Xen: hibernation is x86-only at the moment

In commit 603fb42a66499ab "ARM: 8011/1: ARM hibernation / suspend-to-disk", currently in linux-next, the ARM architecture gains support for hibernation (suspend-to-disk). Xen supports this in principle, but only has an architecture specific hypercall defined on x86, which leads to a build error when both hibernation and Xen support are enabled:

drivers/xen/manage.c:105:2: error: implicit declaration of function 'HYPERVISOR_suspend' [-Werror=implicit-function-declaration]
si->cancelled = HYPERVISOR_suspend(si->arg);

It is probably a good idea to define this hypercall on ARM as well and provide an implementation in the host, but until that is done, this patch helps disable the broken code in the Xen guest by making it depend on CONFIG_X86.

In commit 603fb42a66499ab "ARM: 8011/1: ARM hibernation / suspend-to-disk", currently in linux-next, the ARM architecture gains support for hibernation (suspend-to-disk). Xen supports this in principle, but only has an architecture specific hypercall defined on x86, which leads to a build error when both hibernation and Xen support are enabled:

drivers/xen/manage.c:105:2: error: implicit declaration of function 'HYPERVISOR_suspend' [-Werror=implicit-function-declaration]
si->cancelled = HYPERVISOR_suspend(si->arg);

It is probably a good idea to define this hypercall on ARM as well and provide an implementation in the host, but until that is done, this patch helps disable the broken code in the Xen guest by making it depend on CONFIG_X86.

In commit 603fb42a66499ab "ARM: 8011/1: ARM hibernation / suspend-to-disk", currently in linux-next, the ARM architecture gains support for hibernation (suspend-to-disk). Xen supports this in principle, but only has an architecture specific hypercall defined on x86, which leads to a build error when both hibernation and Xen support are enabled:

drivers/xen/manage.c:105:2: error: implicit declaration of function 'HYPERVISOR_suspend' [-Werror=implicit-function-declaration]
si->cancelled = HYPERVISOR_suspend(si->arg);

It is probably a good idea to define this hypercall on ARM as well and provide an implementation in the host, but until that is done, this patch helps disable the broken code in the Xen guest by making it depend on CONFIG_X86.

Quoted 6 lines · Arnd Bergmann

In commit 603fb42a66499ab "ARM: 8011/1: ARM hibernation / suspend-to-disk", currently in linux-next, the ARM architecture gains support for hibernation (suspend-to-disk). Xen supports this in principle, but only has an architecture specific hypercall defined on x86, which leads to a build error when both hibernation and Xen support are enabled:

Quoted 7 lines

drivers/xen/manage.c:105:2: error: implicit declaration of function 'HYPERVISOR_suspend' [-Werror=implicit-function-declaration]
si->cancelled = HYPERVISOR_suspend(si->arg);

It is probably a good idea to define this hypercall on ARM as well and provide an implementation in the host, but until that is done, this patch helps disable the broken code in the Xen guest by making it depend on CONFIG_X86.

Since this isn't a regression in 3.15-rcX can you provide the appropriate hypercall on ARM. This does not require that there is an implementation on Xen.

When the Xen implementation exists it will be easier to use if the support already exists in Linux.

Quoted 7 lines · David Vrabel

Quoted 6 lines · Arnd Bergmann

In commit 603fb42a66499ab "ARM: 8011/1: ARM hibernation / suspend-to-disk", currently in linux-next, the ARM architecture gains support for hibernation (suspend-to-disk). Xen supports this in principle, but only has an architecture specific hypercall defined on x86, which leads to a build error when both hibernation and Xen support are enabled:

Quoted 7 lines

Quoted 7 lines

drivers/xen/manage.c:105:2: error: implicit declaration of function 'HYPERVISOR_suspend' [-Werror=implicit-function-declaration]
si->cancelled = HYPERVISOR_suspend(si->arg);

It is probably a good idea to define this hypercall on ARM as well and provide an implementation in the host, but until that is done, this patch helps disable the broken code in the Xen guest by making it depend on CONFIG_X86.

Thanks Arnd.

Quoted 6 lines

Since this isn't a regression in 3.15-rcX can you provide the appropriate hypercall on ARM. This does not require that there is an implementation on Xen.

When the Xen implementation exists it will be easier to use if the support already exists in Linux.

