Re: [PATCH v4 04/10] acpi/core: always set SCI_EN when SMM isn't supported

[Igor Mammedov]

On Mon, 15 Feb 2021 17:04:09 -0800
isaku.yamahata@gmail.com wrote:

> From: Isaku Yamahata <isaku.yamahata@intel.com>
> 
> If SMM is not supported, ACPI fixed hardware doesn't support
> legacy-mode. ACPI-only platform. Where SCI_EN in PM1_CNT register is
> always set.
> The bit tells OS legacy mode(SCI_EN cleared) or ACPI mode(SCI_EN set).
> 
> With the next patch (setting fadt.smi_cmd = 0 when smm isn't enabled),
> guest Linux tries to switch to ACPI mode, finds smi_cmd = 0, and then
> fails to initialize acpi subsystem. This patch proactively fixes it.
> 
> This patch changes guest ABI. To keep compatibility, use
> "x-smm-compat-5" introduced by earlier patch.
> If the property is true, disable new behavior.
> 
> ACPI spec 4.8.10.1 PM1 Event Grouping
> PM1 Eanble Registers
> > For ACPI-only platforms (where SCI_EN is always set)  
> 
> Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>

Reviewed-by: Igor Mammedov <imammedo@redhat.com>

> ---
>  hw/acpi/core.c         | 11 ++++++++++-
>  hw/acpi/ich9.c         |  2 +-
>  hw/acpi/piix4.c        |  3 ++-
>  hw/isa/vt82c686.c      |  2 +-
>  include/hw/acpi/acpi.h |  4 +++-
>  5 files changed, 17 insertions(+), 5 deletions(-)
> 
> diff --git a/hw/acpi/core.c b/hw/acpi/core.c
> index 7170bff657..1e004d0078 100644
> --- a/hw/acpi/core.c
> +++ b/hw/acpi/core.c
> @@ -579,6 +579,10 @@ void acpi_pm1_cnt_update(ACPIREGS *ar,
>                           bool sci_enable, bool sci_disable)
>  {
>      /* ACPI specs 3.0, 4.7.2.5 */
> +    if (ar->pm1.cnt.acpi_only) {
> +        return;
> +    }
> +
>      if (sci_enable) {
>          ar->pm1.cnt.cnt |= ACPI_BITMASK_SCI_ENABLE;
>      } else if (sci_disable) {
> @@ -608,11 +612,13 @@ static const MemoryRegionOps acpi_pm_cnt_ops = {
>  };
>  
>  void acpi_pm1_cnt_init(ACPIREGS *ar, MemoryRegion *parent,
> -                       bool disable_s3, bool disable_s4, uint8_t s4_val)
> +                       bool disable_s3, bool disable_s4, uint8_t s4_val,
> +                       bool acpi_only)
>  {
>      FWCfgState *fw_cfg;
>  
>      ar->pm1.cnt.s4_val = s4_val;
> +    ar->pm1.cnt.acpi_only = acpi_only;
>      ar->wakeup.notify = acpi_notify_wakeup;
>      qemu_register_wakeup_notifier(&ar->wakeup);
>  
> @@ -638,6 +644,9 @@ void acpi_pm1_cnt_init(ACPIREGS *ar, MemoryRegion *parent,
>  void acpi_pm1_cnt_reset(ACPIREGS *ar)
>  {
>      ar->pm1.cnt.cnt = 0;
> +    if (ar->pm1.cnt.acpi_only) {
> +        ar->pm1.cnt.cnt |= ACPI_BITMASK_SCI_ENABLE;
> +    }
>  }
>  
>  /* ACPI GPE */
> diff --git a/hw/acpi/ich9.c b/hw/acpi/ich9.c
> index 5ff4e01c36..853447cf9d 100644
