Re: [Qemu-devel] [PATCH v8 12/18] hw/arm/boot: Expose the PC-DIMM nodes in the DT

[Igor Mammedov]

On Tue, 26 Feb 2019 14:50:08 +0100
Eric Auger <address@hidden> wrote:

> From: Shameer Kolothum <address@hidden>
> 
> This patch adds memory nodes corresponding to PC-DIMM regions.
> 
> NVDIMM and ACPI_NVDIMM configs are not yet set for ARM so we
> don't need to care about NVDIMM at this stage.
> 
> Signed-off-by: Shameer Kolothum <address@hidden>
> Signed-off-by: Eric Auger <address@hidden>
> Reviewed-by: Igor Mammedov <address@hidden>
I'm having second thoughts on this one,
maybe we should drop this patch or at least not to do this by default.
In the later case it would mean some kind of property that user could use
to turn this on which in its own turn adds more clutter to user tunables
(which is not desirable). So I'm leaning more towards dropping this patch for 
now.

> 
> ---
> v7 -> v8:
> - s/NV_DIMM/NVDIMM
> - fix indent
> v6 -> v7:
> - rework the error messages, use a switch/case
> v3 -> v4:
> - git rid of @base and @len in fdt_add_hotpluggable_memory_nodes
> 
> v1 -> v2:
> - added qapi_free_MemoryDeviceInfoList and simplify the loop
> ---
>  hw/arm/boot.c | 42 ++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 42 insertions(+)
> 
> diff --git a/hw/arm/boot.c b/hw/arm/boot.c
> index a830655e1a..4caaf91583 100644
> --- a/hw/arm/boot.c
> +++ b/hw/arm/boot.c
> @@ -19,6 +19,7 @@
>  #include "sysemu/numa.h"
>  #include "hw/boards.h"
>  #include "hw/loader.h"
> +#include "hw/mem/memory-device.h"
>  #include "elf.h"
>  #include "sysemu/device_tree.h"
>  #include "qemu/config-file.h"
> @@ -522,6 +523,41 @@ static void fdt_add_psci_node(void *fdt)
>      qemu_fdt_setprop_cell(fdt, "/psci", "migrate", migrate_fn);
>  }
>  
> +static int fdt_add_hotpluggable_memory_nodes(void *fdt,
> +                                             uint32_t acells, uint32_t 
> scells) {
> +    MemoryDeviceInfoList *info, *info_list = qmp_memory_device_list();
> +    MemoryDeviceInfo *mi;
> +    int ret = 0;
> +
> +    for (info = info_list; info != NULL; info = info->next) {
> +        mi = info->value;
> +        switch (mi->type) {
> +        case MEMORY_DEVICE_INFO_KIND_DIMM:
> +        {
> +            PCDIMMDeviceInfo *di = mi->u.dimm.data;
> +
> +            ret = fdt_add_memory_node(fdt, acells, di->addr,
> +                                      scells, di->size, di->node);
> +            if (ret) {
> +                fprintf(stderr,
> +                        "couldn't add PCDIMM /address@hidden"PRIx64" node\n",
> +                        di->addr);
> +                goto out;
> +            }
> +            break;
> +        }
> +        default:
> +            fprintf(stderr, "%s memory nodes are not yet supported\n",
> +                    MemoryDeviceInfoKind_str(mi->type));
> +            ret = -ENOENT;
> +            goto out;
> +        }
> +    }
> +out:
> +    qapi_free_MemoryDeviceInfoList(info_list);
> +    return ret;
> +}
> +
>  int arm_load_dtb(hwaddr addr, const struct arm_boot_info *binfo,
>                   hwaddr addr_limit, AddressSpace *as)
>  {
> @@ -621,6 +657,12 @@ int arm_load_dtb(hwaddr addr, const struct arm_boot_info 
> *binfo,
>          }
>      }
>  
> +    rc = fdt_add_hotpluggable_memory_nodes(fdt, acells, scells);
> +    if (rc < 0) {
> +        fprintf(stderr, "couldn't add hotpluggable memory nodes\n");
> +        goto fail;
> +    }
> +
>      rc = fdt_path_offset(fdt, "/chosen");
>      if (rc < 0) {
>          qemu_fdt_add_subnode(fdt, "/chosen");