Re: [Qemu-devel] [PATCH v12 6/6] tpm: add ACPI memory clear interface

[Marc-André Lureau]

Hi

On Thu, Dec 13, 2018 at 6:08 PM Philippe Mathieu-Daudé
<address@hidden> wrote:
>
> On 12/13/18 1:18 PM, Marc-André Lureau wrote:
> > On Thu, Dec 13, 2018 at 4:01 PM Igor Mammedov <address@hidden> wrote:
> >>
> >> On Wed, 12 Dec 2018 17:22:21 +0100
> >> Philippe Mathieu-Daudé <address@hidden> wrote:
> >>
> >>> On 9/10/18 10:32 AM, Marc-André Lureau wrote:
> >>>> This allows to pass the last failing test from the Windows HLK TPM 2.0
> >>>> TCG PPI 1.3 tests.
> >>>>
> >>>> The interface is described in the "TCG Platform Reset Attack
> >>>> Mitigation Specification", chapter 6 "ACPI _DSM Function". According
> >>>> to Laszlo, it's not so easy to implement in OVMF, he suggested to do
> >>>> it in qemu instead.
> >>>>
> >>>> Signed-off-by: Marc-André Lureau <address@hidden>
> >>>> ---
> >>>>  hw/tpm/tpm_ppi.h     |  2 ++
> >>>>  hw/i386/acpi-build.c | 46 ++++++++++++++++++++++++++++++++++++++++++++
> >>>>  hw/tpm/tpm_crb.c     |  1 +
> >>>>  hw/tpm/tpm_ppi.c     | 22 +++++++++++++++++++++
> >>>>  hw/tpm/tpm_tis.c     |  1 +
> >>>>  docs/specs/tpm.txt   |  2 ++
> >>>>  hw/tpm/trace-events  |  3 +++
> >>>>  7 files changed, 77 insertions(+)
> >>>>
> >>>> diff --git a/hw/tpm/tpm_ppi.h b/hw/tpm/tpm_ppi.h
> >>>> index c2ab2ed300..b8f67962c7 100644
> >>>> --- a/hw/tpm/tpm_ppi.h
> >>>> +++ b/hw/tpm/tpm_ppi.h
> >>>> @@ -23,4 +23,6 @@ typedef struct TPMPPI {
> >>>>  bool tpm_ppi_init(TPMPPI *tpmppi, struct MemoryRegion *m,
> >>>>                    hwaddr addr, Object *obj, Error **errp);
> >>>>
> >>>
> >>> Can you add documentation?
> >>>
> >>>> +void tpm_ppi_reset(TPMPPI *tpmppi);
> >>>> +
> >>>>  #endif /* TPM_TPM_PPI_H */
> >>>> diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> >>>> index c5e9a6e11d..2ab3e8fae7 100644
> >>>> --- a/hw/i386/acpi-build.c
> >>>> +++ b/hw/i386/acpi-build.c
> >>>> @@ -1824,6 +1824,13 @@ build_tpm_ppi(TPMIf *tpm, Aml *dev)
> >>>>      pprq = aml_name("PPRQ");
> >>>>      pprm = aml_name("PPRM");
> >>>>
> >>>> +    aml_append(dev,
> >>>> +               aml_operation_region("TPP3", AML_SYSTEM_MEMORY,
> >>>> +                                    aml_int(TPM_PPI_ADDR_BASE + 0x15a),
> >>>
> >>> Can you add a definition for this magic value?
> >>> Maybe:
> >>>
> >>> #define TPM_PPI_MEMORY_OVERWRITE_OFFSET 0x15a
> >>>
> >>> or
> >>>
> >>> #define TPM_PPI_MOVV_OFFSET 0x15a
> >> I'd prefer explicit numeric values there as it's a bit easier to review
> >> and grep in 'spec' since one doesn't have to jump to define definition
> >> first to find out value to compare with spec.
> >> What I'd add though is verbatim comment from spec like we do
> >> in APCI code so we could jump to the field of interest in spec
> >> just doing copy&paste&search
> >
> > I don't mind.
> > Philippe, are you okay going back to numeric values?
>
> Can we have a consensus using:
>
> #define TPM_PPI_MEMORY_OVERWRITE_OFFSET_0x15A 0x15a
>
> Joking!
>
> I prefer definitions but since Igor maintains ACPI, he rules and I have
> no problem accepting this numeric value :)