> --- a/hw/acpi/ich9.c
> +++ b/hw/acpi/ich9.c
> @@ -282,7 +282,7 @@ void ich9_pm_init(PCIDevice *lpc_pci, ICH9LPCPMRegs *pm,
>      acpi_pm_tmr_init(&pm->acpi_regs, ich9_pm_update_sci_fn, &pm->io);
>      acpi_pm1_evt_init(&pm->acpi_regs, ich9_pm_update_sci_fn, &pm->io);
>      acpi_pm1_cnt_init(&pm->acpi_regs, &pm->io, pm->disable_s3, 
> pm->disable_s4,
> -                      pm->s4_val);
> +                      pm->s4_val, !pm->smm_compat && !smm_enabled);
>  
>      acpi_gpe_init(&pm->acpi_regs, ICH9_PMIO_GPE0_LEN);
>      memory_region_init_io(&pm->io_gpe, OBJECT(lpc_pci), &ich9_gpe_ops, pm,
> diff --git a/hw/acpi/piix4.c b/hw/acpi/piix4.c
> index 30dd9b2309..1efc0ded9f 100644
> --- a/hw/acpi/piix4.c
> +++ b/hw/acpi/piix4.c
> @@ -497,7 +497,8 @@ static void piix4_pm_realize(PCIDevice *dev, Error **errp)
>  
>      acpi_pm_tmr_init(&s->ar, pm_tmr_timer, &s->io);
>      acpi_pm1_evt_init(&s->ar, pm_tmr_timer, &s->io);
> -    acpi_pm1_cnt_init(&s->ar, &s->io, s->disable_s3, s->disable_s4, 
> s->s4_val);
> +    acpi_pm1_cnt_init(&s->ar, &s->io, s->disable_s3, s->disable_s4, 
> s->s4_val,
> +                      !s->smm_compat && !s->smm_enabled);
>      acpi_gpe_init(&s->ar, GPE_LEN);
>  
>      s->powerdown_notifier.notify = piix4_pm_powerdown_req;
> diff --git a/hw/isa/vt82c686.c b/hw/isa/vt82c686.c
> index a6f5a0843d..071b64b497 100644
> --- a/hw/isa/vt82c686.c
> +++ b/hw/isa/vt82c686.c
> @@ -240,7 +240,7 @@ static void vt82c686b_pm_realize(PCIDevice *dev, Error 
> **errp)
>  
>      acpi_pm_tmr_init(&s->ar, pm_tmr_timer, &s->io);
>      acpi_pm1_evt_init(&s->ar, pm_tmr_timer, &s->io);
> -    acpi_pm1_cnt_init(&s->ar, &s->io, false, false, 2);
> +    acpi_pm1_cnt_init(&s->ar, &s->io, false, false, 2, false);
>  }
>  
>  static Property via_pm_properties[] = {
> diff --git a/include/hw/acpi/acpi.h b/include/hw/acpi/acpi.h
> index 22b0b65bb2..9e8a76f2e2 100644
> --- a/include/hw/acpi/acpi.h
> +++ b/include/hw/acpi/acpi.h
> @@ -128,6 +128,7 @@ struct ACPIPM1CNT {
>      MemoryRegion io;
>      uint16_t cnt;
>      uint8_t s4_val;
> +    bool acpi_only;
>  };
>  
>  struct ACPIGPE {
> @@ -163,7 +164,8 @@ void acpi_pm1_evt_init(ACPIREGS *ar, acpi_update_sci_fn 
> update_sci,
>  
>  /* PM1a_CNT: piix and ich9 don't implement PM1b CNT. */
>  void acpi_pm1_cnt_init(ACPIREGS *ar, MemoryRegion *parent,
> -                       bool disable_s3, bool disable_s4, uint8_t s4_val);
> +                       bool disable_s3, bool disable_s4, uint8_t s4_val,
> +                       bool acpi_only);
>  void acpi_pm1_cnt_update(ACPIREGS *ar,
>                           bool sci_enable, bool sci_disable);
>  void acpi_pm1_cnt_reset(ACPIREGS *ar);