Re: [Qemu-devel] [PATCH v3 4/4] tpm: add a fake ACPI memory clear interface

[Igor Mammedov <imammedo@redhat.com>]

On Tue, 15 May 2018 14:14:33 +0200
Marc-André Lureau <marcandre.lureau@redhat.com> 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". Whether or
> not we should have a real implementation remains an open question to me.
might it cause security issues?
What are implications of faking it and how hard it's to implement thing
per spec?

 
> Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> ---
>  hw/i386/acpi-build.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> index 95be4f0710..392a1e50bd 100644
> --- a/hw/i386/acpi-build.c
> +++ b/hw/i386/acpi-build.c
> @@ -2072,6 +2072,15 @@ build_tpm_ppi(Aml *dev)
>              aml_append(ifctx, aml_return(aml_buffer(1, zerobyte)));
>          }
>          aml_append(method, ifctx);
> +
> +       /* dummy MOR Memory Clear for the sake of WLK PPI test */
> +        ifctx = aml_if(
> +            aml_equal(aml_arg(0),
> +                      aml_touuid("376054ED-CC13-4675-901C-4756D7F2D45D")));
> +        {
> +            aml_append(ifctx, aml_return(aml_int(0)));
> +        }
> +        aml_append(method, ifctx);
>      }
>      aml_append(dev, method);
>  }