Re: [PATCH 05/13] microvm: add acpi_dsdt_add_virtio() for x86

[Igor Mammedov <imammedo@redhat.com>]

On Thu, 19 Mar 2020 09:01:09 +0100
Gerd Hoffmann <kraxel@redhat.com> wrote:

> Makes x86 linux kernel find virtio-mmio devices automatically.
> 
> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
> ---
>  hw/i386/acpi-build.c | 51 ++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 51 insertions(+)
> 
> diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> index 0e45a646af56..80844db24d6b 100644
> --- a/hw/i386/acpi-build.c
> +++ b/hw/i386/acpi-build.c
> @@ -21,6 +21,7 @@
>   */
>  
>  #include "qemu/osdep.h"
> +#include "qemu/cutils.h"
>  #include "qapi/error.h"
>  #include "qapi/qmp/qnum.h"
>  #include "acpi-build.h"
> @@ -60,6 +61,7 @@
>  #include "hw/pci-host/q35.h"
>  #include "hw/i386/x86-iommu.h"
>  #include "hw/i386/microvm.h"
> +#include "hw/virtio/virtio-mmio.h"
>  
>  #include "hw/acpi/aml-build.h"
>  #include "hw/acpi/utils.h"
> @@ -2750,6 +2752,54 @@ static bool acpi_get_mcfg(AcpiMcfgInfo *mcfg)
>      return true;
>  }
>  
> +static void acpi_dsdt_add_virtio(Aml *scope)
> +{
> +    gchar *separator;
> +    long int index;
> +    BusState *bus;
> +    BusChild *kid;
> +
> +    bus = sysbus_get_default();
> +    QTAILQ_FOREACH(kid, &bus->children, sibling) {
> +        DeviceState *dev = kid->child;
> +        ObjectClass *class = object_get_class(OBJECT(dev));
> +
> +        if (class == object_class_by_name(TYPE_VIRTIO_MMIO)) {
using object_dynamic_cast() would be cleaner

> +            VirtIOMMIOProxy *mmio = VIRTIO_MMIO(OBJECT(dev));
> +            VirtioBusState *mmio_virtio_bus = &mmio->bus;
> +            BusState *mmio_bus = &mmio_virtio_bus->parent_obj;
> +
> +            if (QTAILQ_EMPTY(&mmio_bus->children)) {
> +                continue;
> +            }
> +            separator = g_strrstr(mmio_bus->name, ".");
> +            if (!separator) {
> +                continue;
> +            }
> +            if (qemu_strtol(separator + 1, NULL, 10, &index) != 0) {
> +                continue;
> +            }
> +
> +            uint32_t irq = VIRTIO_IRQ_BASE + index;
> +            hwaddr base = VIRTIO_MMIO_BASE + index * 512;
> +            hwaddr size = 512;
is it possible to fish these values out from device without poking in its guts
like using sysbus_get_connected_irq() and make up something to do get mmio parameters from sysbus device

> +
> +            Aml *dev = aml_device("VR%02u", (unsigned)index);
> +            aml_append(dev, aml_name_decl("_HID", aml_string("LNRO0005")));
> +            aml_append(dev, aml_name_decl("_UID", aml_int(index)));
> +            aml_append(dev, aml_name_decl("_CCA", aml_int(1)));
> +
> +            Aml *crs = aml_resource_template();
> +            aml_append(crs, aml_memory32_fixed(base, size, AML_READ_WRITE));
> +            aml_append(crs,
> +                       aml_interrupt(AML_CONSUMER, AML_LEVEL, AML_ACTIVE_HIGH,
> +                                     AML_EXCLUSIVE, &irq, 1));
> +            aml_append(dev, aml_name_decl("_CRS", crs));
> +            aml_append(scope, dev);
> +        }
> +    }
> +}
> +
>  static void
>  build_dsdt_microvm(GArray *table_data, BIOSLinker *linker,
>                     MicrovmMachineState *mms)
> @@ -2766,6 +2816,7 @@ build_dsdt_microvm(GArray *table_data, BIOSLinker *linker,
>  
>      sb_scope = aml_scope("_SB");
>      acpi_dsdt_add_fw_cfg(sb_scope, OBJECT(x86ms->fw_cfg));
> +    acpi_dsdt_add_virtio(sb_scope);
>      aml_append(dsdt, sb_scope);
>  
>      scope = aml_scope("\\");