[PATCH v2 0/3] Additional refactoring of Hyper-V arch specific code

[PATCH v2 0/3] Additional refactoring of Hyper-V arch specific code

[Michael Kelley]

This patch set moves additional Hyper-V code under arch/x86 into
arch-neutral hv_common.c where it can be shared by x86 and
and ARM64 implementations.  The move reduces the overall lines
of code across both architectures, and removes code under
arch/ that isn't really architecture-specific.

The code is moved into hv_common.c because it must be
built-in to the kernel image, and not be part of a module.

No functional changes are intended.

---
Changes in v2:
* Fixed problem when building with CONFIG_HYPERV=n
  (reported by kernel test robot <lkp@intel.com>)


Michael Kelley (3):
  Drivers: hv: Make portions of Hyper-V init code be arch neutral
  Drivers: hv: Add arch independent default functions for some Hyper-V
    handlers
  Drivers: hv: Move Hyper-V misc functionality to arch-neutral code

 arch/x86/hyperv/hv_init.c       | 101 +++-----------------
 arch/x86/include/asm/mshyperv.h |   4 -
 arch/x86/kernel/cpu/mshyperv.c  |  20 ----
 drivers/hv/hv_common.c          | 205 ++++++++++++++++++++++++++++++++++++++++
 include/asm-generic/mshyperv.h  |  10 ++
 5 files changed, 226 insertions(+), 114 deletions(-)

-- 
1.8.3.1

[PATCH v2 1/3] Drivers: hv: Make portions of Hyper-V init code be arch neutral

[Michael Kelley]

The code to allocate and initialize the hv_vp_index array is
architecture neutral. Similarly, the code to allocate and
populate the hypercall input and output arg pages is architecture
neutral.  Move both sets of code out from arch/x86 and into
utility functions in drivers/hv/hv_common.c that can be shared
by Hyper-V initialization on ARM64.

No functional changes. However, the allocation of the hypercall
input and output arg pages is done differently so that the
size is always the Hyper-V page size, even if not the same as
the guest page size (such as with ARM64's 64K page size).

Signed-off-by: Michael Kelley <mikelley@microsoft.com>

---
Changes in v2:
* Re-added definitions of hv_root_partition and ms_hyperv in
  arch/x86/kernel/cpu/mshyperv.c so that it will compile
  even when CONFIG_HYPERV=n. But also kept definitions in
  hv_common.c (marked as __weak) since this is really where
  they should live for sharing across architectures.  At
  some point in the future we may revisit the assumptions on
  the x86 side that lead to them being needed even when
  CONFIG_HYPERV=n.

---
 arch/x86/hyperv/hv_init.c       |  91 +++-----------------------
 arch/x86/include/asm/mshyperv.h |   4 --
 arch/x86/kernel/cpu/mshyperv.c  |   3 -
 drivers/hv/hv_common.c          | 138 ++++++++++++++++++++++++++++++++++++++++
 include/asm-generic/mshyperv.h  |  10 +++
 5 files changed, 158 insertions(+), 88 deletions(-)

diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index 6952e21..5cc0c0f 100644
--- a/arch/x86/hyperv/hv_init.c
+++ b/arch/x86/hyperv/hv_init.c
@@ -39,48 +39,17 @@
 /* Storage to save the hypercall page temporarily for hibernation */
 static void *hv_hypercall_pg_saved;
 
-u32 *hv_vp_index;
-EXPORT_SYMBOL_GPL(hv_vp_index);
-
 struct hv_vp_assist_page **hv_vp_assist_page;
 EXPORT_SYMBOL_GPL(hv_vp_assist_page);
 
-void  __percpu **hyperv_pcpu_input_arg;
-EXPORT_SYMBOL_GPL(hyperv_pcpu_input_arg);
-
-void  __percpu **hyperv_pcpu_output_arg;
-EXPORT_SYMBOL_GPL(hyperv_pcpu_output_arg);
-
-u32 hv_max_vp_index;
-EXPORT_SYMBOL_GPL(hv_max_vp_index);
-
 static int hv_cpu_init(unsigned int cpu)
 {
-	u64 msr_vp_index;
 	struct hv_vp_assist_page **hvp = &hv_vp_assist_page[smp_processor_id()];
-	void **input_arg;
-	struct page *pg;
-
-	/* hv_cpu_init() can be called with IRQs disabled from hv_resume() */
-	pg = alloc_pages(irqs_disabled() ? GFP_ATOMIC : GFP_KERNEL, hv_root_partition ? 1 : 0);
-	if (unlikely(!pg))
-		return -ENOMEM;
-
-	input_arg = (void **)this_cpu_ptr(hyperv_pcpu_input_arg);
-	*input_arg = page_address(pg);
-	if (hv_root_partition) {
-		void **output_arg;
-
-		output_arg = (void **)this_cpu_ptr(hyperv_pcpu_output_arg);
-		*output_arg = page_address(pg + 1);
-	}
-
-	msr_vp_index = hv_get_register(HV_REGISTER_VP_INDEX);
-
-	hv_vp_index[smp_processor_id()] = msr_vp_index;
+	int ret;
 
