The patch adds SEV support in QemuFwCfgLib. When SEV is enabled:
* Pei phase support IO-style operations. This is mainly because we need to
use a bounce buffer inorder to support DMA operation. Allocate a memory
for bounce buffer can get painful in Pei phase hence if we detect FWCfg DMA
support then silently fallback to IO.
* Dxe phase supports both IO and DMA style operations.
---
OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgDxe.c | 73 +++++++++++++
OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgDxeLib.inf | 2
OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c | 112 ++++++++++++++++++++
.../Library/QemuFwCfgLib/QemuFwCfgLibInternal.h | 38 +++++++
OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgPei.c | 93 +++++++++++++++++
OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgPeiLib.inf | 2
OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgSec.c | 82 +++++++++++++++
7 files changed, 402 insertions(+)
diff --git a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgDxe.c
b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgDxe.c
index ac05f4c..be8e945 100644
--- a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgDxe.c
+++ b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgDxe.c
@@ -4,6 +4,7 @@
Copyright (C) 2013, Red Hat, Inc.
Copyright (c) 2011 - 2013, Intel Corporation. All rights reserved.<BR>
+ Copyright (c) 2017, Advanced Micro Devices. All rights reserved.<BR>
This program and the accompanying materials are licensed and made available
under the terms and conditions of the BSD License which accompanies this
@@ -14,14 +15,34 @@
WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
**/
+#include "Uefi.h"
+
+#include <Library/BaseLib.h>
#include <Library/DebugLib.h>
#include <Library/QemuFwCfgLib.h>
+#include <Library/UefiBootServicesTableLib.h>
+#include <Library/MemEncryptSevLib.h>
+#include <Library/BmDmaLib.h>
#include "QemuFwCfgLibInternal.h"
STATIC BOOLEAN mQemuFwCfgSupported = FALSE;
STATIC BOOLEAN mQemuFwCfgDmaSupported;
+STATIC BOOLEAN mQemuFwCfgSevIsEnabled = FALSE;
+
+/**
+ Returns a boolean indicating whether the SEV is enabled
+ @retval TRUE SEV is enabled
+ @retval FALSE SEV is not enabled
+**/
+BOOLEAN
+InternalQemuFwCfgSevIsEnabled (
+ VOID
+ )
+{
+ return mQemuFwCfgSevIsEnabled;
+}
/**
Returns a boolean indicating if the firmware configuration interface
@@ -79,6 +100,9 @@ QemuFwCfgInitialize (
mQemuFwCfgDmaSupported = TRUE;
DEBUG ((DEBUG_INFO, "QemuFwCfg interface (DMA) is supported.\n"));
}
+
+ mQemuFwCfgSevIsEnabled = MemEncryptSevIsEnabled ();
+
return RETURN_SUCCESS;
}
@@ -114,3 +138,52 @@ InternalQemuFwCfgDmaIsAvailable (
{
return mQemuFwCfgDmaSupported;
}
+
+/**
+ Allocate a bounce buffer for SEV DMA.
+
+ @param[in] NumPage Number of pages.
+ @param[out] Buffer Allocated DMA Buffer pointer
+
+**/
+VOID
+InternalQemuFwCfgSevDmaAllocateBuffer (
+ IN UINT32 NumPages,
+ OUT VOID **Buffer
+ )
+{
+ EFI_STATUS Status;
+
+ //
+ // Allocate DMA bounce buffer
+ //
+ Status = BmDmaAllocateBuffer (TRUE, EfiBootServicesData, NumPages, Buffer);
+ if (EFI_ERROR(Status)) {
+ DEBUG ((EFI_D_ERROR, "SEV: Failed to allocate bounce buffer %d pages\n",
NumPages));
+ ASSERT_EFI_ERROR (Status);
+ CpuDeadLoop ();
+ }
+
+ DEBUG ((EFI_D_VERBOSE, "QemuFwCfgSevDma allocate buffer 0x%Lx Pages %d\n",
(UINTN)Buffer, NumPages));
+}
+
+/**
+ Free the DMA buffer allocated using InternalQemuFwCfgSevDmaAllocateBuffer
+
+ @param[in] NumPage Number of pages.