The sched_on hypercall is already implemented on ARM. However SCHEDOP_shutdown, defined as it is now, is unusable on ARM:

/*
* 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 this
* hypercall takes an additional extra argument which should be the
* MFN of the guest's start_info_t.
*
* 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 SCHEDOP_shutdown 2

We don't have a start_info, and even if we had, we wouldn't know the MFN.
I think we should make it available on ARM only if we change the interface making the third argument x86 only. Of course that would impact the linux side implementation too.

Quoted 45 lines · Stefano Stabellini

Quoted 7 lines · David Vrabel

Quoted 6 lines · Arnd Bergmann

In commit 603fb42a66499ab "ARM: 8011/1: ARM hibernation / suspend-to-disk", currently in linux-next, the ARM architecture gains support for hibernation (suspend-to-disk). Xen supports this in principle, but only has an architecture specific hypercall defined on x86, which leads to a build error when both hibernation and Xen support are enabled:

Quoted 7 lines

Quoted 7 lines

drivers/xen/manage.c:105:2: error: implicit declaration of function 'HYPERVISOR_suspend' [-Werror=implicit-function-declaration]
si->cancelled = HYPERVISOR_suspend(si->arg);

It is probably a good idea to define this hypercall on ARM as well and provide an implementation in the host, but until that is done, this patch helps disable the broken code in the Xen guest by making it depend on CONFIG_X86.

Thanks Arnd.

Quoted 6 lines

Since this isn't a regression in 3.15-rcX can you provide the appropriate hypercall on ARM. This does not require that there is an implementation on Xen.

When the Xen implementation exists it will be easier to use if the support already exists in Linux.

The sched_on hypercall is already implemented on ARM. However SCHEDOP_shutdown, defined as it is now, is unusable on ARM:

/*
* 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 this
* hypercall takes an additional extra argument which should be the
* MFN of the guest's start_info_t.
*
* 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 SCHEDOP_shutdown 2

Quoted 5 lines

We don't have a start_info, and even if we had, we wouldn't know the MFN.
I think we should make it available on ARM only if we change the interface making the third argument x86 only. Of course that would impact the linux side implementation too.

We do not want a different number of arguments to this hypercall. Just pass 0 for the MFN. This hypercall docs should be updated to say this.

This doesn't seem any different to x86 HVM where the start_info_mfn parameter is also not relevant.

	if (xen_hvm_domain()) {
		si.arg = 0UL;
		si.pre = NULL;
		si.post = &xen_hvm_post_suspend;
	} else {
		si.arg = virt_to_mfn(xen_start_info);
		si.pre = &xen_pre_suspend;
		si.post = &xen_post_suspend;
	}

Changing this to be !xen_pv_domain() would then do the right thing for arm.

Quoted 68 lines · David Vrabel

Quoted 45 lines · Stefano Stabellini

Quoted 7 lines · David Vrabel

Quoted 6 lines · Arnd Bergmann

In commit 603fb42a66499ab "ARM: 8011/1: ARM hibernation / suspend-to-disk", currently in linux-next, the ARM architecture gains support for hibernation (suspend-to-disk). Xen supports this in principle, but only has an architecture specific hypercall defined on x86, which leads to a build error when both hibernation and Xen support are enabled:

Quoted 7 lines

Quoted 7 lines

drivers/xen/manage.c:105:2: error: implicit declaration of function 'HYPERVISOR_suspend' [-Werror=implicit-function-declaration]
si->cancelled = HYPERVISOR_suspend(si->arg);

It is probably a good idea to define this hypercall on ARM as well and provide an implementation in the host, but until that is done, this patch helps disable the broken code in the Xen guest by making it depend on CONFIG_X86.

Thanks Arnd.

Quoted 6 lines

Since this isn't a regression in 3.15-rcX can you provide the appropriate hypercall on ARM. This does not require that there is an implementation on Xen.

When the Xen implementation exists it will be easier to use if the support already exists in Linux.

The sched_on hypercall is already implemented on ARM. However SCHEDOP_shutdown, defined as it is now, is unusable on ARM:

/*
* 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 this
* hypercall takes an additional extra argument which should be the
* MFN of the guest's start_info_t.
*
* 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 SCHEDOP_shutdown 2

Quoted 5 lines

We don't have a start_info, and even if we had, we wouldn't know the MFN.
I think we should make it available on ARM only if we change the interface making the third argument x86 only. Of course that would impact the linux side implementation too.

