Commit Graph

3 Commits

Author SHA1 Message Date
Min M Xu 1b1c58ab32 OvmfPkg: Update CcProbeLib to DxeCcProbeLib
BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=3974

CcProbeLib once was designed to probe the Confidential Computing guest
type by checking the PcdOvmfWorkArea. But this memory is allocated with
either EfiACPIMemoryNVS or EfiBootServicesData. It cannot be accessed
after ExitBootService. Please see the detailed analysis in BZ#3974.

To fix this issue, CcProbeLib is redesigned as 2 implementation:
 - SecPeiCcProbeLib
 - DxeCcProbeLib

In SecPeiCcProbeLib we check the CC guest type by reading the
PcdOvmfWorkArea. Because it is used in SEC / PEI and we don't worry about
the issues in BZ#3974.

In DxeCcProbeLib we cache the GuestType in Ovmf work area in a variable.
After that the Guest type is returned with the cached value. So that we
don't need to worry about the access to Ovmf work area after
ExitBootService.

The reason why we probe CC guest type in 2 different ways is the global
varialbe. Global variable cannot be used in SEC/PEI and CcProbe is called
very frequently.

Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Erdem Aktas <erdemaktas@google.com>
Cc: James Bottomley <jejb@linux.ibm.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Min Xu <min.m.xu@intel.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
2022-09-06 06:03:45 +00:00
Min M Xu c4bc1a9498 OvmfPkg: Add SecPeiCcProbeLib
BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=3974

SecPeiCcProbeLib is designed to probe the Confidential Computing guest
type in SEC/PEI phase. The CC guest type was set by each CC guest at
the beginning of boot up and saved in PcdOvmfWorkArea.

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>
Signed-off-by: Min Xu <min.m.xu@intel.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
2022-09-06 06:03:45 +00:00
Min Xu 2f44d77c68 OvmfPkg: Add CcProbeLib
BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=3902

This is the OvmfPkg specific CcProbeLib. It checks the Ovmf WorkArea
(PcdOvmfWorkAreaBase) to return the guest type.

Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Liming Gao <gaoliming@byosoft.com.cn>
Cc: Zhiguang Liu <zhiguang.liu@intel.com>
Cc: James Bottomley <jejb@linux.ibm.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: Erdem Aktas <erdemaktas@google.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Min Xu <min.m.xu@intel.com>
2022-04-19 01:26:08 +00:00