Re: [Qemu-devel] [PATCH v5 2/4] tpm: implement virtual memory device for TPM PPI

[Igor Mammedov <imammedo@redhat.com>]

On Tue, 26 Jun 2018 14:23:41 +0200
Marc-André Lureau <marcandre.lureau@redhat.com> wrote:

> From: Stefan Berger <stefanb@linux.vnet.ibm.com>
> 
> Implement a virtual memory device for the TPM Physical Presence interface.
> The memory is located at 0xFED45000 and used by ACPI to send messages to the
> firmware (BIOS) and by the firmware to provide parameters for each one of
> the supported codes.
> 
> This device should be used by all TPM interfaces on x86 and can be added
> by calling tpm_ppi_init_io().
> 
> Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
> Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> 
> ---
> 
> v4 (Marc-André):
>  - pass TPM_PPI_ADDR_BASE as argument to tpm_ppi_init_io()
>  - only enable PPI if property is set
> 
> v3 (Marc-André):
>  - merge CRB support
>  - use trace events instead of DEBUG printf
>  - headers inclusion simplification
> 
> v2:
>  - moved to byte access since an infrequently used device;
>    this simplifies code
>  - increase size of device to 0x400
>  - move device to 0xfffef000 since SeaBIOS has some code at 0xffff0000:
>    'On the emulators, the bios at 0xf0000 is also at 0xffff0000'
> ---
>  hw/tpm/tpm_ppi.h      | 27 ++++++++++++++++++++
>  include/hw/acpi/tpm.h |  6 +++++
>  hw/tpm/tpm_crb.c      |  7 ++++++
>  hw/tpm/tpm_ppi.c      | 57 +++++++++++++++++++++++++++++++++++++++++++
>  hw/tpm/tpm_tis.c      |  7 ++++++
>  hw/tpm/Makefile.objs  |  2 +-
>  hw/tpm/trace-events   |  4 +++
>  7 files changed, 109 insertions(+), 1 deletion(-)
>  create mode 100644 hw/tpm/tpm_ppi.h
>  create mode 100644 hw/tpm/tpm_ppi.c
> 
> diff --git a/hw/tpm/tpm_ppi.h b/hw/tpm/tpm_ppi.h
> new file mode 100644
> index 0000000000..ac7ad47238
> --- /dev/null
> +++ b/hw/tpm/tpm_ppi.h
> @@ -0,0 +1,27 @@
> +/*
> + * TPM Physical Presence Interface
> + *
> + * Copyright (C) 2018 IBM Corporation
> + *
> + * Authors:
> + *  Stefan Berger    <stefanb@us.ibm.com>
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2 or later.
> + * See the COPYING file in the top-level directory.
> + */
> +#ifndef TPM_TPM_PPI_H
> +#define TPM_TPM_PPI_H
> +
> +#include "hw/acpi/tpm.h"
> +#include "exec/address-spaces.h"
> +
> +typedef struct TPMPPI {
> +    MemoryRegion mmio;
> +
> +    uint8_t ram[TPM_PPI_ADDR_SIZE];
> +} TPMPPI;
I probably miss something obvious here,
1st:
commit message says that memory reion is supposed to be interface
between FW and OSPM (i.e. totally guest internal thingy).
So question is:
  why do we register memory region at all?
it should be dropped or explained in commit message.

2nd:
If region is really necessary, then where is subsection to migrate
data stored there?