We do not want a different number of arguments to this hypercall. Just pass 0 for the MFN. This hypercall docs should be updated to say this.

This doesn't seem any different to x86 HVM where the start_info_mfn parameter is also not relevant.

	if (xen_hvm_domain()) {
		si.arg = 0UL;
		si.pre = NULL;
		si.post = &xen_hvm_post_suspend;
	} else {
		si.arg = virt_to_mfn(xen_start_info);
		si.pre = &xen_pre_suspend;
		si.post = &xen_post_suspend;
	}

Quoted 1 line

Changing this to be !xen_pv_domain() would then do the right thing for arm.

xen_hvm_domain returns true on arm so that's not needed. Unfortunately the patch turns out a bit ugly because of the way hypercalls are implemented in assembly on arm and arm64. Also I needed to provide quite a few empty stubs for other xen arch specific functions.

arch/arm/include/asm/xen/hypercall.h +11 -0

@@ -34,6 +34,7 @@
 #define _ASM_ARM_XEN_HYPERCALL_H
 
 #include <xen/interface/xen.h>
+#include <xen/interface/sched.h>
 
 long privcmd_call(unsigned call, unsigned long a1,
 		unsigned long a2, unsigned long a3,

@@ -48,6 +49,16 @@ int HYPERVISOR_memory_op(unsigned int cmd, void *arg);
 int HYPERVISOR_physdev_op(int cmd, void *arg);
 int HYPERVISOR_vcpu_op(int cmd, int vcpuid, void *extra_args);
 int HYPERVISOR_tmem_op(void *arg);
+int HYPERVISOR_sched_op_shutdown(int cmd, void *arg, unsigned long unused);
+
+static inline int
+HYPERVISOR_suspend(unsigned long start_info_mfn)
+{
+	struct sched_shutdown r = { .reason = SHUTDOWN_suspend };
+
+	/* start_info_mfn is unused on ARM, pass 0 instead */
+	return HYPERVISOR_sched_op_shutdown(SCHEDOP_shutdown, &r, 0);
+}
 
 static inline void
 MULTI_update_va_mapping(struct multicall_entry *mcl, unsigned long va,

arch/arm/xen/enlighten.c +0 -0

index b96723e..6d88c18 100644

Quoted 69 lines · Stefano Stabellini

Quoted 68 lines · David Vrabel

Quoted 45 lines · Stefano Stabellini

Quoted 7 lines · David Vrabel

Quoted 6 lines · Arnd Bergmann

In commit 603fb42a66499ab "ARM: 8011/1: ARM hibernation / suspend-to-disk", currently in linux-next, the ARM architecture gains support for hibernation (suspend-to-disk). Xen supports this in principle, but only has an architecture specific hypercall defined on x86, which leads to a build error when both hibernation and Xen support are enabled:

Quoted 7 lines

Quoted 7 lines

drivers/xen/manage.c:105:2: error: implicit declaration of function 'HYPERVISOR_suspend' [-Werror=implicit-function-declaration]
si->cancelled = HYPERVISOR_suspend(si->arg);

It is probably a good idea to define this hypercall on ARM as well and provide an implementation in the host, but until that is done, this patch helps disable the broken code in the Xen guest by making it depend on CONFIG_X86.

Thanks Arnd.

Quoted 6 lines

Since this isn't a regression in 3.15-rcX can you provide the appropriate hypercall on ARM. This does not require that there is an implementation on Xen.

When the Xen implementation exists it will be easier to use if the support already exists in Linux.

The sched_on hypercall is already implemented on ARM. However SCHEDOP_shutdown, defined as it is now, is unusable on ARM:

/*
* 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 this
* hypercall takes an additional extra argument which should be the
* MFN of the guest's start_info_t.
*
* 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 SCHEDOP_shutdown 2

Quoted 5 lines

We don't have a start_info, and even if we had, we wouldn't know the MFN.
I think we should make it available on ARM only if we change the interface making the third argument x86 only. Of course that would impact the linux side implementation too.

We do not want a different number of arguments to this hypercall. Just pass 0 for the MFN. This hypercall docs should be updated to say this.

