[PATCH v4 12/35] OvmfPkg/XenPlatformPei: Grab RSDP from PVH guest start of day struct

["Anthony PERARD" <anthony.perard@citrix.com>]

Check if there's a start of the day struct provided to PVH guest, save
the ACPI RSDP address for later.

This patch import import arch-x86/hvm/start_info.h from xen.git.

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

Notes:
    v3:
    - use SPDX
    - use SIGNATURE_32
    - fix coding style

 OvmfPkg/XenPlatformPei/XenPlatformPei.inf     |   3 +
 OvmfPkg/Include/Guid/XenInfo.h                |   4 +
 .../Xen/arch-x86/hvm/start_info.h             | 143 ++++++++++++++++++
 OvmfPkg/XenPlatformPei/Xen.c                  |  25 +++
 4 files changed, 175 insertions(+)
 create mode 100644 OvmfPkg/Include/IndustryStandard/Xen/arch-x86/hvm/start_info.h

diff --git a/OvmfPkg/XenPlatformPei/XenPlatformPei.inf b/OvmfPkg/XenPlatformPei/XenPlatformPei.inf
index d1265c365a..4d00206d09 100644
--- a/OvmfPkg/XenPlatformPei/XenPlatformPei.inf
+++ b/OvmfPkg/XenPlatformPei/XenPlatformPei.inf
@@ -84,6 +84,9 @@ [Pcd]
   gEfiSecurityPkgTokenSpaceGuid.PcdOptionRomImageVerificationPolicy
   gUefiCpuPkgTokenSpaceGuid.PcdCpuLocalApicBaseAddress
 
+  gUefiOvmfPkgTokenSpaceGuid.PcdXenPvhStartOfDayStructPtr
+  gUefiOvmfPkgTokenSpaceGuid.PcdXenPvhStartOfDayStructPtrSize
+
 [FixedPcd]
   gEfiMdePkgTokenSpaceGuid.PcdPciExpressBaseAddress
 
diff --git a/OvmfPkg/Include/Guid/XenInfo.h b/OvmfPkg/Include/Guid/XenInfo.h
index b052d618fd..25743b3884 100644
--- a/OvmfPkg/Include/Guid/XenInfo.h
+++ b/OvmfPkg/Include/Guid/XenInfo.h
@@ -25,6 +25,10 @@ typedef struct {
   /// Hypervisor minor version.
   ///
   UINT16 VersionMinor;
+  ///
+  /// Pointer to the RSDP found in the hvm_start_info provided to a PVH guest
+  ///
+  VOID *RsdpPvh;
 } EFI_XEN_INFO;
 
