[Help] UEFI boot KVM4T vm hang On TianoCore

[Hangaohuai <hangaohuai@huawei.com>]

Hi, Laszlo Ersek;

I have tested the uefi booting KVM vm with the configuration(xml); but start hang.
Enable the memoryhotplug, with usb3.0 config. The config as Config1 below.

Tested branches:
UDK2017     eea98eea4ccbb1d640657770bccb5497fddc6064
Master       76fd5a660d704538a1b14a58d03a4eef9682b01c

Both hang on the snapshot TianoCore in VNC

Try to shoot the problem;
I find the early version can boot success with the same config.
Maybe the patch1 below cause the problem;

Try to ignore the patch does, the master/ UDK2017 both can boot success.
But I don't know why. Hope for your help,thanks.

Patch1
***********************************************
commit 4f5eff8193096eb847639f090a7dfae3cff95fde
Author: Laszlo Ersek <lersek@redhat.com>
Date:   Fri Mar 4 20:06:26 2016 +0100

OvmfPkg: PciHostBridgeLib: install 64-bit PCI host aperture

diff --git a/OvmfPkg/Library/PciHostBridgeLib/PciHostBridgeLib.c b/OvmfPkg/Library/PciHostBridgeLib/PciHostBridgeLib
index 3e02778..1d3d10a 100644
--- a/OvmfPkg/Library/PciHostBridgeLib/PciHostBridgeLib.c
+++ b/OvmfPkg/Library/PciHostBridgeLib/PciHostBridgeLib.c
@@ -132,6 +132,13 @@ InitRootBridge (
   RootBus->MemAbove4G.Base      = 0;
   RootBus->MemAbove4G.Limit     = 0;
+  if (PcdGet64 (PcdPciMmio64Size) > 0) {
+    RootBus->AllocationAttributes |= EFI_PCI_HOST_BRIDGE_MEM64_DECODE;
+    RootBus->MemAbove4G.Base       = PcdGet64 (PcdPciMmio64Base);
+    RootBus->MemAbove4G.Limit      = PcdGet64 (PcdPciMmio64Base) +
+                                     (PcdGet64 (PcdPciMmio64Size) - 1);
+  }
+
   RootBus->Bus.Base  = RootBusNumber;
   RootBus->Bus.Limit = MaxSubBusNumber;
   RootBus->Io.Base   = PcdGet64 (PcdPciIoBase);
diff --git a/OvmfPkg/Library/PciHostBridgeLib/PciHostBridgeLib.inf b/OvmfPkg/Library/PciHostBridgeLib/PciHostBridgeL
index bbec746..7a964c7 100644
--- a/OvmfPkg/Library/PciHostBridgeLib/PciHostBridgeLib.inf
+++ b/OvmfPkg/Library/PciHostBridgeLib/PciHostBridgeLib.inf
@@ -51,4 +51,6 @@
   gUefiOvmfPkgTokenSpaceGuid.PcdPciIoSize
   gUefiOvmfPkgTokenSpaceGuid.PcdPciMmio32Base
   gUefiOvmfPkgTokenSpaceGuid.PcdPciMmio32Size
+  gUefiOvmfPkgTokenSpaceGuid.PcdPciMmio64Base
+  gUefiOvmfPkgTokenSpaceGuid.PcdPciMmio64Size
   gUefiOvmfPkgTokenSpaceGuid.PcdOvmfHostBridgePciDevId
***********************************************


Config1
***********************************************
<maxMemory slots='256' unit='KiB'>4294967296</maxMemory>
  <memory unit='KiB'>4294967</memory>
  <currentMemory unit='KiB'>4294967</currentMemory>
Xxxx
<controller type='usb' index='2' model='nec-xhci'>
    <address type='pci' domain='0x0000' bus='0x00' slot='0x1c' function='0x0'/>
 </controller>
***********************************************