Brijesh Singh via groups.io 19914edc5a OvmfPkg/AmdSevDxe: do not use extended PCI config space ... BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=3275 Commit 85b8eac59b added support to ensure that MMIO is only performed against the un-encrypted memory. If MMIO is performed against encrypted memory, a #GP is raised. The AmdSevDxe uses the functions provided by the MemEncryptSevLib to clear the memory encryption mask from the page table. If the MemEncryptSevLib is extended to include VmgExitLib then depedency chain will look like this: OvmfPkg/AmdSevDxe/AmdSevDxe.inf -----> MemEncryptSevLib class -----> "OvmfPkg/BaseMemEncryptSevLib/DxeMemEncryptSevLib.inf" instance -----> VmgExitLib class -----> "OvmfPkg/VmgExitLib" instance -----> LocalApicLib class -----> "UefiCpuPkg/BaseXApicX2ApicLib/BaseXApicX2ApicLib.inf" instance -----> TimerLib class -----> "OvmfPkg/AcpiTimerLib/DxeAcpiTimerLib.inf" instance -----> PciLib class -----> "OvmfPkg/DxePciLibI440FxQ35/DxePciLibI440FxQ35.inf" instance -----> PciExpressLib class -----> "MdePkg/BasePciExpressLib/BasePciExpressLib.inf" instance The LocalApicLib provides a constructor that gets called before the AmdSevDxe can clear the memory encryption mask from the MMIO regions. When running under the Q35 machine type, the call chain looks like this: AcpiTimerLibConstructor () [AcpiTimerLib] PciRead32 () [DxePciLibI440FxQ35] PciExpressRead32 () [PciExpressLib] The PciExpressRead32 () reads the MMIO region. The MMIO regions are not yet mapped un-encrypted, so the check introduced in the commit 85b8eac59b raises a #GP. The AmdSevDxe driver does not require the access to the extended PCI config space. Accessing a normal PCI config space, via IO port should be sufficent. Use the module-scope override to make the AmdSevDxe use the BasePciLib instead of BasePciExpressLib so that PciRead32 () uses the IO ports instead of the extended config space. Cc: Michael Roth <michael.roth@amd.com> Cc: James Bottomley <jejb@linux.ibm.com> Cc: Min Xu <min.m.xu@intel.com> Cc: Jiewen Yao <jiewen.yao@intel.com> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: Jordan Justen <jordan.l.justen@intel.com> Cc: Ard Biesheuvel <ardb+tianocore@kernel.org> Cc: Erdem Aktas <erdemaktas@google.com> Cc: Gerd Hoffmann <kraxel@redhat.com> Acked-by: Jiewen Yao <Jiewen.yao@intel.com> Acked-by: Gerd Hoffmann <kraxel@redhat.com> Suggested-by: Laszlo Ersek <lersek@redhat.com> Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>		2021-12-09 06:28:10 +00:00
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BlobVerifierLibSevHashes	OvmfPkg: Apply uncrustify changes	2021-12-07 17:24:28 +00:00
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SecretDxe	OvmfPkg: Apply uncrustify changes	2021-12-07 17:24:28 +00:00
SecretPei	OvmfPkg/AmdSev/SecretPei: build hob for full page	2021-07-29 09:49:50 +00:00
AmdSevX64.dsc	OvmfPkg/AmdSevDxe: do not use extended PCI config space	2021-12-09 06:28:10 +00:00
AmdSevX64.fdf	OvmfPkg/AmdSev: update the fdf to use new workarea PCD	2021-10-19 01:36:52 +00:00