This doesn't seem any different to x86 HVM where the start_info_mfn parameter is also not relevant.

	if (xen_hvm_domain()) {
		si.arg = 0UL;
		si.pre = NULL;
		si.post = &xen_hvm_post_suspend;
	} else {
		si.arg = virt_to_mfn(xen_start_info);
		si.pre = &xen_pre_suspend;
		si.post = &xen_post_suspend;
	}

Quoted 7 lines

Quoted 1 line

Changing this to be !xen_pv_domain() would then do the right thing for arm.

xen_hvm_domain returns true on arm so that's not needed. Unfortunately the patch turns out a bit ugly because of the way hypercalls are implemented in assembly on arm and arm64. Also I needed to provide quite a few empty stubs for other xen arch specific functions.

Thanks. If you want to add a commit message and apply to devel/for-linus-3.16:

Reviewed-by David Vrabel <[email protected]>

Quoted 35 lines

arch/arm/include/asm/xen/hypercall.h +11 -0

@@ -34,6 +34,7 @@
 #define _ASM_ARM_XEN_HYPERCALL_H
 
 #include <xen/interface/xen.h>
+#include <xen/interface/sched.h>
 
 long privcmd_call(unsigned call, unsigned long a1,
 		unsigned long a2, unsigned long a3,

@@ -48,6 +49,16 @@ int HYPERVISOR_memory_op(unsigned int cmd, void *arg);
 int HYPERVISOR_physdev_op(int cmd, void *arg);
 int HYPERVISOR_vcpu_op(int cmd, int vcpuid, void *extra_args);
 int HYPERVISOR_tmem_op(void *arg);
+int HYPERVISOR_sched_op_shutdown(int cmd, void *arg, unsigned long unused);
+
+static inline int
+HYPERVISOR_suspend(unsigned long start_info_mfn)
+{
+	struct sched_shutdown r = { .reason = SHUTDOWN_suspend };
+
+	/* start_info_mfn is unused on ARM, pass 0 instead */
+	return HYPERVISOR_sched_op_shutdown(SCHEDOP_shutdown, &r, 0);
+}
 
 static inline void
 MULTI_update_va_mapping(struct multicall_entry *mcl, unsigned long va,

arch/arm/xen/enlighten.c +0 -0

index b96723e..6d88c18 100644
@@ -339,6 +339,17 @@ static int __init xen_pm_init(void)
 }
 late_initcall(xen_pm_init);
 

arch/arm/xen/enlighten.c static int __init xen_pm_init(void) · line 348

Quoted 7 lines

arch/arm/xen/enlighten.c +7 -0

+
+/* empty stubs */
+void xen_arch_pre_suspend(void) { }
+void xen_arch_post_suspend(int suspend_cancelled) { }
+void xen_arch_hvm_post_suspend(int suspend_cancelled) { }
+void xen_mm_pin_all(void) { }
+void xen_mm_unpin_all(void) { }

I wonder if the calls to xen_mm_pin_all() and xen_mm_unpin_all() could be moved into the arch_pre_suspend() and arch_post_suspend() calls instead. So there wouldn't need to be stubs provided for arm.

Quoted 69 lines · Stefano Stabellini

Quoted 68 lines · David Vrabel

Quoted 45 lines · Stefano Stabellini

Quoted 7 lines · David Vrabel

Quoted 6 lines · Arnd Bergmann

In commit 603fb42a66499ab "ARM: 8011/1: ARM hibernation / suspend-to-disk", currently in linux-next, the ARM architecture gains support for hibernation (suspend-to-disk). Xen supports this in principle, but only has an architecture specific hypercall defined on x86, which leads to a build error when both hibernation and Xen support are enabled:

Quoted 7 lines

Quoted 7 lines

drivers/xen/manage.c:105:2: error: implicit declaration of function 'HYPERVISOR_suspend' [-Werror=implicit-function-declaration]
si->cancelled = HYPERVISOR_suspend(si->arg);

It is probably a good idea to define this hypercall on ARM as well and provide an implementation in the host, but until that is done, this patch helps disable the broken code in the Xen guest by making it depend on CONFIG_X86.

Thanks Arnd.

Quoted 6 lines

Since this isn't a regression in 3.15-rcX can you provide the appropriate hypercall on ARM. This does not require that there is an implementation on Xen.

When the Xen implementation exists it will be easier to use if the support already exists in Linux.

