OvmfPkg: Introduce XenPlatformPei

Introduce XenPlatformPei, a copy of OvmfPkg/PlatformPei without some
of QEMU specific initialization, Xen does not support QemuFwCfg.

This new module will be adjusted to accommodate Xen PVH.

fw_cfg dependents that have been removed, which are dynamically skipped
when running PlatformPei on Xen:
- GetFirstNonAddress(): controlling the 64-bit PCI MMIO aperture via the
(experimental) "opt/ovmf/X-PciMmio64Mb" file
- GetFirstNonAddress(): honoring the hotplug DIMM area
("etc/reserved-memory-end") in the placement of the 64-bit PCI MMIO
aperture
- NoexecDxeInitialization() is removed, so PcdPropertiesTableEnable and
PcdSetNxForStack are left constant FALSE (not set dynamically from
fw_cfg "opt/ovmf/PcdXxxx")
- MaxCpuCountInitialization(), PublishPeiMemory(): the max CPU count is
not taken from the QemuFwCfgItemSmpCpuCount fw_cfg key;
PcdCpuMaxLogicalProcessorNumber is used intact and
PcdCpuApInitTimeOutInMicroSeconds is never changed or used.
- InitializeXenPlatform(), S3Verification(): S3 is assumed disabled (not
consulting "etc/system-states" via QemuFwCfgS3Enabled()).
- InstallFeatureControlCallback(): the feature control MSR is not set
from "etc/msr_feature_control"
(also removed FeatureControl.c as there is nothing been executed)

Also removed:
- SMRAM/TSEG-related low mem size adjusting (PcdSmmSmramRequire is
assumed FALSE) in PublishPeiMemory(),
- QemuInitializeRam() entirely,

Xen related changes:
- Have removed the module variable mXen, as it should be always true.
- Have the platform PEI initialization fails if Xen has not been
  detected.

Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=1689
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Message-Id: <20190813113119.14804-5-anthony.perard@citrix.com>

