[Qemu-devel] [PATCH v13 0/2] Add a generic loader

[Qemu-devel] [PATCH v13 0/2] Add a generic loader

[Alistair Francis]

This work is based on the original work by Li Guang with extra
features added by Peter C and myself.

The idea of this loader is to allow the user to load multiple images
or values into QEMU at startup.

Memory values can be loaded like this: -device loader,addr=0xfd1a0104,data=0x8000000e,data-len=4

Images can be loaded like this: -device loader,file=./images/u-boot.elf,cpu=0

This can be useful and we use it a lot in Xilinx to load multiple images
into a machine at creation (ATF, Kernel and DTB for example).

Tested with the latest Xilinx ZynqMP machine, if I enable EL3 and EL2 I can
boot ATF through to u-boot using the loader to load the images.

It can also be used to set registers.

This patch series makes the load_elf() function more generic by not
requiring an architecture. It also adds new functions load_elf_as(),
load_uimage_as and load_image_targphys_as which allows custom
AddressSpaces when loading images.

V12:
 - All patches have been reviewed
 - Most patches have been merged
 - The commit message of the actual device patch has been updated to
   justify why it is a device.


Alistair Francis (2):
  generic-loader: Add a generic loader
  docs: Add a generic loader explanation document

 MAINTAINERS                      |   6 ++
 docs/generic-loader.txt          |  84 ++++++++++++++++
 hw/core/Makefile.objs            |   2 +
 hw/core/generic-loader.c         | 211 +++++++++++++++++++++++++++++++++++++++
 include/hw/core/generic-loader.h |  46 +++++++++
 5 files changed, 349 insertions(+)
 create mode 100644 docs/generic-loader.txt
 create mode 100644 hw/core/generic-loader.c
 create mode 100644 include/hw/core/generic-loader.h

-- 
2.7.4

[Qemu-devel] [PATCH v13 1/2] generic-loader: Add a generic loader

[Alistair Francis]

Add a generic loader to QEMU which can be used to load images or set
memory values.

Internally inside QEMU this is a device. It is a strange device that
provides no hardware interface but allows QEMU to monkey patch memory
specified when it is created. To be able to do this it has a reset
callback that does the memory operations.

This device allows the user to monkey patch memory. To be able to do
this it needs a backend to manage the datas, the same as other
memory-related devices. In this case as the backend is so trivial we
have merged it with the frontend instead of creating and maintaining a
seperate backend.

Signed-off-by: Alistair Francis <alistair.francis@xilinx.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Acked-by: Markus Armbruster <armbru@redhat.com>
---
V13:
 - Include the commit message in the c file.
V12:
 - Update commit message to justify using -device
V11:
 - Small corrections
 - Don't check for !data as writing a value of 0 is valid.
V10:
 - Split out the PC setting and data loading
V9:
 - Fix error messages
 - Updated some incorrect logic
 - Add address space loading support for all image types
 - Explain why the reset is manually registered
V8:
 - Code corrections
 - Rebase
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         | 211 +++++++++++++++++++++++++++++++++++++++
 include/hw/core/generic-loader.h |  46 +++++++++
 4 files changed, 265 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 f3c1f7f..9ecaaa5 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1013,6 +1013,12 @@ M: Dmitry Fleytman <dmitry@daynix.com>
 S: Maintained
 F: hw/net/e1000e*
 