+ @param[in] Buffer DMA Buffer pointer
+
+**/
+VOID
+InternalQemuFwCfgSevDmaFreeBuffer (
+ IN VOID *Buffer,
+ IN UINT32 NumPages
+ )
+{
+ //
+ // Free the bounce buffer
+ //
+ DEBUG ((EFI_D_VERBOSE, "QemuFwCfgSevDma free buffer 0x%Lx Pages %d\n",
(UINTN)Buffer, NumPages));
+ BmDmaFreeBuffer (Buffer, NumPages);
+}
+
diff --git a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgDxeLib.inf
b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgDxeLib.inf
index 346bb88..536887f 100644
--- a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgDxeLib.inf
+++ b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgDxeLib.inf
@@ -47,4 +47,6 @@
DebugLib
IoLib
MemoryAllocationLib
+ MemEncryptSevLib
+ BmDmaLib
diff --git a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c
b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c
index 1bf725d..d2560a3 100644
--- a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c
+++ b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c
@@ -47,6 +47,111 @@ QemuFwCfgSelectItem (
/**
+ Transfer an array of bytes, or skip a number of bytes, using the SEV DMA
bounce
+ interface. The function is same as InternalQemuFwCfgDmaBytes with excpetion
that
+ it uses bounce buffer
+
+ @param[in] Size Size in bytes to transfer or skip.
+
+ @param[in,out] HostBuffer Buffer to read data into or write data from.
Ignored,
+ and may be NULL, if Size is zero, or Control is
+ FW_CFG_DMA_CTL_SKIP.
+
+ @param[in] Control One of the following:
+ FW_CFG_DMA_CTL_WRITE - write to fw_cfg from Buffer.
+ FW_CFG_DMA_CTL_READ - read from fw_cfg into Buffer.
+ FW_CFG_DMA_CTL_SKIP - skip bytes in fw_cfg.
+**/
+VOID
+InternalQemuFwCfgSevDmaBytes (
+ IN UINT32 Size,
+ IN OUT VOID *HostBuffer OPTIONAL,
+ IN UINT32 Control
+ )
+{
+ volatile FW_CFG_DMA_ACCESS *Access;
+ UINT32 AccessHigh, AccessLow;
+ UINT32 Status;
+ UINT32 NumPages;
+ VOID *DmaBuffer, *Buffer;
+
+ //
+ // Calculate number of pages we need to allocate for this operation
+ //
+ if (Control == FW_CFG_DMA_CTL_SKIP) {
+ //
+ // Control data does not need the actual buffer
+ //
+ NumPages = EFI_SIZE_TO_PAGES (sizeof (*Access));
+ } else {
+ NumPages = EFI_SIZE_TO_PAGES (sizeof (*Access) + Size);
+ }
+
+ //
+ // Allocate DMA bounce buffer
+ //
+ InternalQemuFwCfgSevDmaAllocateBuffer (NumPages, &DmaBuffer);
+
+ Access = (FW_CFG_DMA_ACCESS *)DmaBuffer;
+ Buffer = DmaBuffer + sizeof(*Access);
+
+ Access->Control = SwapBytes32 (Control);
+ Access->Length = SwapBytes32 (Size);
+ Access->Address = SwapBytes64 ((UINTN)Buffer);
+
+ //
+ // Copy data from Host buffer into DMA buffer
+ //
+ if (HostBuffer && (Control == FW_CFG_DMA_CTL_WRITE)) {
+ CopyMem (Buffer, HostBuffer, Size);
+ }
+
+ //
+ // Delimit the transfer from (a) modifications to Access, (b) in case of a
+ // write, from writes to Buffer by the caller.