OvmfPkg/XenPlatformPei/Xen.c

@@ -0,0 +1,219 @@
+/**@file
+  Xen Platform PEI support
+
+  Copyright (c) 2006 - 2016, Intel Corporation. All rights reserved.<BR>
+  Copyright (c) 2011, Andrei Warkentin <andreiw@motorola.com>
+  Copyright (c) 2019, Citrix Systems, Inc.
+
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+//
+// The package level header files this module uses
+//
+#include <PiPei.h>
+
+//
+// The Library classes this module consumes
+//
+#include <Library/DebugLib.h>
+#include <Library/HobLib.h>
+#include <Library/MemoryAllocationLib.h>
+#include <Library/PcdLib.h>
+#include <Guid/XenInfo.h>
+#include <IndustryStandard/E820.h>
+#include <Library/ResourcePublicationLib.h>
+#include <Library/MtrrLib.h>
+
+#include "Platform.h"
+#include "Xen.h"
+
+STATIC UINT32 mXenLeaf = 0;
+
+EFI_XEN_INFO mXenInfo;
+
+/**
+  Returns E820 map provided by Xen
+
+  @param Entries      Pointer to E820 map
+  @param Count        Number of entries
+
+  @return EFI_STATUS
+**/
+EFI_STATUS
+XenGetE820Map (
+  EFI_E820_ENTRY64 **Entries,
+  UINT32 *Count
+  )
+{
+  EFI_XEN_OVMF_INFO *Info =
+    (EFI_XEN_OVMF_INFO *)(UINTN) OVMF_INFO_PHYSICAL_ADDRESS;
+
+  if (AsciiStrCmp ((CHAR8 *) Info->Signature, "XenHVMOVMF")) {
+    return EFI_NOT_FOUND;
+  }
+
+  ASSERT (Info->E820 < MAX_ADDRESS);
+  *Entries = (EFI_E820_ENTRY64 *)(UINTN) Info->E820;
+  *Count = Info->E820EntriesCount;
+
+  return EFI_SUCCESS;
+}
+
+/**
+  Connects to the Hypervisor.
+
+  @param  XenLeaf     CPUID index used to connect.
+
+  @return EFI_STATUS
+
+**/
+EFI_STATUS
+XenConnect (
+  UINT32 XenLeaf
+  )
+{
+  UINT32 Index;
+  UINT32 TransferReg;
+  UINT32 TransferPages;
+  UINT32 XenVersion;
+
+  AsmCpuid (XenLeaf + 2, &TransferPages, &TransferReg, NULL, NULL);
+  mXenInfo.HyperPages = AllocatePages (TransferPages);
+  if (!mXenInfo.HyperPages) {
+    return EFI_OUT_OF_RESOURCES;
+  }
+
+  for (Index = 0; Index < TransferPages; Index++) {
+    AsmWriteMsr64 (TransferReg,
+                   (UINTN) mXenInfo.HyperPages +
+                   (Index << EFI_PAGE_SHIFT) + Index);
+  }
+
+  AsmCpuid (XenLeaf + 1, &XenVersion, NULL, NULL, NULL);
+  DEBUG ((DEBUG_ERROR, "Detected Xen version %d.%d\n",
+          XenVersion >> 16, XenVersion & 0xFFFF));
+  mXenInfo.VersionMajor = (UINT16)(XenVersion >> 16);
+  mXenInfo.VersionMinor = (UINT16)(XenVersion & 0xFFFF);
+
+  /* TBD: Locate hvm_info and reserve it away. */
+  mXenInfo.HvmInfo = NULL;
+
+  BuildGuidDataHob (
+    &gEfiXenInfoGuid,
+    &mXenInfo,
+    sizeof(mXenInfo)
+    );
+
+  return EFI_SUCCESS;
+}
+
+/**
+  Figures out if we are running inside Xen HVM.
+
+  @retval TRUE   Xen was detected
+  @retval FALSE  Xen was not detected
+
+**/
+BOOLEAN
+XenDetect (
+  VOID
+  )
+{
+  UINT8 Signature[13];
+
+  if (mXenLeaf != 0) {
+    return TRUE;
+  }
+
+  Signature[12] = '\0';
+  for (mXenLeaf = 0x40000000; mXenLeaf < 0x40010000; mXenLeaf += 0x100) {
+    AsmCpuid (mXenLeaf,
+              NULL,
+              (UINT32 *) &Signature[0],
+              (UINT32 *) &Signature[4],
+              (UINT32 *) &Signature[8]);
+
+    if (!AsciiStrCmp ((CHAR8 *) Signature, "XenVMMXenVMM")) {
+      return TRUE;
+    }
+  }
+
+  mXenLeaf = 0;
+  return FALSE;
+}
+
+
+VOID
+XenPublishRamRegions (
+  VOID
+  )
+{
+  EFI_E820_ENTRY64  *E820Map;
+  UINT32            E820EntriesCount;
+  EFI_STATUS        Status;
+
+  DEBUG ((DEBUG_INFO, "Using memory map provided by Xen\n"));
+
+  //
+  // Parse RAM in E820 map
+  //
+  E820EntriesCount = 0;
+  Status = XenGetE820Map (&E820Map, &E820EntriesCount);
+
+  ASSERT_EFI_ERROR (Status);
+
+  if (E820EntriesCount > 0) {
+    EFI_E820_ENTRY64 *Entry;
+    UINT32 Loop;
+
+    for (Loop = 0; Loop < E820EntriesCount; Loop++) {
+      Entry = E820Map + Loop;
+
+      //
+      // Only care about RAM
+      //
+      if (Entry->Type != EfiAcpiAddressRangeMemory) {
+        continue;
+      }
+
+      AddMemoryBaseSizeHob (Entry->BaseAddr, Entry->Length);
+
+      MtrrSetMemoryAttribute (Entry->BaseAddr, Entry->Length, CacheWriteBack);
+    }
+  }
+}
+
+
+/**
+  Perform Xen PEI initialization.
+
+  @return EFI_SUCCESS     Xen initialized successfully
+  @return EFI_NOT_FOUND   Not running under Xen
+
+**/
+EFI_STATUS
+InitializeXen (
+  VOID
+  )
+{
+  RETURN_STATUS PcdStatus;
+
+  if (mXenLeaf == 0) {
+    return EFI_NOT_FOUND;
+  }
+
+  XenConnect (mXenLeaf);
+
+  //
+  // Reserve away HVMLOADER reserved memory [0xFC000000,0xFD000000).
+  // This needs to match HVMLOADER RESERVED_MEMBASE/RESERVED_MEMSIZE.
+  //
+  AddReservedMemoryBaseSizeHob (0xFC000000, 0x1000000, FALSE);
+
+  PcdStatus = PcdSetBoolS (PcdPciDisableBusEnumeration, TRUE);
+  ASSERT_RETURN_ERROR (PcdStatus);
+
+  return EFI_SUCCESS;
+}