OvmfPkg/QemuFwCfgLib: Add option to dynamic alloc FW_CFG_DMA Access

Update InternalQemuFwCfgDmaBytes() to work with DMA Access pointer.
The change provides the flexibility to dynamically allocate the "Access"
when SEV is enabled.

Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>

diff --git a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c
index 1bf725d8b7ae8ce46e8a42d31a3fb727ed1f1017..73a19772bee1624f4df690272d365842ff46e70e 100644 (file)
--- a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c
+++ b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c
@@ -68,7 +68,8 @@ InternalQemuFwCfgDmaBytes (
   IN     UINT32   Control\r
   )\r
 {\r
-  volatile FW_CFG_DMA_ACCESS Access;\r
+  volatile FW_CFG_DMA_ACCESS LocalAccess;\r
+  volatile FW_CFG_DMA_ACCESS *Access;\r
   UINT32                     AccessHigh, AccessLow;\r
   UINT32                     Status;\r
 \r
@@ -79,9 +80,11 @@ InternalQemuFwCfgDmaBytes (
     return;\r
   }\r
 \r
-  Access.Control = SwapBytes32 (Control);\r
-  Access.Length  = SwapBytes32 (Size);\r
-  Access.Address = SwapBytes64 ((UINTN)Buffer);\r
+  Access = &LocalAccess;\r
+\r
+  Access->Control = SwapBytes32 (Control);\r
+  Access->Length  = SwapBytes32 (Size);\r
+  Access->Address = SwapBytes64 ((UINTN)Buffer);\r
 \r
   //\r
   // Delimit the transfer from (a) modifications to Access, (b) in case of a\r
@@ -92,8 +95,8 @@ InternalQemuFwCfgDmaBytes (
   //\r
   // Start the transfer.\r
   //\r
-  AccessHigh = (UINT32)RShiftU64 ((UINTN)&Access, 32);\r
-  AccessLow  = (UINT32)(UINTN)&Access;\r
+  AccessHigh = (UINT32)RShiftU64 ((UINTN)Access, 32);\r
+  AccessLow  = (UINT32)(UINTN)Access;\r
   IoWrite32 (FW_CFG_IO_DMA_ADDRESS,     SwapBytes32 (AccessHigh));\r
   IoWrite32 (FW_CFG_IO_DMA_ADDRESS + 4, SwapBytes32 (AccessLow));\r
 \r
@@ -106,7 +109,7 @@ InternalQemuFwCfgDmaBytes (
   // Wait for the transfer to complete.\r
   //\r
   do {\r
-    Status = SwapBytes32 (Access.Control);\r
+    Status = SwapBytes32 (Access->Control);\r
     ASSERT ((Status & FW_CFG_DMA_CTL_ERROR) == 0);\r
   } while (Status != 0);\r
 \r