ok, with Igor comments, does it get you review-by?
thanks

>
> >
> > Igor, is this comment what you would expect where the 0x15a value is used:
> > /* 0x15a: movv field in ACPI PPI Interface, see specs/tpm.txt */
> >
> > thanks
> >>
> >>>
> >>>> +                                    0x1));
> >>>> +    field = aml_field("TPP3", AML_BYTE_ACC, AML_NOLOCK, AML_PRESERVE);
> >>>> +    aml_append(field, aml_named_field("MOVV", 8));
> >>>> +    aml_append(dev, field);
> >>>>      /*
> >>>>       * DerefOf in Windows is broken with SYSTEM_MEMORY.  Use a dynamic
> >>>>       * operation region inside of a method for getting FUNC[op].
> >>>> @@ -2166,7 +2173,46 @@ build_tpm_ppi(TPMIf *tpm, Aml *dev)
> >>>>              aml_append(ifctx, aml_return(aml_buffer(1, zerobyte)));
> >>>>          }
> >>>>          aml_append(method, ifctx);
> >>>> +
> >>>> +        ifctx = aml_if(
> >>>> +            aml_equal(uuid,
> >>>> +                      
> >>>> aml_touuid("376054ED-CC13-4675-901C-4756D7F2D45D")));
> >>>> +        {
> >>>> +            /* standard DSM query function */
> >>>> +            ifctx2 = aml_if(aml_equal(function, zero));
> >>>> +            {
> >>>> +                uint8_t byte_list[1] = { 0x03 };
> >>>> +                aml_append(ifctx2, aml_return(aml_buffer(1, 
> >>>> byte_list)));
> >>>> +            }
> >>>> +            aml_append(ifctx, ifctx2);
> >>>> +
> >>>> +            /*
> >>>> +             * TCG Platform Reset Attack Mitigation Specification 1.0 
> >>>> Ch.6
> >>>> +             *
> >>>> +             * Arg 2 (Integer): Function Index = 1
> >>>> +             * Arg 3 (Package): Arguments = Package: Type: Integer
> >>>> +             *                  Operation Value of the Request
> >>>> +             * Returns: Type: Integer
> >>>> +             *          0: Success
> >>>> +             *          1: General Failure
> >>>> +             */
> >>>> +            ifctx2 = aml_if(aml_equal(function, one));
> >>>> +            {
> >>>> +                aml_append(ifctx2,
> >>>> +                           aml_store(aml_derefof(aml_index(arguments, 
> >>>> zero)),
> >>>> +                                     op));
> >>>> +                {
> >>>> +                    aml_append(ifctx2, aml_store(op, aml_name("MOVV")));
> >>>> +
> >>>> +                    /* 0: success */
> >>>> +                    aml_append(ifctx2, aml_return(zero));
> >>>> +                }
> >>>> +            }
> >>>> +            aml_append(ifctx, ifctx2);
> >>>> +        }
> >>>> +        aml_append(method, ifctx);
> >>>>      }
> >>>> +
> >>>>      aml_append(dev, method);
> >>>>  }
> >>>>
> >>>> diff --git a/hw/tpm/tpm_crb.c b/hw/tpm/tpm_crb.c
> >>>> index b243222fd6..48f6a716ad 100644
> >>>> --- a/hw/tpm/tpm_crb.c
> >>>> +++ b/hw/tpm/tpm_crb.c
> >>>> @@ -233,6 +233,7 @@ static void tpm_crb_reset(void *dev)
> >>>>  {
> >>>>      CRBState *s = CRB(dev);
> >>>>
> >>>> +    tpm_ppi_reset(&s->ppi);
> >>>>      tpm_backend_reset(s->tpmbe);
> >>>>
> >>>>      memset(s->regs, 0, sizeof(s->regs));
> >>>> diff --git a/hw/tpm/tpm_ppi.c b/hw/tpm/tpm_ppi.c
> >>>> index f2f07f895e..ac05ba8d3c 100644
> >>>> --- a/hw/tpm/tpm_ppi.c
> >>>> +++ b/hw/tpm/tpm_ppi.c
> >>>> @@ -16,8 +16,30 @@
> >>>>  #include "qapi/error.h"
> >>>>  #include "cpu.h"
> >>>>  #include "sysemu/memory_mapping.h"
