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[Qemu-devel] [PATCH v3] spapr: Ensure all LMBs are represented in ibm, d
From: |
Bharata B Rao |
Subject: |
[Qemu-devel] [PATCH v3] spapr: Ensure all LMBs are represented in ibm, dynamic-memory |
Date: |
Tue, 7 Jun 2016 10:49:03 +0530 |
Memory hotplug can fail for some combinations of RAM and maxmem when
DDW is enabled in the presence of devices like nec-usb-xhci. DDW depends
on maximum addressable memory returned by guest and this value is currently
being calculated wrongly by the guest kernel routine memory_hotplug_max().
While there is an attempt to fix the guest kernel, this patch works
around the problem within QEMU itself.
memory_hotplug_max() routine in the guest kernel arrives at max
addressable memory by multiplying lmb-size with the lmb-count obtained
from ibm,dynamic-memory property. There are two assumptions here:
- All LMBs are part of ibm,dynamic memory: This is not true for PowerKVM
where only hot-pluggable LMBs are present in this property.
- The memory area comprising of RAM and hotplug region is contiguous: This
needn't be true always for PowerKVM as there can be gap between
boot time RAM and hotplug region.
To work around this guest kernel bug, ensure that ibm,dynamic-memory
has information about all the LMBs (RMA, boot-time LMBs, future
hotpluggable LMBs, and dummy LMBs to cover the gap between RAM and
hotpluggable region).
RMA is represented separately by address@hidden node. Hence mark RMA LMBs
and also the LMBs for the gap b/n RAM and hotpluggable region as
reserved so that these LMBs are not recounted/counted by guest.
Signed-off-by: Bharata B Rao <address@hidden>
---
Changes in v3:
- Not touching spapr_create_lmb_dr_connectors() so that we continue
to have DRC objects for only hotpluggable LMBs.
- Simplified the logic of creating dynamic-memory node based on comments
from Michael Roth and David Gibson.
v2: https://lists.gnu.org/archive/html/qemu-devel/2016-06/msg01316.html
hw/ppc/spapr.c | 51 ++++++++++++++++++++++++++++++++------------------
include/hw/ppc/spapr.h | 5 +++--
2 files changed, 36 insertions(+), 20 deletions(-)
diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 0636642..9d1d43d 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -762,14 +762,17 @@ 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 hotplug_lmb_start = spapr->hotplug_memory.base / lmb_size;
+ uint32_t nr_lmbs = (spapr->hotplug_memory.base +
+ 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;
/*
- * Don't create the node if there are no DR LMBs.
+ * Don't create the node if there is no hotpluggable memory
*/
- if (!nr_lmbs) {
+ if (machine->ram_size == machine->maxram_size) {
return 0;
}
@@ -805,24 +808,36 @@ static int spapr_populate_drconf_memory(sPAPRMachineState
*spapr, void *fdt)
for (i = 0; i < nr_lmbs; i++) {
sPAPRDRConnector *drc;
sPAPRDRConnectorClass *drck;
- uint64_t addr = i * lmb_size + spapr->hotplug_memory.base;;
+ uint64_t addr = i * lmb_size;
uint32_t *dynamic_memory = cur_index;
- drc = spapr_dr_connector_by_id(SPAPR_DR_CONNECTOR_TYPE_LMB,
- addr/lmb_size);
- g_assert(drc);
- drck = SPAPR_DR_CONNECTOR_GET_CLASS(drc);
-
- dynamic_memory[0] = cpu_to_be32(addr >> 32);
- dynamic_memory[1] = cpu_to_be32(addr & 0xffffffff);
- dynamic_memory[2] = cpu_to_be32(drck->get_index(drc));
- dynamic_memory[3] = cpu_to_be32(0); /* reserved */
- dynamic_memory[4] = cpu_to_be32(numa_get_node(addr, NULL));
- if (addr < machine->ram_size ||
- memory_region_present(get_system_memory(), addr)) {
- dynamic_memory[5] = cpu_to_be32(SPAPR_LMB_FLAGS_ASSIGNED);
+ if (i >= hotplug_lmb_start) {
+ drc = spapr_dr_connector_by_id(SPAPR_DR_CONNECTOR_TYPE_LMB,
+ addr / lmb_size);
+ g_assert(drc);
+ drck = SPAPR_DR_CONNECTOR_GET_CLASS(drc);
+
+ dynamic_memory[0] = cpu_to_be32(addr >> 32);
+ dynamic_memory[1] = cpu_to_be32(addr & 0xffffffff);
+ dynamic_memory[2] = cpu_to_be32(drck->get_index(drc));
+ dynamic_memory[3] = cpu_to_be32(0); /* reserved */
+ dynamic_memory[4] = cpu_to_be32(numa_get_node(addr, NULL));
+ if (memory_region_present(get_system_memory(), addr)) {
+ dynamic_memory[5] = cpu_to_be32(SPAPR_LMB_FLAGS_ASSIGNED);
+ } else {
+ dynamic_memory[5] = cpu_to_be32(0);
+ }
} else {
- dynamic_memory[5] = cpu_to_be32(0);
+ /*
+ * LMB information for RMA, boot time RAM and gap b/n RAM and
+ * hotplug memory region -- all these are marked as reserved.
