OvmfPkg/XenHypercallLib: Add SchedOp hypercall

Add a new function to allow to make an hypercall to shutdown the
machine.

This import "sched.h" public header from Xen Project's repo. Some
changes have been made to be closer to EDK2's coding style.

Add the entire OvmfPkg/Include/IndustryStandard/Xen/ directory to
LicenseCheck ignore.  All the existing header files, as well as the new
sched.h, are MIT licensed.

Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Signed-off-by: Jason Andryuk <jason.andryuk@amd.com>

OvmfPkg/Include/IndustryStandard/Xen/sched.h

@@ -0,0 +1,50 @@
+/******************************************************************************
+ * sched.h
+ *
+ * Scheduler state interactions
+ *
+ * SPDX-License-Identifier: MIT
+ *
+ * Copyright (c) 2005, Keir Fraser <keir@xensource.com>
+ */
+
+#ifndef __XEN_PUBLIC_SCHED_H__
+#define __XEN_PUBLIC_SCHED_H__
+
+#include "event_channel.h"
+
+/*
+ * Halt execution of this domain (all VCPUs) and notify the system controller.
+ * @arg == pointer to sched_shutdown_t structure.
+ *
+ * If the sched_shutdown_t reason is SHUTDOWN_suspend then
+ * x86 PV guests must also set RDX (EDX for 32-bit guests) to the MFN
+ * of the guest's start info page.  RDX/EDX is the third hypercall
+ * argument.
+ *
+ * In addition, which reason is SHUTDOWN_suspend this hypercall
+ * returns 1 if suspend was cancelled or the domain was merely
+ * checkpointed, and 0 if it is resuming in a new domain.
+ */
+#define XEN_SCHEDOP_SHUTDOWN  2
+
+struct _XEN_SCHED_SHUTDOWN {
+  UINT32    Reason; /* SHUTDOWN_* => enum sched_shutdown_reason */
+};
+
+typedef struct _XEN_SCHED_SHUTDOWN XEN_SCHED_SHUTDOWN;
+DEFINE_XEN_GUEST_HANDLE (XEN_SCHED_SHUTDOWN);
+
+/*
+ * Reason codes for SCHEDOP_shutdown. These may be interpreted by control
+ * software to determine the appropriate action. For the most part, Xen does
+ * not care about the shutdown code.
+ */
+/* ` enum sched_shutdown_reason { */
+#define XEN_SHED_SHUTDOWN_POWEROFF  0  /* Domain exited normally. Clean up and kill. */
+#define XEN_SHED_SHUTDOWN_REBOOT    1  /* Clean up, kill, and then restart.          */
+#define XEN_SHED_SHUTDOWN_SUSPEND   2  /* Clean up, save suspend info, kill.         */
+#define XEN_SHED_SHUTDOWN_CRASH     3  /* Tell controller we've crashed.             */
+#define XEN_SHED_SHUTDOWN_WATCHDOG  4  /* Restart because watchdog time expired.     */
+
+#endif /* __XEN_PUBLIC_SCHED_H__ */

OvmfPkg/Include/Library/XenHypercallLib.h

@@ -101,4 +101,11 @@ XenHypercallEventChannelOp (
   IN OUT VOID  *Arguments
   );
 
+INTN
+EFIAPI
+XenHypercallSchedOp (
+  IN     INTN  Operation,
+  IN OUT VOID  *Arguments
+  );
+
 #endif

OvmfPkg/Library/XenHypercallLib/XenHypercall.c

@@ -87,3 +87,17 @@ XenHypercallEventChannelOp (
            (INTN)Arguments
            );
 }
+
+INTN
+EFIAPI
+XenHypercallSchedOp (
+  IN     INTN  Operation,
+  IN OUT VOID  *Arguments
+  )
+{
+  return XenHypercall2 (
+           __HYPERVISOR_sched_op,
+           Operation,
+           (INTN)Arguments
+           );
+}

OvmfPkg/OvmfPkg.ci.yaml

@@ -11,7 +11,8 @@
 {
     ## options defined .pytool/Plugin/LicenseCheck
     "LicenseCheck": {
-        "IgnoreFiles": []
+        ## Imported from Xen and MIT licensed.
+        "IgnoreFiles": ["OvmfPkg/Include/IndustryStandard/Xen"]
     },
     "EccCheck": {
         ## Exception sample looks like below: