Re: [Qemu-devel] [RFC PATCH v2] spapr: Support ibm, dynamic-memory-v2 property

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

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On Mon, Apr 09, 2018 at 11:55:38AM +0530, Bharata B Rao wrote:
> The new property ibm,dynamic-memory-v2 allows memory to be represented
> in a more compact manner in device tree.

I still need to look at this in more detail, but to start with:
what's the rationale for this new format?

It's more compact, but why do we care?  The embedded people always
whinge about the size of the deivce tree, but I didn't think that was
really a concern with PAPR.

> 
> Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
> ---
> v1: https://lists.nongnu.org/archive/html/qemu-devel/2018-03/msg01788.html
> Changes in v1:
> - Minor cleanups in the error paths
> - Rebased on top of ppc-for-2.13
> 
>  docs/specs/ppc-spapr-hotplug.txt |  19 +++
>  hw/ppc/spapr.c                   | 257 ++++++++++++++++++++++++++++++++-------
>  include/hw/ppc/spapr.h           |   1 +
>  include/hw/ppc/spapr_ovec.h      |   1 +
>  4 files changed, 233 insertions(+), 45 deletions(-)
> 
> diff --git a/docs/specs/ppc-spapr-hotplug.txt b/docs/specs/ppc-spapr-hotplug.txt
> index f57e2a09c6..cc7833108e 100644
> --- a/docs/specs/ppc-spapr-hotplug.txt
> +++ b/docs/specs/ppc-spapr-hotplug.txt
> @@ -387,4 +387,23 @@ Each LMB list entry consists of the following elements:
>  - A 32bit flags word. The bit at bit position 0x00000008 defines whether
>    the LMB is assigned to the the partition as of boot time.
>  
> +ibm,dynamic-memory-v2
> +
> +This property describes the dynamically reconfigurable memory. This is
> +an alternate and newer way to describe dyanamically reconfigurable memory.
> +It is a property encoded array that has an integer N (the number of
> +LMB set entries) followed by N LMB set entries. There is an LMB set entry
> +for each sequential group of LMBs that share common attributes.
> +
> +Each LMB set entry consists of the following elements:
> +
> +- Number of sequential LMBs in the entry represented by a 32bit integer.
> +- Logical address of the first LMB in the set encoded as a 64bit integer.
> +- DRC index of the first LMB in the set.
> +- Associativity list index that is used as an index into
> +  ibm,associativity-lookup-arrays property described earlier. This
> +  is used to retrieve the right associativity list to be used for all
> +  the LMBs in this set.
> +- A 32bit flags word that applies to all the LMBs in the set.
> +
>  [1] http://thread.gmane.org/gmane.linux.ports.ppc.embedded/75350/focus=106867
> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> index 3ffadd6ac7..4a24fac38c 100644
> --- a/hw/ppc/spapr.c
> +++ b/hw/ppc/spapr.c
> @@ -669,63 +669,139 @@ static uint32_t spapr_pc_dimm_node(MemoryDeviceInfoList *list, ram_addr_t addr)
>      return -1;
>  }
>  
> -/*
> - * Adds ibm,dynamic-reconfiguration-memory node.
> - * Refer to docs/specs/ppc-spapr-hotplug.txt for the documentation
> - * of this device tree node.
> - */
> -static int spapr_populate_drconf_memory(sPAPRMachineState *spapr, void *fdt)
> +struct of_drconf_cell_v2 {
> +     uint32_t seq_lmbs;
> +     uint64_t base_addr;
> +     uint32_t drc_index;
> +     uint32_t aa_index;
> +     uint32_t flags;
> +} __attribute__((packed));
> +
> +#define SPAPR_DRCONF_CELL_SIZE 6
> +
> +/* ibm,dynamic-memory-v2 */
> +static int spapr_populate_drmem_v2(sPAPRMachineState *spapr, void *fdt,
> +                                   int offset, MemoryDeviceInfoList *dimms)
>  {
> -    MachineState *machine = MACHINE(spapr);
> -    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 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;
> -    MemoryDeviceInfoList *dimms = NULL;
> +    int ret;
> +    uint64_t lmb_size = SPAPR_MEMORY_BLOCK_SIZE;
> +    uint64_t addr, cur_addr, size;
> +    uint32_t nr_boot_lmbs = (spapr->hotplug_memory.base / lmb_size);
> +    uint64_t mem_end = spapr->hotplug_memory.base +
> +                       memory_region_size(&spapr->hotplug_memory.mr);
> +    uint32_t node, nr_entries = 0;
> +    sPAPRDRConnector *drc;
> +    typedef struct drconf_cell_queue {
> +        struct of_drconf_cell_v2 cell;
> +        QSIMPLEQ_ENTRY(drconf_cell_queue) entry;
> +    } drconf_cell_queue;
> +    QSIMPLEQ_HEAD(, drconf_cell_queue) drconf_queue
> +        = QSIMPLEQ_HEAD_INITIALIZER(drconf_queue);
> +    drconf_cell_queue *elem, *next;
> +    MemoryDeviceInfoList *info;
>  
> -    /*
> -     * Don't create the node if there is no hotpluggable memory
> -     */
> -    if (machine->ram_size == machine->maxram_size) {
> -        return 0;
> -    }
> +    /* Entry to cover RAM and the gap area */
> +    elem = g_malloc0(sizeof(drconf_cell_queue));
> +    elem->cell.seq_lmbs = cpu_to_be32(nr_boot_lmbs);
> +    elem->cell.base_addr = cpu_to_be64(0);
> +    elem->cell.drc_index = cpu_to_be32(0);
> +    elem->cell.aa_index = cpu_to_be32(-1);
> +    elem->cell.flags = cpu_to_be32(SPAPR_LMB_FLAGS_RESERVED |
> +                                   SPAPR_LMB_FLAGS_DRC_INVALID);
> +    QSIMPLEQ_INSERT_TAIL(&drconf_queue, elem, entry);
> +    nr_entries++;
> +
> +    cur_addr = spapr->hotplug_memory.base;
> +    for (info = dimms; info; info = info->next) {
> +        PCDIMMDeviceInfo *di = info->value->u.dimm.data;
> +
> +        addr = di->addr;
> +        size = di->size;
> +        node = di->node;
> +
> +        /* Entry for hot-pluggable area */
> +        if (cur_addr < addr) {
> +            drc = spapr_drc_by_id(TYPE_SPAPR_DRC_LMB, cur_addr / lmb_size);
> +            g_assert(drc);
>  
> -    /*
> -     * Allocate enough buffer size to fit in ibm,dynamic-memory
> -     * or ibm,associativity-lookup-arrays
> -     */
> -    buf_len = MAX(nr_lmbs * SPAPR_DR_LMB_LIST_ENTRY_SIZE + 1, nr_nodes * 4 + 2)
> -              * sizeof(uint32_t);
> -    cur_index = int_buf = g_malloc0(buf_len);
> +            elem = g_malloc0(sizeof(drconf_cell_queue));
> +            elem->cell.seq_lmbs = cpu_to_be32((addr - cur_addr) / lmb_size);
> +            elem->cell.base_addr = cpu_to_be64(cur_addr);
> +            elem->cell.drc_index = cpu_to_be32(spapr_drc_index(drc));
> +            elem->cell.aa_index = cpu_to_be32(-1);
> +            elem->cell.flags = cpu_to_be32(0);
> +            QSIMPLEQ_INSERT_TAIL(&drconf_queue, elem, entry);
> +            nr_entries++;
> +        }
>  
> -    offset = fdt_add_subnode(fdt, 0, "ibm,dynamic-reconfiguration-memory");
> +        /* Entry for DIMM */
> +        drc = spapr_drc_by_id(TYPE_SPAPR_DRC_LMB, addr / lmb_size);
> +        g_assert(drc);
>  
> -    ret = fdt_setprop(fdt, offset, "ibm,lmb-size", prop_lmb_size,
> -                    sizeof(prop_lmb_size));
> -    if (ret < 0) {
> -        goto out;
> +        elem = g_malloc0(sizeof(drconf_cell_queue));
> +        elem->cell.seq_lmbs = cpu_to_be32(size / lmb_size);
> +        elem->cell.base_addr = cpu_to_be64(addr);
> +        elem->cell.drc_index = cpu_to_be32(spapr_drc_index(drc));
> +        elem->cell.aa_index = cpu_to_be32(node);
> +        elem->cell.flags = cpu_to_be32(SPAPR_LMB_FLAGS_ASSIGNED);
> +        QSIMPLEQ_INSERT_TAIL(&drconf_queue, elem, entry);
> +        nr_entries++;
> +        cur_addr = addr + size;
>      }
>  
> -    ret = fdt_setprop_cell(fdt, offset, "ibm,memory-flags-mask", 0xff);
> -    if (ret < 0) {
> -        goto out;
> +    /* Entry for remaining hotpluggable area */
> +    if (cur_addr < mem_end) {
> +        drc = spapr_drc_by_id(TYPE_SPAPR_DRC_LMB, cur_addr / lmb_size);
> +        g_assert(drc);
> +
> +        elem = g_malloc0(sizeof(drconf_cell_queue));
> +        elem->cell.seq_lmbs = cpu_to_be32((mem_end - cur_addr) / lmb_size);
> +        elem->cell.base_addr = cpu_to_be64(cur_addr);
> +        elem->cell.drc_index = cpu_to_be32(spapr_drc_index(drc));
> +        elem->cell.aa_index = cpu_to_be32(-1);
> +        elem->cell.flags = cpu_to_be32(0);
> +        QSIMPLEQ_INSERT_TAIL(&drconf_queue, elem, entry);
> +        nr_entries++;
>      }
>  
> -    ret = fdt_setprop_cell(fdt, offset, "ibm,memory-preservation-time", 0x0);
> -    if (ret < 0) {
> -        goto out;
> +    buf_len = (nr_entries * SPAPR_DRCONF_CELL_SIZE + 1) * sizeof(uint32_t);
> +    int_buf = cur_index = g_malloc0(buf_len);
> +    int_buf[0] = cpu_to_be32(nr_entries);
> +    cur_index++;
> +    QSIMPLEQ_FOREACH_SAFE(elem, &drconf_queue, entry, next) {
> +        memcpy(cur_index, &elem->cell,
> +               SPAPR_DRCONF_CELL_SIZE * sizeof(uint32_t));
> +        cur_index += SPAPR_DRCONF_CELL_SIZE;
> +        QSIMPLEQ_REMOVE(&drconf_queue, elem, drconf_cell_queue, entry);
> +        g_free(elem);
>      }
>  
> -    if (hotplug_lmb_start) {
> -        dimms = qmp_pc_dimm_device_list();
> +    ret = fdt_setprop(fdt, offset, "ibm,dynamic-memory-v2", int_buf, buf_len);
> +    g_free(int_buf);
> +    if (ret < 0) {
> +        return -1;
>      }
> +    return 0;
> +}
>  
> -    /* ibm,dynamic-memory */
> +/* ibm,dynamic-memory */
> +static int spapr_populate_drmem_v1(sPAPRMachineState *spapr, void *fdt,
> +                                   int offset, MemoryDeviceInfoList *dimms)
> +{
> +    int i, ret;
> +    uint64_t lmb_size = SPAPR_MEMORY_BLOCK_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;
> +
> +    /*
> +     * Allocate enough buffer size to fit in ibm,dynamic-memory
> +     */
> +    buf_len = (nr_lmbs * SPAPR_DR_LMB_LIST_ENTRY_SIZE + 1) * sizeof(uint32_t);
> +    cur_index = int_buf = g_malloc0(buf_len);
>      int_buf[0] = cpu_to_be32(nr_lmbs);
>      cur_index++;
>      for (i = 0; i < nr_lmbs; i++) {
> @@ -765,13 +841,71 @@ static int spapr_populate_drconf_memory(sPAPRMachineState *spapr, void *fdt)
>  
>          cur_index += SPAPR_DR_LMB_LIST_ENTRY_SIZE;
>      }
> -    qapi_free_MemoryDeviceInfoList(dimms);
>      ret = fdt_setprop(fdt, offset, "ibm,dynamic-memory", int_buf, buf_len);
> +    g_free(int_buf);
> +    if (ret < 0) {
> +        return -1;
> +    }
> +    return 0;
> +}
> +
> +/*
> + * Adds ibm,dynamic-reconfiguration-memory node.