+Generic Loader
+M: Alistair Francis <alistair.francis@xilinx.com>
+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 cfd4840..939c94e 100644
--- a/hw/core/Makefile.objs
+++ b/hw/core/Makefile.objs
@@ -17,3 +17,5 @@ common-obj-$(CONFIG_SOFTMMU) += loader.o
 common-obj-$(CONFIG_SOFTMMU) += qdev-properties-system.o
 common-obj-$(CONFIG_SOFTMMU) += register.o
 common-obj-$(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..79ab6df
--- /dev/null
+++ b/hw/core/generic-loader.c
@@ -0,0 +1,211 @@
+/*
+ * Generic Loader
+ *
+ * Copyright (C) 2014 Li Guang
+ * Copyright (C) 2016 Xilinx Inc.
+ * Written by Li Guang <lig.fnst@cn.fujitsu.com>
+ *
+ * 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.
+ *
+ */
+
+/*
+ * Internally inside QEMU this is a device. It is a strange device that
+ * provides no hardware interface but allows QEMU to monkey patch memory
+ * specified when it is created. To be able to do this it has a reset
+ * callback that does the memory operations.
+
+ * This device allows the user to monkey patch memory. To be able to do
+ * this it needs a backend to manage the datas, the same as other
+ * memory-related devices. In this case as the backend is so trivial we
+ * have merged it with the frontend instead of creating and maintaining a
+ * seperate backend.
+ */
+
+#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 0xFFFFFFFF
+
+static void generic_loader_reset(void *opaque)
+{
+    GenericLoaderState *s = GENERIC_LOADER(opaque);
+
+    if (s->set_pc) {
+        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->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;
+
+    s->set_pc = false;
+
+    /* Perform some error checking on the user's options */
+    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");
+            return;
+        } else if (s->force_raw) {
+            error_setg(errp, "Specifying force-raw is not supported when "
+                       "loading memory values");
+            return;
+        } else if (!s->data_len) {
+            /* We cant' check for !data here as a value of 0 is still valid. */
+            error_setg(errp, "Both data and data-len must be specified");
+            return;
+        } else if (s->data_len > 8) {
+            error_setg(errp, "data-len cannot be greater then 8 bytes");
+            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;
+        }
+        s->set_pc = true;
+    } else if (s->addr) {
+        /* User is setting the PC */
+        if (s->data || s->data_len || s->data_be) {
+            error_setg(errp, "data can not be specified when setting a "
+                       "program counter");
+            return;
+        } else if (!s->cpu_num) {
+            error_setg(errp, "cpu_num must be specified when setting a "
+                       "program counter");
+            return;
+        }
+        s->set_pc = true;
+    } else {
+        /* Did the user specify anything? */
+        error_setg(errp, "please include valid arguments");
+        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;
+        }
+    } else {
+        s->cpu = first_cpu;
+    }
+
+#ifdef TARGET_WORDS_BIGENDIAN
+    big_endian = 1;
+#else
+    big_endian = 0;
+#endif
+
+    if (s->file) {
+        if (!s->force_raw) {
+            size = load_elf_as(s->file, NULL, NULL, &entry, NULL, NULL,
+                               big_endian, 0, 0, 0, s->cpu->as);
+
+            if (size < 0) {
+                size = load_uimage_as(s->file, &entry, NULL, NULL, NULL, NULL,
+                                      s->cpu->as);
+            }
+        }
+
+        if (size < 0 || s->force_raw) {
+            /* Default to the maximum size being the machine's ram size */
+            size = load_image_targphys_as(s->file, s->addr, ram_size,
+                                          s->cpu->as);
+        } else {
+            s->addr = entry;
+        }
+
+        if (size < 0) {
+            error_setg(errp, "Cannot load specified image %s", s->file);
+            return;
+        }
+    }
+
+    /* 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_UINT32("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);
+
+    /* The reset function is not registered here and is instead registered in
+     * the realize function to allow this device to be added via the device_add
+     * command in the QEMU monitor.
+     * TODO: Improve the device_add functionality to allow resets to be
+     * connected
+     */
+    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..dd27c42
--- /dev/null
+++ b/include/hw/core/generic-loader.h
@@ -0,0 +1,46 @@
+/*
+ * Generic Loader
+ *
+ * Copyright (C) 2014 Li Guang
+ * Written by Li Guang <lig.fnst@cn.fujitsu.com>
+ *
+ * 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;
+    uint32_t cpu_num;
+
+    char *file;
+
+    bool force_raw;
+    bool data_be;
+    bool set_pc;
+} GenericLoaderState;
+
+#define TYPE_GENERIC_LOADER "loader"
+#define GENERIC_LOADER(obj) OBJECT_CHECK(GenericLoaderState, (obj), \
+                                         TYPE_GENERIC_LOADER)
+
+#endif
-- 
2.7.4