 extern EFI_GUID gEfiXenInfoGuid;
diff --git a/OvmfPkg/Include/IndustryStandard/Xen/arch-x86/hvm/start_info.h b/OvmfPkg/Include/IndustryStandard/Xen/arch-x86/hvm/start_info.h
new file mode 100644
index 0000000000..15708d6dd5
--- /dev/null
+++ b/OvmfPkg/Include/IndustryStandard/Xen/arch-x86/hvm/start_info.h
@@ -0,0 +1,143 @@
+/*
+ * SPDX-License-Identifier: MIT
+ *
+ * Copyright (c) 2016, Citrix Systems, Inc.
+ */
+
+#ifndef __XEN_PUBLIC_ARCH_X86_HVM_START_INFO_H__
+#define __XEN_PUBLIC_ARCH_X86_HVM_START_INFO_H__
+
+/*
+ * Start of day structure passed to PVH guests and to HVM guests in %ebx.
+ *
+ * NOTE: nothing will be loaded at physical address 0, so a 0 value in any
+ * of the address fields should be treated as not present.
+ *
+ *  0 +----------------+
+ *    | magic          | Contains the magic value XEN_HVM_START_MAGIC_VALUE
+ *    |                | ("xEn3" with the 0x80 bit of the "E" set).
+ *  4 +----------------+
+ *    | version        | Version of this structure. Current version is 1. New
+ *    |                | versions are guaranteed to be backwards-compatible.
+ *  8 +----------------+
+ *    | flags          | SIF_xxx flags.
+ * 12 +----------------+
+ *    | nr_modules     | Number of modules passed to the kernel.
+ * 16 +----------------+
+ *    | modlist_paddr  | Physical address of an array of modules
+ *    |                | (layout of the structure below).
+ * 24 +----------------+
+ *    | cmdline_paddr  | Physical address of the command line,
+ *    |                | a zero-terminated ASCII string.
+ * 32 +----------------+
+ *    | rsdp_paddr     | Physical address of the RSDP ACPI data structure.
+ * 40 +----------------+
+ *    | memmap_paddr   | Physical address of the (optional) memory map. Only
+ *    |                | present in version 1 and newer of the structure.
+ * 48 +----------------+
+ *    | memmap_entries | Number of entries in the memory map table. Zero
+ *    |                | if there is no memory map being provided. Only
+ *    |                | present in version 1 and newer of the structure.
+ * 52 +----------------+
+ *    | reserved       | Version 1 and newer only.
+ * 56 +----------------+
+ *
+ * The layout of each entry in the module structure is the following:
+ *
+ *  0 +----------------+
+ *    | paddr          | Physical address of the module.
+ *  8 +----------------+
+ *    | size           | Size of the module in bytes.
+ * 16 +----------------+
+ *    | cmdline_paddr  | Physical address of the command line,
+ *    |                | a zero-terminated ASCII string.
+ * 24 +----------------+
+ *    | reserved       |
+ * 32 +----------------+
+ *
+ * The layout of each entry in the memory map table is as follows:
+ *
+ *  0 +----------------+
+ *    | addr           | Base address
+ *  8 +----------------+
+ *    | size           | Size of mapping in bytes
+ * 16 +----------------+
+ *    | type           | Type of mapping as defined between the hypervisor
+ *    |                | and guest. See XEN_HVM_MEMMAP_TYPE_* values below.
+ * 20 +----------------|
+ *    | reserved       |
+ * 24 +----------------+
+ *
+ * The address and sizes are always a 64bit little endian unsigned integer.
+ *
+ * NB: Xen on x86 will always try to place all the data below the 4GiB
+ * boundary.
+ *
+ * Version numbers of the hvm_start_info structure have evolved like this:
+ *
+ * Version 0:  Initial implementation.
+ *
+ * Version 1:  Added the memmap_paddr/memmap_entries fields (plus 4 bytes of
+ *             padding) to the end of the hvm_start_info struct. These new
+ *             fields can be used to pass a memory map to the guest. The
+ *             memory map is optional and so guests that understand version 1
+ *             of the structure must check that memmap_entries is non-zero
+ *             before trying to read the memory map.
+ */
+#define XEN_HVM_START_MAGIC_VALUE 0x336ec578
+
+/*
+ * The values used in the type field of the memory map table entries are
+ * defined below and match the Address Range Types as defined in the "System
+ * Address Map Interfaces" section of the ACPI Specification. Please refer to
+ * section 15 in version 6.2 of the ACPI spec: http://uefi.org/specifications
+ */
+#define XEN_HVM_MEMMAP_TYPE_RAM       1
+#define XEN_HVM_MEMMAP_TYPE_RESERVED  2
+#define XEN_HVM_MEMMAP_TYPE_ACPI      3
+#define XEN_HVM_MEMMAP_TYPE_NVS       4
+#define XEN_HVM_MEMMAP_TYPE_UNUSABLE  5
+#define XEN_HVM_MEMMAP_TYPE_DISABLED  6
+#define XEN_HVM_MEMMAP_TYPE_PMEM      7
+
+/*
+ * C representation of the x86/HVM start info layout.
+ *
+ * The canonical definition of this layout is above, this is just a way to
+ * represent the layout described there using C types.
+ */
+struct hvm_start_info {
+    UINT32 magic;             /* Contains the magic value 0x336ec578       */
+                              /* ("xEn3" with the 0x80 bit of the "E" set).*/
+    UINT32 version;           /* Version of this structure.                */
+    UINT32 flags;             /* SIF_xxx flags.                            */
+    UINT32 nr_modules;        /* Number of modules passed to the kernel.   */
+    UINT64 modlist_paddr;     /* Physical address of an array of           */
+                              /* hvm_modlist_entry.                        */
+    UINT64 cmdline_paddr;     /* Physical address of the command line.     */
+    UINT64 rsdp_paddr;        /* Physical address of the RSDP ACPI data    */
+                              /* structure.                                */
+    /* All following fields only present in version 1 and newer */
+    UINT64 memmap_paddr;      /* Physical address of an array of           */
+                              /* hvm_memmap_table_entry.                   */
+    UINT32 memmap_entries;    /* Number of entries in the memmap table.    */
+                              /* Value will be zero if there is no memory  */
+                              /* map being provided.                       */
+    UINT32 reserved;          /* Must be zero.                             */
+};
+
+struct hvm_modlist_entry {
+    UINT64 paddr;             /* Physical address of the module.           */
+    UINT64 size;              /* Size of the module in bytes.              */
+    UINT64 cmdline_paddr;     /* Physical address of the command line.     */
+    UINT64 reserved;
+};
+
+struct hvm_memmap_table_entry {
+    UINT64 addr;              /* Base address of the memory region         */
+    UINT64 size;              /* Size of the memory region in bytes        */
+    UINT32 type;              /* Mapping type                              */
+    UINT32 reserved;          /* Must be zero for Version 1.               */
+};
+
+#endif /* __XEN_PUBLIC_ARCH_X86_HVM_START_INFO_H__ */
diff --git a/OvmfPkg/XenPlatformPei/Xen.c b/OvmfPkg/XenPlatformPei/Xen.c
index 5c7d7ddc1c..b366139a0a 100644
--- a/OvmfPkg/XenPlatformPei/Xen.c
+++ b/OvmfPkg/XenPlatformPei/Xen.c
@@ -25,6 +25,7 @@
 #include <IndustryStandard/E820.h>
 #include <Library/ResourcePublicationLib.h>
 #include <Library/MtrrLib.h>
+#include <IndustryStandard/Xen/arch-x86/hvm/start_info.h>
 
