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From: Brijesh Singh <brijesh.singh@amd.com>
To: <edk2-devel@lists.01.org>, <lersek@redhat.com>,
	<jordan.l.justen@intel.com>
Cc: <Thomas.Lendacky@amd.com>, <leo.duran@amd.com>,
	Brijesh Singh <brijesh.singh@amd.com>
Subject: [PATCH v5 12/14] OvmfPkg/QemuFwCfgLib: Implement SEV internal function for Dxe phase
Date: Mon, 22 May 2017 11:23:10 -0400	[thread overview]
Message-ID: <1495466592-21641-13-git-send-email-brijesh.singh@amd.com> (raw)
In-Reply-To: <1495466592-21641-1-git-send-email-brijesh.singh@amd.com>

When SEV is enabled, the DMA must be performed on unencrypted pages.
So when get asked to perfom FWCFG DMA read or write, we allocate a
intermediate (bounce buffer) unencrypted buffer and use this buffer
for DMA read or write.


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>
---
 OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgDxeLib.inf |   7 ++
 OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgDxe.c      | 108 ++++++++++++++++++++
 2 files changed, 115 insertions(+)

diff --git a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgDxeLib.inf b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgDxeLib.inf
index d7e368e5435d..ec128f82c702 100644
--- a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgDxeLib.inf
+++ b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgDxeLib.inf
@@ -39,6 +39,7 @@ [Sources]
 
 [Packages]
   MdePkg/MdePkg.dec
+  MdeModulePkg/MdeModulePkg.dec
   OvmfPkg/OvmfPkg.dec
 
 [LibraryClasses]
@@ -47,4 +48,10 @@ [LibraryClasses]
   DebugLib
   IoLib
   MemoryAllocationLib
+  MemEncryptSevLib
 
+[Protocols]
+  gEdkiiIoMmuProtocolGuid                         ## SOMETIMES_CONSUMES
+
+[Depex]
+  gEdkiiIoMmuProtocolGuid OR gIoMmuDetectedProtocolGuid
diff --git a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgDxe.c b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgDxe.c
index ac05f4c347f3..bda1a80b5eb9 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 +15,36 @@
   WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
 **/
 
+#include <Uefi.h>
+
+#include <Protocol/IoMmu.h>
+
+#include <Library/BaseLib.h>
 #include <Library/DebugLib.h>
 #include <Library/QemuFwCfgLib.h>
+#include <Library/UefiBootServicesTableLib.h>
+#include <Library/MemEncryptSevLib.h>
 
 #include "QemuFwCfgLibInternal.h"
 
 STATIC BOOLEAN mQemuFwCfgSupported = FALSE;
 STATIC BOOLEAN mQemuFwCfgDmaSupported;
 
+STATIC EDKII_IOMMU_PROTOCOL        *mIoMmuProtocol;
+/**
+
+ Returns a boolean indicating whether SEV is enabled
+
+ @retval    TRUE    SEV is enabled
+ @retval    FALSE   SEV is disabled
+**/
+BOOLEAN
+InternalQemuFwCfgSevIsEnabled (
+  VOID
+  )
+{
+  return MemEncryptSevIsEnabled ();
+}
 
 /**
   Returns a boolean indicating if the firmware configuration interface
@@ -79,6 +102,22 @@ QemuFwCfgInitialize (
     mQemuFwCfgDmaSupported = TRUE;
     DEBUG ((DEBUG_INFO, "QemuFwCfg interface (DMA) is supported.\n"));
   }
+
+  if (mQemuFwCfgDmaSupported && MemEncryptSevIsEnabled ()) {
+    EFI_STATUS   Status;
+
+    //
+    // IoMmuDxe driver must have installed the IOMMU protocol. If we are not
+    // able to locate the protocol then something must have gone wrong.
+    //
+    Status = gBS->LocateProtocol (&gEdkiiIoMmuProtocolGuid, NULL, (VOID **)&mIoMmuProtocol);
+    if (EFI_ERROR (Status)) {
+      DEBUG ((DEBUG_ERROR, "QemuwCfgSevDma: failed to locate IOMMU protocol\n"));
+      ASSERT (FALSE);
+      CpuDeadLoop ();
+    }
+  }
+
   return RETURN_SUCCESS;
 }
 