+ //
+ MemoryFence ();
+
+ //
+ // Start the transfer.
+ //
+ AccessHigh = (UINT32)RShiftU64 ((UINTN)Access, 32);
+ AccessLow = (UINT32)(UINTN)Access;
+ IoWrite32 (FW_CFG_IO_DMA_ADDRESS, SwapBytes32 (AccessHigh));
+ IoWrite32 (FW_CFG_IO_DMA_ADDRESS + 4, SwapBytes32 (AccessLow));
+
+ //
+ // Don't look at Access->Control before starting the transfer.
+ //
+ MemoryFence ();
+
+ //
+ // Wait for the transfer to complete.
+ //
+ do {
+ Status = SwapBytes32 (Access->Control);
+ ASSERT ((Status & FW_CFG_DMA_CTL_ERROR) == 0);
+ } while (Status != 0);
+
+ //
+ // After a read, the caller will want to use Buffer.
+ //
+ MemoryFence ();
+
+ //
+ // Copy data from DMA buffer into Host Buffer
+ //
+ if (HostBuffer && (Control == FW_CFG_DMA_CTL_READ)) {
+ CopyMem (HostBuffer, Buffer, Size);
+ }
+
+ //
+ // Free the DMA bounce buffer
+ //
+ InternalQemuFwCfgSevDmaFreeBuffer (DmaBuffer, NumPages);
+}
+
+/**
Transfer an array of bytes, or skip a number of bytes, using the DMA
interface.
@@ -79,6 +184,13 @@ InternalQemuFwCfgDmaBytes (
return;
}
+ //
+ // When SEV is enabled then use SEV version of DmaReadWrite
+ //
+ if (InternalQemuFwCfgSevIsEnabled ()) {
+ return InternalQemuFwCfgSevDmaBytes (Size, Buffer, Control);
+ }
+
Access.Control = SwapBytes32 (Control);
Access.Length = SwapBytes32 (Size);
Access.Address = SwapBytes64 ((UINTN)Buffer);
diff --git a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLibInternal.h
b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLibInternal.h
index 6e87c62..8e2ff45 100644
--- a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLibInternal.h
+++ b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLibInternal.h
@@ -2,6 +2,7 @@
Internal interfaces specific to the QemuFwCfgLib instances in OvmfPkg.
Copyright (C) 2016, Red Hat, Inc.
+ Copyright (C) 2017, Advanced Micro Devices.
This program and the accompanying materials are licensed and made available
under the terms and conditions of the BSD License which accompanies this
@@ -43,4 +44,41 @@ InternalQemuFwCfgDmaIsAvailable (
VOID
);
+/**
+ Returns a boolean indicating whether the SEV is enabled
+
+ @retval TRUE SEV is enabled
+ @retval FALSE SEV is not enabled
+**/
+BOOLEAN
+InternalQemuFwCfgSevIsEnabled (
+ VOID
+ );
+
+/**
+ Allocate a bounce buffer for SEV DMA.
+
+ @param[in] NumPage Number of pages.
+ @param[out] Buffer Allocated DMA Buffer pointer
+
+**/
+VOID
+InternalQemuFwCfgSevDmaAllocateBuffer (
+ IN UINT32 NumPages,
+ OUT VOID **Buffer
+ );
+
+/**
+ Free the DMA buffer allocated using InternalQemuFwCfgSevDmaAllocateBuffer
+
+ @param[in] NumPage Number of pages.
+ @param[in] Buffer DMA Buffer pointer
+
+**/
+VOID
+InternalQemuFwCfgSevDmaFreeBuffer (
+ IN VOID *Buffer,
+ IN UINT32 NumPages
+ );
+
#endif
diff --git a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgPei.c
b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgPei.c
index ac05f4c..3dc9270 100644
--- a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgPei.c
+++ b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgPei.c
@@ -4,6 +4,7 @@
Copyright (C) 2013, Red Hat, Inc.
