aboutsummaryrefslogtreecommitdiff
path: root/hw/ppc
diff options
context:
space:
mode:
authorGreg Kurz <groug@kaod.org>2021-01-08 18:31:27 +0100
committerDavid Gibson <david@gibson.dropbear.id.au>2021-01-19 10:20:29 +1100
commit73598c75df0585e039825e642adede21912dabc7 (patch)
treea93fe89b0b8877e353c7ec73711ca24ae71633a1 /hw/ppc
parentf17969db719ef563d2f7a1b62ea5dd5087ad774a (diff)
spapr: Improve handling of memory unplug with old guests
Since commit 1e8b5b1aa16b ("spapr: Allow memory unplug to always succeed") trying to unplug memory from a guest that doesn't support it (eg. rhel6) no longer generates an error like it used to. Instead, it leaves the memory around : only a subsequent reboot or manual use of drmgr within the guest can complete the hot-unplug sequence. A flag was added to SpaprMachineClass so that this new behavior only applies to the default machine type. We can do better. CAS processes all pending hot-unplug requests. This means that we don't really care about what the guest supports if the hot-unplug request happens before CAS. All guests that we care for, even old ones, set enough bits in OV5 that lead to a non-empty bitmap in spapr->ov5_cas. Use that as a heuristic to decide if CAS has already occured or not. Always accept unplug requests that happen before CAS since CAS will process them. Restore the previous behavior of rejecting them after CAS when we know that the guest doesn't support memory hot-unplug. This behavior is suitable for all machine types : this allows to drop the pre_6_0_memory_unplug flag. Fixes: 1e8b5b1aa16b ("spapr: Allow memory unplug to always succeed") Signed-off-by: Greg Kurz <groug@kaod.org> Message-Id: <161012708715.801107.11418801796987916516.stgit@bahia.lan> Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com> Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Diffstat (limited to 'hw/ppc')
-rw-r--r--hw/ppc/spapr.c24
-rw-r--r--hw/ppc/spapr_events.c3
-rw-r--r--hw/ppc/spapr_ovec.c7
3 files changed, 21 insertions, 13 deletions
diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 2c403b574e..6c47466fc2 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -4048,6 +4048,18 @@ static void spapr_machine_device_unplug(HotplugHandler *hotplug_dev,
}
}
+bool spapr_memory_hot_unplug_supported(SpaprMachineState *spapr)
+{
+ return spapr_ovec_test(spapr->ov5_cas, OV5_HP_EVT) ||
+ /*
+ * CAS will process all pending unplug requests.
+ *
+ * HACK: a guest could theoretically have cleared all bits in OV5,
+ * but none of the guests we care for do.
+ */
+ spapr_ovec_empty(spapr->ov5_cas);
+}
+
static void spapr_machine_device_unplug_request(HotplugHandler *hotplug_dev,
DeviceState *dev, Error **errp)
{
@@ -4056,16 +4068,9 @@ static void spapr_machine_device_unplug_request(HotplugHandler *hotplug_dev,
SpaprMachineClass *smc = SPAPR_MACHINE_CLASS(mc);
if (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM)) {
- if (!smc->pre_6_0_memory_unplug ||
- spapr_ovec_test(sms->ov5_cas, OV5_HP_EVT)) {
+ if (spapr_memory_hot_unplug_supported(sms)) {
spapr_memory_unplug_request(hotplug_dev, dev, errp);
} else {
- /* NOTE: this means there is a window after guest reset, prior to
- * CAS negotiation, where unplug requests will fail due to the
- * capability not being detected yet. This is a bit different than
- * the case with PCI unplug, where the events will be queued and
- * eventually handled by the guest after boot
- */
error_setg(errp, "Memory hot unplug not supported for this guest");
}
} else if (object_dynamic_cast(OBJECT(dev), TYPE_SPAPR_CPU_CORE)) {
@@ -4543,11 +4548,8 @@ DEFINE_SPAPR_MACHINE(6_0, "6.0", true);
*/
static void spapr_machine_5_2_class_options(MachineClass *mc)
{
- SpaprMachineClass *smc = SPAPR_MACHINE_CLASS(mc);
-
spapr_machine_6_0_class_options(mc);
compat_props_add(mc->compat_props, hw_compat_5_2, hw_compat_5_2_len);
- smc->pre_6_0_memory_unplug = true;
}
DEFINE_SPAPR_MACHINE(5_2, "5.2", false);
diff --git a/hw/ppc/spapr_events.c b/hw/ppc/spapr_events.c
index 6aedd988b3..d51daedfa6 100644
--- a/hw/ppc/spapr_events.c
+++ b/hw/ppc/spapr_events.c
@@ -658,8 +658,7 @@ static void spapr_hotplug_req_event(uint8_t hp_id, uint8_t hp_action,
/* we should not be using count_indexed value unless the guest
* supports dedicated hotplug event source
*/
- g_assert(!SPAPR_MACHINE_GET_CLASS(spapr)->pre_6_0_memory_unplug ||
- spapr_ovec_test(spapr->ov5_cas, OV5_HP_EVT));
+ g_assert(spapr_memory_hot_unplug_supported(spapr));
hp->drc_id.count_indexed.count =
cpu_to_be32(drc_id->count_indexed.count);
hp->drc_id.count_indexed.index =
diff --git a/hw/ppc/spapr_ovec.c b/hw/ppc/spapr_ovec.c
index dd003f1763..b2567caa5c 100644
--- a/hw/ppc/spapr_ovec.c
+++ b/hw/ppc/spapr_ovec.c
@@ -125,6 +125,13 @@ bool spapr_ovec_test(SpaprOptionVector *ov, long bitnr)
return test_bit(bitnr, ov->bitmap) ? true : false;
}
+bool spapr_ovec_empty(SpaprOptionVector *ov)
+{
+ g_assert(ov);
+
+ return bitmap_empty(ov->bitmap, OV_MAXBITS);
+}
+
static void guest_byte_to_bitmap(uint8_t entry, unsigned long *bitmap,
long bitmap_offset)
{