Re: [PATCH v13 1/2] generic-loader: Add a generic loader

[Philippe Mathieu-Daudé]

Hi,

[very old patch merged as commit e481a1f63c93]

On 30/9/16 02:25, Alistair Francis wrote:
> Add a generic loader to QEMU which can be used to load images or set
> memory values.
> 
> Internally inside QEMU this is a device. It is a strange device that
> provides no hardware interface but allows QEMU to monkey patch memory
> specified when it is created. To be able to do this it has a reset
> callback that does the memory operations.
> 
> This device allows the user to monkey patch memory. To be able to do
> this it needs a backend to manage the datas, the same as other
> memory-related devices. In this case as the backend is so trivial we
> have merged it with the frontend instead of creating and maintaining a
> seperate backend.
> 
> Signed-off-by: Alistair Francis <alistair.francis@xilinx.com>
> Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
> Acked-by: Markus Armbruster <armbru@redhat.com>
> ---

> diff --git a/hw/core/generic-loader.c b/hw/core/generic-loader.c
> new file mode 100644
> index 0000000..79ab6df
> --- /dev/null
> +++ b/hw/core/generic-loader.c
> @@ -0,0 +1,211 @@
> +/*
> + * Generic Loader
> + *
> + * Copyright (C) 2014 Li Guang
> + * Copyright (C) 2016 Xilinx Inc.
> + * Written by Li Guang <lig.fnst@cn.fujitsu.com>
> + *
> + * 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.
> + *
> + */
> +
> +/*
> + * Internally inside QEMU this is a device. It is a strange device that
> + * provides no hardware interface but allows QEMU to monkey patch memory
> + * specified when it is created. To be able to do this it has a reset
> + * callback that does the memory operations.
> +
> + * This device allows the user to monkey patch memory. To be able to do
> + * this it needs a backend to manage the datas, the same as other
> + * memory-related devices. In this case as the backend is so trivial we
> + * have merged it with the frontend instead of creating and maintaining a
> + * seperate backend.
> + */
> +
> +#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 0xFFFFFFFF
> +
> +static void generic_loader_reset(void *opaque)
> +{
> +    GenericLoaderState *s = GENERIC_LOADER(opaque);
> +
> +    if (s->set_pc) {
> +        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->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;
> +
> +    s->set_pc = false;
> +
> +    /* Perform some error checking on the user's options */
> +    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");
> +            return;
> +        } else if (s->force_raw) {
> +            error_setg(errp, "Specifying force-raw is not supported when "
> +                       "loading memory values");
> +            return;
> +        } else if (!s->data_len) {
> +            /* We cant' check for !data here as a value of 0 is still valid. */
> +            error_setg(errp, "Both data and data-len must be specified");
> +            return;
> +        } else if (s->data_len > 8) {
> +            error_setg(errp, "data-len cannot be greater then 8 bytes");

If s->data_len < 8 (like 4 or 2) ...

> +            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;
> +        }
> +        s->set_pc = true;
> +    } else if (s->addr) {
> +        /* User is setting the PC */
> +        if (s->data || s->data_len || s->data_be) {
> +            error_setg(errp, "data can not be specified when setting a "
> +                       "program counter");
> +            return;
> +        } else if (!s->cpu_num) {
> +            error_setg(errp, "cpu_num must be specified when setting a "
> +                       "program counter");
> +            return;
> +        }
> +        s->set_pc = true;
> +    } else {
> +        /* Did the user specify anything? */
> +        error_setg(errp, "please include valid arguments");
> +        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;
> +        }
> +    } else {
> +        s->cpu = first_cpu;
> +    }
> +
> +#ifdef TARGET_WORDS_BIGENDIAN
> +    big_endian = 1;
> +#else
> +    big_endian = 0;
> +#endif
> +
> +    if (s->file) {
> +        if (!s->force_raw) {
> +            size = load_elf_as(s->file, NULL, NULL, &entry, NULL, NULL,
> +                               big_endian, 0, 0, 0, s->cpu->as);
> +
> +            if (size < 0) {
> +                size = load_uimage_as(s->file, &entry, NULL, NULL, NULL, NULL,
> +                                      s->cpu->as);
> +            }
> +        }
> +
> +        if (size < 0 || s->force_raw) {
> +            /* Default to the maximum size being the machine's ram size */
> +            size = load_image_targphys_as(s->file, s->addr, ram_size,
> +                                          s->cpu->as);
> +        } else {
> +            s->addr = entry;
> +        }
> +
> +        if (size < 0) {
> +            error_setg(errp, "Cannot load specified image %s", s->file);
> +            return;
> +        }
> +    }
> +
> +    /* Convert the data endiannes */
> +    if (s->data_be) {
> +        s->data = cpu_to_be64(s->data);
> +    } else {
> +        s->data = cpu_to_le64(s->data);

