Re: [Qemu-devel] [PATCH v3 01/52] acpi: introduce AML composer aml_append()

["Michael S. Tsirkin" <mst@redhat.com>]

On Mon, Feb 09, 2015 at 10:53:23AM +0000, Igor Mammedov wrote:
> Adds for dynamic AML creation, which will be used
> for piecing ASL/AML primitives together and hiding
> from user/caller details about how nested context
> should be closed/packed leaving less space for
> mistakes and necessity to know how AML should be
> encoded, allowing user to concentrate on ASL
> representation instead.
> 
> For example it will allow to create AML like this:
> 
> init_aml_allocator();
> ...
> Aml *scope = aml_scope("PCI0")
> Aml *dev = aml_device("PM")
>     aml_append(dev, aml_name_decl("_ADR", aml_int(addr)))
> aml_append(scope, dev);
> ...
> free_aml_allocator();
> 
> Signed-off-by: Igor Mammedov <imammedo@redhat.com>
> ---
>  hw/acpi/aml-build.c         | 91 +++++++++++++++++++++++++++++++++++++++++++++
>  hw/i386/acpi-build.c        |  1 -
>  include/hw/acpi/aml-build.h | 61 ++++++++++++++++++++++++++++++
>  3 files changed, 152 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/acpi/aml-build.c b/hw/acpi/aml-build.c
> index bcb288e..096f347 100644
> --- a/hw/acpi/aml-build.c
> +++ b/hw/acpi/aml-build.c
> @@ -25,6 +25,8 @@
>  #include <stdbool.h>
>  #include <string.h>
>  #include "hw/acpi/aml-build.h"
> +#include "qemu/bswap.h"
> +#include "hw/acpi/bios-linker-loader.h"
>  
>  GArray *build_alloc_array(void)
>  {
> @@ -257,3 +259,92 @@ void build_append_int(GArray *table, uint32_t value)
>          build_append_value(table, value, 4);
>      }
>  }
> +
> +static GPtrArray *alloc_list;
> +
> +static Aml *aml_alloc(void)
> +{
> +    Aml *var = g_new0(typeof(*var), 1);
> +
> +    g_ptr_array_add(alloc_list, var);
> +    var->block_flags = AML_HELPER;
> +    var->buf = build_alloc_array();
> +    return var;
> +}
> +
> +static void aml_free(gpointer data)
> +{
> +    Aml *var = data;
> +    build_free_array(var->buf);
> +}
> +
> +Aml *init_aml_allocator(GArray *linker)
> +{
> +    Aml *var;
> +
> +    assert(!alloc_list);
> +    alloc_list = g_ptr_array_new_with_free_func(aml_free);
> +    var = aml_alloc();
> +    var->linker = linker;
> +    return var;
> +}
> +
> +void free_aml_allocator(void)
> +{
> +    g_ptr_array_free(alloc_list, true);
> +    alloc_list = 0;
> +}
> +
> +static void build_buffer(GArray *array, uint8_t op)
> +{
> +    GArray *data = build_alloc_array();
> +
> +    build_append_int(data, array->len);
> +    g_array_prepend_vals(array, data->data, data->len);
> +    build_free_array(data);
> +    build_package(array, op);
> +}
> +
> +void aml_append(Aml *parent_ctx, Aml *child)
> +{
> +    switch (child->block_flags) {
> +    case AML_NON_BLOCK:
> +        build_append_byte(parent_ctx->buf, child->op);
> +        break;
> +    case AML_EXT_PACKAGE:
> +        build_extop_package(child->buf, child->op);
> +        break;
> +    case AML_PACKAGE:
> +        build_package(child->buf, child->op);
> +        break;
> +    case AML_RES_TEMPLATE:
> +        build_append_byte(child->buf, 0x79); /* EndTag */
> +        /*
> +         * checksum operations is treated as succeeded if checksum
> +         * field is zero. [ACPI Spec 5.0, 6.4.2.9 End Tag]
> +         */
> +        build_append_byte(child->buf, 0);
> +        /* fall through, to pack resources in buffer */
> +    case AML_BUFFER:
> +        build_buffer(child->buf, child->op);
> +        break;
> +    case AML_DEF_BLOCK: {

This one is inelegant.
It's not a definition block, and the patching and
manual offset calculation are scary.

