Re: [PATCH] hw/acpi/microvm: turn on 8042 bit in FADT boot architecture flags if present

[Michael S. Tsirkin]

On Fri, Mar 04, 2022 at 06:47:41PM +0530, Ani Sinha wrote:
> The second bit of IAPC_BOOT_ARCH in FADT table indicates the presence of
> keyboard controller implemented as 8042 or equivalent micro controller. This
> change enables this flag for microvms if such a device exists (for example,
> when added explicitly from the QEMU commandline). Change
> 1f810294bb31bf6ac ("hw/acpi: add indication for i8042 in IA-PC boot flags of 
> the FADT table")
> enabled this flag for i386 q35 based machines. The reason for doing the same
> for micro-vms is to make sure we provide the correct tables to the guest OS
> uniformly in all cases when an i8042 device is present. When this bit is not
> enabled, guest OSes has to find other indirect methods to detect the device
> which we would like to avoid.
> 
> Signed-off-by: Ani Sinha <ani@anisinha.ca>
> ---
>  hw/i386/acpi-microvm.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/hw/i386/acpi-microvm.c b/hw/i386/acpi-microvm.c
> index 68ca7e7fc2..12452cb2e5 100644
> --- a/hw/i386/acpi-microvm.c
> +++ b/hw/i386/acpi-microvm.c
> @@ -37,6 +37,7 @@
>  #include "hw/pci/pcie_host.h"
>  #include "hw/usb/xhci.h"
>  #include "hw/virtio/virtio-mmio.h"
> +#include "hw/input/i8042.h"
>  
>  #include "acpi-common.h"
>  #include "acpi-microvm.h"
> @@ -187,6 +188,11 @@ static void acpi_build_microvm(AcpiBuildTables *tables,
>              .address = GED_MMIO_BASE_REGS + ACPI_GED_REG_RESET,
>          },
>          .reset_val = ACPI_GED_RESET_VALUE,
> +        /*
> +         * ACPI v2, Table 5-10 - Fixed ACPI Description Table Boot 
> Architecture
> +         * Flags, bit offset 1 - 8042.
> +         */
> +        .iapc_boot_arch = i8042_present() ? 0x1 << 1 : 0x0,


Please, move this logic to a function, do not duplicate it.

>      };
>  
>      table_offsets = g_array_new(false, true /* clear */,
> -- 
> 2.25.1