Re: [Qemu-devel] [PATCH v7 2/3] generic-loader: Add a generic loader

[Peter Maydell]

On 25 May 2016 at 19:49, Alistair Francis <address@hidden> wrote:
> Add a generic loader to QEMU which can be used to load images or set
> memory values.
>
> Signed-off-by: Alistair Francis <address@hidden>
> ---
> V7:
>  - Rebase
> V6:
>  - Add error checking
> V5:
>  - Rebase
> V4:
>  - Allow the loader to work with every architecture
>  - Move the file to hw/core
>  - Increase the maximum number of CPUs
>  - Make the CPU operations conditional
>  - Convert the cpu option to cpu-num
>  - Require the user to specify endianess
> V3:
>  - Pass the ram_size to load_image_targphys()
> V2:
>  - Add maintainers entry
>  - Perform bounds checking
>  - Register and unregister the reset in the realise/unrealise
> Changes since RFC:
>  - Add BE support
>
>  MAINTAINERS                      |   6 ++
>  hw/core/Makefile.objs            |   2 +
>  hw/core/generic-loader.c         | 170 
> +++++++++++++++++++++++++++++++++++++++
>  include/hw/core/generic-loader.h |  45 +++++++++++
>  4 files changed, 223 insertions(+)
>  create mode 100644 hw/core/generic-loader.c
>  create mode 100644 include/hw/core/generic-loader.h
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 81e7fac..b4a77d8 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -972,6 +972,12 @@ F: hw/acpi/nvdimm.c
>  F: hw/mem/nvdimm.c
>  F: include/hw/mem/nvdimm.h
>
> +Generic Loader
> +M: Alistair Francis <address@hidden>
> +S: Maintained
> +F: hw/core/generic-loader.c
> +F: include/hw/core/generic-loader.h
> +
>  Subsystems
>  ----------
>  Audio
> diff --git a/hw/core/Makefile.objs b/hw/core/Makefile.objs
> index 70951d4..eb00e7d 100644
> --- a/hw/core/Makefile.objs
> +++ b/hw/core/Makefile.objs
> @@ -15,3 +15,5 @@ common-obj-$(CONFIG_SOFTMMU) += null-machine.o
>  common-obj-$(CONFIG_SOFTMMU) += loader.o
>  common-obj-$(CONFIG_SOFTMMU) += qdev-properties-system.o
>  common-obj-$(CONFIG_PLATFORM_BUS) += platform-bus.o
> +
> +obj-$(CONFIG_SOFTMMU) += generic-loader.o
> diff --git a/hw/core/generic-loader.c b/hw/core/generic-loader.c
> new file mode 100644
> index 0000000..7160d58
> --- /dev/null
> +++ b/hw/core/generic-loader.c
> @@ -0,0 +1,170 @@
> +/*
> + * Generic Loader
> + *
> + * Copyright (C) 2014 Li Guang
> + * Copyright (C) 2016 Xilinx Inc.
> + * Written by Li Guang <address@hidden>
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms of the GNU General Public License as published by the
> + * Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful, but 
> WITHOUT
> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
> + * for more details.
> + */
> +
> +#include "qemu/osdep.h"
> +#include "qom/cpu.h"
> +#include "hw/sysbus.h"
> +#include "sysemu/dma.h"
> +#include "hw/loader.h"
> +#include "qapi/error.h"
> +#include "hw/core/generic-loader.h"
> +
> +#define CPU_NONE 0xFFFF
> +
> +static void generic_loader_reset(void *opaque)
> +{
> +    GenericLoaderState *s = GENERIC_LOADER(opaque);
> +
> +    if (s->cpu) {
> +        CPUClass *cc = CPU_GET_CLASS(s->cpu);
> +        cpu_reset(s->cpu);
> +        if (cc) {
> +            cc->set_pc(s->cpu, s->addr);
> +        }
> +    }
> +
> +    if (s->data_len) {
> +        assert(s->data_len < sizeof(s->data));
> +        dma_memory_write((s->cpu ? s->cpu : first_cpu)->as, s->addr, 
> &s->data,
> +                         s->data_len);
> +    }
> +}
> +
> +static void generic_loader_realize(DeviceState *dev, Error **errp)
> +{
> +    GenericLoaderState *s = GENERIC_LOADER(dev);
> +    hwaddr entry;
> +    int big_endian;
> +    int size = 0;
> +
> +    /* Perform some eror checking on the users options */

"error". "user's".

> +    if (s->data || s->data_len  || s->data_be) {
> +        /* User is loading memory values */
> +        if (s->file) {
> +            error_setg(errp, "Specifying a file is not supported when 
> loading "
> +                       "memory values.");

I think we don't generally have trailing '.' for error_setg() messages.

