On Thu, Jul 31, 2025 at 11:38 AM Philippe Mathieu-Daudé
<phi...@linaro.org> wrote:
>
> Hi Manos,
>
> On 30/7/25 14:21, Manos Pitsidianakis wrote:
> > NVDIMM is used for fast rootfs with EROFS, for example by kata
> > containers. To allow booting with static NVDIMM memory, add them to the
> > device tree in arm virt machine.
> >
> > This allows users to boot directly with nvdimm memory devices without
> > having to rely on ACPI and hotplug.
> >
> > Verified to work with command invocation:
> >
> > ./qemu-system-aarch64 \
> > -M virt,nvdimm=on \
> > -cpu cortex-a57 \
> > -m 4G,slots=2,maxmem=8G \
> > -object
> > memory-backend-file,id=mem1,share=on,mem-path=/tmp/nvdimm,size=4G,readonly=off
> > \
> > -device nvdimm,id=nvdimm1,memdev=mem1,unarmed=off \
> > -drive file=./debian-12-nocloud-arm64-commited.qcow2,format=qcow2 \
> > -kernel ./vmlinuz-6.1.0-13-arm64 \
> > -append "root=/dev/vda1 console=ttyAMA0,115200 acpi=off"
> > -initrd ./initrd.img-6.1.0-13-arm64 \
> > -nographic \
> > -serial mon:stdio
>
Hi Philippe,
> Should we add a functional test covering this non-ACPI case?
Sure, if the patch makes sense to people who know more about how
hotplug works (I don't know much) and can be merged in the first
place. If it does, I can add a subtest in e.g.
tests/functional/test_aarch64_virt.py as a separate patch.
>
> >
> > Signed-off-by: Manos Pitsidianakis <manos.pitsidiana...@linaro.org>
> > ---
> > hw/arm/boot.c | 39 +++++++++++++++++++++++++++++++++++++++
> > hw/arm/virt.c | 8 +++++---
> > 2 files changed, 44 insertions(+), 3 deletions(-)
> >
> > diff --git a/hw/arm/boot.c b/hw/arm/boot.c
> > index
> > d391cd01bb1b92ff213e69b84e5a69413b36c4f8..a0c1bcdf946ca98bb5da63f1a518018eb578dd81
> > 100644
> > --- a/hw/arm/boot.c
> > +++ b/hw/arm/boot.c
> > @@ -25,6 +25,7 @@
> > #include "hw/boards.h"
> > #include "system/reset.h"
> > #include "hw/loader.h"
> > +#include "hw/mem/memory-device.h"
> > #include "elf.h"
> > #include "system/device_tree.h"
> > #include "qemu/config-file.h"
> > @@ -515,6 +516,26 @@ static void fdt_add_psci_node(void *fdt, ARMCPU
> > *armcpu)
> > qemu_fdt_setprop_cell(fdt, "/psci", "migrate", migrate_fn);
> > }
> >
> > +static int fdt_add_pmem_node(void *fdt, uint32_t acells, uint32_t scells,
> > + int64_t mem_base, int64_t size, int64_t node)
> > +{
> > + int ret;
> > +
> > + g_autofree char *nodename = g_strdup_printf("/pmem@%" PRIx64,
> > mem_base);
> > +
> > + qemu_fdt_add_subnode(fdt, nodename);
> > + qemu_fdt_setprop_string(fdt, nodename, "compatible", "pmem-region");
> > + ret = qemu_fdt_setprop_sized_cells(fdt, nodename, "reg", acells,
> > + mem_base, scells, size);
> > + /* only set the NUMA ID if it is specified */
> > + if (!ret && node >= 0) {
> > + ret = qemu_fdt_setprop_cell(fdt, nodename, "numa-node-id",
> > + node);
> > + }
> > +
> > + return ret;
> > +}
> > +
> > int arm_load_dtb(hwaddr addr, const struct arm_boot_info *binfo,
> > hwaddr addr_limit, AddressSpace *as, MachineState *ms,
> > ARMCPU *cpu)
> > @@ -525,6 +546,7 @@ int arm_load_dtb(hwaddr addr, const struct
> > arm_boot_info *binfo,
> > unsigned int i;
> > hwaddr mem_base, mem_len;
> > char **node_path;
> > + g_autofree MemoryDeviceInfoList *md_list = NULL;
> > Error *err = NULL;
> >
> > if (binfo->dtb_filename) {
> > @@ -628,6 +650,23 @@ int arm_load_dtb(hwaddr addr, const struct
> > arm_boot_info *binfo,
> > }
> > }
> >
> > + md_list = qmp_memory_device_list();
> > + for (MemoryDeviceInfoList *m = md_list; m != NULL; m = m->next) {
> > + MemoryDeviceInfo *mi = m->value;
> > +
> > + if (mi->type == MEMORY_DEVICE_INFO_KIND_NVDIMM) {
> > + PCDIMMDeviceInfo *di = mi->u.nvdimm.data;
> > +
> > + rc = fdt_add_pmem_node(fdt, acells, scells,
> > + di->addr, di->size, di->node);
> > + if (rc < 0) {
> > + fprintf(stderr, "couldn't add NVDIMM /pmem@%"PRIx64"
> > node\n",
> > + di->addr);
> > + goto fail;
> > + }
> > + }
> > + }
> > +
> > rc = fdt_path_offset(fdt, "/chosen");
> > if (rc < 0) {
> > qemu_fdt_add_subnode(fdt, "/chosen");
> > diff --git a/hw/arm/virt.c b/hw/arm/virt.c
> > index
> > ef6be3660f5fb38da84235c32dc2d13a5c61889c..910f5bb5f66ee217a9140f9128804a5b9f69b5b6
> > 100644
> > --- a/hw/arm/virt.c
> > +++ b/hw/arm/virt.c
> > @@ -2917,7 +2917,7 @@ static void virt_memory_pre_plug(HotplugHandler
> > *hotplug_dev, DeviceState *dev,
> > const MachineState *ms = MACHINE(hotplug_dev);
> > const bool is_nvdimm = object_dynamic_cast(OBJECT(dev), TYPE_NVDIMM);
> >
> > - if (!vms->acpi_dev) {
> > + if (!vms->acpi_dev && !(is_nvdimm && !dev->hotplugged)) {
> > error_setg(errp,
> > "memory hotplug is not enabled: missing acpi-ged
> > device");
> > return;
> > @@ -2949,8 +2949,10 @@ static void virt_memory_plug(HotplugHandler
> > *hotplug_dev,
> > nvdimm_plug(ms->nvdimms_state);
> > }
> >
> > - hotplug_handler_plug(HOTPLUG_HANDLER(vms->acpi_dev),
> > - dev, &error_abort);
> > + if (vms->acpi_dev) {
> > + hotplug_handler_plug(HOTPLUG_HANDLER(vms->acpi_dev),
> > + dev, &error_abort);
> > + }
> > }
> >
> > static void virt_machine_device_pre_plug_cb(HotplugHandler *hotplug_dev,
> >
> > ---
> > base-commit: 9b80226ece693197af8a981b424391b68b5bc38e
> > change-id: 20250730-nvdimm_arm64_virt-931a764bbe0c
> >
> > --
> > γαῖα πυρί μιχθήτω
> >
> >
>
