pc: memhp: force gaps between DIMM's GPA

mapping DIMMs non contiguously allows to workaround
virtio bug reported earlier:
http://lists.nongnu.org/archive/html/qemu-devel/2015-08/msg00522.html
in this case guest kernel doesn't allocate buffers
that can cross DIMM boundary keeping each buffer
local to a DIMM.

Suggested-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Acked-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Igor Mammedov 2015-09-29 16:53:29 +02:00 committed by Michael S. Tsirkin
parent df0acded19
commit aa8580cddf
4 changed files with 7 additions and 2 deletions

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@ -1629,6 +1629,7 @@ static void pc_dimm_plug(HotplugHandler *hotplug_dev,
HotplugHandlerClass *hhc; HotplugHandlerClass *hhc;
Error *local_err = NULL; Error *local_err = NULL;
PCMachineState *pcms = PC_MACHINE(hotplug_dev); PCMachineState *pcms = PC_MACHINE(hotplug_dev);
PCMachineClass *pcmc = PC_MACHINE_GET_CLASS(pcms);
PCDIMMDevice *dimm = PC_DIMM(dev); PCDIMMDevice *dimm = PC_DIMM(dev);
PCDIMMDeviceClass *ddc = PC_DIMM_GET_CLASS(dimm); PCDIMMDeviceClass *ddc = PC_DIMM_GET_CLASS(dimm);
MemoryRegion *mr = ddc->get_memory_region(dimm); MemoryRegion *mr = ddc->get_memory_region(dimm);
@ -1644,8 +1645,8 @@ static void pc_dimm_plug(HotplugHandler *hotplug_dev,
goto out; goto out;
} }
pc_dimm_memory_plug(dev, &pcms->hotplug_memory, mr, align, false, pc_dimm_memory_plug(dev, &pcms->hotplug_memory, mr, align,
&local_err); pcmc->inter_dimm_gap, &local_err);
if (local_err) { if (local_err) {
goto out; goto out;
} }
@ -1946,6 +1947,7 @@ static void pc_machine_class_init(ObjectClass *oc, void *data)
PCMachineClass *pcmc = PC_MACHINE_CLASS(oc); PCMachineClass *pcmc = PC_MACHINE_CLASS(oc);
HotplugHandlerClass *hc = HOTPLUG_HANDLER_CLASS(oc); HotplugHandlerClass *hc = HOTPLUG_HANDLER_CLASS(oc);
pcmc->inter_dimm_gap = true;
pcmc->get_hotplug_handler = mc->get_hotplug_handler; pcmc->get_hotplug_handler = mc->get_hotplug_handler;
mc->get_hotplug_handler = pc_get_hotpug_handler; mc->get_hotplug_handler = pc_get_hotpug_handler;
mc->cpu_index_to_socket_id = pc_cpu_index_to_socket_id; mc->cpu_index_to_socket_id = pc_cpu_index_to_socket_id;

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@ -489,6 +489,7 @@ static void pc_i440fx_2_4_machine_options(MachineClass *m)
m->alias = NULL; m->alias = NULL;
m->is_default = 0; m->is_default = 0;
pcmc->broken_reserved_end = true; pcmc->broken_reserved_end = true;
pcmc->inter_dimm_gap = false;
SET_MACHINE_COMPAT(m, PC_COMPAT_2_4); SET_MACHINE_COMPAT(m, PC_COMPAT_2_4);
} }

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@ -392,6 +392,7 @@ static void pc_q35_2_4_machine_options(MachineClass *m)
pc_q35_2_5_machine_options(m); pc_q35_2_5_machine_options(m);
m->alias = NULL; m->alias = NULL;
pcmc->broken_reserved_end = true; pcmc->broken_reserved_end = true;
pcmc->inter_dimm_gap = false;
SET_MACHINE_COMPAT(m, PC_COMPAT_2_4); SET_MACHINE_COMPAT(m, PC_COMPAT_2_4);
} }

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@ -60,6 +60,7 @@ struct PCMachineClass {
/*< public >*/ /*< public >*/
bool broken_reserved_end; bool broken_reserved_end;
bool inter_dimm_gap;
HotplugHandler *(*get_hotplug_handler)(MachineState *machine, HotplugHandler *(*get_hotplug_handler)(MachineState *machine,
DeviceState *dev); DeviceState *dev);
}; };