Re: [Qemu-devel] [PATCH v2 2/2] ARM: Virt: ACPI: Build an IORT table with RC and ITS nodes

[Auger Eric]

Hi Drew,

On 14/10/2016 13:57, Andrew Jones wrote:
> On Fri, Oct 14, 2016 at 10:54:55AM +0200, Eric Auger wrote:
>> From: Prem Mallappa <address@hidden>
>>
>> This patch builds an IORT table that features a root complex node and
>> an ITS node. This complements the ITS description in the ACPI MADT
>> table and allows vhost-net on ACPI guest.
>>
>> Signed-off-by: Prem Mallappa <address@hidden>
>> Signed-off-by: Eric Auger <address@hidden>
>>
>> ---
>>
>> v1 -> v2:
>> - its_class_name() || !guest_info->no_its now wraps acpi_add_table
>>   and build_iort
>> - add cpu_to_le*
>> - CCA = CPM = DACS = 1
>> - cleanup according to Drew's comments
>> - remove comments listing tables and spec revisions
>> ---
>>  hw/arm/virt-acpi-build.c | 73 
>> ++++++++++++++++++++++++++++++++++++++++--------
>>  1 file changed, 62 insertions(+), 11 deletions(-)
>>
>> diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c
>> index fa0655a..5fc0fd7 100644
>> --- a/hw/arm/virt-acpi-build.c
>> +++ b/hw/arm/virt-acpi-build.c
>> @@ -384,6 +384,63 @@ build_rsdp(GArray *rsdp_table, BIOSLinker *linker, 
>> unsigned rsdt_tbl_offset)
>>  }
>>  
>>  static void
>> +build_iort(GArray *table_data, BIOSLinker *linker, VirtGuestInfo 
>> *guest_info)
>> +{
>> +    int iort_start = table_data->len;
>> +    AcpiIortIdMapping *idmap;
>> +    AcpiIortItsGroup *its;
>> +    AcpiIortTable *iort;
>> +    size_t node_size, iort_length;
>> +    AcpiIortRC *rc;
>> +
>> +    iort = acpi_data_push(table_data, sizeof(*iort));
>> +
>> +    iort_length = sizeof(*iort);
>> +    iort->node_count = cpu_to_le32(2); /* RC and ITS nodes */
>> +    iort->node_offset = cpu_to_le32(table_data->len - iort_start);
> 
> table_data->len - iort_start = sizeof(*iort), I think the later would
> be nicer to use.
hum yes looks sensible :-)
> 
>> +
>> +    /* ITS group node */
>> +    node_size =  sizeof(*its) + sizeof(uint32_t);
>> +    iort_length += node_size;
>> +    its = acpi_data_push(table_data, node_size);
>> +
>> +    its->type = ACPI_IORT_NODE_ITS_GROUP;
>> +    its->length = cpu_to_le16(node_size);
> unnecessary blank line
OK
>> +
>> +    its->its_count = cpu_to_le32(1);
>> +    its->identifiers[0] = 0; /* madt translation_id = 0 */
> 
> /madt/MADT/
> can probably drop the '= 0' in the comment
OK
> 
>> +
>> +    /* Root Complex Node */
>> +    node_size = sizeof(*rc) + sizeof(*idmap);
>> +    iort_length += node_size;
>> +    rc = acpi_data_push(table_data, node_size);
>> +
>> +    rc->type = ACPI_IORT_NODE_PCI_ROOT_COMPLEX;
>> +    rc->length = cpu_to_le16(node_size);
> unnecessary blank line
OK
>> +
>> +    rc->mapping_count = cpu_to_le32(1);
>> +    rc->mapping_offset = cpu_to_le32(sizeof(*rc));
>> +
>> +    /* fully coherent device */
>> +    rc->memory_properties.cache_coherency = cpu_to_le32(1);
>> +    rc->memory_properties.memory_flags = 0x3; /* CCA = CPM = DCAS = 1 */
>> +    rc->pci_segment_number = 0; /* MCFG pci_segment */
>> +
>> +    /* Identity RID mapping covering the whole input RID range */
>> +    idmap = &rc->id_mapping_array[0];
>> +    idmap->input_base = 0;
>> +    idmap->id_count = cpu_to_le32(0xFFFF);
>> +    idmap->output_base = 0;
>> +    idmap->output_reference = cpu_to_le32(iort->node_offset);
> 
> I'd still like a comment for output_reference stating that this is where
> we're mapping the output of the root complex to the ITS group node.
yep
> 
>> +    idmap->flags = 0;
> 
> I think we can drop this flags assignment, otherwise we need to comment
> it.
yep

Thanks

Eric
> 
>> +
>> +    iort->length = cpu_to_le32(iort_length);
>> +
>> +    build_header(linker, table_data, (void *)(table_data->data + 
>> iort_start),
>> +                 "IORT", table_data->len - iort_start, 0, NULL, NULL);
>> +}
>> +
>> +static void
>>  build_spcr(GArray *table_data, BIOSLinker *linker, VirtGuestInfo 
>> *guest_info)
>>  {
>>      AcpiSerialPortConsoleRedirection *spcr;
>> @@ -667,17 +724,6 @@ void virt_acpi_build(VirtGuestInfo *guest_info, 
>> AcpiBuildTables *tables)
>>                               ACPI_BUILD_TABLE_FILE, tables_blob,
>>                               64, false /* high memory */);
>>  
>> -    /*
>> -     * The ACPI v5.1 tables for Hardware-reduced ACPI platform are:
>> -     * RSDP
>> -     * RSDT
>> -     * FADT
>> -     * GTDT
>> -     * MADT
>> -     * MCFG
>> -     * DSDT
>> -     */
>> -
>>      /* DSDT is pointed to by FADT */
>>      dsdt = tables_blob->len;
>>      build_dsdt(tables_blob, tables->linker, guest_info);
>> @@ -703,6 +749,11 @@ void virt_acpi_build(VirtGuestInfo *guest_info, 
>> AcpiBuildTables *tables)
>>          build_srat(tables_blob, tables->linker, guest_info);
>>      }
>>  
>> +    if (its_class_name() && !guest_info->no_its) {
>> +        acpi_add_table(table_offsets, tables_blob);
>> +        build_iort(tables_blob, tables->linker, guest_info);
>> +    }
>> +
>>      /* RSDT is pointed to by RSDP */
>>      rsdt = tables_blob->len;
>>      build_rsdt(tables_blob, tables->linker, table_offsets, NULL, NULL);
>> -- 
>> 2.5.5
>>
>>
> 
> Thanks,
> drew 
>