The sched_on hypercall is already implemented on ARM. However SCHEDOP_shutdown, defined as it is now, is unusable on ARM:

/*
* 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 this
* hypercall takes an additional extra argument which should be the
* MFN of the guest's start_info_t.
*
* 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 SCHEDOP_shutdown 2

Quoted 5 lines

We don't have a start_info, and even if we had, we wouldn't know the MFN.
I think we should make it available on ARM only if we change the interface making the third argument x86 only. Of course that would impact the linux side implementation too.

We do not want a different number of arguments to this hypercall. Just pass 0 for the MFN. This hypercall docs should be updated to say this.

This doesn't seem any different to x86 HVM where the start_info_mfn parameter is also not relevant.

	if (xen_hvm_domain()) {
		si.arg = 0UL;
		si.pre = NULL;
		si.post = &xen_hvm_post_suspend;
	} else {
		si.arg = virt_to_mfn(xen_start_info);
		si.pre = &xen_pre_suspend;
		si.post = &xen_post_suspend;
	}

Quoted 7 lines

Quoted 1 line

Changing this to be !xen_pv_domain() would then do the right thing for arm.

xen_hvm_domain returns true on arm so that's not needed. Unfortunately the patch turns out a bit ugly because of the way hypercalls are implemented in assembly on arm and arm64. Also I needed to provide quite a few empty stubs for other xen arch specific functions.

Thanks. If you want to add a commit message and apply to devel/for-linus-3.16:

Reviewed-by David Vrabel <[email protected]>

Quoted 35 lines

arch/arm/include/asm/xen/hypercall.h +11 -0

@@ -34,6 +34,7 @@
 #define _ASM_ARM_XEN_HYPERCALL_H
 
 #include <xen/interface/xen.h>
+#include <xen/interface/sched.h>
 
 long privcmd_call(unsigned call, unsigned long a1,
 		unsigned long a2, unsigned long a3,

@@ -48,6 +49,16 @@ int HYPERVISOR_memory_op(unsigned int cmd, void *arg);
 int HYPERVISOR_physdev_op(int cmd, void *arg);
 int HYPERVISOR_vcpu_op(int cmd, int vcpuid, void *extra_args);
 int HYPERVISOR_tmem_op(void *arg);
+int HYPERVISOR_sched_op_shutdown(int cmd, void *arg, unsigned long unused);
+
+static inline int
+HYPERVISOR_suspend(unsigned long start_info_mfn)
+{
+	struct sched_shutdown r = { .reason = SHUTDOWN_suspend };
+
+	/* start_info_mfn is unused on ARM, pass 0 instead */
+	return HYPERVISOR_sched_op_shutdown(SCHEDOP_shutdown, &r, 0);
+}
 
 static inline void
 MULTI_update_va_mapping(struct multicall_entry *mcl, unsigned long va,

arch/arm/xen/enlighten.c +0 -0

index b96723e..6d88c18 100644
@@ -339,6 +339,17 @@ static int __init xen_pm_init(void)
 }
 late_initcall(xen_pm_init);
 

arch/arm/xen/enlighten.c static int __init xen_pm_init(void) · line 348

Quoted 7 lines

arch/arm/xen/enlighten.c +7 -0

+
+/* empty stubs */
+void xen_arch_pre_suspend(void) { }
+void xen_arch_post_suspend(int suspend_cancelled) { }
+void xen_arch_hvm_post_suspend(int suspend_cancelled) { }
+void xen_mm_pin_all(void) { }
+void xen_mm_unpin_all(void) { }

I wonder if the calls to xen_mm_pin_all() and xen_mm_unpin_all() could be moved into the arch_pre_suspend() and arch_post_suspend() calls instead. So there wouldn't need to be stubs provided for arm.

Quoted 68 lines · David Vrabel

Quoted 45 lines · Stefano Stabellini

Quoted 7 lines · David Vrabel

Quoted 6 lines · Arnd Bergmann

In commit 603fb42a66499ab "ARM: 8011/1: ARM hibernation / suspend-to-disk", currently in linux-next, the ARM architecture gains support for hibernation (suspend-to-disk). Xen supports this in principle, but only has an architecture specific hypercall defined on x86, which leads to a build error when both hibernation and Xen support are enabled:

Quoted 7 lines

Quoted 7 lines

drivers/xen/manage.c:105:2: error: implicit declaration of function 'HYPERVISOR_suspend' [-Werror=implicit-function-declaration]
si->cancelled = HYPERVISOR_suspend(si->arg);

It is probably a good idea to define this hypercall on ARM as well and provide an implementation in the host, but until that is done, this patch helps disable the broken code in the Xen guest by making it depend on CONFIG_X86.

