From 5277540e37e88a1a69f9517c4ad895051b4b3ed3 Mon Sep 17 00:00:00 2001 From: Tom Lendacky Date: Wed, 12 Aug 2020 15:21:36 -0500 Subject: UefiCpuPkg/CpuExceptionHandler: Add base support for the #VC exception BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=2198 Add base support to handle #VC exceptions. Update the common exception handlers to invoke the VmgExitHandleVc () function of the VmgExitLib library when a #VC is encountered. A non-zero return code will propagate to the targeted exception handler. Under SEV-ES, a DR7 read or write intercept generates a #VC exception. To avoid exception recursion, a #VC exception will not try to read and push the actual debug registers into the EFI_SYSTEM_CONTEXT_X64 struct and instead push zeroes. The #VC exception handler does not make use of the debug registers from the saved context and the exception processing exit code does not attempt to restore the debug register values. Cc: Eric Dong Cc: Ray Ni Cc: Laszlo Ersek Reviewed-by: Eric Dong Signed-off-by: Tom Lendacky Regression-tested-by: Laszlo Ersek --- .../CpuExceptionHandlerLib/CpuExceptionCommon.c | 10 +++++++++- .../DxeCpuExceptionHandlerLib.inf | 1 + .../PeiCpuExceptionHandlerLib.inf | 1 + .../CpuExceptionHandlerLib/PeiDxeSmmCpuException.c | 20 +++++++++++++++++++- .../CpuExceptionHandlerLib/SecPeiCpuException.c | 19 +++++++++++++++++++ .../SecPeiCpuExceptionHandlerLib.inf | 1 + .../SmmCpuExceptionHandlerLib.inf | 1 + .../X64/ExceptionHandlerAsm.nasm | 17 +++++++++++++++++ .../X64/Xcode5ExceptionHandlerAsm.nasm | 17 +++++++++++++++++ .../Xcode5SecPeiCpuExceptionHandlerLib.inf | 1 + 10 files changed, 86 insertions(+), 2 deletions(-) (limited to 'UefiCpuPkg') diff --git a/UefiCpuPkg/Library/CpuExceptionHandlerLib/CpuExceptionCommon.c b/UefiCpuPkg/Library/CpuExceptionHandlerLib/CpuExceptionCommon.c index 8adbd43fef..c9003b10e5 100644 --- a/UefiCpuPkg/Library/CpuExceptionHandlerLib/CpuExceptionCommon.c +++ b/UefiCpuPkg/Library/CpuExceptionHandlerLib/CpuExceptionCommon.c @@ -14,7 +14,7 @@ // // 1 means an error code will be pushed, otherwise 0 // -CONST UINT32 mErrorCodeFlag = 0x00227d00; +CONST UINT32 mErrorCodeFlag = 0x20227d00; // // Define the maximum message length @@ -45,6 +45,14 @@ CONST CHAR8 *mExceptionNameStr[] = { "#XM - SIMD floating-point", "#VE - Virtualization", "#CP - Control Protection" + "Reserved", + "Reserved", + "Reserved", + "Reserved", + "Reserved", + "Reserved", + "Reserved", + "#VC - VMM Communication", }; #define EXCEPTION_KNOWN_NAME_NUM (sizeof (mExceptionNameStr) / sizeof (CHAR8 *)) diff --git a/UefiCpuPkg/Library/CpuExceptionHandlerLib/DxeCpuExceptionHandlerLib.inf b/UefiCpuPkg/Library/CpuExceptionHandlerLib/DxeCpuExceptionHandlerLib.inf index 61e2ec30b0..07b34c92a8 100644 --- a/UefiCpuPkg/Library/CpuExceptionHandlerLib/DxeCpuExceptionHandlerLib.inf +++ b/UefiCpuPkg/Library/CpuExceptionHandlerLib/DxeCpuExceptionHandlerLib.inf @@ -57,3 +57,4 @@ PeCoffGetEntryPointLib MemoryAllocationLib DebugLib + VmgExitLib diff --git a/UefiCpuPkg/Library/CpuExceptionHandlerLib/PeiCpuExceptionHandlerLib.inf b/UefiCpuPkg/Library/CpuExceptionHandlerLib/PeiCpuExceptionHandlerLib.inf index 093374944d..feae7b3e06 100644 --- a/UefiCpuPkg/Library/CpuExceptionHandlerLib/PeiCpuExceptionHandlerLib.inf +++ b/UefiCpuPkg/Library/CpuExceptionHandlerLib/PeiCpuExceptionHandlerLib.inf @@ -52,6 +52,7 @@ HobLib MemoryAllocationLib SynchronizationLib + VmgExitLib [Pcd] gEfiMdeModulePkgTokenSpaceGuid.PcdCpuStackGuard # CONSUMES diff --git a/UefiCpuPkg/Library/CpuExceptionHandlerLib/PeiDxeSmmCpuException.c b/UefiCpuPkg/Library/CpuExceptionHandlerLib/PeiDxeSmmCpuException.c index 6a2670d559..892d349d4b 100644 --- a/UefiCpuPkg/Library/CpuExceptionHandlerLib/PeiDxeSmmCpuException.c +++ b/UefiCpuPkg/Library/CpuExceptionHandlerLib/PeiDxeSmmCpuException.c @@ -6,8 +6,9 @@ SPDX-License-Identifier: BSD-2-Clause-Patent **/ -#include "CpuExceptionCommon.h" #include +#include +#include "CpuExceptionCommon.h" /** Internal worker function for common exception handler. @@ -27,6 +28,23 @@ CommonExceptionHandlerWorker ( RESERVED_VECTORS_DATA *ReservedVectors; EFI_CPU_INTERRUPT_HANDLER *ExternalInterruptHandler; + if (ExceptionType == VC_EXCEPTION) { + EFI_STATUS Status; + // + // #VC needs to be handled immediately upon enabling exception handling + // and therefore can't use the RegisterCpuInterruptHandler() interface. + // + // Handle the #VC: + // On EFI_SUCCESS - Exception has been handled, return + // On other - ExceptionType contains (possibly new) exception + // value + // + Status = VmgExitHandleVc (&ExceptionType, SystemContext); + if (!EFI_ERROR (Status)) { + return; + } + } + ExceptionHandlerContext = (EXCEPTION_HANDLER_CONTEXT *) (UINTN) (SystemContext.SystemContextIa32); ReservedVectors = ExceptionHandlerData->ReservedVectors; ExternalInterruptHandler = ExceptionHandlerData->ExternalInterruptHandler; diff --git a/UefiCpuPkg/Library/CpuExceptionHandlerLib/SecPeiCpuException.c b/UefiCpuPkg/Library/CpuExceptionHandlerLib/SecPeiCpuException.c index d4ae153c57..01b5a2f1f4 100644 --- a/UefiCpuPkg/Library/CpuExceptionHandlerLib/SecPeiCpuException.c +++ b/UefiCpuPkg/Library/CpuExceptionHandlerLib/SecPeiCpuException.c @@ -7,6 +7,7 @@ SPDX-License-Identifier: BSD-2-Clause-Patent **/ #include +#include #include "CpuExceptionCommon.h" CONST UINTN mDoFarReturnFlag = 0; @@ -24,6 +25,24 @@ CommonExceptionHandler ( IN EFI_SYSTEM_CONTEXT SystemContext ) { + if (ExceptionType == VC_EXCEPTION) { + EFI_STATUS Status; + // + // #VC needs to be handled immediately upon enabling exception handling + // and therefore can't use the RegisterCpuInterruptHandler() interface + // (which isn't supported under Sec and Pei anyway). + // + // Handle the #VC: + // On EFI_SUCCESS - Exception has been handled, return + // On other - ExceptionType contains (possibly new) exception + // value + // + Status = VmgExitHandleVc (&ExceptionType, SystemContext); + if (!EFI_ERROR (Status)) { + return; + } + } + // // Initialize the serial port before dumping. // diff --git a/UefiCpuPkg/Library/CpuExceptionHandlerLib/SecPeiCpuExceptionHandlerLib.inf b/UefiCpuPkg/Library/CpuExceptionHandlerLib/SecPeiCpuExceptionHandlerLib.inf index 6d25cafe2c..967cb61ba6 100644 --- a/UefiCpuPkg/Library/CpuExceptionHandlerLib/SecPeiCpuExceptionHandlerLib.inf +++ b/UefiCpuPkg/Library/CpuExceptionHandlerLib/SecPeiCpuExceptionHandlerLib.inf @@ -48,3 +48,4 @@ PrintLib LocalApicLib PeCoffGetEntryPointLib + VmgExitLib diff --git