From 19914edc5a0202cc7830f819ffac7e7b2368166a Mon Sep 17 00:00:00 2001 From: "Brijesh Singh via groups.io" Date: Thu, 9 Dec 2021 11:27:41 +0800 Subject: [PATCH] OvmfPkg/AmdSevDxe: do not use extended PCI config space BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=3275 Commit 85b8eac59b8c5bd9c7eb9afdb64357ce1aa2e803 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 85b8eac59b8c5bd9c7eb9afdb64357ce1aa2e803 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 Cc: James Bottomley Cc: Min Xu Cc: Jiewen Yao Cc: Tom Lendacky Cc: Jordan Justen Cc: Ard Biesheuvel Cc: Erdem Aktas Cc: Gerd Hoffmann Acked-by: Jiewen Yao Acked-by: Gerd Hoffmann Suggested-by: Laszlo Ersek Signed-off-by: Brijesh Singh --- OvmfPkg/AmdSev/AmdSevX64.dsc | 5 ++++- OvmfPkg/Bhyve/BhyveX64.dsc | 5 ++++- OvmfPkg/OvmfPkgIa32X64.dsc | 5 ++++- OvmfPkg/OvmfPkgX64.dsc | 5 ++++- OvmfPkg/OvmfXen.dsc | 5 ++++- 5 files changed, 20 insertions(+), 5 deletions(-) diff --git a/OvmfPkg/AmdSev/AmdSevX64.dsc b/OvmfPkg/AmdSev/AmdSevX64.dsc index 5ee5445116..2997929faa 100644 --- a/OvmfPkg/AmdSev/AmdSevX64.dsc +++ b/OvmfPkg/AmdSev/AmdSevX64.dsc @@ -816,7 +816,10 @@ !endif OvmfPkg/PlatformDxe/Platform.inf - OvmfPkg/AmdSevDxe/AmdSevDxe.inf + OvmfPkg/AmdSevDxe/AmdSevDxe.inf { + + PciLib|MdePkg/Library/BasePciLibCf8/BasePciLibCf8.inf + } OvmfPkg/IoMmuDxe/IoMmuDxe.inf # diff --git a/OvmfPkg/Bhyve/BhyveX64.dsc b/OvmfPkg/Bhyve/BhyveX64.dsc index d8fe607d1c..f456349962 100644 --- a/OvmfPkg/Bhyve/BhyveX64.dsc +++ b/OvmfPkg/Bhyve/BhyveX64.dsc @@ -790,7 +790,10 @@ !endif OvmfPkg/PlatformDxe/Platform.inf - OvmfPkg/AmdSevDxe/AmdSevDxe.inf + OvmfPkg/AmdSevDxe/AmdSevDxe.inf { + + PciLib|MdePkg/Library/BasePciLibCf8/BasePciLibCf8.inf + } OvmfPkg/IoMmuDxe/IoMmuDxe.inf diff --git a/OvmfPkg/OvmfPkgIa32X64.dsc b/OvmfPkg/OvmfPkgIa32X64.dsc index 71227d1b70..13d9a1f111 100644 --- a/OvmfPkg/OvmfPkgIa32X64.dsc +++ b/OvmfPkg/OvmfPkgIa32X64.dsc @@ -969,7 +969,10 @@ !endif OvmfPkg/PlatformDxe/Platform.inf - OvmfPkg/AmdSevDxe/AmdSevDxe.inf + OvmfPkg/AmdSevDxe/AmdSevDxe.inf { + + PciLib|MdePkg/Library/BasePciLibCf8/BasePciLibCf8.inf + } OvmfPkg/IoMmuDxe/IoMmuDxe.inf !if $(SMM_REQUIRE) == TRUE diff --git a/OvmfPkg/OvmfPkgX64.dsc b/OvmfPkg/OvmfPkgX64.dsc index 52f7598cf1..97b7cb40ff 100644 --- a/OvmfPkg/OvmfPkgX64.dsc +++ b/OvmfPkg/OvmfPkgX64.dsc @@ -967,7 +967,10 @@ !endif OvmfPkg/PlatformDxe/Platform.inf - OvmfPkg/AmdSevDxe/AmdSevDxe.inf + OvmfPkg/AmdSevDxe/AmdSevDxe.inf { + + PciLib|MdePkg/Library/BasePciLibCf8/BasePciLibCf8.inf + } OvmfPkg/IoMmuDxe/IoMmuDxe.inf !if $(SMM_REQUIRE) == TRUE diff --git a/OvmfPkg/OvmfXen.dsc b/OvmfPkg/OvmfXen.dsc index a31519e356..383cb03d2a 100644 --- a/OvmfPkg/OvmfXen.dsc +++ b/OvmfPkg/OvmfXen.dsc @@ -729,7 +729,10 @@ } OvmfPkg/PlatformDxe/Platform.inf - OvmfPkg/AmdSevDxe/AmdSevDxe.inf + OvmfPkg/AmdSevDxe/AmdSevDxe.inf { + + PciLib|MdePkg/Library/BasePciLibCf8/BasePciLibCf8.inf + } OvmfPkg/IoMmuDxe/IoMmuDxe.inf # -- 2.39.2