[v2,04/11] x86/xen: add system core suspend and resume callbacks

Commit Message

Anchal Agarwal July 2, 2020, 6:22 p.m. UTC

From: Munehisa Kamata <[e-mail]>

Add Xen PVHVM specific system core callbacks for PM
hibernation support. The callbacks suspend and resume
Xen primitives like shared_info, pvclock and grant table.
These syscore_ops are specifically for domU hibernation.
xen_suspend() calls syscore_suspend() during Xen suspend
operation however, during xen suspend lock_system_sleep()
lock is taken and thus system cannot trigger hibernation.
These system core callbacks will be called only from the
hibernation context.

[Anchal Agarwal: Changelog]:
v1->v2: Edit commit message
        Fixed syscore_suspend() to call gnntab_suspend
	Removed suspend mode check in syscore_suspend()/
	syscore_resume()
Signed-off-by: Agarwal Anchal <[e-mail]>
Signed-off-by: Munehisa Kamata <[e-mail]>
---
 arch/x86/xen/enlighten_hvm.c |  1 +
 arch/x86/xen/suspend.c       | 47 ++++++++++++++++++++++++++++++++++++
 include/xen/xen-ops.h        |  2 ++
 3 files changed, 50 insertions(+)

Comments

Julien Grall July 22, 2020, 9:08 a.m. UTC | #1

Hi,

On 02/07/2020 19:22, Anchal Agarwal wrote:
> diff --git a/include/xen/xen-ops.h b/include/xen/xen-ops.h
> index 2521d6a306cd..9fa8a4082d68 100644
> --- a/include/xen/xen-ops.h
> +++ b/include/xen/xen-ops.h
> @@ -41,6 +41,8 @@ u64 xen_steal_clock(int cpu);
>   int xen_setup_shutdown_event(void);
>   
>   bool xen_is_xen_suspend(void);
> +void xen_setup_syscore_ops(void);

The function is only implemented and used by x86. So shouldn't this be 
declared in an x86 header?

Cheers,

Patch

diff --git a/arch/x86/xen/enlighten_hvm.c b/arch/x86/xen/enlighten_hvm.c
index d91099928746..bd6bf6eb2052 100644
--- a/arch/x86/xen/enlighten_hvm.c
+++ b/arch/x86/xen/enlighten_hvm.c
@@ -215,6 +215,7 @@  static void __init xen_hvm_guest_init(void)
 	if (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..e8c924e93fc5 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 +87,45 @@  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;
+
+	gnttab_suspend();
+
+	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)
+{
+	/* 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 2521d6a306cd..9fa8a4082d68 100644
--- a/include/xen/xen-ops.h
+++ b/include/xen/xen-ops.h
@@ -41,6 +41,8 @@  u64 xen_steal_clock(int cpu);
 int xen_setup_shutdown_event(void);
 
 bool xen_is_xen_suspend(void);
+void xen_setup_syscore_ops(void);
+
 extern unsigned long *xen_contiguous_bitmap;
 
 #if defined(CONFIG_XEN_PV) || defined(CONFIG_ARM) || defined(CONFIG_ARM64)