a/UefiCpuPkg/Library/CpuExceptionHandlerLib/SmmCpuExceptionHandlerLib.inf b/UefiCpuPkg/Library/CpuExceptionHandlerLib/SmmCpuExceptionHandlerLib.inf index 2ffbbccc30..4cdb11c04e 100644 --- a/UefiCpuPkg/Library/CpuExceptionHandlerLib/SmmCpuExceptionHandlerLib.inf +++ b/UefiCpuPkg/Library/CpuExceptionHandlerLib/SmmCpuExceptionHandlerLib.inf @@ -51,4 +51,5 @@ LocalApicLib PeCoffGetEntryPointLib DebugLib + VmgExitLib diff --git a/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/ExceptionHandlerAsm.nasm b/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/ExceptionHandlerAsm.nasm index 3814f9de37..2a5545ecfd 100644 --- a/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/ExceptionHandlerAsm.nasm +++ b/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/ExceptionHandlerAsm.nasm @@ -18,6 +18,8 @@ ; CommonExceptionHandler() ; +%define VC_EXCEPTION 29 + extern ASM_PFX(mErrorCodeFlag) ; Error code flags for exceptions extern ASM_PFX(mDoFarReturnFlag) ; Do far return flag extern ASM_PFX(CommonExceptionHandler) @@ -224,6 +226,9 @@ HasErrorCode: push rax ;; UINT64 Dr0, Dr1, Dr2, Dr3, Dr6, Dr7; + cmp qword [rbp + 8], VC_EXCEPTION + je VcDebugRegs ; For SEV-ES (#VC) Debug registers ignored + mov rax, dr7 push rax mov rax, dr6 @@ -236,7 +241,19 @@ HasErrorCode: push rax mov rax, dr0 push rax + jmp DrFinish + +VcDebugRegs: +;; UINT64 Dr0, Dr1, Dr2, Dr3, Dr6, Dr7 are skipped for #VC to avoid exception recursion + xor rax, rax + push rax + push rax + push rax + push rax + push rax + push rax +DrFinish: ;; FX_SAVE_STATE_X64 FxSaveState; sub rsp, 512 mov rdi, rsp diff --git a/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/Xcode5ExceptionHandlerAsm.nasm b/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/Xcode5ExceptionHandlerAsm.nasm index 19198f2731..26cae56cc5 100644 --- a/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/Xcode5ExceptionHandlerAsm.nasm +++ b/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/Xcode5ExceptionHandlerAsm.nasm @@ -18,6 +18,8 @@ ; CommonExceptionHandler() ; +%define VC_EXCEPTION 29 + extern ASM_PFX(mErrorCodeFlag) ; Error code flags for exceptions extern ASM_PFX(mDoFarReturnFlag) ; Do far return flag extern ASM_PFX(CommonExceptionHandler) @@ -225,6 +227,9 @@ HasErrorCode: push rax ;; UINT64 Dr0, Dr1, Dr2, Dr3, Dr6, Dr7; + cmp qword [rbp + 8], VC_EXCEPTION + je VcDebugRegs ; For SEV-ES (#VC) Debug registers ignored + mov rax, dr7 push rax mov rax, dr6 @@ -237,7 +242,19 @@ HasErrorCode: push rax mov rax, dr0 push rax + jmp DrFinish + +VcDebugRegs: +;; UINT64 Dr0, Dr1, Dr2, Dr3, Dr6, Dr7 are skipped for #VC to avoid exception recursion + xor rax, rax + push rax + push rax + push rax + push rax + push rax + push rax +DrFinish: ;; FX_SAVE_STATE_X64 FxSaveState; sub rsp, 512 mov rdi, rsp diff --git a/UefiCpuPkg/Library/CpuExceptionHandlerLib/Xcode5SecPeiCpuExceptionHandlerLib.inf b/UefiCpuPkg/Library/CpuExceptionHandlerLib/Xcode5SecPeiCpuExceptionHandlerLib.inf index 7e21beaab6..743c2aa766 100644 --- a/UefiCpuPkg/Library/CpuExceptionHandlerLib/Xcode5SecPeiCpuExceptionHandlerLib.inf +++ b/UefiCpuPkg/Library/CpuExceptionHandlerLib/Xcode5SecPeiCpuExceptionHandlerLib.inf @@ -53,3 +53,4 @@ PrintLib LocalApicLib PeCoffGetEntryPointLib + VmgExitLib -- cgit v1.2.3