> + * Refer to docs/specs/ppc-spapr-hotplug.txt for the documentation
> + * of this device tree node.
> + */
> +static int spapr_populate_drconf_memory(sPAPRMachineState *spapr, void *fdt)
> +{
> +    MachineState *machine = MACHINE(spapr);
> +    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 *int_buf, *cur_index, buf_len;
> +    int nr_nodes = nb_numa_nodes ? nb_numa_nodes : 1;
> +    MemoryDeviceInfoList *dimms = NULL;
> +
> +    /*
> +     * Don't create the node if there is no hotpluggable memory
> +     */
> +    if (machine->ram_size == machine->maxram_size) {
> +        return 0;
> +    }
> +
> +    offset = fdt_add_subnode(fdt, 0, "ibm,dynamic-reconfiguration-memory");
> +
> +    ret = fdt_setprop(fdt, offset, "ibm,lmb-size", prop_lmb_size,
> +                    sizeof(prop_lmb_size));
> +    if (ret < 0) {
> +        goto out;
> +    }
> +
> +    ret = fdt_setprop_cell(fdt, offset, "ibm,memory-flags-mask", 0xff);
> +    if (ret < 0) {
> +        goto out;
> +    }
> +
> +    ret = fdt_setprop_cell(fdt, offset, "ibm,memory-preservation-time", 0x0);
> +    if (ret < 0) {
> +        goto out;
> +    }
> +
> +    /* ibm,dynamic-memory or ibm,dynamic-memory-v2 */
> +    dimms = qmp_pc_dimm_device_list();
> +    if (spapr_ovec_test(spapr->ov5_cas, OV5_DRMEM_V2)) {
> +        ret = spapr_populate_drmem_v2(spapr, fdt, offset, dimms);
> +    } else {
> +        ret = spapr_populate_drmem_v1(spapr, fdt, offset, dimms);
> +    }
> +    qapi_free_MemoryDeviceInfoList(dimms);
> +
>      if (ret < 0) {
>          goto out;
>      }
>  
>      /* ibm,associativity-lookup-arrays */
> +    buf_len = (nr_nodes * 4 + 2) * sizeof(uint32_t);
> +    cur_index = int_buf = g_malloc0(buf_len);
> +
>      cur_index = int_buf;
>      int_buf[0] = cpu_to_be32(nr_nodes);
>      int_buf[1] = cpu_to_be32(4); /* Number of entries per associativity list */
> @@ -788,8 +922,9 @@ static int spapr_populate_drconf_memory(sPAPRMachineState *spapr, void *fdt)
>      }
>      ret = fdt_setprop(fdt, offset, "ibm,associativity-lookup-arrays", int_buf,
>              (cur_index - int_buf) * sizeof(uint32_t));
> -out:
>      g_free(int_buf);
> +
> +out:
>      return ret;
>  }
>  
> @@ -2500,6 +2635,11 @@ static void spapr_machine_init(MachineState *machine)
>          spapr_ovec_set(spapr->ov5, OV5_HPT_RESIZE);
>      }
>  
> +    /* advertise support for ibm,dyamic-memory-v2 */
> +    if (spapr->use_ibm_dynamic_memory_v2) {
> +        spapr_ovec_set(spapr->ov5, OV5_DRMEM_V2);
> +    }
> +
>      /* init CPUs */
>      spapr_init_cpus(spapr);
>  
> @@ -2907,12 +3047,27 @@ static void spapr_set_vsmt(Object *obj, Visitor *v, const char *name,
>      visit_type_uint32(v, name, (uint32_t *)opaque, errp);
>  }
>  
> +static bool spapr_get_drmem_v2(Object *obj, Error **errp)
> +{
> +    sPAPRMachineState *spapr = SPAPR_MACHINE(obj);
> +
> +    return spapr->use_ibm_dynamic_memory_v2;
> +}
> +
> +static void spapr_set_drmem_v2(Object *obj, bool value, Error **errp)
> +{
> +    sPAPRMachineState *spapr = SPAPR_MACHINE(obj);
