Re: [PATCH v2 05/11] tpm_crb: use the ISA bus

[Igor Mammedov <imammedo@redhat.com>]

On Fri, 14 Jul 2023 00:09:21 -0700
Joelle van Dyne <j@getutm.app> wrote:

> Since this device is gated to only build for targets with the PC
> configuration, we should use the ISA bus like with TPM TIS.

does it affect migration in any way?
From guest pov it looks like there a new ISA device will appear
and then if you do ping pong migration between old - new QEMU will really it work?

If it will, then commit message here shall describe why it safe and why it works


> Signed-off-by: Joelle van Dyne <j@getutm.app>
> ---
>  hw/tpm/tpm_crb.c | 52 ++++++++++++++++++++++++------------------------
>  hw/tpm/Kconfig   |  2 +-
>  2 files changed, 27 insertions(+), 27 deletions(-)
> 
> diff --git a/hw/tpm/tpm_crb.c b/hw/tpm/tpm_crb.c
> index 07c6868d8d..6144081d30 100644
> --- a/hw/tpm/tpm_crb.c
> +++ b/hw/tpm/tpm_crb.c
> @@ -22,6 +22,7 @@
>  #include "hw/qdev-properties.h"
>  #include "hw/pci/pci_ids.h"
>  #include "hw/acpi/tpm.h"
> +#include "hw/isa/isa.h"
>  #include "migration/vmstate.h"
>  #include "sysemu/tpm_backend.h"
>  #include "sysemu/tpm_util.h"
> @@ -34,7 +35,7 @@
>  #include "tpm_crb.h"
>  
>  struct CRBState {
> -    DeviceState parent_obj;
> +    ISADevice parent_obj;
>  
>      TPMCRBState state;
>  };
> @@ -43,49 +44,49 @@ typedef struct CRBState CRBState;
>  DECLARE_INSTANCE_CHECKER(CRBState, CRB,
>                           TYPE_TPM_CRB)
>  
> -static void tpm_crb_none_request_completed(TPMIf *ti, int ret)
> +static void tpm_crb_isa_request_completed(TPMIf *ti, int ret)
>  {
>      CRBState *s = CRB(ti);
>  
>      tpm_crb_request_completed(&s->state, ret);
>  }
>  
> -static enum TPMVersion tpm_crb_none_get_version(TPMIf *ti)
> +static enum TPMVersion tpm_crb_isa_get_version(TPMIf *ti)
>  {
>      CRBState *s = CRB(ti);
>  
>      return tpm_crb_get_version(&s->state);
>  }
>  
> -static int tpm_crb_none_pre_save(void *opaque)
> +static int tpm_crb_isa_pre_save(void *opaque)
>  {
>      CRBState *s = opaque;
>  
>      return tpm_crb_pre_save(&s->state);
>  }
>  
> -static const VMStateDescription vmstate_tpm_crb_none = {
> +static const VMStateDescription vmstate_tpm_crb_isa = {
>      .name = "tpm-crb",
> -    .pre_save = tpm_crb_none_pre_save,
> +    .pre_save = tpm_crb_isa_pre_save,
>      .fields = (VMStateField[]) {
>          VMSTATE_END_OF_LIST(),
>      }
>  };
>  
> -static Property tpm_crb_none_properties[] = {
> +static Property tpm_crb_isa_properties[] = {
>      DEFINE_PROP_TPMBE("tpmdev", CRBState, state.tpmbe),
>      DEFINE_PROP_BOOL("ppi", CRBState, state.ppi_enabled, true),
>      DEFINE_PROP_END_OF_LIST(),
>  };
>  
> -static void tpm_crb_none_reset(void *dev)
> +static void tpm_crb_isa_reset(void *dev)
>  {
>      CRBState *s = CRB(dev);
>  
>      return tpm_crb_reset(&s->state, TPM_CRB_ADDR_BASE);
>  }
>  
