From 3ef3209d3028b77af9f56f183370e7b67cd7c849 Mon Sep 17 00:00:00 2001 From: Laszlo Ersek Date: Thu, 18 Aug 2016 11:51:33 +0200 Subject: ArmVirtPkg: remove PcdKludgeMapPciMmioAsCached In ARM/AARCH64 guests that run on KVM, we can now use virtio-gpu-pci, so PcdKludgeMapPciMmioAsCached is no longer necessary. Standard VGA continues to work on TCG without the kludge. Cc: Ard Biesheuvel Cc: Jordan Justen Ref: https://tianocore.acgmultimedia.com/show_bug.cgi?id=66 Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Laszlo Ersek Reviewed-by: Ard Biesheuvel Reviewed-by: Jordan Justen --- ArmVirtPkg/ArmVirtPkg.dec | 24 ------------------------ 1 file changed, 24 deletions(-) (limited to 'ArmVirtPkg/ArmVirtPkg.dec') diff --git a/ArmVirtPkg/ArmVirtPkg.dec b/ArmVirtPkg/ArmVirtPkg.dec index 9f98f28..a5ec421 100644 --- a/ArmVirtPkg/ArmVirtPkg.dec +++ b/ArmVirtPkg/ArmVirtPkg.dec @@ -61,30 +61,6 @@ [PcdsFeatureFlag] # - # "Map PCI MMIO as Cached" - # - # Due to the way Stage1 and Stage2 mappings are combined on Aarch64, and - # because KVM -- for the time being -- does not try to interfere with the - # Stage1 mappings, we must not set EFI_MEMORY_UC for emulated PCI MMIO - # regions. - # - # EFI_MEMORY_UC is mapped to Device-nGnRnE, and that Stage1 attribute would - # direct guest writes to host DRAM immediately, bypassing the cache - # regardless of Stage2 attributes. However, QEMU's reads of the same range - # can easily be served from the (stale) CPU cache. - # - # Setting this PCD to TRUE will use EFI_MEMORY_WB for mapping PCI MMIO - # regions, which ensures that guest writes to such regions go through the CPU - # cache. Strictly speaking this is wrong, but it is needed as a temporary - # workaround for emulated PCI devices. Setting the PCD to FALSE results in - # the theoretically correct EFI_MEMORY_UC mapping, and should be the long - # term choice, especially with assigned devices. - # - # The default is to turn off the kludge; DSC's can selectively enable it. - # - gArmVirtTokenSpaceGuid.PcdKludgeMapPciMmioAsCached|FALSE|BOOLEAN|0x00000006 - - # # Pure ACPI boot # # Inhibit installation of the FDT as a configuration table if this feature -- cgit v1.1