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Violators will be prosecuted for from ; Tue, 7 Jun 2016 15:19:40 +1000 From: Bharata B Rao Date: Tue, 7 Jun 2016 10:49:03 +0530 Message-Id: <1465276743-7340-1-git-send-email-bharata@linux.vnet.ibm.com> Subject: [Qemu-devel] [PATCH v3] spapr: Ensure all LMBs are represented in ibm, dynamic-memory List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: david@gibson.dropbear.id.au, mdroth@linux.vnet.ibm.com, nfont@linux.vnet.ibm.com, aik@ozlabs.ru, qemu-ppc@nongnu.org, Bharata B Rao 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 memory@0 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 --- 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