> -static void tpm_crb_none_realize(DeviceState *dev, Error **errp)
> +static void tpm_crb_isa_realize(DeviceState *dev, Error **errp)
>  {
>      CRBState *s = CRB(dev);
>  
> @@ -100,52 +101,51 @@ static void tpm_crb_none_realize(DeviceState *dev, Error **errp)
>  
>      tpm_crb_init_memory(OBJECT(s), &s->state, errp);
>  
> -    memory_region_add_subregion(get_system_memory(),
> +    memory_region_add_subregion(isa_address_space(ISA_DEVICE(dev)),
>          TPM_CRB_ADDR_BASE, &s->state.mmio);
>  
>      if (s->state.ppi_enabled) {
> -        memory_region_add_subregion(get_system_memory(),
> +        memory_region_add_subregion(isa_address_space(ISA_DEVICE(dev)),
>              TPM_PPI_ADDR_BASE, &s->state.ppi.ram);
>      }
>  
>      if (xen_enabled()) {
> -        tpm_crb_none_reset(dev);
> +        tpm_crb_isa_reset(dev);
>      } else {
> -        qemu_register_reset(tpm_crb_none_reset, dev);
> +        qemu_register_reset(tpm_crb_isa_reset, dev);
>      }
>  }
>  
> -static void tpm_crb_none_class_init(ObjectClass *klass, void *data)
> +static void tpm_crb_isa_class_init(ObjectClass *klass, void *data)
>  {
>      DeviceClass *dc = DEVICE_CLASS(klass);
>      TPMIfClass *tc = TPM_IF_CLASS(klass);
>  
> -    dc->realize = tpm_crb_none_realize;
> -    device_class_set_props(dc, tpm_crb_none_properties);
> -    dc->vmsd  = &vmstate_tpm_crb_none;
> +    dc->realize = tpm_crb_isa_realize;
> +    device_class_set_props(dc, tpm_crb_isa_properties);
> +    dc->vmsd  = &vmstate_tpm_crb_isa;
>      dc->user_creatable = true;
>      tc->model = TPM_MODEL_TPM_CRB;
> -    tc->get_version = tpm_crb_none_get_version;
> -    tc->request_completed = tpm_crb_none_request_completed;
> +    tc->get_version = tpm_crb_isa_get_version;
> +    tc->request_completed = tpm_crb_isa_request_completed;
>  
>      set_bit(DEVICE_CATEGORY_MISC, dc->categories);
>  }
>  
> -static const TypeInfo tpm_crb_none_info = {
> +static const TypeInfo tpm_crb_isa_info = {
>      .name = TYPE_TPM_CRB,
> -    /* could be TYPE_SYS_BUS_DEVICE (or LPC etc) */
> -    .parent = TYPE_DEVICE,
> +    .parent = TYPE_ISA_DEVICE,
>      .instance_size = sizeof(CRBState),
> -    .class_init  = tpm_crb_none_class_init,
> +    .class_init  = tpm_crb_isa_class_init,
>      .interfaces = (InterfaceInfo[]) {
>          { TYPE_TPM_IF },
>          { }
>      }
>  };
>  
> -static void tpm_crb_none_register(void)
> +static void tpm_crb_isa_register(void)
>  {
> -    type_register_static(&tpm_crb_none_info);
> +    type_register_static(&tpm_crb_isa_info);
>  }
>  
> -type_init(tpm_crb_none_register)
> +type_init(tpm_crb_isa_register)
> diff --git a/hw/tpm/Kconfig b/hw/tpm/Kconfig
> index a46663288c..1fd73fe617 100644
> --- a/hw/tpm/Kconfig
> +++ b/hw/tpm/Kconfig
> @@ -22,7 +22,7 @@ config TPM_TIS
>  
>  config TPM_CRB
>      bool
> -    depends on TPM && PC
> +    depends on TPM && ISA_BUS
>      select TPM_BACKEND
>  
>  config TPM_SPAPR