, qapi_error);
         }
 
         return RTAS_OUT_SUCCESS; /* Nothing to do */
-- 
2.31.1