On Mon, Dec 14, 2020 at 11:05:50AM +0100, Greg Kurz wrote: 65;6201;1c> 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 <gr...@kaod.org> > --- > This patch was initially posted before the compat machine types > for 6.0 got merged upstream. During the same period, David was > also transitioning from github to gitlab, and the patch didn't > applied cleanly. Now it does. Just reposting it unchanged for > convenience.
Applied to ppc-for-6.0, thanks.
> ---
> hw/ppc/spapr.c | 6 +++++-
> hw/ppc/spapr_events.c | 3 ++-
> include/hw/ppc/spapr.h | 1 +
> 3 files changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> index dee48a0043bb..481c800a5a33 100644
> --- a/hw/ppc/spapr.c
> +++ b/hw/ppc/spapr.c
> @@ -4051,7 +4051,8 @@ 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
> @@ -4537,8 +4538,11 @@ 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 3f37b49fd8ad..6aedd988b3d0 100644
> --- a/hw/ppc/spapr_events.c
> +++ b/hw/ppc/spapr_events.c
> @@ -658,7 +658,8 @@ 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 e0f10f252c08..06a5b4259f20 100644
> --- a/include/hw/ppc/spapr.h
> +++ b/include/hw/ppc/spapr.h
> @@ -139,6 +139,7 @@ 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 (*phb_placement)(SpaprMachineState *spapr, uint32_t index,
> uint64_t *buid, hwaddr *pio,
>
>
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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