[PATCH v3 4/4] OvmfPkg: don't assign PCI BARs above 4GiB when CSM enabled

["David Woodhouse" <dwmw2@infradead.org>]

Mostly, this is only necessary for devices that the CSM might have
native support for, such as VirtIO and NVMe; PciBusDxe will already
degrade devices to 32-bit if they have an OpROM.

However, there doesn't seem to be a generic way of requesting PciBusDxe
to downgrade specific devices.

There's IncompatiblePciDeviceSupportProtocol but that doesn't provide
the PCI class information or a handle to the device itself, so there's
no simple way to just match on all NVMe devices, for example.

Just leave gUefiOvmfPkgTokenSpaceGuid.PcdPciMmio64Size set to zero for
CSM builds, until/unless that can be fixed.

Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
---
 OvmfPkg/OvmfPkgIa32X64.dsc | 4 ++++
 OvmfPkg/OvmfPkgX64.dsc     | 4 ++++
 2 files changed, 8 insertions(+)

diff --git a/OvmfPkg/OvmfPkgIa32X64.dsc b/OvmfPkg/OvmfPkgIa32X64.dsc
index 639e33cb285f..ad20531ceb8b 100644
--- a/OvmfPkg/OvmfPkgIa32X64.dsc
+++ b/OvmfPkg/OvmfPkgIa32X64.dsc
@@ -543,7 +543,11 @@ [PcdsDynamicDefault]
   gUefiOvmfPkgTokenSpaceGuid.PcdPciMmio32Base|0x0
   gUefiOvmfPkgTokenSpaceGuid.PcdPciMmio32Size|0x0
   gUefiOvmfPkgTokenSpaceGuid.PcdPciMmio64Base|0x0
+!ifdef $(CSM_ENABLE)
+  gUefiOvmfPkgTokenSpaceGuid.PcdPciMmio64Size|0x0
+!else
   gUefiOvmfPkgTokenSpaceGuid.PcdPciMmio64Size|0x800000000
+!endif
 
   gEfiMdePkgTokenSpaceGuid.PcdPlatformBootTimeOut|0
 
diff --git a/OvmfPkg/OvmfPkgX64.dsc b/OvmfPkg/OvmfPkgX64.dsc
index 69a3497c2c9e..0542ac2235b4 100644
--- a/OvmfPkg/OvmfPkgX64.dsc
+++ b/OvmfPkg/OvmfPkgX64.dsc
@@ -542,7 +542,11 @@ [PcdsDynamicDefault]
   gUefiOvmfPkgTokenSpaceGuid.PcdPciMmio32Base|0x0
   gUefiOvmfPkgTokenSpaceGuid.PcdPciMmio32Size|0x0
   gUefiOvmfPkgTokenSpaceGuid.PcdPciMmio64Base|0x0
+!ifdef $(CSM_ENABLE)
+  gUefiOvmfPkgTokenSpaceGuid.PcdPciMmio64Size|0x0
+!else
   gUefiOvmfPkgTokenSpaceGuid.PcdPciMmio64Size|0x800000000
+!endif
 
   gEfiMdePkgTokenSpaceGuid.PcdPlatformBootTimeOut|0
 
-- 
2.21.0