-	if (msr_vp_index > hv_max_vp_index)
-		hv_max_vp_index = msr_vp_index;
+	ret = hv_common_cpu_init(cpu);
+	if (ret)
+		return ret;
 
 	if (!hv_vp_assist_page)
 		return 0;
@@ -198,25 +167,8 @@ static int hv_cpu_die(unsigned int cpu)
 {
 	struct hv_reenlightenment_control re_ctrl;
 	unsigned int new_cpu;
-	unsigned long flags;
-	void **input_arg;
-	void *pg;
 
-	local_irq_save(flags);
-	input_arg = (void **)this_cpu_ptr(hyperv_pcpu_input_arg);
-	pg = *input_arg;
-	*input_arg = NULL;
-
-	if (hv_root_partition) {
-		void **output_arg;
-
-		output_arg = (void **)this_cpu_ptr(hyperv_pcpu_output_arg);
-		*output_arg = NULL;
-	}
-
-	local_irq_restore(flags);
-
-	free_pages((unsigned long)pg, hv_root_partition ? 1 : 0);
+	hv_common_cpu_die(cpu);
 
 	if (hv_vp_assist_page && hv_vp_assist_page[cpu])
 		wrmsrl(HV_X64_MSR_VP_ASSIST_PAGE, 0);
@@ -368,7 +320,7 @@ void __init hyperv_init(void)
 {
 	u64 guest_id, required_msrs;
 	union hv_x64_msr_hypercall_contents hypercall_msr;
-	int cpuhp, i;
+	int cpuhp;
 
 	if (x86_hyper_type != X86_HYPER_MS_HYPERV)
 		return;
@@ -380,36 +332,14 @@ void __init hyperv_init(void)
 	if ((ms_hyperv.features & required_msrs) != required_msrs)
 		return;
 
-	/*
-	 * Allocate the per-CPU state for the hypercall input arg.
-	 * If this allocation fails, we will not be able to setup
-	 * (per-CPU) hypercall input page and thus this failure is
-	 * fatal on Hyper-V.
-	 */
-	hyperv_pcpu_input_arg = alloc_percpu(void  *);
-
-	BUG_ON(hyperv_pcpu_input_arg == NULL);
-
-	/* Allocate the per-CPU state for output arg for root */
-	if (hv_root_partition) {
-		hyperv_pcpu_output_arg = alloc_percpu(void *);
-		BUG_ON(hyperv_pcpu_output_arg == NULL);
-	}
-
-	/* Allocate percpu VP index */
-	hv_vp_index = kmalloc_array(num_possible_cpus(), sizeof(*hv_vp_index),
-				    GFP_KERNEL);
-	if (!hv_vp_index)
+	if (hv_common_init())
 		return;
 
-	for (i = 0; i < num_possible_cpus(); i++)
-		hv_vp_index[i] = VP_INVAL;
-
 	hv_vp_assist_page = kcalloc(num_possible_cpus(),
 				    sizeof(*hv_vp_assist_page), GFP_KERNEL);
 	if (!hv_vp_assist_page) {
 		ms_hyperv.hints &= ~HV_X64_ENLIGHTENED_VMCS_RECOMMENDED;
-		goto free_vp_index;
+		goto common_free;
 	}
 
 	cpuhp = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/hyperv_init:online",
@@ -507,9 +437,8 @@ void __init hyperv_init(void)
 free_vp_assist_page:
 	kfree(hv_vp_assist_page);
 	hv_vp_assist_page = NULL;
-free_vp_index:
-	kfree(hv_vp_index);
-	hv_vp_index = NULL;
+common_free:
+	hv_common_free();
 }
 
