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

[Igor Mammedov]

On Sun, 6 Mar 2022 19:56:04 +0530
Ani Sinha <ani@anisinha.ca> wrote:

> On Sun, Mar 6, 2022 at 4:06 PM Michael S. Tsirkin <mst@redhat.com> wrote:
> >
> > 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.

I'd keep spec version though,
 all chapter/table numbering is version depended. 

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