Re: [PATCH v3 3/4] hw/acpi: add indication for i8042 in IA-PC boot flags of the FADT table

[Bernhard Beschow]

Am 26. Februar 2022 06:30:18 UTC schrieb 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.
>
>Signed-off-by: Liav Albani <liavalb@gmail.com>
>---
> hw/acpi/aml-build.c         | 7 ++++++-
> hw/i386/acpi-build.c        | 8 ++++++++
> hw/i386/acpi-microvm.c      | 9 +++++++++
> include/hw/acpi/acpi-defs.h | 1 +
> 4 files changed, 24 insertions(+), 1 deletion(-)
>
>diff --git a/hw/acpi/aml-build.c b/hw/acpi/aml-build.c
>index 8966e16320..ef5f4cad87 100644
>--- a/hw/acpi/aml-build.c
>+++ b/hw/acpi/aml-build.c
>@@ -2152,7 +2152,12 @@ 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 {
>+        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..65dbc1ec36 100644
>--- a/hw/i386/acpi-build.c
>+++ b/hw/i386/acpi-build.c
>@@ -192,6 +192,14 @@ static void init_common_fadt_data(MachineState *ms, 
>Object *o,
>             .address = object_property_get_uint(o, ACPI_PM_PROP_GPE0_BLK, 
> NULL)
>         },
>     };
>+    /*
>+     * second bit of 16 but IAPC_BOOT_ARCH indicates presence of 8042 or
>+     * equivalent micro controller. See table 5-10 of APCI spec version 2.0
>+     * (the earliest acpi revision that supports this).
>+     */
>+
>+    fadt.iapc_boot_arch = isa_check_device_existence("i8042") ? 0x0002 : 
>0x0000;

Couldn't qdev_find_recursive() be used here instead? This would also make patch 
1 unneccessary. Same below.

Best regards
Bernhard

>+
>     *data = fadt;
> }
> 
>diff --git a/hw/i386/acpi-microvm.c b/hw/i386/acpi-microvm.c
>index 68ca7e7fc2..e5f89164be 100644
>--- a/hw/i386/acpi-microvm.c
>+++ b/hw/i386/acpi-microvm.c
>@@ -189,6 +189,15 @@ static void acpi_build_microvm(AcpiBuildTables *tables,
>         .reset_val = ACPI_GED_RESET_VALUE,
>     };
> 
>+    /*
>+     * second bit of 16 but IAPC_BOOT_ARCH indicates presence of 8042 or
>+     * equivalent micro controller. See table 5-10 of APCI spec version 2.0
>+     * (the earliest acpi revision that supports this).
>+     */
>+
>+    pmfadt.iapc_boot_arch = isa_check_device_existence("i8042") ? 0x0002
>+                            : 0x0000;
>+
>     table_offsets = g_array_new(false, true /* clear */,
>                                         sizeof(uint32_t));
>     bios_linker_loader_alloc(tables->linker,
>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 */
> 
>     /*