 #include "Platform.h"
 #include "Xen.h"
@@ -86,6 +87,7 @@ XenConnect (
   UINT32 XenVersion;
   EFI_XEN_OVMF_INFO *Info;
   CHAR8 Sig[sizeof (Info->Signature) + 1];
+  UINT32 *PVHResetVectorData;
 
   AsmCpuid (XenLeaf + 2, &TransferPages, &TransferReg, NULL, NULL);
   mXenInfo.HyperPages = AllocatePages (TransferPages);
@@ -121,6 +123,29 @@ XenConnect (
     mXenHvmloaderInfo = NULL;
   }
 
+  mXenInfo.RsdpPvh = NULL;
+
+  //
+  // Locate and use information from the start of day structure if we have
+  // booted via the PVH entry point.
+  //
+
+  PVHResetVectorData = (VOID *)(UINTN) PcdGet32 (PcdXenPvhStartOfDayStructPtr);
+  //
+  // That magic value is written in XenResetVector/Ia32/XenPVHMain.asm
+  //
+  if (PVHResetVectorData[1] == SIGNATURE_32 ('X', 'P', 'V', 'H')) {
+    struct hvm_start_info *HVMStartInfo;
+
+    HVMStartInfo = (VOID *)(UINTN) PVHResetVectorData[0];
+    if (HVMStartInfo->magic == XEN_HVM_START_MAGIC_VALUE) {
+      ASSERT (HVMStartInfo->rsdp_paddr != 0);
+      if (HVMStartInfo->rsdp_paddr != 0) {
+        mXenInfo.RsdpPvh = (VOID *)(UINTN)HVMStartInfo->rsdp_paddr;
+      }
+    }
+  }
+
   BuildGuidDataHob (
     &gEfiXenInfoGuid,
     &mXenInfo,
-- 
Anthony PERARD