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[Qemu-devel] [PATCH v3 2/2] pc: memhp: force gaps between DIMM's GPA
From: |
Igor Mammedov |
Subject: |
[Qemu-devel] [PATCH v3 2/2] pc: memhp: force gaps between DIMM's GPA |
Date: |
Tue, 29 Sep 2015 16:53:29 +0200 |
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 <address@hidden>
Signed-off-by: Igor Mammedov <address@hidden>
Acked-by: Eduardo Habkost <address@hidden>
---
v3:
use pc_machine_class_init() for default. (Eduardo)
v2:
make inter_dimm_gap boolean
benefit of this workaround is that no guest side
changes are required.
---
hw/i386/pc.c | 6 ++++--
hw/i386/pc_piix.c | 1 +
hw/i386/pc_q35.c | 1 +
include/hw/i386/pc.h | 1 +
4 files changed, 7 insertions(+), 2 deletions(-)
diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index ef02736..efbd41a 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -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;
diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
index 3ffb05f..d97ca2a 100644
--- a/hw/i386/pc_piix.c
+++ b/hw/i386/pc_piix.c
@@ -482,6 +482,7 @@ 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);
}
diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
index 1b7d3b6..c28f0da 100644
--- a/hw/i386/pc_q35.c
+++ b/hw/i386/pc_q35.c
@@ -385,6 +385,7 @@ 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);
}
diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
index ab5413f..c13e91d 100644
--- a/include/hw/i386/pc.h
+++ b/include/hw/i386/pc.h
@@ -60,6 +60,7 @@ struct PCMachineClass {
/*< public >*/
bool broken_reserved_end;
+ bool inter_dimm_gap;
HotplugHandler *(*get_hotplug_handler)(MachineState *machine,
DeviceState *dev);
};
--
1.8.3.1