[edk2-devel] [PATCH] OvmfPkg/BaseMemEncryptTdxLib: Make SetOrClearSharedBit() handle retry error

[Isaku Yamahata]

From: Isaku Yamahata <isaku.yamah...@intel.com>

TDG.VP.VMCALL<MAPGPA> can return TDG.VP.VMCALL_RETRY when the length is too
large so that VMM can avoid too long processing time.  The caller should
retry with the updated starting GPA on the error.  Add check
TDG.VP.VMCALL_RETRY check.

Signed-off-by: Isaku Yamahata <isaku.yamah...@intel.com>
---
 MdePkg/Include/IndustryStandard/Tdx.h                  |  4 ++++
 MdePkg/Library/BaseLib/X64/TdVmcall.nasm               |  4 +---
 .../Library/BaseMemEncryptTdxLib/MemoryEncryption.c    | 10 ++++++++--
 3 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/MdePkg/Include/IndustryStandard/Tdx.h 
b/MdePkg/Include/IndustryStandard/Tdx.h
index 81df1361842b..4ea2960a70f9 100644
--- a/MdePkg/Include/IndustryStandard/Tdx.h
+++ b/MdePkg/Include/IndustryStandard/Tdx.h
@@ -103,6 +103,10 @@
 #define TDVMCALL_REPORT_FATAL_ERR    0x10003
 #define TDVMCALL_SETUP_EVENT_NOTIFY  0x10004
 
+// TDVMCALL API sub-function Completion Status Codes
+#define TDG_VP_VMCALL_SUCCESS   0x0000000000000000
+#define TDG_VP_VMCALL_RETRY     0x0000000000000001
+
 #pragma pack(1)
 typedef struct {
   UINT64    Data[6];
diff --git a/MdePkg/Library/BaseLib/X64/TdVmcall.nasm 
b/MdePkg/Library/BaseLib/X64/TdVmcall.nasm
index 5ecc10b17193..8dd9bfcbfa14 100644
--- a/MdePkg/Library/BaseLib/X64/TdVmcall.nasm
+++ b/MdePkg/Library/BaseLib/X64/TdVmcall.nasm
@@ -133,9 +133,7 @@ ASM_PFX(TdVmCall):
        test r9, r9
        jz .no_return_data
 
-       ; On success, propagate TDVMCALL output value to output param
-       test rax, rax
-       jnz .no_return_data
+       ; Propagate TDVMCALL output value to output param
        mov [r9], r11
 .no_return_data:
        tdcall_regs_postamble
diff --git a/OvmfPkg/Library/BaseMemEncryptTdxLib/MemoryEncryption.c 
b/OvmfPkg/Library/BaseMemEncryptTdxLib/MemoryEncryption.c
index a01dc98852b8..d55c2a34a44e 100644
--- a/OvmfPkg/Library/BaseMemEncryptTdxLib/MemoryEncryption.c
+++ b/OvmfPkg/Library/BaseMemEncryptTdxLib/MemoryEncryption.c
@@ -526,6 +526,8 @@ SetOrClearSharedBit (
   UINT64                        TdStatus;
   EFI_STATUS                    Status;
   EDKII_MEMORY_ACCEPT_PROTOCOL  *MemoryAcceptProtocol;
+  PHYSICAL_ADDRESS              TmpPhysicalAddress;
+  UINT64                        TmpLength;
 
   AddressEncMask = GetMemEncryptionAddressMask ();
 
@@ -540,8 +542,12 @@ SetOrClearSharedBit (
     PhysicalAddress   &= ~AddressEncMask;
   }
 
-  TdStatus = TdVmCall (TDVMCALL_MAPGPA, PhysicalAddress, Length, 0, 0, NULL);
-  if (TdStatus != 0) {
+  TmpPhysicalAddress = PhysicalAddress;
+  do {
+    TmpLength = PhysicalAddress + Length - TmpPhysicalAddress;
+    TdStatus = TdVmCall (TDVMCALL_MAPGPA, TmpPhysicalAddress, TmpLength, 0, 0, 
&TmpPhysicalAddress);
+  } while (TdStatus == TDG_VP_VMCALL_RETRY);
+  if (TdStatus != TDG_VP_VMCALL_SUCCESS) {
     DEBUG ((DEBUG_ERROR, "%a: TdVmcall(MAPGPA) failed with %llx\n", __func__, 
TdStatus));
     ASSERT (FALSE);
     return EFI_DEVICE_ERROR;

base-commit: 677f2c6f1509da21258e02957b869b71b008fc61
-- 
2.25.1



-=-=-=-=-=-=-=-=-=-=-=-
Groups.io Links: You receive all messages sent to this group.
View/Reply Online (#107477): https://edk2.groups.io/g/devel/message/107477
Mute This Topic: https://groups.io/mt/100514591/21656
Group Owner: devel+ow...@edk2.groups.io
Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com]
-=-=-=-=-=-=-=-=-=-=-=-