[edk2-devel] [PATCH v15 11/46] UefiCpuPkg/CpuExceptionHandler: Add base support for the #VC exception
Lendacky, Thomas
thomas.lendacky at amd.com
Thu Aug 13 13:22:58 UTC 2020
From: Tom Lendacky <thomas.lendacky at amd.com>
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 <eric.dong at intel.com>
Cc: Ray Ni <ray.ni at intel.com>
Cc: Laszlo Ersek <lersek at redhat.com>
Reviewed-by: Eric Dong <eric.dong at intel.com>
Signed-off-by: Tom Lendacky <thomas.lendacky at amd.com>
---
UefiCpuPkg/Library/CpuExceptionHandlerLib/DxeCpuExceptionHandlerLib.inf | 1 +
UefiCpuPkg/Library/CpuExceptionHandlerLib/PeiCpuExceptionHandlerLib.inf | 1 +
UefiCpuPkg/Library/CpuExceptionHandlerLib/SecPeiCpuExceptionHandlerLib.inf | 1 +
UefiCpuPkg/Library/CpuExceptionHandlerLib/SmmCpuExceptionHandlerLib.inf | 1 +
UefiCpuPkg/Library/CpuExceptionHandlerLib/Xcode5SecPeiCpuExceptionHandlerLib.inf | 1 +
UefiCpuPkg/Library/CpuExceptionHandlerLib/CpuExceptionCommon.c | 10 +++++++++-
UefiCpuPkg/Library/CpuExceptionHandlerLib/PeiDxeSmmCpuException.c | 20 +++++++++++++++++++-
UefiCpuPkg/Library/CpuExceptionHandlerLib/SecPeiCpuException.c | 19 +++++++++++++++++++
UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/ExceptionHandlerAsm.nasm | 17 +++++++++++++++++
UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/Xcode5ExceptionHandlerAsm.nasm | 17 +++++++++++++++++
10 files changed, 86 insertions(+), 2 deletions(-)
diff --git a/UefiCpuPkg/Library/CpuExceptionHandlerLib/DxeCpuExceptionHandlerLib.inf b/UefiCpuPkg/Library/CpuExceptionHandlerLib/DxeCpuExceptionHandlerLib.inf
index 61e2ec30b089..07b34c92a892 100644
--- a/UefiCpuPkg/Library/CpuExceptionHandlerLib/DxeCpuExceptionHandlerLib.inf
+++ b/UefiCpuPkg/Library/CpuExceptionHandlerLib/DxeCpuExceptionHandlerLib.inf
@@ -57,3 +57,4 @@ [LibraryClasses]
PeCoffGetEntryPointLib
MemoryAllocationLib
DebugLib
+ VmgExitLib
diff --git a/UefiCpuPkg/Library/CpuExceptionHandlerLib/PeiCpuExceptionHandlerLib.inf b/UefiCpuPkg/Library/CpuExceptionHandlerLib/PeiCpuExceptionHandlerLib.inf
index 093374944df6..feae7b3e06de 100644
--- a/UefiCpuPkg/Library/CpuExceptionHandlerLib/PeiCpuExceptionHandlerLib.inf
+++ b/UefiCpuPkg/Library/CpuExceptionHandlerLib/PeiCpuExceptionHandlerLib.inf
@@ -52,6 +52,7 @@ [LibraryClasses]
HobLib
MemoryAllocationLib
SynchronizationLib
+ VmgExitLib
[Pcd]
gEfiMdeModulePkgTokenSpaceGuid.PcdCpuStackGuard # CONSUMES
diff --git a/UefiCpuPkg/Library/CpuExceptionHandlerLib/SecPeiCpuExceptionHandlerLib.inf b/UefiCpuPkg/Library/CpuExceptionHandlerLib/SecPeiCpuExceptionHandlerLib.inf
index 6d25cafe2ca3..967cb61ba6d9 100644
--- a/UefiCpuPkg/Library/CpuExceptionHandlerLib/SecPeiCpuExceptionHandlerLib.inf
+++ b/UefiCpuPkg/Library/CpuExceptionHandlerLib/SecPeiCpuExceptionHandlerLib.inf
@@ -48,3 +48,4 @@ [LibraryClasses]
PrintLib
LocalApicLib
PeCoffGetEntryPointLib
+ VmgExitLib
diff --git a/UefiCpuPkg/Library/CpuExceptionHandlerLib/SmmCpuExceptionHandlerLib.inf b/UefiCpuPkg/Library/CpuExceptionHandlerLib/SmmCpuExceptionHandlerLib.inf
index 2ffbbccc302f..4cdb11c04ea0 100644
--- a/UefiCpuPkg/Library/CpuExceptionHandlerLib/SmmCpuExceptionHandlerLib.inf
+++ b/UefiCpuPkg/Library/CpuExceptionHandlerLib/SmmCpuExceptionHandlerLib.inf
@@ -51,4 +51,5 @@ [LibraryClasses]
LocalApicLib
PeCoffGetEntryPointLib
DebugLib
+ VmgExitLib
diff --git a/UefiCpuPkg/Library/CpuExceptionHandlerLib/Xcode5SecPeiCpuExceptionHandlerLib.inf b/UefiCpuPkg/Library/CpuExceptionHandlerLib/Xcode5SecPeiCpuExceptionHandlerLib.inf
index 7e21beaab6f2..743c2aa76684 100644
--- a/UefiCpuPkg/Library/CpuExceptionHandlerLib/Xcode5SecPeiCpuExceptionHandlerLib.inf
+++ b/UefiCpuPkg/Library/CpuExceptionHandlerLib/Xcode5SecPeiCpuExceptionHandlerLib.inf
@@ -53,3 +53,4 @@ [LibraryClasses]
PrintLib
LocalApicLib
PeCoffGetEntryPointLib
+ VmgExitLib
diff --git a/UefiCpuPkg/Library/CpuExceptionHandlerLib/CpuExceptionCommon.c b/UefiCpuPkg/Library/CpuExceptionHandlerLib/CpuExceptionCommon.c
index 8adbd43fefb4..c9003b10e552 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/PeiDxeSmmCpuException.c b/UefiCpuPkg/Library/CpuExceptionHandlerLib/PeiDxeSmmCpuException.c
index 6a2670d55918..892d349d4b37 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 <Library/DebugLib.h>
+#include <Library/VmgExitLib.h>
+#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 d4ae153c5742..01b5a2f1f4fc 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 <PiPei.h>
+#include <Library/VmgExitLib.h>
#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/X64/ExceptionHandlerAsm.nasm b/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/ExceptionHandlerAsm.nasm
index 3814f9de3703..2a5545ecfd41 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 19198f273137..26cae56cc5cf 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
--
2.28.0
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