Re: [Qemu-devel] [RFC PATCH] hw/arm/virt-acpi-build: Add GICv2m description in ACPI MADT table

[Peter Maydell]

On 1 June 2015 at 11:15,  <address@hidden> wrote:
> From: Shannon Zhao <address@hidden>
>
> Add GICv2m description in ACPI MADT table, so guest can use MSI when
> booting with ACPI.
>
> Signed-off-by: Shannon Zhao <address@hidden>
> Signed-off-by: Shannon Zhao <address@hidden>
> ---
>     This is based on Christoffer's GICv2m patchset.
>         Test virtio-net-pci, e1000.
> ---
>  hw/arm/virt-acpi-build.c    | 11 +++++++++++
>  include/hw/acpi/acpi-defs.h | 12 ++++++++++++
>  2 files changed, 23 insertions(+)
>
> diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c
> index a9373cc..d8dcf45 100644
> --- a/hw/arm/virt-acpi-build.c
> +++ b/hw/arm/virt-acpi-build.c
> @@ -385,8 +385,10 @@ build_madt(GArray *table_data, GArray *linker, 
> VirtGuestInfo *guest_info,
>  {
>      int madt_start = table_data->len;
>      const MemMapEntry *memmap = guest_info->memmap;
> +    const int *irqmap = guest_info->irqmap;
>      AcpiMultipleApicTable *madt;
>      AcpiMadtGenericDistributor *gicd;
> +    AcpiMadtGenericMsiFrame *gic_msi;
>      int i;
>
>      madt = acpi_data_push(table_data, sizeof *madt);
> @@ -410,6 +412,15 @@ build_madt(GArray *table_data, GArray *linker, 
> VirtGuestInfo *guest_info,
>      gicd->length = sizeof(*gicd);
>      gicd->base_address = memmap[VIRT_GIC_DIST].base;
>
> +    gic_msi = acpi_data_push(table_data, sizeof *gic_msi);
> +    gic_msi->type = ACPI_APIC_GENERIC_MSI_FRAME;
> +    gic_msi->length = sizeof(*gic_msi);
> +    gic_msi->gic_msi_frame_id = 0;
> +    gic_msi->base_address = memmap[VIRT_GIC_V2M].base;
> +    gic_msi->flags = cpu_to_le32(1);
> +    gic_msi->spi_count = NUM_GICV2M_SPIS;
> +    gic_msi->spi_base = irqmap[VIRT_GIC_V2M] + ARM_SPI_BASE;

Why do we need to convert the flags to little-endian,
but not the length, base address or other fields?

thanks
-- PMM