> >>>> +#include "sysemu/reset.h"
> >>>>  #include "migration/vmstate.h"
> >>>>  #include "tpm_ppi.h"
> >>>> +#include "trace.h"
> >>>> +
> >>>> +void tpm_ppi_reset(TPMPPI *tpmppi)
> >>>> +{
> >>>> +    if (tpmppi->buf[0x15a] & 0x1) {
> >>>
> >>> TPM_PPI_MOVV_OFFSET
> >>>
> >>>> +        GuestPhysBlockList guest_phys_blocks;
> >>>> +        GuestPhysBlock *block;
> >>>> +
> >>>> +        guest_phys_blocks_init(&guest_phys_blocks);
> >>>> +        guest_phys_blocks_append(&guest_phys_blocks);
> >>>> +        QTAILQ_FOREACH(block, &guest_phys_blocks.head, next) {
> >>>> +            trace_tpm_ppi_memset(block->host_addr,
> >>>> +                             block->target_end - block->target_start);
> >>>> +            memset(block->host_addr, 0,
> >>>> +                   block->target_end - block->target_start);
> >>>> +            memory_region_set_dirty(block->mr, 0,
> >>>> +                                    block->target_end - 
> >>>> block->target_start);
> >>>> +        }
> >>>> +        guest_phys_blocks_free(&guest_phys_blocks);
> >>>> +    }
> >>>> +}
> >>>>
> >>>>  bool tpm_ppi_init(TPMPPI *tpmppi, struct MemoryRegion *m,
> >>>>                    hwaddr addr, Object *obj, Error **errp)
> >>>> diff --git a/hw/tpm/tpm_tis.c b/hw/tpm/tpm_tis.c
> >>>> index 70432ffe8b..d9bfa956cc 100644
> >>>> --- a/hw/tpm/tpm_tis.c
> >>>> +++ b/hw/tpm/tpm_tis.c
> >>>> @@ -868,6 +868,7 @@ static void tpm_tis_reset(DeviceState *dev)
> >>>>      s->be_buffer_size = MIN(tpm_backend_get_buffer_size(s->be_driver),
> >>>>                              TPM_TIS_BUFFER_MAX);
> >>>>
> >>>> +    tpm_ppi_reset(&s->ppi);
> >>>>      tpm_backend_reset(s->be_driver);
> >>>>
> >>>>      s->active_locty = TPM_TIS_NO_LOCALITY;
> >>>> diff --git a/docs/specs/tpm.txt b/docs/specs/tpm.txt
> >>>> index 332c2ae597..ce9bda3c89 100644
> >>>> --- a/docs/specs/tpm.txt
> >>>> +++ b/docs/specs/tpm.txt
> >>>> @@ -121,6 +121,8 @@ layout:
> >>>>   
> >>>> +----------+--------+--------+-------------------------------------------+
> >>>>   | next_step|   0x1  |  0x159 | Operation to execute after reboot by    
> >>>>   |
> >>>>   |          |        |        | firmware. Used by firmware.             
> >>>>   |
> >>>> + 
> >>>> +----------+--------+--------+-------------------------------------------+
> >>>> + | movv     |   0x1  |  0x15a | Memory overwrite variable               
> >>>>   |
> >>>>   
> >>>> +----------+--------+--------+-------------------------------------------+
> >>>>
> >>>>     The following values are supported for the 'func' field. They 
> >>>> correspond
> >>>> diff --git a/hw/tpm/trace-events b/hw/tpm/trace-events
> >>>> index 25bee0cecf..920d32ad55 100644
> >>>> --- a/hw/tpm/trace-events
> >>>> +++ b/hw/tpm/trace-events
> >>>> @@ -51,3 +51,6 @@ tpm_tis_mmio_write_init_abort(void) "Initiating abort"
> >>>>  tpm_tis_mmio_write_lowering_irq(void) "Lowering IRQ"
> >>>>  tpm_tis_mmio_write_data2send(uint32_t value, unsigned size) "Data to 
> >>>> send to TPM: 0x%08x (size=%d)"
> >>>>  tpm_tis_pre_save(uint8_t locty, uint32_t rw_offset) "locty: %d, 
> >>>> rw_offset = %u"
> >>>> +
> >>>> +# hw/tpm/tpm_ppi.c
> >>>> +tpm_ppi_memset(uint8_t *ptr, size_t size) "memset: %p %zu"
> >>>>
> >>>
> >>> I'd split this patch in 2: Add ACPI, Add tpm_ppi_reset.
> >>
>


-- 
Marc-André Lureau