From c1d1910be6e04a8b1a73090cf2881fb698947a6e Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Mon, 17 Jun 2024 17:07:41 +0200 Subject: OvmfPkg/QemuVideoDxe: add feature PCD to remap framebuffer W/C Some platforms (such as SBSA-QEMU on recent builds of the emulator) only tolerate misaligned accesses to normal memory, and raise alignment faults on such accesses to device memory, which is the default for PCIe MMIO BARs. When emulating a PCIe graphics controller, the framebuffer is typically exposed via a MMIO BAR, while the disposition of the region is closer to memory (no side effects on reads or writes, except for the changing picture on the screen; direct random access to any pixel in the image). In order to permit the use of such controllers on platforms that only tolerate these types of accesses for normal memory, it is necessary to remap the memory. Use the DXE services to set the desired capabilities and attributes. Hide this behavior under a feature PCD so only platforms that really need it can enable it. (OVMF on x86 has no need for this) Signed-off-by: Ard Biesheuvel --- OvmfPkg/OvmfPkg.dec | 5 +++++ OvmfPkg/QemuVideoDxe/Gop.c | 19 +++++++++++++++++++ OvmfPkg/QemuVideoDxe/Qemu.h | 2 +- OvmfPkg/QemuVideoDxe/QemuVideoDxe.inf | 4 ++++ 4 files changed, 29 insertions(+), 1 deletion(-) diff --git a/OvmfPkg/OvmfPkg.dec b/OvmfPkg/OvmfPkg.dec index e1ef8420ce..c1c8198061 100644 --- a/OvmfPkg/OvmfPkg.dec +++ b/OvmfPkg/OvmfPkg.dec @@ -449,3 +449,8 @@ ## This feature flag indicates the firmware build supports secure boot. gUefiOvmfPkgTokenSpaceGuid.PcdSecureBootSupported|FALSE|BOOLEAN|0x6d + + ## Whether QemuVideoDxe should perform a EFI_MEMORY_WC remap of the PCI + # framebuffer. This might be required on platforms that do not tolerate + # misaligned accesses otherwise. + gUefiOvmfPkgTokenSpaceGuid.PcdRemapFrameBufferWriteCombine|FALSE|BOOLEAN|0x75 diff --git a/OvmfPkg/QemuVideoDxe/Gop.c b/OvmfPkg/QemuVideoDxe/Gop.c index b11eed7558..a29c025afd 100644 --- a/OvmfPkg/QemuVideoDxe/Gop.c +++ b/OvmfPkg/QemuVideoDxe/Gop.c @@ -9,6 +9,8 @@ #include "Qemu.h" +#include + STATIC VOID QemuVideoCompleteModeInfo ( @@ -54,6 +56,7 @@ QemuVideoCompleteModeData ( EFI_GRAPHICS_OUTPUT_MODE_INFORMATION *Info; EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR *FrameBufDesc; QEMU_VIDEO_MODE_DATA *ModeData; + EFI_STATUS Status; ModeData = &Private->ModeData[Mode->Mode]; Info = Mode->Info; @@ -79,6 +82,22 @@ QemuVideoCompleteModeData ( (UINT64)Mode->FrameBufferSize )); + if (FeaturePcdGet (PcdRemapFrameBufferWriteCombine)) { + Status = gDS->SetMemorySpaceCapabilities ( + FrameBufDesc->AddrRangeMin, + FrameBufDesc->AddrLen, + EFI_MEMORY_UC | EFI_MEMORY_WC | EFI_MEMORY_XP + ); + ASSERT_EFI_ERROR (Status); + + Status = gDS->SetMemorySpaceAttributes ( + FrameBufDesc->AddrRangeMin, + FrameBufDesc->AddrLen, + EFI_MEMORY_WC | EFI_MEMORY_XP + ); + ASSERT_EFI_ERROR (Status); + } + FreePool (FrameBufDesc); return EFI_SUCCESS; } diff --git a/OvmfPkg/QemuVideoDxe/Qemu.h b/OvmfPkg/QemuVideoDxe/Qemu.h index bd6198dd50..3a190ae0b1 100644 --- a/OvmfPkg/QemuVideoDxe/Qemu.h +++ b/OvmfPkg/QemuVideoDxe/Qemu.h @@ -13,7 +13,7 @@ #ifndef _QEMU_H_ #define _QEMU_H_ -#include +#include #include #include #include diff --git a/OvmfPkg/QemuVideoDxe/QemuVideoDxe.inf b/OvmfPkg/QemuVideoDxe/QemuVideoDxe.inf index 6b7baa8525..4f11365423 100644 --- a/OvmfPkg/QemuVideoDxe/QemuVideoDxe.inf +++ b/OvmfPkg/QemuVideoDxe/QemuVideoDxe.inf @@ -40,6 +40,7 @@ [LibraryClasses] BaseMemoryLib + DxeServicesTableLib FrameBufferBltLib DebugLib DevicePathLib @@ -57,6 +58,9 @@ gEfiDevicePathProtocolGuid # PROTOCOL BY_START gEfiPciIoProtocolGuid # PROTOCOL TO_START +[FeaturePcd] + gUefiOvmfPkgTokenSpaceGuid.PcdRemapFrameBufferWriteCombine + [Pcd] gUefiOvmfPkgTokenSpaceGuid.PcdOvmfHostBridgePciDevId gUefiOvmfPkgTokenSpaceGuid.PcdVideoResolutionSource -- cgit v1.2.3