+ */
+ dynamic_memory[0] = cpu_to_be32(0);
+ dynamic_memory[1] = cpu_to_be32(0);
+ dynamic_memory[2] = cpu_to_be32(0);
+ dynamic_memory[3] = cpu_to_be32(0); /* reserved */
+ dynamic_memory[4] = cpu_to_be32(-1);
+ dynamic_memory[5] = cpu_to_be32(SPAPR_LMB_FLAGS_RESERVED);
}
cur_index += SPAPR_DR_LMB_LIST_ENTRY_SIZE;
diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
index 971df3d..bb265a2 100644
--- a/include/hw/ppc/spapr.h
+++ b/include/hw/ppc/spapr.h
@@ -620,9 +620,10 @@ int spapr_rng_populate_dt(void *fdt);
#define SPAPR_DR_LMB_LIST_ENTRY_SIZE 6
/*
- * This flag value defines the LMB as assigned in ibm,dynamic-memory
- * property under ibm,dynamic-reconfiguration-memory node.
+ * Defines for flag value in ibm,dynamic-memory property under
+ * ibm,dynamic-reconfiguration-memory node.
*/
#define SPAPR_LMB_FLAGS_ASSIGNED 0x00000008
+#define SPAPR_LMB_FLAGS_RESERVED 0x00000080
#endif /* !defined (__HW_SPAPR_H__) */
--
2.1.0
- [Qemu-devel] [PATCH v3] spapr: Ensure all LMBs are represented in ibm, dynamic-memory,
Bharata B Rao <=
- Re: [Qemu-devel] [PATCH v3] spapr: Ensure all LMBs are represented in ibm, dynamic-memory, Michael Roth, 2016/06/07
- Re: [Qemu-devel] [PATCH v3] spapr: Ensure all LMBs are represented in ibm, dynamic-memory, Bharata B Rao, 2016/06/07
- Re: [Qemu-devel] [PATCH v3] spapr: Ensure all LMBs are represented in ibm, dynamic-memory, Michael Roth, 2016/06/08
- Re: [Qemu-devel] [PATCH v3] spapr: Ensure all LMBs are represented in ibm, dynamic-memory, Bharata B Rao, 2016/06/08
- Re: [Qemu-devel] [PATCH v3] spapr: Ensure all LMBs are represented in ibm, dynamic-memory, Michael Roth, 2016/06/08
- Re: [Qemu-devel] [PATCH v3] spapr: Ensure all LMBs are represented in ibm, dynamic-memory, David Gibson, 2016/06/08
- Re: [Qemu-devel] [PATCH v3] spapr: Ensure all LMBs are represented in ibm, dynamic-memory, David Gibson, 2016/06/08
- Re: [Qemu-devel] [PATCH v3] spapr: Ensure all LMBs are represented in ibm, dynamic-memory, Bharata B Rao, 2016/06/10