... and if we swap, we ignore the data-len and swap 64-bit
regardless, returning invalid data.

I.e. data=0x1122, data-len=2, once swapped we get data=0x0000.

Is that expected?

> +    }
> +}
> +
> +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_UINT32("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(),
> +};

Re: [PATCH v13 1/2] generic-loader: Add a generic loader

[Alistair Francis]

On Thu, Nov 28, 2024 at 2:09 AM Philippe Mathieu-Daudé
<philmd@linaro.org> wrote:
>
> Hi,
>
> [very old patch merged as commit e481a1f63c93]
>
> On 30/9/16 02:25, Alistair Francis wrote:
> > Add a generic loader to QEMU which can be used to load images or set
> > memory values.
> >
> > Internally inside QEMU this is a device. It is a strange device that
> > provides no hardware interface but allows QEMU to monkey patch memory
> > specified when it is created. To be able to do this it has a reset
> > callback that does the memory operations.
> >
> > This device allows the user to monkey patch memory. To be able to do
> > this it needs a backend to manage the datas, the same as other
> > memory-related devices. In this case as the backend is so trivial we
> > have merged it with the frontend instead of creating and maintaining a
> > seperate backend.
> >
> > Signed-off-by: Alistair Francis <alistair.francis@xilinx.com>
> > Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
> > Acked-by: Markus Armbruster <armbru@redhat.com>
> > ---
>
> > diff --git a/hw/core/generic-loader.c b/hw/core/generic-loader.c
> > new file mode 100644
> > index 0000000..79ab6df
> > --- /dev/null
> > +++ b/hw/core/generic-loader.c
> > @@ -0,0 +1,211 @@
> > +/*
> > + * Generic Loader
> > + *
> > + * Copyright (C) 2014 Li Guang
> > + * Copyright (C) 2016 Xilinx Inc.
> > + * Written by Li Guang <lig.fnst@cn.fujitsu.com>
> > + *
> > + * 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.
> > + *
> > + */
> > +
> > +/*
> > + * Internally inside QEMU this is a device. It is a strange device that
> > + * provides no hardware interface but allows QEMU to monkey patch memory
> > + * specified when it is created. To be able to do this it has a reset
> > + * callback that does the memory operations.
> > +
> > + * This device allows the user to monkey patch memory. To be able to do
> > + * this it needs a backend to manage the datas, the same as other
> > + * memory-related devices. In this case as the backend is so trivial we
> > + * have merged it with the frontend instead of creating and maintaining a
> > + * seperate backend.
> > + */
> > +
> > +#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 0xFFFFFFFF
> > +
> > +static void generic_loader_reset(void *opaque)
> > +{
> > +    GenericLoaderState *s = GENERIC_LOADER(opaque);
> > +
> > +    if (s->set_pc) {
> > +        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->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;
> > +
> > +    s->set_pc = false;
> > +
> > +    /* Perform some error checking on the user's options */
