Commit aa8580cd authored by Igor Mammedov's avatar Igor Mammedov Committed by Michael S. Tsirkin
Browse files

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: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarIgor Mammedov <imammedo@redhat.com>
Acked-by: default avatarEduardo Habkost <ehabkost@redhat.com>
Reviewed-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent df0acded

hw/i386/pc.c

+4 −2
Original line number Diff line number Diff line
@@ -1629,6 +1629,7 @@ static void pc_dimm_plug(HotplugHandler *hotplug_dev, 
    HotplugHandlerClass *hhc;

    Error *local_err = NULL;

    PCMachineState *pcms = PC_MACHINE(hotplug_dev);

    PCMachineClass *pcmc = PC_MACHINE_GET_CLASS(pcms);

    PCDIMMDevice *dimm = PC_DIMM(dev);

    PCDIMMDeviceClass *ddc = PC_DIMM_GET_CLASS(dimm);

    MemoryRegion *mr = ddc->get_memory_region(dimm);
@@ -1644,8 +1645,8 @@ static void pc_dimm_plug(HotplugHandler *hotplug_dev, 
        goto out;

    }



    pc_dimm_memory_plug(dev, &pcms->hotplug_memory, mr, align, false,

                        &local_err);

    pc_dimm_memory_plug(dev, &pcms->hotplug_memory, mr, align,

                        pcmc->inter_dimm_gap, &local_err);

    if (local_err) {

        goto out;

    }
@@ -1946,6 +1947,7 @@ static void pc_machine_class_init(ObjectClass *oc, void *data) 
    PCMachineClass *pcmc = PC_MACHINE_CLASS(oc);

    HotplugHandlerClass *hc = HOTPLUG_HANDLER_CLASS(oc);



    pcmc->inter_dimm_gap = true;

    pcmc->get_hotplug_handler = mc->get_hotplug_handler;

    mc->get_hotplug_handler = pc_get_hotpug_handler;

    mc->cpu_index_to_socket_id = pc_cpu_index_to_socket_id;

hw/i386/pc_piix.c

+1 −0
Original line number Diff line number Diff line
@@ -489,6 +489,7 @@ static void pc_i440fx_2_4_machine_options(MachineClass *m) 
    m->alias = NULL;

    m->is_default = 0;

    pcmc->broken_reserved_end = true;

    pcmc->inter_dimm_gap = false;

    SET_MACHINE_COMPAT(m, PC_COMPAT_2_4);

}

hw/i386/pc_q35.c

+1 −0
Original line number Diff line number Diff line
@@ -392,6 +392,7 @@ static void pc_q35_2_4_machine_options(MachineClass *m) 
    pc_q35_2_5_machine_options(m);

    m->alias = NULL;

    pcmc->broken_reserved_end = true;

    pcmc->inter_dimm_gap = false;

    SET_MACHINE_COMPAT(m, PC_COMPAT_2_4);

}

include/hw/i386/pc.h

+1 −0
Original line number Diff line number Diff line
@@ -60,6 +60,7 @@ struct PCMachineClass { 


    /*< public >*/

    bool broken_reserved_end;

    bool inter_dimm_gap;

    HotplugHandler *(*get_hotplug_handler)(MachineState *machine,

                                           DeviceState *dev);

};