[RFC PATCH 10/19] OvmfPkg: Define the Page State Change VMGEXIT structures

["Brijesh Singh" <brijesh.singh@amd.com>]

BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=3275

The Page State Change NAE exit will be used by the SEV-SNP guest to
request a page state change using the GHCB protocol. See the GHCB
spec section 4.1.6 and 2.3.1 for more detail on the structure
definitions.

Cc: James Bottomley <jejb@linux.ibm.com>
Cc: Min Xu <min.m.xu@intel.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Cc: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 MdePkg/Include/Register/Amd/Fam17Msr.h | 17 +++++++++
 MdePkg/Include/Register/Amd/Ghcb.h     | 39 +++++++++++++++++---
 2 files changed, 50 insertions(+), 6 deletions(-)

diff --git a/MdePkg/Include/Register/Amd/Fam17Msr.h b/MdePkg/Include/Register/Amd/Fam17Msr.h
index c074e871a7..084e7fb63a 100644
--- a/MdePkg/Include/Register/Amd/Fam17Msr.h
+++ b/MdePkg/Include/Register/Amd/Fam17Msr.h
@@ -53,6 +53,19 @@ typedef union {
     UINT64  GuestFrameNumber:52;
   } GhcbGpaRegister;
 
+  struct {
+    UINT64 Function:12;
+    UINT64 GuestFrameNumber:40;
+    UINT64 Operation:4;
+    UINT64 Reserved:8;
+  } SnpPageStateChangeRequest;
+
+  struct {
+    UINT32 Function:12;
+    UINT32 Reserved:20;
+    UINT32 ErrorCode;
+  } SnpPageStateChangeResponse;
+
   VOID    *Ghcb;
 
   UINT64  GhcbPhysicalAddress;
@@ -65,6 +78,10 @@ typedef union {
 #define GHCB_INFO_TERMINATE_REQUEST        256
 #define GHCB_INFO_GHCB_GPA_REGISTER_REQUEST   18
 #define GHCB_INFO_GHCB_GPA_REGISTER_RESPONSE  19
+#define GHCB_INFO_SNP_PAGE_STATE_CHANGE_REQUEST   20
+#define GHCB_INFO_SNP_PAGE_STATE_CHANGE_RESPONSE  21
+#define   SNP_PAGE_STATE_PRIVATE          1
+#define   SNP_PAGE_STATE_SHARED           2
 
 #define GHCB_TERMINATE_GHCB                0
 #define GHCB_TERMINATE_GHCB_GENERAL        0
diff --git a/MdePkg/Include/Register/Amd/Ghcb.h b/MdePkg/Include/Register/Amd/Ghcb.h
index ccdb662af7..f3c719e70e 100644
--- a/MdePkg/Include/Register/Amd/Ghcb.h
+++ b/MdePkg/Include/Register/Amd/Ghcb.h
@@ -49,12 +49,13 @@
 //
 // VMG Special Exit Codes
 //
-#define SVM_EXIT_MMIO_READ      0x80000001ULL
-#define SVM_EXIT_MMIO_WRITE     0x80000002ULL
-#define SVM_EXIT_NMI_COMPLETE   0x80000003ULL
-#define SVM_EXIT_AP_RESET_HOLD  0x80000004ULL
-#define SVM_EXIT_AP_JUMP_TABLE  0x80000005ULL
-#define SVM_EXIT_UNSUPPORTED    0x8000FFFFULL
+#define SVM_EXIT_MMIO_READ                0x80000001ULL
+#define SVM_EXIT_MMIO_WRITE               0x80000002ULL
+#define SVM_EXIT_NMI_COMPLETE             0x80000003ULL
+#define SVM_EXIT_AP_RESET_HOLD            0x80000004ULL
+#define SVM_EXIT_AP_JUMP_TABLE            0x80000005ULL
+#define SVM_EXIT_SNP_PAGE_STATE_CHANGE    0x80000010ULL
+#define SVM_EXIT_UNSUPPORTED              0x8000FFFFULL
 
 //
 // IOIO Exit Information
@@ -154,4 +155,30 @@ typedef union {
 #define GHCB_EVENT_INJECTION_TYPE_EXCEPTION  3
 #define GHCB_EVENT_INJECTION_TYPE_SOFT_INT   4
 
+#define SNP_PAGE_STATE_MAX_NPAGES           4095
+#define SNP_PAGE_STATE_MAX_ENTRY            253
+#define SNP_PAGE_STATE_PRIVATE              1
+#define SNP_PAGE_STATE_SHARED               2
+#define SNP_PAGE_STATE_PSMASH               3
+#define SNP_PAGE_STATE_UNSMASH              4
+
+typedef PACKED struct {
+  UINT64  CurrentPage:12;
+  UINT64  GuestFrameNumber:40;
+  UINT64  Op:4;
+  UINT64  PageSize:1;
+  UINT64  Rsvd: 7;
+} SNP_PAGE_STATE_ENTRY;
+
+typedef PACKED struct {
+  UINT16 CurrentEntry;
+  UINT16 EndEntry;
+  UINT32 Rsvd;
+} SNP_PAGE_STATE_HEADER;
+
+typedef struct {
+  SNP_PAGE_STATE_HEADER  Header;
+  SNP_PAGE_STATE_ENTRY   Entry[SNP_PAGE_STATE_MAX_ENTRY];
+} SNP_PAGE_STATE_CHANGE_INFO;
+
 #endif
-- 
2.17.1