[SRU][kinetic/linux-aws][PATCH 05/20] UBUNTU: SAUCE: x86/xen: add system core suspend and resume callbacks

[Gerald Yang]

From: Munehisa Kamata <kamatam at amazon.com>

BugLink: https://bugs.launchpad.net/bugs/1968062

Add Xen PVHVM specific system core callbacks for PM suspend and
hibernation support. The callbacks suspend and resume Xen primitives,
like shared_info, pvclock and grant table. Note that Xen suspend can
handle them in a different manner, but system core callbacks are called
from the context. So if the callbacks are called from Xen suspend
context, return immediately.

Signed-off-by: Munehisa Kamata <kamatam at amazon.com>
Signed-off-by: Anchal Agarwal <anchalag at amazon.com>
Reviewed-by: Munehisa Kamata <kamatam at amazon.com>
Reviewed-by: Eduardo Valentin <eduval at amazon.com>
CR: https://cr.amazon.com/r/8273204/
(cherry picked from commit bcb1b39880df2f69ec45652a88367861f96de60c amazon-5.15.y/mainline)
Signed-off-by: Gerald Yang <gerald.yang at canonical.com>
Signed-off-by: Matthew Ruffell <matthew.ruffell at canonical.com>
---
 arch/x86/xen/enlighten_hvm.c |  1 +
 arch/x86/xen/suspend.c       | 53 ++++++++++++++++++++++++++++++++++++
 include/xen/xen-ops.h        |  2 ++
 3 files changed, 56 insertions(+)

diff --git a/arch/x86/xen/enlighten_hvm.c b/arch/x86/xen/enlighten_hvm.c
index 0d6c38c767aa..ebe29d6834f6 100644
--- a/arch/x86/xen/enlighten_hvm.c
+++ b/arch/x86/xen/enlighten_hvm.c
@@ -221,6 +221,7 @@ static void __init xen_hvm_guest_init(void)
 	if (!no_vector_callback && xen_feature(XENFEAT_hvm_callback_vector))
 		xen_have_vector_callback = 1;
 
+	xen_setup_syscore_ops();
 	xen_hvm_smp_init();
 	WARN_ON(xen_cpuhp_setup(xen_cpu_up_prepare_hvm, xen_cpu_dead_hvm));
 	xen_unplug_emulated_devices();
diff --git a/arch/x86/xen/suspend.c b/arch/x86/xen/suspend.c
index 1d83152c761b..784c4484100b 100644
--- a/arch/x86/xen/suspend.c
+++ b/arch/x86/xen/suspend.c
@@ -2,17 +2,22 @@
 #include <linux/types.h>
 #include <linux/tick.h>
 #include <linux/percpu-defs.h>
+#include <linux/syscore_ops.h>
+#include <linux/kernel_stat.h>
 
 #include <xen/xen.h>
 #include <xen/interface/xen.h>
+#include <xen/interface/memory.h>
 #include <xen/grant_table.h>
 #include <xen/events.h>
+#include <xen/xen-ops.h>
 
 #include <asm/cpufeatures.h>
 #include <asm/msr-index.h>
 #include <asm/xen/hypercall.h>
 #include <asm/xen/page.h>
 #include <asm/fixmap.h>
+#include <asm/pvclock.h>
 
 #include "xen-ops.h"
 #include "mmu.h"
@@ -82,3 +87,51 @@ void xen_arch_suspend(void)
 
 	on_each_cpu(xen_vcpu_notify_suspend, NULL, 1);
 }
+
+static int xen_syscore_suspend(void)
+{
+	struct xen_remove_from_physmap xrfp;
+	int ret;
+
+	/* Xen suspend does similar stuffs in its own logic */
+	if (xen_suspend_mode_is_xen_suspend())
+		return 0;
+
+	xrfp.domid = DOMID_SELF;
+	xrfp.gpfn = __pa(HYPERVISOR_shared_info) >> PAGE_SHIFT;
+
+	ret = HYPERVISOR_memory_op(XENMEM_remove_from_physmap, &xrfp);
+	if (!ret)
+		HYPERVISOR_shared_info = &xen_dummy_shared_info;
+
+	return ret;
+}
+
+static void xen_syscore_resume(void)
+{
+	/* Xen suspend does similar stuffs in its own logic */
+	if (xen_suspend_mode_is_xen_suspend())
+		return;
+
+	/* No need to setup vcpu_info as it's already moved off */
+	xen_hvm_map_shared_info();
+
+	pvclock_resume();
+
+	gnttab_resume();
+}
+
+/*
+ * These callbacks will be called with interrupts disabled and when having only
+ * one CPU online.
+ */
+static struct syscore_ops xen_hvm_syscore_ops = {
+	.suspend = xen_syscore_suspend,
+	.resume = xen_syscore_resume
+};
+
+void __init xen_setup_syscore_ops(void)
+{
+	if (xen_hvm_domain())
+		register_syscore_ops(&xen_hvm_syscore_ops);
+}
diff --git a/include/xen/xen-ops.h b/include/xen/xen-ops.h
index d37328f2af0f..59bc4417385e 100644
--- a/include/xen/xen-ops.h
+++ b/include/xen/xen-ops.h
@@ -44,6 +44,8 @@ bool xen_suspend_mode_is_xen_suspend(void);
 bool xen_suspend_mode_is_pm_suspend(void);
 bool xen_suspend_mode_is_pm_hibernation(void);
 
+void xen_setup_syscore_ops(void);
+
 extern unsigned long *xen_contiguous_bitmap;
 
 #if defined(CONFIG_XEN_PV)
-- 
2.34.1