BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=4654
In preparation for running under an SVSM at VMPL1 or higher (higher
numerically, lower privilege), re-organize the way a page state change
is performed in order to free up the GHCB for use by the SVSM support.
Currently, the page state change logic directly uses the GHCB shared
buffer to build the page state change structures. However, this will be
in conflict with the use of the GHCB should an SVSM call be required.
Instead, use a separate buffer (an area in the workarea during SEC and
an allocated page during PEI/DXE) to hold the page state change request
and only update the GHCB shared buffer as needed.
Since the information is copied to, and operated on, in the GHCB shared
buffer this has the added benefit of not requiring to save the start and
end entries for use when validating the memory during the page state
change sequence.
Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Cc: Erdem Aktas <erdemaktas@google.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Michael Roth <michael.roth@amd.com>
Cc: Min Xu <min.m.xu@intel.com>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=4243
From the perspective of security any external input should be measured
and extended to some registers (TPM PCRs or TDX RTMR registers).
There are below 2 external input in a Td guest:
- TdHob
- Configuration FV (CFV)
TdHob contains the resource information passed from VMM, such as
unaccepted memory region. CFV contains the configurations, such as
secure boot variables.
TdHob and CFV should be measured and extended to RTMRs before they're
consumed. TdHob is consumed in the very early stage of boot process.
At that moment the memory service is not ready. Cfv is consumed in
PlatformPei to initialize the EmuVariableNvStore. To make the
implementation simple and clean, these 2 external input are measured
and extended to RTMRs in SEC phase. That is to say the tdx measurement
is only supported in SEC phase.
After the measurement the hash values are stored in WorkArea. Then after
the Hob service is available, these 2 measurement values are retrieved
and GuidHobs for these 2 tdx measurements are generated.
This patch defines the structure of TDX_MEASUREMENTS_DATA in
SEC_TDX_WORK_AREA to store above 2 tdx measurements. It can be extended
to store more tdx measurements if needed in the future.
Cc: Erdem Aktas <erdemaktas@google.com>
Cc: James Bottomley <jejb@linux.ibm.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Michael Roth <michael.roth@amd.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
Signed-off-by: Min Xu <min.m.xu@intel.com>
SEC checks in IsSevGuest if the PCD defined WorkAreaHeader size
matches the size of the WorkAreaHeader struct definition. Set a
default value for the PCD to avoid unnecessary DSC/FDF file
changes in all OVMF DSC/FDF files.
Signed-off-by: Corvin Köhne <c.koehne@beckhoff.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