> > +    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");
> > +            return;
> > +        } else if (s->force_raw) {
> > +            error_setg(errp, "Specifying force-raw is not supported when "
> > +                       "loading memory values");
> > +            return;
> > +        } else if (!s->data_len) {
> > +            /* We cant' check for !data here as a value of 0 is still valid. */
> > +            error_setg(errp, "Both data and data-len must be specified");
> > +            return;
> > +        } else if (s->data_len > 8) {
> > +            error_setg(errp, "data-len cannot be greater then 8 bytes");
>
> If s->data_len < 8 (like 4 or 2) ...
>
> > +            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;
> > +        }
> > +        s->set_pc = true;
> > +    } else if (s->addr) {
> > +        /* User is setting the PC */
> > +        if (s->data || s->data_len || s->data_be) {
> > +            error_setg(errp, "data can not be specified when setting a "
> > +                       "program counter");
> > +            return;
> > +        } else if (!s->cpu_num) {
> > +            error_setg(errp, "cpu_num must be specified when setting a "
> > +                       "program counter");
> > +            return;
> > +        }
> > +        s->set_pc = true;
> > +    } else {
> > +        /* Did the user specify anything? */
> > +        error_setg(errp, "please include valid arguments");
> > +        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;
> > +        }
> > +    } else {
> > +        s->cpu = first_cpu;
> > +    }
> > +
> > +#ifdef TARGET_WORDS_BIGENDIAN
> > +    big_endian = 1;
> > +#else
> > +    big_endian = 0;
> > +#endif
> > +
> > +    if (s->file) {
> > +        if (!s->force_raw) {
> > +            size = load_elf_as(s->file, NULL, NULL, &entry, NULL, NULL,
> > +                               big_endian, 0, 0, 0, s->cpu->as);
> > +
> > +            if (size < 0) {
> > +                size = load_uimage_as(s->file, &entry, NULL, NULL, NULL, NULL,
> > +                                      s->cpu->as);
> > +            }
> > +        }
> > +
> > +        if (size < 0 || s->force_raw) {
> > +            /* Default to the maximum size being the machine's ram size */
> > +            size = load_image_targphys_as(s->file, s->addr, ram_size,
> > +                                          s->cpu->as);
> > +        } else {
> > +            s->addr = entry;
> > +        }
> > +
> > +        if (size < 0) {
> > +            error_setg(errp, "Cannot load specified image %s", s->file);
> > +            return;
> > +        }
> > +    }
> > +
> > +    /* Convert the data endiannes */
> > +    if (s->data_be) {
> > +        s->data = cpu_to_be64(s->data);
> > +    } else {
> > +        s->data = cpu_to_le64(s->data);
>
> ... and if we swap, we ignore the data-len and swap 64-bit
> regardless, returning invalid data.
>
> I.e. data=0x1122, data-len=2, once swapped we get data=0x0000.
>
> Is that expected?