Thanks Arnd.

Quoted 6 lines

Since this isn't a regression in 3.15-rcX can you provide the appropriate hypercall on ARM. This does not require that there is an implementation on Xen.

When the Xen implementation exists it will be easier to use if the support already exists in Linux.

The sched_on hypercall is already implemented on ARM. However SCHEDOP_shutdown, defined as it is now, is unusable on ARM:

/*
* 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 this
* hypercall takes an additional extra argument which should be the
* MFN of the guest's start_info_t.
*
* 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 SCHEDOP_shutdown 2

Quoted 5 lines

We don't have a start_info, and even if we had, we wouldn't know the MFN.
I think we should make it available on ARM only if we change the interface making the third argument x86 only. Of course that would impact the linux side implementation too.

We do not want a different number of arguments to this hypercall. Just pass 0 for the MFN. This hypercall docs should be updated to say this.

This doesn't seem any different to x86 HVM where the start_info_mfn parameter is also not relevant.

	if (xen_hvm_domain()) {
		si.arg = 0UL;
		si.pre = NULL;
		si.post = &xen_hvm_post_suspend;
	} else {
		si.arg = virt_to_mfn(xen_start_info);
		si.pre = &xen_pre_suspend;
		si.post = &xen_post_suspend;
	}

Quoted 1 line

Changing this to be !xen_pv_domain() would then do the right thing for arm.

xen_hvm_domain returns true on arm so that's not needed. Unfortunately the patch turns out a bit ugly because of the way hypercalls are implemented in assembly on arm and arm64. Also I needed to provide quite a few empty stubs for other xen arch specific functions.

arch/arm/include/asm/xen/hypercall.h +11 -0

@@ -34,6 +34,7 @@
 #define _ASM_ARM_XEN_HYPERCALL_H
 
 #include <xen/interface/xen.h>
+#include <xen/interface/sched.h>
 
 long privcmd_call(unsigned call, unsigned long a1,
 		unsigned long a2, unsigned long a3,

@@ -48,6 +49,16 @@ int HYPERVISOR_memory_op(unsigned int cmd, void *arg);
 int HYPERVISOR_physdev_op(int cmd, void *arg);
 int HYPERVISOR_vcpu_op(int cmd, int vcpuid, void *extra_args);
 int HYPERVISOR_tmem_op(void *arg);
+int HYPERVISOR_sched_op_shutdown(int cmd, void *arg, unsigned long unused);
+
+static inline int
+HYPERVISOR_suspend(unsigned long start_info_mfn)
+{
+	struct sched_shutdown r = { .reason = SHUTDOWN_suspend };
+
+	/* start_info_mfn is unused on ARM, pass 0 instead */
+	return HYPERVISOR_sched_op_shutdown(SCHEDOP_shutdown, &r, 0);
+}
 
 static inline void
 MULTI_update_va_mapping(struct multicall_entry *mcl, unsigned long va,

arch/arm/xen/enlighten.c +0 -0

index b96723e..6d88c18 100644

Quoted 45 lines · Stefano Stabellini

Quoted 7 lines · David Vrabel

Quoted 6 lines · Arnd Bergmann

In commit 603fb42a66499ab "ARM: 8011/1: ARM hibernation / suspend-to-disk", currently in linux-next, the ARM architecture gains support for hibernation (suspend-to-disk). Xen supports this in principle, but only has an architecture specific hypercall defined on x86, which leads to a build error when both hibernation and Xen support are enabled:

Quoted 7 lines

Quoted 7 lines

drivers/xen/manage.c:105:2: error: implicit declaration of function 'HYPERVISOR_suspend' [-Werror=implicit-function-declaration]
si->cancelled = HYPERVISOR_suspend(si->arg);

It is probably a good idea to define this hypercall on ARM as well and provide an implementation in the host, but until that is done, this patch helps disable the broken code in the Xen guest by making it depend on CONFIG_X86.

Thanks Arnd.

Quoted 6 lines

Since this isn't a regression in 3.15-rcX can you provide the appropriate hypercall on ARM. This does not require that there is an implementation on Xen.

When the Xen implementation exists it will be easier to use if the support already exists in Linux.

