Commit Graph

2 Commits

Author SHA1 Message Date
Marc-André Lureau ffab1be706 tpm: clear RAM when "memory overwrite" requested
Note: the "Platform Reset Attack Mitigation" specification isn't
explicit about NVDIMM, since they could have different usages. It uses
the term "system memory" generally (and also "volatile memory RAM" in
its introduction). For initial support, I propose to consider
non-volatile memory as not being subject to the memory clear. There is
an on-going discussion in the TCG "pcclientwg" working group for
future revisions.

CPU cache clearing is done unconditionally in edk2 since commit
d20ae95a13e851 (edk2-stable201811).

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@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>
2019-01-17 21:10:57 -05:00
Stefan Berger 3b97c01e9c tpm: allocate/map buffer for TPM Physical Presence interface
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 interface should be used by all TPM devices on x86 and can be
added by calling tpm_ppi_init_io().

Note: bios_linker cannot be used to allocate the PPI memory region,
since the reserved memory should stay stable across reboots, and might
be needed before the ACPI tables are installed.

Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@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>
2019-01-17 21:10:57 -05:00