> +            return;
> +        } else if (s->force_raw) {
> +            error_setg(errp, "Specifying force raw is not supported when "
> +                       "loading memory values.");
> +            return;
> +        } else if (!s->data || !s->data_len) {
> +            error_setg(errp, "Both data and data length must be specified.");
> +            return;
> +        }
> +    } else if (s->file || s->force_raw)  {
> +        /* User is loading an image */
> +        if (s->data || s->data_len || s->data_be) {
> +            error_setg(errp, "Data can not be specified when loading an "
> +                       "image.");
> +            return;
> +        }
> +    }
> +
> +    qemu_register_reset(generic_loader_reset, dev);
> +
> +    if (s->cpu_num != CPU_NONE) {
> +        s->cpu = qemu_get_cpu(s->cpu_num);
> +        if (!s->cpu) {
> +            error_setg(errp, "Specified boot CPU#%d is nonexistent",
> +                       s->cpu_num);
> +            return;
> +        }
> +    }
> +
> +#ifdef TARGET_WORDS_BIGENDIAN
> +    big_endian = 1;
> +#else
> +    big_endian = 0;
> +#endif
> +
> +    if (s->file) {
> +        if (!s->force_raw) {
> +            size = load_elf(s->file, NULL, NULL, &entry, NULL, NULL,
> +                            big_endian, 0, 0, 0);
> +
> +            if (size < 0) {
> +                size = load_uimage(s->file, &entry, NULL, NULL, NULL, NULL);
> +            }
> +        }
> +
> +        if (size < 0) {
> +            /* Default to the maximum size being the machine's ram size */
> +            size = load_image_targphys(s->file, s->addr, ram_size);
> +        } else {
> +            s->addr = entry;
> +        }
> +
> +        if (size < 0) {
> +            error_setg(errp, "Cannot load specified image %s", s->file);
> +            return;
> +        }
> +    }
> +
> +    if (s->data_len && (s->data_len > sizeof(s->data))) {
> +        error_setg(errp, "data-len cannot be more then the data size");
> +        return;
> +    }

This seems like it should go earlier, with the other parameter
validation checks. (Also, isn't this actually checking "is data-len
larger than our supported maximum of 8" ?)

> +
> +    /* Convert the data endiannes */
> +    if (s->data_be) {
> +        s->data = cpu_to_be64(s->data);
> +    } else {
> +        s->data = cpu_to_le64(s->data);
> +    }
> +}
> +
> +static void generic_loader_unrealize(DeviceState *dev, Error **errp)
> +{
> +    qemu_unregister_reset(generic_loader_reset, dev);
> +}
> +
> +static Property generic_loader_props[] = {
> +    DEFINE_PROP_UINT64("addr", GenericLoaderState, addr, 0),
> +    DEFINE_PROP_UINT64("data", GenericLoaderState, data, 0),
> +    DEFINE_PROP_UINT8("data-len", GenericLoaderState, data_len, 0),
> +    DEFINE_PROP_BOOL("data-be", GenericLoaderState, data_be, false),
> +    DEFINE_PROP_UINT16("cpu-num", GenericLoaderState, cpu_num, CPU_NONE),
> +    DEFINE_PROP_BOOL("force-raw", GenericLoaderState, force_raw, false),
> +    DEFINE_PROP_STRING("file", GenericLoaderState, file),
> +    DEFINE_PROP_END_OF_LIST(),
> +};
> +
> +static void generic_loader_class_init(ObjectClass *klass, void *data)
> +{
> +    DeviceClass *dc = DEVICE_CLASS(klass);
> +
> +    dc->realize = generic_loader_realize;
> +    dc->unrealize = generic_loader_unrealize;
> +    dc->props = generic_loader_props;
> +    dc->desc = "Generic Loader";
> +}
> +
> +static TypeInfo generic_loader_info = {
> +    .name = TYPE_GENERIC_LOADER,
> +    .parent = TYPE_DEVICE,
> +    .instance_size = sizeof(GenericLoaderState),
> +    .class_init = generic_loader_class_init,
> +};
> +
> +static void generic_loader_register_type(void)
> +{
> +    type_register_static(&generic_loader_info);
> +}
> +
> +type_init(generic_loader_register_type)
> diff --git a/include/hw/core/generic-loader.h 
> b/include/hw/core/generic-loader.h
> new file mode 100644
> index 0000000..ceec51f
> --- /dev/null
> +++ b/include/hw/core/generic-loader.h
> @@ -0,0 +1,45 @@
> +/*
> + * Generic Loader
> + *
> + * Copyright (C) 2014 Li Guang
> + * Written by Li Guang <address@hidden>
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms of the GNU General Public License as published by the
> + * Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful, but 
> WITHOUT
> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
> + * for more details.
> + */
> +
> +#ifndef GENERIC_LOADER_H
> +#define GENERIC_LOADER_H
> +
> +#include "elf.h"
> +
> +typedef struct GenericLoaderState {
> +    /* <private> */
> +    DeviceState parent_obj;
> +
> +    /* <public> */
> +    CPUState *cpu;
> +
> +    uint64_t addr;
> +    uint64_t data;
> +    uint8_t data_len;
> +    uint16_t cpu_num;

(Why 16 bits in particular?)

> +
> +    char *file;
> +
> +    bool force_raw;
> +    bool data_be;
> +} GenericLoaderState;
> +
> +#define TYPE_GENERIC_LOADER "loader"
> +#define GENERIC_LOADER(obj) OBJECT_CHECK(GenericLoaderState, (obj), \
> +                                         TYPE_GENERIC_LOADER)
> +
> +#endif

thanks
-- PMM