Re: [PATCH 10/12] hw/vmapple/cfg: Introduce vmapple cfg region

[Philippe Mathieu-Daudé]

On 15/6/23 00:57, Alexander Graf wrote:
> Instead of device tree or other more standardized means, VMApple passes
> platform configuration to the first stage boot loader in a binary encoded
> format that resides at a dedicated RAM region in physical address space.
>
> This patch models this configuration space as a qdev device which we can
> then map at the fixed location in the address space. That way, we can
> influence and annotate all configuration fields easily.
>
> Signed-off-by: Alexander Graf <graf@amazon.com>
> ---
>   hw/vmapple/Kconfig       |   3 ++
>   hw/vmapple/cfg.c         | 105 +++++++++++++++++++++++++++++++++++++++
>   hw/vmapple/meson.build   |   1 +
>   include/hw/vmapple/cfg.h |  68 +++++++++++++++++++++++++
>   4 files changed, 177 insertions(+)
>   create mode 100644 hw/vmapple/cfg.c
>   create mode 100644 include/hw/vmapple/cfg.h


> diff --git a/hw/vmapple/cfg.c b/hw/vmapple/cfg.c
> new file mode 100644
> index 0000000000..d48e3c3afa
> --- /dev/null
> +++ b/hw/vmapple/cfg.c
> @@ -0,0 +1,105 @@
> +/*
> + * VMApple Configuration Region
> + *
> + * Copyright © 2023 Amazon.com, Inc. or its affiliates. All Rights Reserved.
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2 or later.
> + * See the COPYING file in the top-level directory.
> + */
> +
> +#include "qemu/osdep.h"
> +#include "hw/vmapple/cfg.h"
> +#include "qemu/log.h"
> +#include "qemu/module.h"
> +#include "qapi/error.h"
> +
> +static void vmapple_cfg_reset(DeviceState *dev)
> +{
> +    VMAppleCfgState *s = VMAPPLE_CFG(dev);
> +    VMAppleCfg *cfg;
> +
> +    cfg = memory_region_get_ram_ptr(&s->mem);
> +    memset((void *)cfg, 0, VMAPPLE_CFG_SIZE);

I'm a bit confused here: DeviceReset() handler is called _after_
DeviceRealize().

> +    *cfg = s->cfg;
> +}
> +
> +static void vmapple_cfg_realize(DeviceState *dev, Error **errp)
> +{
> +    VMAppleCfgState *s = VMAPPLE_CFG(dev);
> +    uint32_t i;
> +
> +    strncpy(s->cfg.serial, s->serial, sizeof(s->cfg.serial));
> +    strncpy(s->cfg.model, s->model, sizeof(s->cfg.model));
> +    strncpy(s->cfg.soc_name, s->soc_name, sizeof(s->cfg.soc_name));
> +    strncpy(s->cfg.unk8, "D/A", sizeof(s->cfg.soc_name));
> +    s->cfg.ecid = cpu_to_be64(s->cfg.ecid);
> +    s->cfg.version = 2;
> +    s->cfg.unk1 = 1;
> +    s->cfg.unk2 = 1;
> +    s->cfg.unk3 = 0x20;
> +    s->cfg.unk4 = 0;
> +    s->cfg.unk5 = 1;
> +    s->cfg.unk6 = 1;
> +    s->cfg.unk7 = 0;
> +    s->cfg.unk10 = 1;
> +
> +    g_assert(s->cfg.nr_cpus < ARRAY_SIZE(s->cfg.cpu_ids));
> +    for (i = 0; i < s->cfg.nr_cpus; i++) {
> +        s->cfg.cpu_ids[i] = i;
> +    }
> +}


> diff --git a/include/hw/vmapple/cfg.h b/include/hw/vmapple/cfg.h
> new file mode 100644
> index 0000000000..3337064e44
> --- /dev/null
> +++ b/include/hw/vmapple/cfg.h
> @@ -0,0 +1,68 @@
> +/*
> + * VMApple Configuration Region
> + *
> + * Copyright © 2023 Amazon.com, Inc. or its affiliates. All Rights Reserved.
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2 or later.
> + * See the COPYING file in the top-level directory.
> + */
> +
> +#ifndef HW_VMAPPLE_CFG_H
> +#define HW_VMAPPLE_CFG_H
> +
> +#include "hw/sysbus.h"
> +#include "qom/object.h"
> +#include "net/net.h"
> +
> +typedef struct VMAppleCfg {
> +    uint32_t version;         /* 0x000 */
> +    uint32_t nr_cpus;         /* 0x004 */
> +    uint32_t unk1;            /* 0x008 */
> +    uint32_t unk2;            /* 0x00c */
> +    uint32_t unk3;            /* 0x010 */
> +    uint32_t unk4;            /* 0x014 */
> +    uint64_t ecid;            /* 0x018 */
> +    uint64_t ram_size;        /* 0x020 */
> +    uint32_t run_installer1;  /* 0x028 */
> +    uint32_t unk5;            /* 0x02c */
> +    uint32_t unk6;            /* 0x030 */
> +    uint32_t run_installer2;  /* 0x034 */
> +    uint32_t rnd;             /* 0x038 */
> +    uint32_t unk7;            /* 0x03c */
> +    MACAddr mac_en0;          /* 0x040 */
> +    uint8_t pad1[2];
> +    MACAddr mac_en1;          /* 0x048 */
> +    uint8_t pad2[2];
> +    MACAddr mac_wifi0;        /* 0x050 */
> +    uint8_t pad3[2];
> +    MACAddr mac_bt0;          /* 0x058 */
> +    uint8_t pad4[2];
> +    uint8_t reserved[0xa0];   /* 0x060 */
> +    uint32_t cpu_ids[0x80];   /* 0x100 */
> +    uint8_t scratch[0x200];   /* 0x180 */
> +    char serial[32];          /* 0x380 */
> +    char unk8[32];            /* 0x3a0 */
> +    char model[32];           /* 0x3c0 */
> +    uint8_t unk9[32];         /* 0x3e0 */
> +    uint32_t unk10;           /* 0x400 */
> +    char soc_name[32];        /* 0x404 */
> +} VMAppleCfg;

Since you access this structure via qdev properties (which is
good), then we can restrict its definition to cfg.c (no need to
expose it).