Copyright (c) 2011 - 2013, Intel Corporation. All rights reserved.<BR>
+ Copyright (c) 2017, Advanced Micro Devices. All rights reserved.<BR>
This program and the accompanying materials are licensed and made available
under the terms and conditions of the BSD License which accompanies this
@@ -14,14 +15,55 @@
WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
**/
+#include <Library/BaseLib.h>
#include <Library/DebugLib.h>
#include <Library/QemuFwCfgLib.h>
+#include <Register/Cpuid.h>
+#include <Register/AmdSevMap.h>
#include "QemuFwCfgLibInternal.h"
STATIC BOOLEAN mQemuFwCfgSupported = FALSE;
STATIC BOOLEAN mQemuFwCfgDmaSupported;
+/**
+ Returns a boolean indicating whether the SEV is enabled
+
+ @retval TRUE SEV is enabled
+ @retval FALSE SEV is not enabled
+**/
+BOOLEAN
+InternalQemuFwCfgSevIsEnabled (
+ VOID
+ )
+{
+ UINT32 RegEax;
+ MSR_SEV_STATUS_REGISTER Msr;
+ CPUID_MEMORY_ENCRYPTION_INFO_EAX Eax;
+
+ //
+ // Check if memory encryption leaf exist
+ //
+ AsmCpuid (CPUID_EXTENDED_FUNCTION, &RegEax, NULL, NULL, NULL);
+ if (RegEax >= CPUID_MEMORY_ENCRYPTION_INFO) {
+ //
+ // CPUID Fn8000_001F[EAX] Bit 1 (Sev supported)
+ //
+ AsmCpuid (CPUID_MEMORY_ENCRYPTION_INFO, &Eax.Uint32, NULL, NULL, NULL);
+
+ if (Eax.Bits.SevBit) {
+ //
+ // Check MSR_0xC0010131 Bit 0 (Sev Enabled)
+ //
+ Msr.Uint32 = AsmReadMsr32 (MSR_SEV_STATUS);
+ if (Msr.Bits.SevBit) {
+ return TRUE;
+ }
+ }
+ }
+
+ return FALSE;
+}
/**
Returns a boolean indicating if the firmware configuration interface
@@ -79,6 +121,17 @@ QemuFwCfgInitialize (
mQemuFwCfgDmaSupported = TRUE;
DEBUG ((DEBUG_INFO, "QemuFwCfg interface (DMA) is supported.\n"));
}
+
+ //
+ // When SEV is enabled then we do not support DMA interface.
+ // This is because we need to use bounce buffer to support DMA operation in
SEV guest.
+ // Allocating memory for bounce buffer can get painful in Pei phase
+ //
+ if (mQemuFwCfgDmaSupported && InternalQemuFwCfgSevIsEnabled ()) {
+ mQemuFwCfgDmaSupported = FALSE;
+ DEBUG ((DEBUG_INFO, "QemuFwCfg disabling DMA interface and defaulting to
IO Port.\n"));
+ }
+
return RETURN_SUCCESS;
}
@@ -114,3 +167,43 @@ InternalQemuFwCfgDmaIsAvailable (
{
return mQemuFwCfgDmaSupported;
}
+
+/**
+ Allocate a bounce buffer for SEV DMA.
+
+ @param[in] NumPage Number of pages.
+ @param[out] Buffer Allocated DMA Buffer pointer
+
+**/
+VOID
+InternalQemuFwCfgSevDmaAllocateBuffer (
+ IN UINT32 NumPages,
+ OUT VOID **Buffer
+ )
+{
+ //
+ // We should never reach here
+ //
+ ASSERT (FALSE);
+ CpuDeadLoop ();
+}
+
+/**
+ Free the DMA buffer allocated using InternalQemuFwCfgSevDmaAllocateBuffer
+
+ @param[in] NumPage Number of pages.
