Re: [Qemu-devel] [PATCH v3 6/6] acpi: pci: use build_append_foo() API to construct MCFG

[Igor Mammedov <imammedo@redhat.com>]

On Wed, 17 Apr 2019 09:40:38 +0800
Wei Yang <richardw.yang@linux.intel.com> wrote:

> build_append_foo() API doesn't need explicit endianness conversions
> which eliminates a source of errors and it makes build_mcfg() look like
> declarative definition of MCFG table in ACPI spec, which makes it easy
> to review.
> 
> Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
> Suggested-by: Igor Mammedov <imammedo@redhat.com>
Thanks for nice cleanup!

with comment fixed up:
Reviewed-by: Igor Mammedov <imammedo@redhat.com>

> ---
>  hw/acpi/pci.c               | 30 ++++++++++++++++++------------
>  include/hw/acpi/acpi-defs.h | 18 ------------------
>  2 files changed, 18 insertions(+), 30 deletions(-)
> 
> diff --git a/hw/acpi/pci.c b/hw/acpi/pci.c
> index fa0fa30bb9..05050fa087 100644
> --- a/hw/acpi/pci.c
> +++ b/hw/acpi/pci.c
> @@ -30,17 +30,23 @@
>  
>  void build_mcfg(GArray *table_data, BIOSLinker *linker, AcpiMcfgInfo *info)
>  {
> -    AcpiTableMcfg *mcfg;
> -    int len = sizeof(*mcfg) + sizeof(mcfg->allocation[0]);
> -
> -    mcfg = acpi_data_push(table_data, len);
> -    mcfg->allocation[0].address = cpu_to_le64(info->base);
> -
> -    /* Only a single allocation so no need to play with segments */
> -    mcfg->allocation[0].pci_segment = cpu_to_le16(0);
> -    mcfg->allocation[0].start_bus_number = 0;
> -    mcfg->allocation[0].end_bus_number = PCIE_MMCFG_BUS(info->size - 1);
> -
> -    build_header(linker, table_data, (void *)mcfg, "MCFG", len, 1, NULL, NULL);
> +    int mcfg_start = table_data->len;
> +
> +    acpi_data_push(table_data, sizeof(AcpiTableHeader));
> +
> +    /* PCI fw r3.0 MCFG table. */
It would be better to put spec name as is here so simple search
could immediately point to it.

like: PCI Firmware Specification, Revision 3.0
      4.1.2 MCFG Table Description

> +    /* Base address, processor-relative */
> +    build_append_int_noprefix(table_data, info->base, 8);
> +    /* PCI segment group number */
> +    build_append_int_noprefix(table_data, 0, 2);
> +    /* Starting PCI Bus number */
> +    build_append_int_noprefix(table_data, 0, 1);
> +    /* Final PCI Bus number */
> +    build_append_int_noprefix(table_data, PCIE_MMCFG_BUS(info->size - 1), 1);
> +    /* Reserved */
> +    build_append_int_noprefix(table_data, 0, 4);
> +
> +    build_header(linker, table_data, (void *)(table_data->data + mcfg_start),
> +                 "MCFG", table_data->len - mcfg_start, 1, NULL, NULL);
>  }
>  
> diff --git a/include/hw/acpi/acpi-defs.h b/include/hw/acpi/acpi-defs.h
> index f9aa4bd398..57a3f58b0c 100644
> --- a/include/hw/acpi/acpi-defs.h
> +++ b/include/hw/acpi/acpi-defs.h
> @@ -449,24 +449,6 @@ struct AcpiSratProcessorGiccAffinity {
>  
>  typedef struct AcpiSratProcessorGiccAffinity AcpiSratProcessorGiccAffinity;
>  
> -/* PCI fw r3.0 MCFG table. */
> -/* Subtable */
> -struct AcpiMcfgAllocation {
> -    uint64_t address;                /* Base address, processor-relative */
> -    uint16_t pci_segment;            /* PCI segment group number */
> -    uint8_t start_bus_number;       /* Starting PCI Bus number */
> -    uint8_t end_bus_number;         /* Final PCI Bus number */
> -    uint32_t reserved;
> -} QEMU_PACKED;
> -typedef struct AcpiMcfgAllocation AcpiMcfgAllocation;
> -
> -struct AcpiTableMcfg {
> -    ACPI_TABLE_HEADER_DEF;
> -    uint8_t reserved[8];
> -    AcpiMcfgAllocation allocation[0];
> -} QEMU_PACKED;
> -typedef struct AcpiTableMcfg AcpiTableMcfg;
> -
>  /*
>   * TCPA Description Table
>   *