 /*
diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index 67ff0d6..adccbc20 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -36,8 +36,6 @@ static inline u64 hv_get_register(unsigned int reg)
 extern int hyperv_init_cpuhp;
 
 extern void *hv_hypercall_pg;
-extern void  __percpu  **hyperv_pcpu_input_arg;
-extern void  __percpu  **hyperv_pcpu_output_arg;
 
 extern u64 hv_current_partition_id;
 
@@ -170,8 +168,6 @@ int hyperv_fill_flush_guest_mapping_list(
 		struct hv_guest_mapping_flush_list *flush,
 		u64 start_gfn, u64 end_gfn);
 
-extern bool hv_root_partition;
-
 #ifdef CONFIG_X86_64
 void hv_apic_init(void);
 void __init hv_init_spinlocks(void);
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index cc8f177..4e78643 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -36,10 +36,7 @@
 
 /* Is Linux running as the root partition? */
 bool hv_root_partition;
-EXPORT_SYMBOL_GPL(hv_root_partition);
-
 struct ms_hyperv_info ms_hyperv;
-EXPORT_SYMBOL_GPL(ms_hyperv);
 
 #if IS_ENABLED(CONFIG_HYPERV)
 static void (*vmbus_handler)(void);
diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c
index 7f42da9..e836002b 100644
--- a/drivers/hv/hv_common.c
+++ b/drivers/hv/hv_common.c
@@ -15,9 +15,147 @@
 #include <linux/types.h>
 #include <linux/export.h>
 #include <linux/bitfield.h>
+#include <linux/cpumask.h>
+#include <linux/slab.h>
 #include <asm/hyperv-tlfs.h>
 #include <asm/mshyperv.h>
 
+/*
+ * hv_root_partition and ms_hyperv are defined here with other Hyper-V
+ * specific globals so they are shared across all architectures and are
+ * built only when CONFIG_HYPERV is defined.  But on x86,
+ * ms_hyperv_init_platform() is built even when CONFIG_HYPERV is not
+ * defined, and it uses these two variables.  So mark them as __weak
+ * here, allowing for an overriding definition in the module containing
+ * ms_hyperv_init_platform().
+ */
+bool __weak hv_root_partition;
+EXPORT_SYMBOL_GPL(hv_root_partition);
+
+struct ms_hyperv_info __weak ms_hyperv;
+EXPORT_SYMBOL_GPL(ms_hyperv);
+
+u32 *hv_vp_index;
+EXPORT_SYMBOL_GPL(hv_vp_index);
+
+u32 hv_max_vp_index;
+EXPORT_SYMBOL_GPL(hv_max_vp_index);
+
+void  __percpu **hyperv_pcpu_input_arg;
+EXPORT_SYMBOL_GPL(hyperv_pcpu_input_arg);
+
+void  __percpu **hyperv_pcpu_output_arg;
+EXPORT_SYMBOL_GPL(hyperv_pcpu_output_arg);
+
+/*
+ * Hyper-V specific initialization and shutdown code that is
+ * common across all architectures.  Called from architecture
+ * specific initialization functions.
+ */
+
+void __init hv_common_free(void)
+{
+	kfree(hv_vp_index);
+	hv_vp_index = NULL;
+
+	free_percpu(hyperv_pcpu_output_arg);
+	hyperv_pcpu_output_arg = NULL;
+
+	free_percpu(hyperv_pcpu_input_arg);
+	hyperv_pcpu_input_arg = NULL;
+}
+
+int __init hv_common_init(void)
+{
+	int i;
+
+	/*
+	 * Allocate the per-CPU state for the hypercall input arg.
+	 * If this allocation fails, we will not be able to setup
+	 * (per-CPU) hypercall input page and thus this failure is
+	 * fatal on Hyper-V.
+	 */
+	hyperv_pcpu_input_arg = alloc_percpu(void  *);
+	BUG_ON(!hyperv_pcpu_input_arg);
+
+	/* Allocate the per-CPU state for output arg for root */
+	if (hv_root_partition) {
+		hyperv_pcpu_output_arg = alloc_percpu(void *);
+		BUG_ON(!hyperv_pcpu_output_arg);
+	}
+
+	hv_vp_index = kmalloc_array(num_possible_cpus(), sizeof(*hv_vp_index),
+				    GFP_KERNEL);
+	if (!hv_vp_index) {
+		hv_common_free();
+		return -ENOMEM;
+	}
+
+	for (i = 0; i < num_possible_cpus(); i++)
+		hv_vp_index[i] = VP_INVAL;
+
+	return 0;
+}
+
+/*
+ * Hyper-V specific initialization and die code for
+ * individual CPUs that is common across all architectures.
+ * Called by the CPU hotplug mechanism.
+ */
+
+int hv_common_cpu_init(unsigned int cpu)
+{
+	void **inputarg, **outputarg;
+	u64 msr_vp_index;
+	gfp_t flags;
+	int pgcount = hv_root_partition ? 2 : 1;
+
+	/* hv_cpu_init() can be called with IRQs disabled from hv_resume() */
+	flags = irqs_disabled() ? GFP_ATOMIC : GFP_KERNEL;
+
+	inputarg = (void **)this_cpu_ptr(hyperv_pcpu_input_arg);
+	*inputarg = kmalloc(pgcount * HV_HYP_PAGE_SIZE, flags);
+	if (!(*inputarg))
+		return -ENOMEM;
+
+	if (hv_root_partition) {
+		outputarg = (void **)this_cpu_ptr(hyperv_pcpu_output_arg);
+		*outputarg = (char *)(*inputarg) + HV_HYP_PAGE_SIZE;
+	}
+
+	msr_vp_index = hv_get_register(HV_REGISTER_VP_INDEX);
+
+	hv_vp_index[cpu] = msr_vp_index;
+
+	if (msr_vp_index > hv_max_vp_index)
+		hv_max_vp_index = msr_vp_index;
+
+	return 0;
+}
+
+int hv_common_cpu_die(unsigned int cpu)
+{
+	unsigned long flags;
+	void **inputarg, **outputarg;
+	void *mem;
+
+	local_irq_save(flags);
+
+	inputarg = (void **)this_cpu_ptr(hyperv_pcpu_input_arg);
+	mem = *inputarg;
+	*inputarg = NULL;
+
+	if (hv_root_partition) {
+		outputarg = (void **)this_cpu_ptr(hyperv_pcpu_output_arg);
+		*outputarg = NULL;
+	}
+
+	local_irq_restore(flags);
+
+	kfree(mem);
+
+	return 0;
+}
 