I don't think that's expected

Alistair

[Qemu-devel] [PATCH v13 2/2] docs: Add a generic loader explanation document

[Alistair Francis]

Signed-off-by: Alistair Francis <alistair.francis@xilinx.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
---
V11:
 - Fix corrections
V10:
 - Split the data loading and PC setting
V9:
 - Clarify the image loading options
V8:
 - Improve documentation
V6:
 - Fixup documentation
V4:
 - Re-write to be more comprehensive

 docs/generic-loader.txt | 84 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 84 insertions(+)
 create mode 100644 docs/generic-loader.txt

diff --git a/docs/generic-loader.txt b/docs/generic-loader.txt
new file mode 100644
index 0000000..8fcb550
--- /dev/null
+++ b/docs/generic-loader.txt
@@ -0,0 +1,84 @@
+Copyright (c) 2016 Xilinx Inc.
+
+This work is licensed under the terms of the GNU GPL, version 2 or later.  See
+the COPYING file in the top-level directory.
+
+
+The 'loader' device allows the user to load multiple images or values into
+QEMU at startup.
+
+Loading Data into Memory Values
+---------------------
+The loader device allows memory values to be set from the command line. This
+can be done by following the syntax below:
+
+     -device loader,addr=<addr>,data=<data>,data-len=<data-len>
+                   [,data-be=<data-be>][,cpu-num=<cpu-num>]
+
+    <addr>      - The address to store the data in.
+    <data>      - The value to be written to the address. The maximum size of
+                  the data is 8 bytes.
+    <data-len>  - The length of the data in bytes. This argument must be
+                  included if the data argument is.
+    <data-be>   - Set to true if the data to be stored on the guest should be
+                  written as big endian data. The default is to write little
+                  endian data.
+    <cpu-num>   - The number of the CPU's address space where the data should
+                  be loaded. If not specified the address space of the first
+                  CPU is used.
+
+All values are parsed using the standard QemuOps parsing. This allows the user
+to specify any values in any format supported. By default the values
+will be parsed as decimal. To use hex values the user should prefix the number
+with a '0x'.
+
+An example of loading value 0x8000000e to address 0xfd1a0104 is:
+    -device loader,addr=0xfd1a0104,data=0x8000000e,data-len=4
+
+Setting a CPU's Program Counter
+---------------------
+The loader device allows the CPU's PC to be set from the command line. This
+can be done by following the syntax below:
+
+     -device loader,addr=<addr>,cpu-num=<cpu-num>
+
+    <addr>      - The value to use as the CPU's PC.
+    <cpu-num>   - The number of the CPU whose PC should be set to the
+                  specified value.
+
+All values are parsed using the standard QemuOps parsing. This allows the user
+to specify any values in any format supported. By default the values
+will be parsed as decimal. To use hex values the user should prefix the number
+with a '0x'.
+
+An example of setting CPU 0's PC to 0x8000 is:
+    -device loader,addr=0x8000,cpu-num=0
+
+Loading Files
+---------------------
+The loader device also allows files to be loaded into memory. This can be done
+similarly to setting memory values. The syntax is shown below:
+
+    -device loader,file=<file>[,addr=<addr>][,cpu-num=<cpu-num>][,force-raw=<raw>]
+
+    <file>      - A file to be loaded into memory
+    <addr>      - The addr in memory that the file should be loaded. This is
+                  ignored if you are using an ELF (unless force-raw is true).
+                  This is required if you aren't loading an ELF.
+    <cpu-num>   - This specifies the CPU that should be used. This is an
+                  optional argument and will cause the CPU's PC to be set to
+                  where the image is stored or in the case of an ELF file to
+                  the value in the header. This option should only be used
+                  for the boot image.
+                  This will also cause the image to be written to the specified
+                  CPU's address space. If not specified, the default is CPU 0.
+    <force-raw> - Forces the file to be treated as a raw image. This can be
+                  used to specify the load address of ELF files.
+
+All values are parsed using the standard QemuOps parsing. This allows the user
+to specify any values in any format supported. By default the values
+will be parsed as decimal. To use hex values the user should prefix the number
+with a '0x'.
+
+An example of loading an ELF file which CPU0 will boot is shown below:
+    -device loader,file=./images/boot.elf,cpu-num=0
-- 
2.7.4

Re: [Qemu-devel] [PATCH v13 0/2] Add a generic loader

[Peter Maydell]

On 29 September 2016 at 17:25, Alistair Francis
<alistair.francis@xilinx.com> wrote:
> This work is based on the original work by Li Guang with extra
> features added by Peter C and myself.
>
> The idea of this loader is to allow the user to load multiple images
> or values into QEMU at startup.
>
> Memory values can be loaded like this: -device loader,addr=0xfd1a0104,data=0x8000000e,data-len=4
>
> Images can be loaded like this: -device loader,file=./images/u-boot.elf,cpu=0
>
> This can be useful and we use it a lot in Xilinx to load multiple images
> into a machine at creation (ATF, Kernel and DTB for example).
>
> Tested with the latest Xilinx ZynqMP machine, if I enable EL3 and EL2 I can
> boot ATF through to u-boot using the loader to load the images.
>
> It can also be used to set registers.
>
> This patch series makes the load_elf() function more generic by not
> requiring an architecture. It also adds new functions load_elf_as(),
> load_uimage_as and load_image_targphys_as which allows custom
> AddressSpaces when loading images.
>
> V12:
>  - All patches have been reviewed
>  - Most patches have been merged
>  - The commit message of the actual device patch has been updated to
>    justify why it is a device.
>
>
> Alistair Francis (2):
>   generic-loader: Add a generic loader
>   docs: Add a generic loader explanation document

Applied to target-arm.next, thanks.

-- PMM