@@ -114,3 +153,72 @@ 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 (
+  OUT    VOID     **Buffer,
+  IN     UINT32   NumPages
+  )
+{
+  EFI_STATUS    Status;
+
+  ASSERT (mIoMmuProtocol != NULL);
+
+  Status = mIoMmuProtocol->AllocateBuffer (
+                            mIoMmuProtocol,
+                            0,
+                            EfiBootServicesData,
+                            NumPages,
+                            Buffer,
+                            EDKII_IOMMU_ATTRIBUTE_MEMORY_CACHED
+                          );
+  if (EFI_ERROR (Status)) {
+    DEBUG ((DEBUG_ERROR, "%a:%a failed to allocate %u pages\n", gEfiCallerBaseName,
+          __FUNCTION__, NumPages));
+    ASSERT (FALSE);
+    CpuDeadLoop ();
+  }
+
+  DEBUG ((DEBUG_VERBOSE, "%a:%a buffer 0x%Lx Pages %u\n", gEfiCallerBaseName,
+        __FUNCTION__, (UINT64)(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
+  )
+{
+  EFI_STATUS    Status;
+
+  ASSERT (mIoMmuProtocol != NULL);
+
+  Status = mIoMmuProtocol->FreeBuffer (
+                            mIoMmuProtocol,
+                            NumPages,
+                            Buffer
+                          );
+  if (EFI_ERROR (Status)) {
+    DEBUG ((DEBUG_ERROR, "%a:%a failed to free buffer 0x%Lx pages %u\n",
+          gEfiCallerBaseName, __FUNCTION__, (UINT64)(UINTN)Buffer, NumPages));
+    ASSERT (FALSE);
+    CpuDeadLoop ();
+  }
+
+  DEBUG ((DEBUG_VERBOSE, "%a:%a buffer 0x%Lx Pages %u\n", gEfiCallerBaseName,
+        __FUNCTION__, (UINT64)(UINTN)Buffer, NumPages));
+}
-- 
2.7.4



  parent reply	other threads:[~2017-05-22 15:23 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-05-22 15:22 [PATCH v5 00/14] x86: Secure Encrypted Virtualization (AMD) Brijesh Singh
2017-05-22 15:22 ` [PATCH v5 01/14] UefiCpuPkg: Define AMD Memory Encryption specific CPUID and MSR Brijesh Singh
2017-05-22 15:23 ` [PATCH v5 02/14] OvmfPkg/ResetVector: Set C-bit when building initial page table Brijesh Singh
2017-05-22 15:23 ` [PATCH v5 03/14] OvmfPkg: Update dsc to use IoLib from BaseIoLibIntrinsicSev.inf Brijesh Singh
2017-05-22 15:23 ` [PATCH v5 04/14] OvmfPkg/BaseMemcryptSevLib: Add SEV helper library Brijesh Singh
2017-05-24 13:06   ` Laszlo Ersek
2017-05-24 13:23     ` Brijesh Singh
2017-05-24 22:12     ` Brijesh Singh
2017-05-25 15:10       ` Laszlo Ersek
2017-05-25 18:23         ` Brijesh Singh
2017-05-22 15:23 ` [PATCH v5 05/14] OvmfPkg/PlatformPei: Set memory encryption PCD when SEV is enabled Brijesh Singh
2017-05-22 15:23 ` [PATCH v5 06/14] OvmfPkg:AmdSevDxe: Add AmdSevDxe driver Brijesh Singh
2017-05-24 14:17   ` Laszlo Ersek
2017-05-22 15:23 ` [PATCH v5 07/14] OvmfPkg:IoMmuDxe: Add IoMmuDxe driver Brijesh Singh
2017-05-24 15:09   ` Laszlo Ersek
2017-05-25 17:58     ` Laszlo Ersek
2017-05-25 18:56       ` Jordan Justen
2017-05-25 19:58         ` Laszlo Ersek
2017-05-22 15:23 ` [PATCH v5 08/14] OvmfPkg/QemuFwCfgLib: Provide Pei and Dxe specific library Brijesh Singh
2017-05-22 15:23 ` [PATCH v5 09/14] OvmfPkg/QemuFwCfgLib: Prepare for SEV support Brijesh Singh
2017-05-22 15:23 ` [PATCH v5 10/14] OvmfPkg/QemuFwCfgLib: Implement SEV internal function for SEC phase Brijesh Singh
2017-05-24 13:17   ` Laszlo Ersek
2017-05-22 15:23 ` [PATCH v5 11/14] OvmfPkg/QemuFwCfgLib: Implement SEV internal functions for PEI phase Brijesh Singh
2017-05-22 15:23 ` Brijesh Singh [this message]
2017-05-24 13:45   ` [PATCH v5 12/14] OvmfPkg/QemuFwCfgLib: Implement SEV internal function for Dxe phase Laszlo Ersek
2017-05-22 15:23 ` [PATCH v5 13/14] OvmfPkg/QemuFwCfgLib: Add option to dynamic alloc FW_CFG_DMA Access Brijesh Singh
2017-05-22 15:23 ` [PATCH v5 14/14] OvmfPkg/QemuFwCfgLib: Add SEV support Brijesh Singh
2017-05-24 13:55   ` Laszlo Ersek

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