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 <[email protected]> Cc: Eric Dong <[email protected]> Cc: Star Zeng <[email protected]> Cc: Laszlo Ersek <[email protected]> Cc: Justen, Jordan L <[email protected]> Cc: Kinney, Michael D <[email protected]> Cc: Wolman, Ayellet <[email protected]> Suggested-by: Wolman, Ayellet <[email protected]> Contributed-under: TianoCore Contribution Agreement 1.1 Signed-off-by: Wang, Jian J <[email protected]> --- 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 _______________________________________________ edk2-devel mailing list [email protected] https://lists.01.org/mailman/listinfo/edk2-devel