> +
> +void tpm_ppi_init_io(TPMPPI *tpmppi, struct MemoryRegion *m,
> +                     hwaddr addr, Object *obj);
> +
> +#endif /* TPM_TPM_PPI_H */
> diff --git a/include/hw/acpi/tpm.h b/include/hw/acpi/tpm.h
> index 46ac4dc581..c082df7d1d 100644
> --- a/include/hw/acpi/tpm.h
> +++ b/include/hw/acpi/tpm.h
> @@ -187,4 +187,10 @@ REG32(CRB_DATA_BUFFER, 0x80)
>  #define TPM2_START_METHOD_MMIO      6
>  #define TPM2_START_METHOD_CRB       7
>  
> +/*
> + * Physical Presence Interface
> + */
> +#define TPM_PPI_ADDR_SIZE           0x400
> +#define TPM_PPI_ADDR_BASE           0xFED45000
> +
>  #endif /* HW_ACPI_TPM_H */
> diff --git a/hw/tpm/tpm_crb.c b/hw/tpm/tpm_crb.c
> index d5b0ac5920..37c095f00f 100644
> --- a/hw/tpm/tpm_crb.c
> +++ b/hw/tpm/tpm_crb.c
> @@ -29,6 +29,7 @@
>  #include "sysemu/reset.h"
>  #include "tpm_int.h"
>  #include "tpm_util.h"
> +#include "tpm_ppi.h"
>  #include "trace.h"
>  
>  typedef struct CRBState {
> @@ -43,6 +44,7 @@ typedef struct CRBState {
>      size_t be_buffer_size;
>  
>      bool ppi_enabled;
> +    TPMPPI ppi;
>  } CRBState;
>  
>  #define CRB(obj) OBJECT_CHECK(CRBState, (obj), TYPE_TPM_CRB)
> @@ -294,6 +296,11 @@ static void tpm_crb_realize(DeviceState *dev, Error **errp)
>      memory_region_add_subregion(get_system_memory(),
>          TPM_CRB_ADDR_BASE + sizeof(s->regs), &s->cmdmem);
>  
> +    if (s->ppi_enabled) {
> +        tpm_ppi_init_io(&s->ppi, get_system_memory(),
> +                        TPM_PPI_ADDR_BASE, OBJECT(s));
> +    }
> +
>      qemu_register_reset(tpm_crb_reset, dev);
>  }
>  
> diff --git a/hw/tpm/tpm_ppi.c b/hw/tpm/tpm_ppi.c
> new file mode 100644
> index 0000000000..79bec186c7
> --- /dev/null
> +++ b/hw/tpm/tpm_ppi.c
> @@ -0,0 +1,57 @@
> +/*
> + * tpm_ppi.c - TPM Physical Presence Interface
> + *
> + * Copyright (C) 2018 IBM Corporation
> + *
> + * Authors:
> + *  Stefan Berger <stefanb@us.ibm.com>
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2 or later.
> + * See the COPYING file in the top-level directory.
> + *
> + */
> +
> +#include "qemu/osdep.h"
> +
> +#include "tpm_ppi.h"
> +#include "trace.h"
> +
> +static uint64_t tpm_ppi_mmio_read(void *opaque, hwaddr addr,
> +                                  unsigned size)
> +{
> +    TPMPPI *s = opaque;
> +
> +    trace_tpm_ppi_mmio_read(addr, size, s->ram[addr]);
> +
> +    return s->ram[addr];
> +}
> +
> +static void tpm_ppi_mmio_write(void *opaque, hwaddr addr,
> +                               uint64_t val, unsigned size)
> +{
> +    TPMPPI *s = opaque;
> +
> +    trace_tpm_ppi_mmio_write(addr, size, val);
> +
> +    s->ram[addr] = val;
> +}
> +
> +static const MemoryRegionOps tpm_ppi_memory_ops = {
> +    .read = tpm_ppi_mmio_read,
> +    .write = tpm_ppi_mmio_write,
> +    .endianness = DEVICE_NATIVE_ENDIAN,
> +    .valid = {
> +        .min_access_size = 1,
> +        .max_access_size = 1,
> +    },
> +};
> +
> +void tpm_ppi_init_io(TPMPPI *tpmppi, struct MemoryRegion *m,
> +                     hwaddr addr, Object *obj)
> +{
> +    memory_region_init_io(&tpmppi->mmio, obj, &tpm_ppi_memory_ops,
> +                          tpmppi, "tpm-ppi-mmio",
> +                          TPM_PPI_ADDR_SIZE);
> +
> +    memory_region_add_subregion(m, addr, &tpmppi->mmio);
> +}
> diff --git a/hw/tpm/tpm_tis.c b/hw/tpm/tpm_tis.c
> index d9ddf9b723..e7f45a05b9 100644
> --- a/hw/tpm/tpm_tis.c
> +++ b/hw/tpm/tpm_tis.c
> @@ -31,6 +31,7 @@
>  #include "sysemu/tpm_backend.h"
>  #include "tpm_int.h"
>  #include "tpm_util.h"
> +#include "tpm_ppi.h"
>  #include "trace.h"
>  
>  #define TPM_TIS_NUM_LOCALITIES      5     /* per spec */
> @@ -83,6 +84,7 @@ typedef struct TPMState {
>      size_t be_buffer_size;
>  
>      bool ppi_enabled;
> +    TPMPPI ppi;
>  } TPMState;
>  
>  #define TPM(obj) OBJECT_CHECK(TPMState, (obj), TYPE_TPM_TIS)
> @@ -979,6 +981,11 @@ static void tpm_tis_realizefn(DeviceState *dev, Error **errp)
>  
>      memory_region_add_subregion(isa_address_space(ISA_DEVICE(dev)),
>                                  TPM_TIS_ADDR_BASE, &s->mmio);
> +
> +    if (s->ppi_enabled) {
> +        tpm_ppi_init_io(&s->ppi, isa_address_space(ISA_DEVICE(dev)),
> +                        TPM_PPI_ADDR_BASE, OBJECT(s));
> +    }
>  }
>  
>  static void tpm_tis_initfn(Object *obj)
> diff --git a/hw/tpm/Makefile.objs b/hw/tpm/Makefile.objs
> index 1dc9f8bf2c..eedd8b6858 100644
> --- a/hw/tpm/Makefile.objs
> +++ b/hw/tpm/Makefile.objs
> @@ -1,4 +1,4 @@
> -common-obj-y += tpm_util.o
> +common-obj-y += tpm_util.o tpm_ppi.o
>  common-obj-$(CONFIG_TPM_TIS) += tpm_tis.o
>  common-obj-$(CONFIG_TPM_CRB) += tpm_crb.o
>  common-obj-$(CONFIG_TPM_PASSTHROUGH) += tpm_passthrough.o
> diff --git a/hw/tpm/trace-events b/hw/tpm/trace-events
> index 25bee0cecf..81f9923401 100644
> --- a/hw/tpm/trace-events
> +++ b/hw/tpm/trace-events
> @@ -8,6 +8,10 @@ tpm_crb_mmio_write(uint64_t addr, unsigned size, uint32_t val) "CRB write 0x" TA
>  tpm_passthrough_handle_request(void *cmd) "processing command %p"
>  tpm_passthrough_reset(void) "reset"
>  
> +# hw/tpm/tpm_ppi.c
> +tpm_ppi_mmio_read(uint64_t addr, unsigned size, uint32_t val) "PPI read 0x" TARGET_FMT_plx " len:%u val: 0x%" PRIx32
> +tpm_ppi_mmio_write(uint64_t addr, unsigned size, uint32_t val) "PPI write 0x" TARGET_FMT_plx " len:%u val: 0x%" PRIx32
> +
>  # hw/tpm/tpm_util.c
>  tpm_util_get_buffer_size_hdr_len(uint32_t len, size_t expected) "tpm_resp->hdr.len = %u, expected = %zu"
>  tpm_util_get_buffer_size_len(uint32_t len, size_t expected) "tpm_resp->len = %u, expected = %zu"