Re: [PATCH v3 02/35] acpi: build_rsdt: use acpi_table_begin()/acpi_table_end() instead of build_header()

[Igor Mammedov <imammedo@redhat.com>]

On Mon, 20 Sep 2021 18:21:22 +0200
Eric Auger <eauger@redhat.com> wrote:

> Hi,
> 
> On 9/7/21 4:47 PM, Igor Mammedov wrote:
> > it replaces error-prone pointer arithmetic for build_header() API,
> > with 2 calls to start and finish table creation,
> > which hides offests magic from API user.
> > 
> > While at it switch to build_append_int_noprefix() to build
> > entries to other tables (which also removes some manual offset
> > calculations).
> > 
> > Signed-off-by: Igor Mammedov <imammedo@redhat.com>  
> 
> > ---
> > v3:
> >  * s/acpi_init_table|acpi_table_composed/acpi_table_begin|acpi_table_end/
> > ---
> >  include/hw/acpi/acpi-defs.h | 10 ----------
> >  hw/acpi/aml-build.c         | 27 ++++++++++++---------------
> >  2 files changed, 12 insertions(+), 25 deletions(-)
> > 
> > diff --git a/include/hw/acpi/acpi-defs.h b/include/hw/acpi/acpi-defs.h
> > index cf9f44299c..ccfa3382aa 100644
> > --- a/include/hw/acpi/acpi-defs.h
> > +++ b/include/hw/acpi/acpi-defs.h
> > @@ -149,16 +149,6 @@ struct AcpiSerialPortConsoleRedirection {
> >  typedef struct AcpiSerialPortConsoleRedirection
> >                 AcpiSerialPortConsoleRedirection;
> >  
> > -/*
> > - * ACPI 1.0 Root System Description Table (RSDT)  
> nit: you may move that comment to aml-build.c

yep, existing build_rsdt/build_xsdt are missing expected spec
reference comment. I'll post an additional patch to fix it.

> 
> Reviewed-by: Eric Auger <eric.auger@redhat.com>

Thanks!

> 
> Eric
> > - */
> > -struct AcpiRsdtDescriptorRev1 {
> > -    ACPI_TABLE_HEADER_DEF       /* ACPI common table header */
> > -    uint32_t table_offset_entry[];  /* Array of pointers to other */
> > -    /* ACPI tables */
> > -} QEMU_PACKED;
> > -typedef struct AcpiRsdtDescriptorRev1 AcpiRsdtDescriptorRev1;
> > -
> >  /*
> >   * ACPI 2.0 eXtended System Description Table (XSDT)
> >   */
> > diff --git a/hw/acpi/aml-build.c b/hw/acpi/aml-build.c
> > index 229a3eb654..32f14d4a78 100644
> > --- a/hw/acpi/aml-build.c
> > +++ b/hw/acpi/aml-build.c
> > @@ -1890,27 +1890,24 @@ build_rsdt(GArray *table_data, BIOSLinker *linker, GArray *table_offsets,
> >             const char *oem_id, const char *oem_table_id)
> >  {
> >      int i;
> > -    unsigned rsdt_entries_offset;
> > -    AcpiRsdtDescriptorRev1 *rsdt;
> > -    int rsdt_start = table_data->len;
> > -    const unsigned table_data_len = (sizeof(uint32_t) * table_offsets->len);
> > -    const unsigned rsdt_entry_size = sizeof(rsdt->table_offset_entry[0]);
> > -    const size_t rsdt_len = sizeof(*rsdt) + table_data_len;
> > -
> > -    rsdt = acpi_data_push(table_data, rsdt_len);
> > -    rsdt_entries_offset = (char *)rsdt->table_offset_entry - table_data->data;
> > +    AcpiTable table = { .sig = "RSDT", .rev = 1,
> > +                        .oem_id = oem_id, .oem_table_id = oem_table_id };
> > +
> > +    acpi_table_begin(&table, table_data);
> >      for (i = 0; i < table_offsets->len; ++i) {
> >          uint32_t ref_tbl_offset = g_array_index(table_offsets, uint32_t, i);
> > -        uint32_t rsdt_entry_offset = rsdt_entries_offset + rsdt_entry_size * i;
> > +        uint32_t rsdt_entry_offset = table.array->len;
> > +
> > +        /* reserve space for entry */
> > +        build_append_int_noprefix(table.array, 0, 4);
> >  
> > -        /* rsdt->table_offset_entry to be filled by Guest linker */
> > +        /* mark position of RSDT entry to be filled by Guest linker */
> >          bios_linker_loader_add_pointer(linker,
> > -            ACPI_BUILD_TABLE_FILE, rsdt_entry_offset, rsdt_entry_size,
> > +            ACPI_BUILD_TABLE_FILE, rsdt_entry_offset, 4,
> >              ACPI_BUILD_TABLE_FILE, ref_tbl_offset);
> > +
> >      }
> > -    build_header(linker, table_data,
> > -                 (void *)(table_data->data + rsdt_start),
> > -                 "RSDT", rsdt_len, 1, oem_id, oem_table_id);
> > +    acpi_table_end(linker, &table);
> >  }
> >  
> >  /* Build xsdt table */
> >   
>