Re: [Qemu-devel] [RFC PATCH v4 2/5] spapr: Add LMB DR connectors

[David Gibson <david@gibson.dropbear.id.au>]

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On Fri, Jun 19, 2015 at 03:47:54PM +0530, Bharata B Rao wrote:
> Enable memory hotplug for pseries 2.4 and add LMB DR connectors.
> With memory hotplug, enforce NUMA node memory size and maxmem to be
> a multiple of SPAPR_MEMORY_BLOCK_SIZE (256M) since that's the granularity
> in which LMBs are represented and hot-added.
> 
> LMB DR connectors will be used by the memory hotplug code.
> 
> Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
> Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
>                [spapr_drc_reset implementation]
> ---
>  hw/ppc/spapr.c         | 78 ++++++++++++++++++++++++++++++++++++++++++++++++++
>  include/hw/ppc/spapr.h |  2 ++
>  2 files changed, 80 insertions(+)
> 
> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> index 87a29dc..f9af89b 100644
> --- a/hw/ppc/spapr.c
> +++ b/hw/ppc/spapr.c
> @@ -59,6 +59,7 @@
>  #include "hw/nmi.h"
>  
>  #include "hw/compat.h"
> +#include "qemu-common.h"
>  
>  #include <libfdt.h>
>  
> @@ -1436,10 +1437,76 @@ static void spapr_cpu_init(sPAPRMachineState *spapr, PowerPCCPU *cpu)
>      qemu_register_reset(spapr_cpu_reset, cpu);
>  }
>  
> +static void spapr_drc_reset(void *opaque)

This function needs a different name, since it's only called for LMB
drcs, not all drcs.

> +{
> +    sPAPRDRConnector *drc = opaque;
> +    DeviceState *d = DEVICE(drc);
> +
> +    if (d) {
> +        device_reset(d);
> +    }
> +}
> +
> +static void spapr_create_lmb_dr_connectors(sPAPRMachineState *spapr)
> +{
> +    MachineState *machine = MACHINE(qdev_get_machine());
> +    uint64_t lmb_size = SPAPR_MEMORY_BLOCK_SIZE;
> +    uint32_t nr_rma_lmbs = spapr->rma_size/lmb_size;
> +    uint32_t nr_lmbs = machine->maxram_size/lmb_size - nr_rma_lmbs;
> +    uint32_t nr_assigned_lmbs = machine->ram_size/lmb_size - nr_rma_lmbs;
> +    int i;
> +
> +    for (i = 0; i < nr_lmbs; i++) {
> +        sPAPRDRConnector *drc;
> +        uint64_t addr;
> +
> +        if (i < nr_assigned_lmbs) {
> +            addr = (i + nr_rma_lmbs) * lmb_size;
> +        } else {
> +            addr = (i - nr_assigned_lmbs) * lmb_size +
> +                SPAPR_MACHINE(qdev_get_machine())->hotplug_memory.base;
> +        }
> +
> +        drc = spapr_dr_connector_new(qdev_get_machine(),
> +                SPAPR_DR_CONNECTOR_TYPE_LMB, addr/lmb_size);
> +        qemu_register_reset(spapr_drc_reset, drc);

Actually.. I'm not sure what spapr_drc_reset is needed for at all.
Won't the device reset hook get called through the normal qdev path
anyway?  The PCI hotplug code doesn't have an explicit register_reset,
so why does the memory hotplug code need it?

> +    }
> +}
> +
> +/*
> + * If LMB DR is enabled node memory size and max memory size should
> + * be a multiple of SPAPR_MEMORY_BLOCK_SIZE (256M).
> + */
> +static void spapr_validate_node_memory(sPAPRMachineState *spapr)
> +{
> +    int i;
> +    MachineState *machine = MACHINE(qdev_get_machine());
> +
> +    if (!spapr->dr_lmb_enabled) {
> +        return;
> +    }
> +
> +    if (machine->maxram_size % SPAPR_MEMORY_BLOCK_SIZE) {
> +        error_report("maxmem should be a multiple of %lld MB",
> +                      SPAPR_MEMORY_BLOCK_SIZE/M_BYTE);
> +        exit(EXIT_FAILURE);
> +    }
> +
> +    for (i = 0; i < nb_numa_nodes; i++) {
> +        if (numa_info[i].node_mem &&
> +            numa_info[i].node_mem % SPAPR_MEMORY_BLOCK_SIZE) {
> +            error_report("Memory size on node %d should be a multiple "
> +                         "of %lld MB", i, SPAPR_MEMORY_BLOCK_SIZE/M_BYTE);
> +            exit(EXIT_FAILURE);
> +        }
> +    }
> +}
> +
>  /* pSeries LPAR / sPAPR hardware init */
>  static void ppc_spapr_init(MachineState *machine)
>  {
>      sPAPRMachineState *spapr = SPAPR_MACHINE(machine);
> +    sPAPRMachineClass *smc = SPAPR_MACHINE_GET_CLASS(machine);
>      const char *kernel_filename = machine->kernel_filename;
>      const char *kernel_cmdline = machine->kernel_cmdline;
>      const char *initrd_filename = machine->initrd_filename;
> @@ -1518,6 +1585,9 @@ static void ppc_spapr_init(MachineState *machine)
>                                                 smp_threads),
>                                    XICS_IRQS);
>  
> +    spapr->dr_lmb_enabled = smc->dr_lmb_enabled;

