Re: [PATCH v3 1/4] acpi: Convert build_tpm2() to build_append* API

[Stefan Berger]

On 6/2/20 9:55 AM, Auger Eric wrote:
> Hi Stefan,
> On 6/2/20 3:30 PM, Stefan Berger wrote:
> > On 6/1/20 5:57 AM, Eric Auger wrote:
> > > In preparation of its move to the generic acpi code,
> > > let's convert build_tpm2() to use build_append API. This
> > > latter now is prefered in place of direct ACPI struct field
> > > settings with manual endianness conversion.
> > >
> > > Signed-off-by: Eric Auger <eric.auger@redhat.com>
> > > ---
> > >    hw/i386/acpi-build.c | 28 +++++++++++++++++++---------
> > >    1 file changed, 19 insertions(+), 9 deletions(-)
> > >
> > > diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> > > index b5669d6c65..f0d35d7b17 100644
> > > --- a/hw/i386/acpi-build.c
> > > +++ b/hw/i386/acpi-build.c
> > > @@ -2298,30 +2298,40 @@ build_tpm_tcpa(GArray *table_data, BIOSLinker
> > > *linker, GArray *tcpalog)
> > >    static void
> > >    build_tpm2(GArray *table_data, BIOSLinker *linker, GArray *tcpalog)
> > >    {
> > > -    Acpi20TPM2 *tpm2_ptr = acpi_data_push(table_data, sizeof *tpm2_ptr);
> > > +    Acpi20TPM2 *tpm2_ptr = acpi_data_push(table_data,
> > > sizeof(AcpiTableHeader));
> > And now you want to build the data structure by pushing fields? I would
> > definitely NOT do this.
> If I didn't misinterpret things, this was recommended by Drew and Igor
> as buid_append* API avoids to take care of endianness and this is the
> API now used in the generic ACPI code. Besides I also think that in that
> case it does not simplify things but maybe I did that the wrong way? Or
> maybe I didn't understand your remark?


If that's what they are saying... I would prefer filling out data 
structures with functions like cpu_to_acpi16() because that seems to be 
less error prone.


> > >        unsigned log_addr_size = sizeof(tpm2_ptr->log_area_start_address);
> > >        unsigned log_addr_offset =
> > >            (char *)&tpm2_ptr->log_area_start_address - table_data->data;
> > > +    uint8_t start_method_params[12] = {};
> > >    -    tpm2_ptr->platform_class = cpu_to_le16(TPM2_ACPI_CLASS_CLIENT);
> > > +    /* platform class */
> > > +    build_append_int_noprefix(table_data, TPM2_ACPI_CLASS_CLIENT, 2);
> > > +    /* reserved */
> > > +    build_append_int_noprefix(table_data, 0, 2);
> > >        if (TPM_IS_TIS_ISA(tpm_find())) {
> > > -        tpm2_ptr->control_area_address = cpu_to_le64(0);
> > > -        tpm2_ptr->start_method = cpu_to_le32(TPM2_START_METHOD_MMIO);
> > > +        /* address of control area */
> > > +        build_append_int_noprefix(table_data, 0, 8);
> > > +        /* start method */
> > > +        build_append_int_noprefix(table_data, TPM2_START_METHOD_MMIO,
> > > 4);
> > >        } else if (TPM_IS_CRB(tpm_find())) {
> > > -        tpm2_ptr->control_area_address = cpu_to_le64(TPM_CRB_ADDR_CTRL);
> > > -        tpm2_ptr->start_method = cpu_to_le32(TPM2_START_METHOD_CRB);
> > > +        build_append_int_noprefix(table_data, TPM_CRB_ADDR_CTRL, 8);
> > > +        build_append_int_noprefix(table_data, TPM2_START_METHOD_CRB, 4);
> > >        } else {
> > >            g_warn_if_reached();
> > >        }
> > >    -    tpm2_ptr->log_area_minimum_length =
> > > -        cpu_to_le32(TPM_LOG_AREA_MINIMUM_SIZE);
> > > +    /* platform specific parameters */
> > > +    g_array_append_vals(table_data, &start_method_params, 12);

Maybe this should be wrapped in an inline function like 
build_append_array() or so.


> > >    -    acpi_data_push(tcpalog,
> > > le32_to_cpu(tpm2_ptr->log_area_minimum_length));
> > > +    /* log area minimum length */
> > > +    build_append_int_noprefix(table_data, TPM_LOG_AREA_MINIMUM_SIZE, 4);
> > > +
> > > +    acpi_data_push(tcpalog, TPM_LOG_AREA_MINIMUM_SIZE);


At this point we have a double-allocation of log memory on x86_64. You'd 
need the patch I posted to create the TCPA table only for TPM 1.2.



> > >        bios_linker_loader_alloc(linker, ACPI_BUILD_TPMLOG_FILE,
> > > tcpalog, 1,
> > >                                 false);
> > >          /* log area start address to be filled by Guest linker */
> > > +    build_append_int_noprefix(table_data, 0, 8);
> > >        bios_linker_loader_add_pointer(linker, ACPI_BUILD_TABLE_FILE,
> > >                                       log_addr_offset, log_addr_size,
> > >                                       ACPI_BUILD_TPMLOG_FILE, 0);