diff options
| author | Brijesh Singh <brijesh.singh@amd.com> | 2017-07-06 09:29:19 -0400 |
|---|---|---|
| committer | Jordan Justen <jordan.l.justen@intel.com> | 2017-07-10 21:17:28 -0700 |
| commit | 66c548be509d75b44360c22068788a416509ab58 (patch) | |
| tree | f705e4af1b26babfc30273f0d1616fc8dabd66d8 /OvmfPkg | |
| parent | 7cfe445d7f4b936497dbf9c8752de476a157752f (diff) | |
| download | edk2-66c548be509d75b44360c22068788a416509ab58.tar.gz edk2-66c548be509d75b44360c22068788a416509ab58.tar.bz2 edk2-66c548be509d75b44360c22068788a416509ab58.zip | |
OvmfPkg/QemuFwCfgLib: Add SEV support
When SEV is enabled, use a bounce buffer to perform the DMA operation.
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>
Diffstat (limited to 'OvmfPkg')
| -rw-r--r-- | OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c | 54 |
1 files changed, 52 insertions, 2 deletions
diff --git a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c index 73a19772be..dbebd36b18 100644 --- a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c +++ b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c @@ -72,6 +72,8 @@ InternalQemuFwCfgDmaBytes ( volatile FW_CFG_DMA_ACCESS *Access;
UINT32 AccessHigh, AccessLow;
UINT32 Status;
+ UINT32 NumPages;
+ VOID *DmaBuffer, *BounceBuffer;
ASSERT (Control == FW_CFG_DMA_CTL_WRITE || Control == FW_CFG_DMA_CTL_READ ||
Control == FW_CFG_DMA_CTL_SKIP);
@@ -80,11 +82,44 @@ InternalQemuFwCfgDmaBytes ( return;
}
- Access = &LocalAccess;
+ //
+ // When SEV is enabled then allocate DMA bounce buffer
+ //
+ if (InternalQemuFwCfgSevIsEnabled ()) {
+ UINTN TotalSize;
+
+ TotalSize = sizeof (*Access);
+ //
+ // Skip operation does not need buffer
+ //
+ if (Control != FW_CFG_DMA_CTL_SKIP) {
+ TotalSize += Size;
+ }
+
+ //
+ // Allocate SEV DMA buffer
+ //
+ NumPages = (UINT32)EFI_SIZE_TO_PAGES (TotalSize);
+ InternalQemuFwCfgSevDmaAllocateBuffer (&BounceBuffer, NumPages);
+
+ Access = BounceBuffer;
+ DmaBuffer = (UINT8*)BounceBuffer + sizeof (*Access);
+
+ //
+ // Decrypt data from encrypted guest buffer into DMA buffer
+ //
+ if (Control == FW_CFG_DMA_CTL_WRITE) {
+ CopyMem (DmaBuffer, Buffer, Size);
+ }
+ } else {
+ Access = &LocalAccess;
+ DmaBuffer = Buffer;
+ BounceBuffer = NULL;
+ }
Access->Control = SwapBytes32 (Control);
Access->Length = SwapBytes32 (Size);
- Access->Address = SwapBytes64 ((UINTN)Buffer);
+ Access->Address = SwapBytes64 ((UINTN)DmaBuffer);
//
// Delimit the transfer from (a) modifications to Access, (b) in case of a
@@ -117,6 +152,21 @@ InternalQemuFwCfgDmaBytes ( // After a read, the caller will want to use Buffer.
//
MemoryFence ();
+
+ //
+ // If Bounce buffer was allocated then copy the data into guest buffer and
+ // free the bounce buffer
+ //
+ if (BounceBuffer != NULL) {
+ //
+ // Encrypt the data from DMA buffer into guest buffer
+ //
+ if (Control == FW_CFG_DMA_CTL_READ) {
+ CopyMem (Buffer, DmaBuffer, Size);
+ }
+
+ InternalQemuFwCfgSevDmaFreeBuffer (BounceBuffer, NumPages);
+ }
}
|