ArmVirtualizationPkg/PciHostBridgeDxe: MMIO aperture must not be uncached

[mirror_edk2.git] / ArmPlatformPkg / ArmVirtualizationPkg / ArmVirtualizationPkg.dec

diff --git a/ArmPlatformPkg/ArmVirtualizationPkg/ArmVirtualizationPkg.dec b/ArmPlatformPkg/ArmVirtualizationPkg/ArmVirtualizationPkg.dec
index c07fce94a4797700550eb130edc11fb24050b02b..d53dab9f65e115e6e24e364a14f6bc41b0d93d13 100644 (file)
--- a/ArmPlatformPkg/ArmVirtualizationPkg/ArmVirtualizationPkg.dec
+++ b/ArmPlatformPkg/ArmVirtualizationPkg/ArmVirtualizationPkg.dec
@@ -43,5 +43,41 @@
   #\r
   gArmVirtualizationTokenSpaceGuid.PcdDeviceTreeInitialBaseAddress|0x0|UINT64|0x00000001\r
 \r
-[PcdsDynamic,PcdsFixedAtBuild]\r
+[PcdsDynamic, PcdsFixedAtBuild]\r
   gArmVirtualizationTokenSpaceGuid.PcdDeviceTreeBaseAddress|0x0|UINT64|0x00000002\r
+\r
+  #\r
+  # ARM PSCI function invocations can be done either through hypervisor\r
+  # calls (HVC) or secure monitor calls (SMC).\r
+  # PcdArmPsciMethod == 1 : use HVC\r
+  # PcdArmPsciMethod == 2 : use SMC\r
+  #\r
+  gArmVirtualizationTokenSpaceGuid.PcdArmPsciMethod|0|UINT32|0x00000003\r
+\r
+  gArmVirtualizationTokenSpaceGuid.PcdFwCfgSelectorAddress|0x0|UINT64|0x00000004\r
+  gArmVirtualizationTokenSpaceGuid.PcdFwCfgDataAddress|0x0|UINT64|0x00000005\r
+\r
+[PcdsFeatureFlag]\r
+  #\r
+  # "Map PCI MMIO as Cached"\r
+  #\r
+  # Due to the way Stage1 and Stage2 mappings are combined on Aarch64, and\r
+  # because KVM -- for the time being -- does not try to interfere with the\r
+  # Stage1 mappings, we must not set EFI_MEMORY_UC for emulated PCI MMIO\r
+  # regions.\r
+  #\r
+  # EFI_MEMORY_UC is mapped to Device-nGnRnE, and that Stage1 attribute would\r
+  # direct guest writes to host DRAM immediately, bypassing the cache\r
+  # regardless of Stage2 attributes. However, QEMU's reads of the same range\r
+  # can easily be served from the (stale) CPU cache.\r
+  #\r
+  # Setting this PCD to TRUE will use EFI_MEMORY_WB for mapping PCI MMIO\r
+  # regions, which ensures that guest writes to such regions go through the CPU\r
+  # cache. Strictly speaking this is wrong, but it is needed as a temporary\r
+  # workaround for emulated PCI devices. Setting the PCD to FALSE results in\r
+  # the theoretically correct EFI_MEMORY_UC mapping, and should be the long\r
+  # term choice, especially with assigned devices.\r
+  #\r
+  # The default is to turn off the kludge; DSC's can selectively enable it.\r
+  #\r
+  gArmVirtualizationTokenSpaceGuid.PcdKludgeMapPciMmioAsCached|FALSE|BOOLEAN|0x00000006\r