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From: "Johnson, Brian (EXL - Eagan)" <brian.johnson@hpe.com>
To: "Wang, Jian J" <jian.j.wang@intel.com>,
	"edk2-devel@lists.01.org" <edk2-devel@lists.01.org>
Cc: "Justen@ml01.01.org" <Justen@ml01.01.org>,
	Eric Dong <eric.dong@intel.com>,
	"Kinney@ml01.01.org" <Kinney@ml01.01.org>,
	Jordan L <jordan.l.justen@intel.com>,
	"Wolman@ml01.01.org" <Wolman@ml01.01.org>,
	Jiewen Yao <jiewen.yao@intel.com>,
	Ayellet <ayellet.wolman@intel.com>,
	Michael D <michael.d.kinney@intel.com>,
	Laszlo Ersek <lersek@redhat.com>, Star Zeng <star.zeng@intel.com>
Subject: Re: [PATCH 4/4] OvmfPkg/QemuVideoDxe: Update QemuVideoDxe driver to bypass NULL pointer detection if enabled.
Date: Wed, 13 Sep 2017 16:33:44 +0000	[thread overview]
Message-ID: <DF4PR84MB0155CEA90D87B23EBC9E8F68E16E0@DF4PR84MB0155.NAMPRD84.PROD.OUTLOOK.COM> (raw)
In-Reply-To: <20170913092507.12504-5-jian.j.wang@intel.com>

Acked-by: Brian J. Johnson <brian.johnson@hpe.com>

-----Original Message-----
From: edk2-devel [mailto:edk2-devel-bounces@lists.01.org] On Behalf Of Wang, Jian J
Sent: Wednesday, September 13, 2017 4:25 AM
To: edk2-devel@lists.01.org
Cc: Justen@ml01.01.org; Eric Dong <eric.dong@intel.com>; Kinney@ml01.01.org; Jordan L <jordan.l.justen@intel.com>; Wolman@ml01.01.org; Jiewen Yao <jiewen.yao@intel.com>; Ayellet <ayellet.wolman@intel.com>; Michael D <michael.d.kinney@intel.com>; Laszlo Ersek <lersek@redhat.com>; Star Zeng <star.zeng@intel.com>
Subject: [edk2] [PATCH 4/4] OvmfPkg/QemuVideoDxe: Update QemuVideoDxe driver to bypass NULL pointer detection if enabled.

QemuVideoDxe driver will install VBE SHIM into page 0. If NULL pointer detection is enabled, page 0 must be enabled temporarily before installing and disabled again afterwards. For Windows 7 boot, BIT7 of PcdNullPointerDetectionPropertyMask must still be set to avoid hang.

Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Eric Dong <eric.dong@intel.com>
Cc: Star Zeng <star.zeng@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Justen, Jordan L <jordan.l.justen@intel.com>
Cc: Kinney, Michael D <michael.d.kinney@intel.com>
Cc: Wolman, Ayellet <ayellet.wolman@intel.com>
Suggested-by: Wolman, Ayellet <ayellet.wolman@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Wang, Jian J <jian.j.wang@intel.com>
---
 OvmfPkg/QemuVideoDxe/Driver.c         | 15 ++++++++++++++-
 OvmfPkg/QemuVideoDxe/Qemu.h           | 16 ++++++++++++++++
 OvmfPkg/QemuVideoDxe/QemuVideoDxe.inf |  2 ++
 3 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/OvmfPkg/QemuVideoDxe/Driver.c b/OvmfPkg/QemuVideoDxe/Driver.c
index 0dce80e59b..ee0eed7214 100644
--- a/OvmfPkg/QemuVideoDxe/Driver.c
+++ b/OvmfPkg/QemuVideoDxe/Driver.c
@@ -194,6 +194,7 @@ QemuVideoControllerDriverStart (
   PCI_TYPE00                        Pci;
   QEMU_VIDEO_CARD                   *Card;
   EFI_PCI_IO_PROTOCOL               *ChildPciIo;
+  EFI_CPU_ARCH_PROTOCOL             *Cpu;
 
   OldTpl = gBS->RaiseTPL (TPL_CALLBACK);
 
@@ -479,7 +480,19 @@ QemuVideoControllerDriverStart (
 #if defined MDE_CPU_IA32 || defined MDE_CPU_X64
   if (Private->Variant == QEMU_VIDEO_BOCHS_MMIO ||
       Private->Variant == QEMU_VIDEO_BOCHS) {
-    InstallVbeShim (Card->Name, Private->GraphicsOutput.Mode->FrameBufferBase);
+    //
+    // Prepare CPU arch protocol for NULL pointer detection
+    //
+    Status = gBS->LocateProtocol (
+                    &gEfiCpuArchProtocolGuid,
+                    NULL, 
+                    (VOID **) &Cpu
+                    );
+    ASSERT_EFI_ERROR (Status);
+
+    DISABLE_NULL_DETECTION(Cpu);
+      InstallVbeShim (Card->Name, Private->GraphicsOutput.Mode->FrameBufferBase);
+    ENABLE_NULL_DETECTION(Cpu);
   }
 #endif
 
diff --git a/OvmfPkg/QemuVideoDxe/Qemu.h b/OvmfPkg/QemuVideoDxe/Qemu.h
index 7fbb25b3ef..bb3bc6eb0f 100644
--- a/OvmfPkg/QemuVideoDxe/Qemu.h
+++ b/OvmfPkg/QemuVideoDxe/Qemu.h
@@ -25,6 +25,7 @@
 #include <Protocol/PciIo.h>
 #include <Protocol/DriverSupportedEfiVersion.h>
 #include <Protocol/DevicePath.h>
+#include <Protocol/Cpu.h>
 
 #include <Library/DebugLib.h>
 #include <Library/UefiDriverEntryPoint.h>
@@ -82,6 +83,21 @@ typedef struct {
 
 #define GRAPHICS_OUTPUT_INVALIDE_MODE_NUMBER  0xffff
 
+//
+// VBE code will access memory between 0-4095 which will cause page fault exception 
+// if NULL pointer detection mechanism is enabled. Following macros can be used to 
+// disable/enable NULL pointer detection before/after accessing those memory.
+//
+#define NULL_DETECTION_ENABLED  ((PcdGet8(PcdNullPointerDetectionPropertyMask) & (BIT0|BIT7)) == BIT0)
+#define DISABLE_NULL_DETECTION(Cpu)                                             \
+  if (NULL_DETECTION_ENABLED) {                                                 \
+    (Cpu)->SetMemoryAttributes((Cpu), 0, EFI_PAGE_SIZE, 0);                     \
+  }
+#define ENABLE_NULL_DETECTION(Cpu)                                              \
+  if (NULL_DETECTION_ENABLED) {                                                 \
+    (Cpu)->SetMemoryAttributes((Cpu), 0, EFI_PAGE_SIZE, EFI_MEMORY_RP);         \
+  }
+
 //
 // QEMU Video Private Data Structure
 //
diff --git a/OvmfPkg/QemuVideoDxe/QemuVideoDxe.inf b/OvmfPkg/QemuVideoDxe/QemuVideoDxe.inf
index 7c7d429bca..5d166eb99c 100644
--- a/OvmfPkg/QemuVideoDxe/QemuVideoDxe.inf
+++ b/OvmfPkg/QemuVideoDxe/QemuVideoDxe.inf
@@ -72,7 +72,9 @@
   gEfiGraphicsOutputProtocolGuid                # PROTOCOL BY_START
   gEfiDevicePathProtocolGuid                    # PROTOCOL BY_START
   gEfiPciIoProtocolGuid                         # PROTOCOL TO_START
+  gEfiCpuArchProtocolGuid
 
 [Pcd]
   gOptionRomPkgTokenSpaceGuid.PcdDriverSupportedEfiVersion
+  gEfiMdeModulePkgTokenSpaceGuid.PcdNullPointerDetectionPropertyMask
 
-- 
2.14.1.windows.1

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  reply	other threads:[~2017-09-13 16:30 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <Implement NULL pointer detection feature>
2017-09-13  9:25 ` [PATCH 0/4] Implement NULL pointer detection feature for special pool Wang, Jian J
2017-09-13  9:25   ` [PATCH 1/4] MdeModulePkg/Core: Implement NULL pointer detection in EDK-II Core Wang, Jian J
2017-09-13 16:33     ` Johnson, Brian (EXL - Eagan)
2017-09-14  1:37       ` Wang, Jian J
2017-09-13 17:28     ` Jordan Justen
2017-09-14  1:25       ` Wang, Jian J
2017-09-14  6:33         ` Jordan Justen
2017-09-14  6:51           ` Wang, Jian J
2017-09-14  8:22             ` Laszlo Ersek
2017-09-13  9:25   ` [PATCH 2/4] UefiCpuPkg/PiSmmCpuDxeSmm: Implement NULL pointer detection for SMM mode code Wang, Jian J
2017-09-13 16:33     ` Johnson, Brian (EXL - Eagan)
2017-09-14  1:31       ` Wang, Jian J
2017-09-13 17:31     ` Jordan Justen
2017-09-14  1:20       ` Wang, Jian J
2017-09-13  9:25   ` [PATCH 3/4] IntelFrameworkModulePkg/Csm: Update CSM code to temporarily bypass NULL pointer detection if enabled Wang, Jian J
2017-09-13 16:33     ` Johnson, Brian (EXL - Eagan)
2017-09-13  9:25   ` [PATCH 4/4] OvmfPkg/QemuVideoDxe: Update QemuVideoDxe driver to " Wang, Jian J
2017-09-13 16:33     ` Johnson, Brian (EXL - Eagan) [this message]
2017-09-13 23:34     ` Laszlo Ersek
2017-09-14  1:17       ` Wang, Jian J
2017-09-14  3:17         ` Wang, Jian J
2017-09-14  8:30           ` Laszlo Ersek
2017-09-14  8:38             ` Yao, Jiewen
2017-09-14  8:46               ` Wang, Jian J
2017-09-14  8:48                 ` Yao, Jiewen
2017-09-14  8:54                 ` Laszlo Ersek
2017-09-14  9:39                   ` Zeng, Star
2017-09-14  9:55                     ` Laszlo Ersek
2017-09-14 10:16                       ` Zeng, Star
2017-09-15  0:15                         ` Wang, Jian J
2017-09-15  6:05                           ` Wang, Jian J
2017-09-15  6:28                             ` Zeng, Star
2017-09-14  8:52               ` Laszlo Ersek
2017-09-14  5:50         ` Jordan Justen
2017-09-14  6:52           ` Wang, Jian J
2017-09-14  8:26         ` Laszlo Ersek
2017-09-13  8:07 Wang, Jian J

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