> -----Original Message-----
> From: Auger Eric [mailto:eric.au...@redhat.com]
> Sent: 12 March 2019 15:38
> To: Shameerali Kolothum Thodi <shameerali.kolothum.th...@huawei.com>;
> Igor Mammedov <imamm...@redhat.com>
> Cc: peter.mayd...@linaro.org; sa...@linux.intel.com;
> shannon.zha...@gmail.com; qemu-devel@nongnu.org; Linuxarm
> <linux...@huawei.com>; qemu-...@nongnu.org; xuwei (O)
> <xuw...@huawei.com>; sebastien.bo...@intel.com
> Subject: Re: [Qemu-devel] [PATCH v2 08/11] hw/arm/boot: Expose the
> PC-DIMM nodes in the DT
>
> Hi Shameer,
>
> On 3/12/19 4:13 PM, Shameerali Kolothum Thodi wrote:
> >
> >
> >> -----Original Message-----
> >> From: Igor Mammedov [mailto:imamm...@redhat.com]
> >> Sent: 11 March 2019 14:59
> >> To: Shameerali Kolothum Thodi <shameerali.kolothum.th...@huawei.com>
> >> Cc: qemu-devel@nongnu.org; qemu-...@nongnu.org;
> >> eric.au...@redhat.com; peter.mayd...@linaro.org;
> >> shannon.zha...@gmail.com; sa...@linux.intel.com;
> >> sebastien.bo...@intel.com; Linuxarm <linux...@huawei.com>; xuwei (O)
> >> <xuw...@huawei.com>
> >> Subject: Re: [PATCH v2 08/11] hw/arm/boot: Expose the PC-DIMM nodes in
> the
> >> DT
> >>
> >> On Fri, 8 Mar 2019 11:42:15 +0000
> >> Shameer Kolothum <shameerali.kolothum.th...@huawei.com> wrote:
> >>
> >>> 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
> <shameerali.kolothum.th...@huawei.com>
> >>> Signed-off-by: Eric Auger <eric.au...@redhat.com>
> >>> ---
> >>> hw/arm/boot.c | 42 ++++++++++++++++++++++++++++++++++++++++++
> >>> 1 file changed, 42 insertions(+)
> >>>
> >>> diff --git a/hw/arm/boot.c b/hw/arm/boot.c
> >>> index a830655..4caaf91 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
> /memory@%"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);
> >> According to Eric's test, guest kernel picks this up. So it probably
> >> should be an opt-in feature to avoid conflict with ACPI definition in DSDT.
> >
> > Ok. My take away from that discussion was that if we properly describe the
> > PNP0C80 (which is what #06 of this series does) then we don't have to worry
> > about DT entries as ACPI will "override" it. But it looks like that is not
> > the
> case
> > and describing DT will anyway cause the memory being end up in UEFI
> > GeTMemoryMap() and results in being used as normal memory early at boot.
> >
> > Hi Eric,
> >
> > How do we verify that this is actually happening? I tried running the
> /proc/meminfo
> > on a Qemu build upto #06 of this series, and it reported memory including
> > the
> > cold plugged dimm memory.
> >
> > But not sure how to verify that this dimm mem is being treated as normal
> mem on
> > boot time or not? Please let me know.
>
> At the time I tested I did not have PNP0C80 build. I confirm that if you
> remove the dt description in ACPI mode, /proc/meminfo does not report
> the DIMMs. Now that you have #06, if you remove the DT hotpluggables
> memory mode generation in ACPI mode, you should see them and if I
> understand correctly this is what you confirm. I have not tested
> anything else at the moment.
Yes, that is what I confirmed. But the concern now is having DT memory node
generation will result in the problem described above - UEFI GetMemoryMap().
I was looking for a way to check that is a valid issue or not. I will try to
look for
a way to verify that. Please update if you come across anything.
Thanks,
Shameer
> Thanks
>
> Eric
> >
> > Thanks,
> > Shameer
> >
> >
> >>> + 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");
> >
> >