> +        uint8_t *start = (uint8_t *)parent_ctx->buf->data +
> +                         parent_ctx->buf->len;
> +        uint32_t le32_len = cpu_to_le32(child->buf->len);
> +
> +        /* create linker entry for the DefinitionBlock */
> +        bios_linker_loader_add_checksum(parent_ctx->linker,
> +            ACPI_BUILD_TABLE_FILE,

Hard-coding file name here is very ugly.
All this does not belong in this file, this
is fw cfg interface.


> +            parent_ctx->buf->data,
> +            start, child->buf->len, start + 9 /* checksum offset */);
> +
> +        /* set DefinitionBlock length at TableLength offset*/
> +        memcpy(child->buf->data + 4, &le32_len, sizeof le32_len);


This make no sense.
In AML, there are no objects which are higher level
than the table.

So for now, please just leave this alone:
drop linker completely, keep table_data
a simple GArray, not AML, and reuse build_header
to fill in headers.

This way this file just deals with AML and ACPI spec.


> +        break;
> +    }
> +    default:

This should assert.

> +        break;
> +    }
> +    build_append_array(parent_ctx->buf, child->buf);
> +}
> diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> index 6d84f38..237080f 100644
> --- a/hw/i386/acpi-build.c
> +++ b/hw/i386/acpi-build.c
> @@ -258,7 +258,6 @@ static void acpi_get_pci_info(PcPciInfo *info)
>  #define ACPI_BUILD_APPNAME6 "BOCHS "
>  #define ACPI_BUILD_APPNAME4 "BXPC"
>  
> -#define ACPI_BUILD_TABLE_FILE "etc/acpi/tables"
>  #define ACPI_BUILD_RSDP_FILE "etc/acpi/rsdp"
>  #define ACPI_BUILD_TPMLOG_FILE "etc/tpm/log"
>  
> diff --git a/include/hw/acpi/aml-build.h b/include/hw/acpi/aml-build.h
> index 199f003..4033796 100644
> --- a/include/hw/acpi/aml-build.h
> +++ b/include/hw/acpi/aml-build.h
> @@ -5,6 +5,67 @@
>  #include <glib.h>
>  #include "qemu/compiler.h"
>  
> +#define ACPI_BUILD_TABLE_FILE "etc/acpi/tables"
> +
> +typedef enum {
> +    AML_HELPER = 0,
> +    AML_NON_BLOCK,
> +    AML_PACKAGE,
> +    AML_EXT_PACKAGE,
> +    AML_BUFFER,
> +    AML_RES_TEMPLATE,
> +    AML_DEF_BLOCK,
> +} AmlBlockFlags;
> +
> +struct Aml {
> +    GArray *buf;
> +
> +    /*< private >*/
> +    uint8_t op;
> +    AmlBlockFlags block_flags;
> +    GArray *linker;
> +};
> +typedef struct Aml Aml;
> +
> +/**
> + * init_aml_allocator:
> + * @linker: linker that used by API for registering ACPI tables
> + *          with linker firmware interfac
> + *
> + * Called for initializing API allocator which allow to use
> + * AML API.
> + * Returns: toplevel container which accumulates all other
> + * ACPI tables.
> + */
> +Aml *init_aml_allocator(GArray *linker);
> +
> +/**
> + * free_aml_allocator:
> + *
> + * Releases all elements used by AML API, frees associated memory
> + * and invalidates AML allocator. After this call @init_aml_allocator
> + * should be called again if AML API is to be used again.
> + */
> +void free_aml_allocator(void);
> +
> +/**
> + * aml_append:
> + * @parent_ctx: context to which @child element is added
> + * @child: element that is copied into @parent_ctx context
> + *
> + * Joins Aml elements together and helps to construct AML tables
> + * Examle of usage:
> + *   Aml *table = aml_def_block("SSDT", ...);
> + *   Aml *sb = aml_scope("\_SB");
> + *   Aml *dev = aml_device("PCI0");
> + *
> + *   aml_append(dev, aml_name_decl("HID", aml_eisaid("PNP0A03")));
> + *   aml_append(sb, dev);
> + *   aml_append(table, sb);
> + */
> +void aml_append(Aml *parent_ctx, Aml *child);
> +
> +/* other helpers */
>  GArray *build_alloc_array(void);
>  void build_free_array(GArray *array);
>  void build_prepend_byte(GArray *array, uint8_t val);
> -- 
> 1.8.3.1