The sched_on hypercall is already implemented on ARM. However SCHEDOP_shutdown, defined as it is now, is unusable on ARM:

/*
* 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 this
* hypercall takes an additional extra argument which should be the
* MFN of the guest's start_info_t.
*
* 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 SCHEDOP_shutdown 2

Quoted 5 lines

We don't have a start_info, and even if we had, we wouldn't know the MFN.
I think we should make it available on ARM only if we change the interface making the third argument x86 only. Of course that would impact the linux side implementation too.

We do not want a different number of arguments to this hypercall. Just pass 0 for the MFN. This hypercall docs should be updated to say this.

This doesn't seem any different to x86 HVM where the start_info_mfn parameter is also not relevant.

	if (xen_hvm_domain()) {
		si.arg = 0UL;
		si.pre = NULL;
		si.post = &xen_hvm_post_suspend;
	} else {
		si.arg = virt_to_mfn(xen_start_info);
		si.pre = &xen_pre_suspend;
		si.post = &xen_post_suspend;
	}

Changing this to be !xen_pv_domain() would then do the right thing for arm.

Quoted 7 lines · David Vrabel

Quoted 6 lines · Arnd Bergmann

In commit 603fb42a66499ab "ARM: 8011/1: ARM hibernation / suspend-to-disk", currently in linux-next, the ARM architecture gains support for hibernation (suspend-to-disk). Xen supports this in principle, but only has an architecture specific hypercall defined on x86, which leads to a build error when both hibernation and Xen support are enabled:

Quoted 7 lines

Quoted 7 lines

drivers/xen/manage.c:105:2: error: implicit declaration of function 'HYPERVISOR_suspend' [-Werror=implicit-function-declaration]
si->cancelled = HYPERVISOR_suspend(si->arg);

It is probably a good idea to define this hypercall on ARM as well and provide an implementation in the host, but until that is done, this patch helps disable the broken code in the Xen guest by making it depend on CONFIG_X86.

Thanks Arnd.

Quoted 6 lines

Since this isn't a regression in 3.15-rcX can you provide the appropriate hypercall on ARM. This does not require that there is an implementation on Xen.

When the Xen implementation exists it will be easier to use if the support already exists in Linux.

The sched_on hypercall is already implemented on ARM. However SCHEDOP_shutdown, defined as it is now, is unusable on ARM:

/*
* 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 this
* hypercall takes an additional extra argument which should be the
* MFN of the guest's start_info_t.
*
* 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 SCHEDOP_shutdown 2

We don't have a start_info, and even if we had, we wouldn't know the MFN.
I think we should make it available on ARM only if we change the interface making the third argument x86 only. Of course that would impact the linux side implementation too.

Quoted 6 lines · Arnd Bergmann

In commit 603fb42a66499ab "ARM: 8011/1: ARM hibernation / suspend-to-disk", currently in linux-next, the ARM architecture gains support for hibernation (suspend-to-disk). Xen supports this in principle, but only has an architecture specific hypercall defined on x86, which leads to a build error when both hibernation and Xen support are enabled:

Quoted 7 lines

drivers/xen/manage.c:105:2: error: implicit declaration of function 'HYPERVISOR_suspend' [-Werror=implicit-function-declaration]
si->cancelled = HYPERVISOR_suspend(si->arg);

It is probably a good idea to define this hypercall on ARM as well and provide an implementation in the host, but until that is done, this patch helps disable the broken code in the Xen guest by making it depend on CONFIG_X86.

Since this isn't a regression in 3.15-rcX can you provide the appropriate hypercall on ARM. This does not require that there is an implementation on Xen.

When the Xen implementation exists it will be easier to use if the support already exists in Linux.

In commit 603fb42a66499ab "ARM: 8011/1: ARM hibernation / suspend-to-disk", currently in linux-next, the ARM architecture gains support for hibernation (suspend-to-disk). Xen supports this in principle, but only has an architecture specific hypercall defined on x86, which leads to a build error when both hibernation and Xen support are enabled:

drivers/xen/manage.c:105:2: error: implicit declaration of function 'HYPERVISOR_suspend' [-Werror=implicit-function-declaration]
si->cancelled = HYPERVISOR_suspend(si->arg);

It is probably a good idea to define this hypercall on ARM as well and provide an implementation in the host, but until that is done, this patch helps disable the broken code in the Xen guest by making it depend on CONFIG_X86.