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acpi: add ACPI memory clear interface

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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.

See specification documentation for more details, and next commit for
memory clear on reset handling.

The underlying TCG specification is accessible from the following
page.

https://trustedcomputinggroup.org/resource/pc-client-work-group-platform-reset-attack-mitigation-specification-version-1-0/

This patch implements version 1.0.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Tested-by: Stefan Berger <stefanb@linux.ibm.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Marc-André Lureau 2019-01-15 02:27:53 +04:00 committed by Michael S. Tsirkin
parent ac6dd31e3f
commit ec86c0f678
2 changed files with 57 additions and 0 deletions
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2
docs/specs/tpm.txt
View File

@ -135,6 +135,8 @@ 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

55
hw/acpi/tpm.c
View File

@ -53,6 +53,16 @@ void tpm_build_ppi_acpi(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 /* movv, docs/specs/tpm.txt */),
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].
@ -399,6 +409,51 @@ void tpm_build_ppi_acpi(TPMIf *tpm, Aml *dev)
aml_append(ifctx, aml_return(aml_buffer(1, zerobyte)));
}
aml_append(method, ifctx);
/*
* "TCG Platform Reset Attack Mitigation Specification 1.00",
* Chapter 6 "ACPI _DSM Function"
*/
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 }; /* functions 1-2 supported */
aml_append(ifctx2,
aml_return(aml_buffer(sizeof(byte_list),
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);
}