Re: [Qemu-devel] [V9 2/4] hw/i386: ACPI table for AMD IOMMU

[Igor Mammedov <imammedo@redhat.com>]

On Mon, 2 May 2016 11:27:35 +0300
David Kiarie <davidkiarie4@gmail.com> wrote:

> On Sun, May 1, 2016 at 4:45 PM, Michael S. Tsirkin <mst@redhat.com> wrote:
> > On Sat, Apr 30, 2016 at 01:42:41AM +0300, David Kiarie wrote:  
> >> Add IVRS table for AMD IOMMU. Generate IVRS or DMAR
> >> depending on emulated IOMMU
> >>
> >> Signed-off-by: David Kiarie <davidkiarie4@gmail.com>
> >> ---
> >>  hw/acpi/aml-build.c         |  2 +-
> >>  hw/acpi/core.c              | 13 -------
> >>  hw/i386/acpi-build.c        | 93 +++++++++++++++++++++++++++++++++++++++------
> >>  include/hw/acpi/acpi-defs.h | 14 +++++++
> >>  include/hw/acpi/acpi.h      | 16 ++++++++
> >>  include/hw/acpi/aml-build.h |  1 +
> >>  include/hw/boards.h         |  6 +++
> >>  7 files changed, 120 insertions(+), 25 deletions(-)
> >>
> >> diff --git a/hw/acpi/aml-build.c b/hw/acpi/aml-build.c
> >> index ab89ca6..da11bf8 100644
> >> --- a/hw/acpi/aml-build.c
> >> +++ b/hw/acpi/aml-build.c
> >> @@ -227,7 +227,7 @@ static void build_extop_package(GArray *package, uint8_t op)
> >>      build_prepend_byte(package, 0x5B); /* ExtOpPrefix */
> >>  }
> >>
> >> -static void build_append_int_noprefix(GArray *table, uint64_t value, int size)
> >> +void build_append_int_noprefix(GArray *table, uint64_t value, int size)
> >>  {
> >>      int i;
> >>
> >> diff --git a/hw/acpi/core.c b/hw/acpi/core.c
> >> index 7925a1a..ee0e687 100644
> >> --- a/hw/acpi/core.c
> >> +++ b/hw/acpi/core.c
> >> @@ -29,19 +29,6 @@
> >>  #include "qapi-visit.h"
> >>  #include "qapi-event.h"
> >>
> >> -struct acpi_table_header {
> >> -    uint16_t _length;         /* our length, not actual part of the hdr */
> >> -                              /* allows easier parsing for fw_cfg clients */
> >> -    char sig[4];              /* ACPI signature (4 ASCII characters) */
> >> -    uint32_t length;          /* Length of table, in bytes, including header */
> >> -    uint8_t revision;         /* ACPI Specification minor version # */
> >> -    uint8_t checksum;         /* To make sum of entire table == 0 */
> >> -    char oem_id[6];           /* OEM identification */
> >> -    char oem_table_id[8];     /* OEM table identification */
> >> -    uint32_t oem_revision;    /* OEM revision number */
> >> -    char asl_compiler_id[4];  /* ASL compiler vendor ID */
> >> -    uint32_t asl_compiler_revision; /* ASL compiler revision number */
> >> -} QEMU_PACKED;
it's internal struct used for loading external tables
leave it here and don't use, there is another public one for header.
Looks like acpi/core.c needs some cleanup to avoid confusion.


> >>
> >>  #define ACPI_TABLE_HDR_SIZE sizeof(struct acpi_table_header)
> >>  #define ACPI_TABLE_PFX_SIZE sizeof(uint16_t)  /* size of the extra prefix */
> >> diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> >> index 6477003..74ae994 100644
> >> --- a/hw/i386/acpi-build.c
> >> +++ b/hw/i386/acpi-build.c
> >> @@ -52,6 +52,7 @@
> >>  #include "hw/pci/pci_bus.h"
> >>  #include "hw/pci-host/q35.h"
> >>  #include "hw/i386/intel_iommu.h"
> >> +#include "hw/i386/amd_iommu.h"
> >>  #include "hw/timer/hpet.h"
> >>
> >>  #include "hw/acpi/aml-build.h"
> >> @@ -59,6 +60,8 @@
> >>  #include "qapi/qmp/qint.h"
> >>  #include "qom/qom-qobject.h"
> >>
> >> +#include "hw/boards.h"
> >> +
> >>  /* These are used to size the ACPI tables for -M pc-i440fx-1.7 and
> >>   * -M pc-i440fx-2.0.  Even if the actual amount of AML generated grows
> >>   * a little bit, there should be plenty of free space since the DSDT
> >> @@ -2598,6 +2601,77 @@ build_dmar_q35(GArray *table_data, GArray *linker)
> >>                   "DMAR", table_data->len - dmar_start, 1, NULL, NULL);
> >>  }
> >>
> >> +static void
> >> +build_amd_iommu(GArray *table_data, GArray *linker)
> >> +{
> >> +    int iommu_start = table_data->len;
> >> +    bool iommu_ambig;
> >> +
> >> +    /* IVRS definition  - table header has an extra 2-byte field */
> >> +    acpi_data_push(table_data, (sizeof(acpi_table_header) - 2));  
> >
> > why won't build_header overwrite the extra fields?
> > Even if not, that's too hacky. Pls find another way to do this.  
> 
> I was advised to do this by Igor, to get rid of structs defining IVRS
> table. He actually said it should be done
>         acpi_data_push(table_data, (sizeof(acpi_table_header) - 2));
> but looking at acpi_table_header, I noted there's an extra 2-byte
> field for internal use which corrupts IVRS.
IVRS table has standard ACPI header so just do as other tables do:

for example:
acpi_data_push(dsdt->buf, sizeof(AcpiTableHeader)); 


> The other way I could do this, since I know the size of IVRS table, is
> to use a constant
>         acpi_data_push(table_data, 0x30));
> am not sure whether this isn't even more hacky otherwise I'd have to
> go back to using the original structs.