From 1365bf10ad49fd7c0a3b4e2eabeaacd1abf60d18 Mon Sep 17 00:00:00 2001 From: Greg Kurz Date: Tue, 19 Jan 2021 15:20:43 -0500 Subject: [PATCH 1/5] spapr: Allow memory unplug to always succeed RH-Author: Greg Kurz Message-id: <20210119152044.1019191-2-gkurz@redhat.com> Patchwork-id: 100690 O-Subject: [RHEL-AV-8.4.0 qemu-kvm PATCH 1/2] spapr: Allow memory unplug to always succeed Bugzilla: 1914069 RH-Acked-by: Miroslav Rezanina RH-Acked-by: Laurent Vivier RH-Acked-by: David Gibson From: Greg Kurz It is currently impossible to hot-unplug a memory device between machine reset and CAS. (qemu) device_del dimm1 Error: Memory hot unplug not supported for this guest This limitation was introduced in order to provide an explicit error path for older guests that didn't support hot-plug event sources (and thus memory hot-unplug). The linux kernel has been supporting these since 4.11. All recent enough guests are thus capable of handling the removal of a memory device at all time, including during early boot. Lift the limitation for the latest machine type. This means that trying to unplug memory from a guest that doesn't support it will likely just do nothing and the memory will only get removed at next reboot. Such older guests can still get the existing behavior by using an older machine type. Signed-off-by: Greg Kurz Message-Id: <160794035064.23292.17560963281911312439.stgit@bahia.lan> Signed-off-by: David Gibson (cherry picked from commit 1e8b5b1aa16b7d73ba8ba52c95d0b52329d5c9d0) Signed-off-by: Greg Kurz Conflicts: hw/ppc/spapr.c Conflict because RHEL-AV doesn't have upstream 576a00bdeb5b ("hw: add compat machines for 6.0"). Just ignore the change that sets pre_6_0_memory_unplug for older machine types since the next patch removes the flag. Signed-off-by: Eduardo Lima (Etrunko) --- hw/ppc/spapr.c | 3 ++- hw/ppc/spapr_events.c | 3 ++- include/hw/ppc/spapr.h | 1 + 3 files changed, 5 insertions(+), 2 deletions(-) diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c index 4f61b64a21..65a647134a 100644 --- a/hw/ppc/spapr.c +++ b/hw/ppc/spapr.c @@ -4064,7 +4064,8 @@ 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 (spapr_ovec_test(sms->ov5_cas, OV5_HP_EVT)) { + if (!smc->pre_6_0_memory_unplug || + spapr_ovec_test(sms->ov5_cas, OV5_HP_EVT)) { spapr_memory_unplug_request(hotplug_dev, dev, errp); } else { /* NOTE: this means there is a window after guest reset, prior to diff --git a/hw/ppc/spapr_events.c b/hw/ppc/spapr_events.c index 1add53547e..c30123177b 100644 --- a/hw/ppc/spapr_events.c +++ b/hw/ppc/spapr_events.c @@ -659,7 +659,8 @@ 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_ovec_test(spapr->ov5_cas, OV5_HP_EVT)); + g_assert(!SPAPR_MACHINE_GET_CLASS(spapr)->pre_6_0_memory_unplug || + spapr_ovec_test(spapr->ov5_cas, OV5_HP_EVT)); hp->drc_id.count_indexed.count = cpu_to_be32(drc_id->count_indexed.count); hp->drc_id.count_indexed.index = diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h index 28bbf07f8f..4941fe9b4f 100644 --- a/include/hw/ppc/spapr.h +++ b/include/hw/ppc/spapr.h @@ -142,6 +142,7 @@ struct SpaprMachineClass { hwaddr rma_limit; /* clamp the RMA to this size */ bool pre_5_1_assoc_refpoints; bool pre_5_2_numa_associativity; + bool pre_6_0_memory_unplug; bool has_power9_support; void (*phb_placement)(SpaprMachineState *spapr, uint32_t index, -- 2.18.4