> +
> +    spapr->use_ibm_dynamic_memory_v2 = value;
> +}
> +
>  static void spapr_instance_init(Object *obj)
>  {
>      sPAPRMachineState *spapr = SPAPR_MACHINE(obj);
>  
>      spapr->htab_fd = -1;
>      spapr->use_hotplug_event_source = true;
> +    spapr->use_ibm_dynamic_memory_v2 = true;
>      object_property_add_str(obj, "kvm-type",
>                              spapr_get_kvm_type, spapr_set_kvm_type, NULL);
>      object_property_set_description(obj, "kvm-type",
> @@ -2927,6 +3082,15 @@ static void spapr_instance_init(Object *obj)
>                                      " place of standard EPOW events when possible"
>                                      " (required for memory hot-unplug support)",
>                                      NULL);
> +    object_property_add_bool(obj, "drmem-v2",
> +                             spapr_get_drmem_v2,
> +                             spapr_set_drmem_v2,
> +                             NULL);
> +    object_property_set_description(obj, "ibm-dynamic-memory-v2",
> +                                    "Use ibm-dynamic-memory-v2 representation"
> +                                    " in place of ibm-dynamic-memory when"
> +                                    " possible",
> +                                    NULL);
>  
>      ppc_compat_add_property(obj, "max-cpu-compat", &spapr->max_compat_pvr,
>                              "Maximum permitted CPU compatibility mode",
> @@ -4042,7 +4206,10 @@ DEFINE_SPAPR_MACHINE(2_12_sxxm, "2.12-sxxm", false);
>  
>  static void spapr_machine_2_11_instance_options(MachineState *machine)
>  {
> +    sPAPRMachineState *spapr = SPAPR_MACHINE(machine);
> +
>      spapr_machine_2_12_instance_options(machine);
> +    spapr->use_ibm_dynamic_memory_v2 = false;
>  }
>  
>  static void spapr_machine_2_11_class_options(MachineClass *mc)
> diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
> index d60b7c6d7a..5e044c44af 100644
> --- a/include/hw/ppc/spapr.h
> +++ b/include/hw/ppc/spapr.h
> @@ -149,6 +149,7 @@ struct sPAPRMachineState {
>      sPAPROptionVector *ov5;         /* QEMU-supported option vectors */
>      sPAPROptionVector *ov5_cas;     /* negotiated (via CAS) option vectors */
>      uint32_t max_compat_pvr;
> +    bool use_ibm_dynamic_memory_v2;
>  
>      /* Migration state */
>      int htab_save_index;
> diff --git a/include/hw/ppc/spapr_ovec.h b/include/hw/ppc/spapr_ovec.h
> index bf25e5d954..0f2d8d715d 100644
> --- a/include/hw/ppc/spapr_ovec.h
> +++ b/include/hw/ppc/spapr_ovec.h
> @@ -51,6 +51,7 @@ typedef struct sPAPROptionVector sPAPROptionVector;
>  #define OV5_FORM1_AFFINITY      OV_BIT(5, 0)
>  #define OV5_HP_EVT              OV_BIT(6, 5)
>  #define OV5_HPT_RESIZE          OV_BIT(6, 7)
> +#define OV5_DRMEM_V2            OV_BIT(22, 0)
>  #define OV5_XIVE_BOTH           OV_BIT(23, 0)
>  #define OV5_XIVE_EXPLOIT        OV_BIT(23, 1) /* 1=exploitation 0=legacy */
>  

-- 
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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