OvmfPkg/PvScsiDxe: Install stubbed EXT_SCSI_PASS_THRU

Support dynamic insertion and removal of the protocol.

Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=2567
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Liran Alon <liran.alon@oracle.com>
Message-Id: <20200328200100.60786-6-liran.alon@oracle.com>
Reviewed-by: Nikita Leshenko <nikita.leshchenko@oracle.com>

OvmfPkg/PvScsiDxe/PvScsi.h

@@ -0,0 +1,29 @@
+/** @file
+
+  Internal definitions for the PVSCSI driver, which produces Extended SCSI
+  Pass Thru Protocol instances for pvscsi devices.
+
+  Copyright (C) 2020, Oracle and/or its affiliates.
+
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#ifndef __PVSCSI_DXE_H_
+#define __PVSCSI_DXE_H_
+
+#include <Library/DebugLib.h>
+#include <Protocol/ScsiPassThruExt.h>
+
+#define PVSCSI_SIG SIGNATURE_32 ('P', 'S', 'C', 'S')
+
+typedef struct {
+  UINT32                          Signature;
+  EFI_EXT_SCSI_PASS_THRU_PROTOCOL PassThru;
+  EFI_EXT_SCSI_PASS_THRU_MODE     PassThruMode;
+} PVSCSI_DEV;
+
+#define PVSCSI_FROM_PASS_THRU(PassThruPointer) \
+  CR (PassThruPointer, PVSCSI_DEV, PassThru, PVSCSI_SIG)
+
+#endif // __PVSCSI_DXE_H_