+ @param[in] Buffer DMA Buffer pointer
+
+**/
+VOID
+InternalQemuFwCfgSevDmaFreeBuffer (
+ IN VOID *Buffer,
+ IN UINT32 NumPages
+ )
+{
+ //
+ // We should never reach here
+ //
+ ASSERT (FALSE);
+ CpuDeadLoop ();
+}
diff --git a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgPeiLib.inf
b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgPeiLib.inf
index 4f966a8..83cc0de 100644
--- a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgPeiLib.inf
+++ b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgPeiLib.inf
@@ -39,7 +39,9 @@
[Packages]
MdePkg/MdePkg.dec
+ MdeModulePkg/MdeModulePkg.dec
OvmfPkg/OvmfPkg.dec
+ UefiCpuPkg/UefiCpuPkg.dec
[LibraryClasses]
BaseLib
diff --git a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgSec.c
b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgSec.c
index 465ccbe..70b0a47 100644
--- a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgSec.c
+++ b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgSec.c
@@ -16,8 +16,11 @@
WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
**/
+#include <Library/BaseLib.h>
#include <Library/DebugLib.h>
#include <Library/QemuFwCfgLib.h>
+#include <Register/Cpuid.h>
+#include <Register/AmdSevMap.h>
#include "QemuFwCfgLibInternal.h"
@@ -94,3 +97,82 @@ InternalQemuFwCfgDmaIsAvailable (
{
return FALSE;
}
+
+/**
+ Returns a boolean indicating whether the SEV is enabled
+
+ @retval TRUE SEV is enabled
+ @retval FALSE SEV is not enabled
+**/
+BOOLEAN
+InternalQemuFwCfgSevIsEnabled (
+ VOID
+ )
+{
+ UINT32 RegEax;
+ MSR_SEV_STATUS_REGISTER Msr;
+ CPUID_MEMORY_ENCRYPTION_INFO_EAX Eax;
+
+ //
+ // Check if memory encryption leaf exist
+ //
+ AsmCpuid (CPUID_EXTENDED_FUNCTION, &RegEax, NULL, NULL, NULL);
+ if (RegEax >= CPUID_MEMORY_ENCRYPTION_INFO) {
+ //
+ // CPUID Fn8000_001F[EAX] Bit 1 (Sev supported)
+ //
+ AsmCpuid (CPUID_MEMORY_ENCRYPTION_INFO, &Eax.Uint32, NULL, NULL, NULL);
+
+ if (Eax.Bits.SevBit) {
+ //
+ // Check MSR_0xC0010131 Bit 0 (Sev Enabled)
+ //
+ Msr.Uint32 = AsmReadMsr32 (MSR_SEV_STATUS);
+ if (Msr.Bits.SevBit) {
+ return TRUE;
+ }
+ }
+ }
+
+ return FALSE;
+}
+
+/**
+ Allocate a bounce buffer for SEV DMA.
+
+ @param[in] NumPage Number of pages.
+ @param[out] Buffer Allocated DMA Buffer pointer
+
+**/
+VOID
+InternalQemuFwCfgSevDmaAllocateBuffer (
+ IN UINT32 NumPages,
+ OUT VOID **Buffer
+ )
+{
+ //
+ // We should never reach here
+ //
+ ASSERT (FALSE);
+ CpuDeadLoop ();
+}
+
+/**
+ Free the DMA buffer allocated using InternalQemuFwCfgSevDmaAllocateBuffer
+
+ @param[in] NumPage Number of pages.
+ @param[in] Buffer DMA Buffer pointer
+
+**/
+VOID
+InternalQemuFwCfgSevDmaFreeBuffer (
+ IN VOID *Buffer,
+ IN UINT32 NumPages
+ )
+{
+ //
+ // We should never reach here
+ //
+ ASSERT (FALSE);
+ CpuDeadLoop ();
+}
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