Re: [PATCH v7 2/4] hw/acpi: add indication for i8042 in IA-PC boot flags of the FADT table

["Michael S. Tsirkin" <mst@redhat.com>]

On Fri, Mar 04, 2022 at 09:10:30PM +0530, Ani Sinha wrote:
> From: Liav Albani <liavalb@gmail.com>
> 
> This can allow the guest OS to determine more easily if i8042 controller
> is present in the system or not, so it doesn't need to do probing of the
> controller, but just initialize it immediately, before enumerating the
> ACPI AML namespace.
> 
> The 8042 bit in IAPC_BOOT_ARCH was introduced from ACPI spec v2 (FADT
> revision 2 and above). Therefore, in this change, we only enable this bit for
> x86/q35 machine types since x86/i440fx machines use FADT ACPI table with
> revision 1.
> 
> Signed-off-by: Liav Albani <liavalb@gmail.com>
> Signed-off-by: Ani Sinha <ani@anisinha.ca>
> ---
>  hw/acpi/aml-build.c         |  8 +++++++-
>  hw/i386/acpi-build.c        |  8 ++++++++
>  include/hw/acpi/acpi-defs.h |  1 +
>  include/hw/input/i8042.h    | 15 +++++++++++++++
>  4 files changed, 31 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/acpi/aml-build.c b/hw/acpi/aml-build.c
> index 8966e16320..1773cf55f1 100644
> --- a/hw/acpi/aml-build.c
> +++ b/hw/acpi/aml-build.c
> @@ -2152,7 +2152,13 @@ void build_fadt(GArray *tbl, BIOSLinker *linker, const AcpiFadtData *f,
>      build_append_int_noprefix(tbl, 0, 1); /* DAY_ALRM */
>      build_append_int_noprefix(tbl, 0, 1); /* MON_ALRM */
>      build_append_int_noprefix(tbl, f->rtc_century, 1); /* CENTURY */
> -    build_append_int_noprefix(tbl, 0, 2); /* IAPC_BOOT_ARCH */
> +    /* IAPC_BOOT_ARCH */
> +    if (f->rev == 1) {
> +        build_append_int_noprefix(tbl, 0, 2);
> +    } else {
> +        /* since ACPI v2.0 */
> +        build_append_int_noprefix(tbl, f->iapc_boot_arch, 2);
> +    }
>      build_append_int_noprefix(tbl, 0, 1); /* Reserved */
>      build_append_int_noprefix(tbl, f->flags, 4); /* Flags */
>  
> diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> index ebd47aa26f..4ad4d7286c 100644
> --- a/hw/i386/acpi-build.c
> +++ b/hw/i386/acpi-build.c
> @@ -38,6 +38,7 @@
>  #include "hw/nvram/fw_cfg.h"
>  #include "hw/acpi/bios-linker-loader.h"
>  #include "hw/isa/isa.h"
> +#include "hw/input/i8042.h"
>  #include "hw/block/fdc.h"
>  #include "hw/acpi/memory_hotplug.h"
>  #include "sysemu/tpm.h"
> @@ -192,6 +193,13 @@ static void init_common_fadt_data(MachineState *ms, Object *o,
>              .address = object_property_get_uint(o, ACPI_PM_PROP_GPE0_BLK, NULL)
>          },
>      };
> +
> +    /*
> +     * ACPI v2, Table 5-10 - Fixed ACPI Description Table Boot Architecture
> +     * Flags, bit offset 1 - 8042.
> +     */

I think we should drop this comment (and one for microvm).
If you like, add

/*
Table 5-8 Fixed ACPI Description Table (FADT) Format
IAPC_BOOT_ARCH
*/

instead.


Let's do that with a patch on top, we have a soft freeze to consider.

> +    fadt.iapc_boot_arch = iapc_boot_arch_8042();
> +
>      *data = fadt;
>  }
>  
> diff --git a/include/hw/acpi/acpi-defs.h b/include/hw/acpi/acpi-defs.h
> index c97e8633ad..2b42e4192b 100644
> --- a/include/hw/acpi/acpi-defs.h
> +++ b/include/hw/acpi/acpi-defs.h
> @@ -77,6 +77,7 @@ typedef struct AcpiFadtData {
>      uint16_t plvl2_lat;        /* P_LVL2_LAT */
>      uint16_t plvl3_lat;        /* P_LVL3_LAT */
>      uint16_t arm_boot_arch;    /* ARM_BOOT_ARCH */
> +    uint16_t iapc_boot_arch;   /* IAPC_BOOT_ARCH */
>      uint8_t minor_ver;         /* FADT Minor Version */
>  
>      /*
> diff --git a/include/hw/input/i8042.h b/include/hw/input/i8042.h
> index 1d90432dae..e070f546e4 100644
> --- a/include/hw/input/i8042.h
> +++ b/include/hw/input/i8042.h
> @@ -23,4 +23,19 @@ void i8042_mm_init(qemu_irq kbd_irq, qemu_irq mouse_irq,
>  void i8042_isa_mouse_fake_event(ISAKBDState *isa);
>  void i8042_setup_a20_line(ISADevice *dev, qemu_irq a20_out);
>  
> +static inline bool i8042_present(void)
> +{
> +    bool amb = false;
> +    return object_resolve_path_type("", TYPE_I8042, &amb) || amb;
> +}
> +
> +/*
> + * ACPI v2, Table 5-10 - Fixed ACPI Description Table Boot Architecture
> + * Flags, bit offset 1 - 8042.
> + */
> +static inline uint16_t iapc_boot_arch_8042(void)
> +{
> +    return i8042_present() ? 0x1 << 1 : 0x0 ;
> +}
> +
>  #endif /* HW_INPUT_I8042_H */
> -- 
> 2.25.1