I don't see any point to copying this value into the MachineState -
I'm guessing this is a leftover from sPAPREnvironment.  Anywhere you
have the MachineState you can get to the MachineClass and use the
value directly from there.

> +    spapr_validate_node_memory(spapr);
> +
>      /* init CPUs */
>      if (machine->cpu_model == NULL) {
>          machine->cpu_model = kvm_enabled() ? "host" : "POWER7";
> @@ -1577,6 +1647,10 @@ static void ppc_spapr_init(MachineState *machine)
>                                      &spapr->hotplug_memory.mr);
>      }
>  
> +    if (spapr->dr_lmb_enabled) {
> +        spapr_create_lmb_dr_connectors(spapr);
> +    }
> +
>      filename = qemu_find_file(QEMU_FILE_TYPE_BIOS, "spapr-rtas.bin");
>      if (!filename) {
>          error_report("Could not find LPAR rtas '%s'", "spapr-rtas.bin");
> @@ -1850,6 +1924,7 @@ static void spapr_nmi(NMIState *n, int cpu_index, Error **errp)
>  static void spapr_machine_class_init(ObjectClass *oc, void *data)
>  {
>      MachineClass *mc = MACHINE_CLASS(oc);
> +    sPAPRMachineClass *smc = SPAPR_MACHINE_CLASS(oc);
>      FWPathProviderClass *fwc = FW_PATH_PROVIDER_CLASS(oc);
>      NMIClass *nc = NMI_CLASS(oc);
>  
> @@ -1863,6 +1938,7 @@ static void spapr_machine_class_init(ObjectClass *oc, void *data)
>      mc->kvm_type = spapr_kvm_type;
>      mc->has_dynamic_sysbus = true;
>  
> +    smc->dr_lmb_enabled = false;
>      fwc->get_dev_path = spapr_get_fw_dev_path;
>      nc->nmi_monitor_handler = spapr_nmi;
>  }
> @@ -1998,11 +2074,13 @@ static const TypeInfo spapr_machine_2_3_info = {
>  static void spapr_machine_2_4_class_init(ObjectClass *oc, void *data)
>  {
>      MachineClass *mc = MACHINE_CLASS(oc);
> +    sPAPRMachineClass *smc = SPAPR_MACHINE_CLASS(oc);
>  
>      mc->name = "pseries-2.4";
>      mc->desc = "pSeries Logical Partition (PAPR compliant) v2.4";
>      mc->alias = "pseries";
>      mc->is_default = 1;
> +    smc->dr_lmb_enabled = true;
>  }
>  
>  static const TypeInfo spapr_machine_2_4_info = {
> diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
> index 8a1929b..b3fba76 100644
> --- a/include/hw/ppc/spapr.h
> +++ b/include/hw/ppc/spapr.h
> @@ -35,6 +35,7 @@ struct sPAPRMachineClass {
>      MachineClass parent_class;
>  
>      /*< public >*/
> +    bool dr_lmb_enabled; /* enable dynamic-reconfig/hotplug of LMBs */
>  };
>  
>  /**
> @@ -74,6 +75,7 @@ struct sPAPRMachineState {
>  
>      /* RTAS state */
>      QTAILQ_HEAD(, sPAPRConfigureConnectorState) ccs_list;
> +    bool dr_lmb_enabled; /* hotplug / dynamic-reconfiguration of LMBs */
>  
>      /*< public >*/
>      char *kvm_type;

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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