* [Qemu-devel] [PATCH v2 1/2] spapr: Accommadate alignment gaps in hotplug memory region
2015-10-26 8:00 [Qemu-devel] [PATCH v2 0/2] Enforce gaps between DIMMs Bharata B Rao
@ 2015-10-26 8:00 ` Bharata B Rao
2015-10-26 8:00 ` [Qemu-devel] [PATCH v2 2/2] spapr: Force gaps between DIMM's GPA Bharata B Rao
2015-10-26 10:21 ` [Qemu-devel] [PATCH v2 0/2] Enforce gaps between DIMMs Michael S. Tsirkin
2 siblings, 0 replies; 4+ messages in thread
From: Bharata B Rao @ 2015-10-26 8:00 UTC (permalink / raw)
To: qemu-devel; +Cc: imammedo, mst, Bharata B Rao, david
Accommodate enough space in hotplug memory region so that it will
be possible to align memory in each slot to 256M. When PowerPC memory
hotplug enables inter-dimm gaps, then we could end up having
unused/unassigned 256M memory chucks between DIMMs in the hotplug memory
region. Hence create DRC objects spanning the entire alignment-adjusted
hotplug memory region instead of just the acutal
hotpluggable size (machine->maxram_size - machine->ram_size).
In addition, pass 256M alignment to pc_dimm_memory_plug() so that
the DIMM address gets aligned to 256M.
Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
---
hw/ppc/spapr.c | 21 +++++++++++++++++----
1 file changed, 17 insertions(+), 4 deletions(-)
diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index e1202ce..f29bb10 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -753,7 +753,7 @@ static int spapr_populate_drconf_memory(sPAPRMachineState *spapr, void *fdt)
int ret, i, offset;
uint64_t lmb_size = SPAPR_MEMORY_BLOCK_SIZE;
uint32_t prop_lmb_size[] = {0, cpu_to_be32(lmb_size)};
- uint32_t nr_lmbs = (machine->maxram_size - machine->ram_size)/lmb_size;
+ uint32_t nr_lmbs = memory_region_size(&spapr->hotplug_memory.mr)/lmb_size;
uint32_t *int_buf, *cur_index, buf_len;
int nr_nodes = nb_numa_nodes ? nb_numa_nodes : 1;
@@ -1647,9 +1647,8 @@ static void spapr_drc_reset(void *opaque)
static void spapr_create_lmb_dr_connectors(sPAPRMachineState *spapr)
{
- MachineState *machine = MACHINE(spapr);
uint64_t lmb_size = SPAPR_MEMORY_BLOCK_SIZE;
- uint32_t nr_lmbs = (machine->maxram_size - machine->ram_size)/lmb_size;
+ uint32_t nr_lmbs = memory_region_size(&spapr->hotplug_memory.mr)/lmb_size;
int i;
for (i = 0; i < nr_lmbs; i++) {
@@ -1825,6 +1824,20 @@ static void ppc_spapr_init(MachineState *machine)
spapr->hotplug_memory.base = ROUND_UP(machine->ram_size,
SPAPR_HOTPLUG_MEM_ALIGN);
+
+ /*
+ * Ensure that there is enough space in the hotplug memory
+ * region to support a maximum alignment of 256M per slot.
+ * Though PowerPC has 16M and 16G huge pages, PowerKVM supports
+ * only 16M and hence 256M alignment works until we start
+ * supporting 16G hugepage.
+ *
+ * Instead of max hugepage size alignment, we go with 256M
+ * alignment because we require the DIMM address to be 256M
+ * aligned as we maintain a DRC object for every 256M memory
+ * chunk in the hotplug memory region.
+ */
+ hotplug_mem_size += SPAPR_MEMORY_BLOCK_SIZE * machine->ram_slots;
memory_region_init(&spapr->hotplug_memory.mr, OBJECT(spapr),
"hotplug-memory", hotplug_mem_size);
memory_region_add_subregion(sysmem, spapr->hotplug_memory.base,
@@ -2147,7 +2160,7 @@ static void spapr_memory_plug(HotplugHandler *hotplug_dev, DeviceState *dev,
PCDIMMDevice *dimm = PC_DIMM(dev);
PCDIMMDeviceClass *ddc = PC_DIMM_GET_CLASS(dimm);
MemoryRegion *mr = ddc->get_memory_region(dimm);
- uint64_t align = memory_region_get_alignment(mr);
+ uint64_t align = SPAPR_MEMORY_BLOCK_SIZE;
uint64_t size = memory_region_size(mr);
uint64_t addr;
--
2.1.0
^ permalink raw reply related [flat|nested] 4+ messages in thread* [Qemu-devel] [PATCH v2 2/2] spapr: Force gaps between DIMM's GPA
2015-10-26 8:00 [Qemu-devel] [PATCH v2 0/2] Enforce gaps between DIMMs Bharata B Rao
2015-10-26 8:00 ` [Qemu-devel] [PATCH v2 1/2] spapr: Accommadate alignment gaps in hotplug memory region Bharata B Rao
@ 2015-10-26 8:00 ` Bharata B Rao
2015-10-26 10:21 ` [Qemu-devel] [PATCH v2 0/2] Enforce gaps between DIMMs Michael S. Tsirkin
2 siblings, 0 replies; 4+ messages in thread
From: Bharata B Rao @ 2015-10-26 8:00 UTC (permalink / raw)
To: qemu-devel; +Cc: imammedo, mst, Bharata B Rao, david
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: Bharata B Rao <bharata@linux.vnet.ibm.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
---
hw/ppc/spapr.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index f29bb10..1a8df95 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -2170,7 +2170,7 @@ static void spapr_memory_plug(HotplugHandler *hotplug_dev, DeviceState *dev,
goto out;
}
- pc_dimm_memory_plug(dev, &ms->hotplug_memory, mr, align, false, &local_err);
+ pc_dimm_memory_plug(dev, &ms->hotplug_memory, mr, align, true, &local_err);
if (local_err) {
goto out;
}
--
2.1.0
^ permalink raw reply related [flat|nested] 4+ messages in thread