 /* Bit mask of the extended capability to query: see HV_EXT_CAPABILITY_xxx */
 bool hv_query_ext_cap(u64 cap_query)
diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h
index 9a000ba..2a187fe 100644
--- a/include/asm-generic/mshyperv.h
+++ b/include/asm-generic/mshyperv.h
@@ -38,6 +38,9 @@ struct ms_hyperv_info {
 };
 extern struct ms_hyperv_info ms_hyperv;
 
+extern void  __percpu  **hyperv_pcpu_input_arg;
+extern void  __percpu  **hyperv_pcpu_output_arg;
+
 extern u64 hv_do_hypercall(u64 control, void *inputaddr, void *outputaddr);
 extern u64 hv_do_fast_hypercall8(u16 control, u64 input8);
 
@@ -151,6 +154,8 @@ static inline void vmbus_signal_eom(struct hv_message *msg, u32 old_msg_type)
 extern int vmbus_interrupt;
 extern int vmbus_irq;
 
+extern bool hv_root_partition;
+
 #if IS_ENABLED(CONFIG_HYPERV)
 /*
  * Hypervisor's notion of virtual processor ID is different from
@@ -164,6 +169,11 @@ static inline void vmbus_signal_eom(struct hv_message *msg, u32 old_msg_type)
 /* Sentinel value for an uninitialized entry in hv_vp_index array */
 #define VP_INVAL	U32_MAX
 
+int __init hv_common_init(void);
+void __init hv_common_free(void);
+int hv_common_cpu_init(unsigned int cpu);
+int hv_common_cpu_die(unsigned int cpu);
+
 void *hv_alloc_hyperv_page(void);
 void *hv_alloc_hyperv_zeroed_page(void);
 void hv_free_hyperv_page(unsigned long addr);
-- 
1.8.3.1

[PATCH v2 2/3] Drivers: hv: Add arch independent default functions for some Hyper-V handlers

[Michael Kelley]

Architecture independent Hyper-V code calls various arch-specific handlers
when needed.  To aid in supporting multiple architectures, provide weak
defaults that can be overridden by arch-specific implementations where
appropriate.  But when arch-specific overrides aren't needed or haven't
been implemented yet for a particular architecture, these stubs reduce
the amount of clutter under arch/.

No functional change.

Signed-off-by: Michael Kelley <mikelley@microsoft.com>
---
 arch/x86/hyperv/hv_init.c      |  2 --
 arch/x86/kernel/cpu/mshyperv.c |  6 ------
 drivers/hv/hv_common.c         | 49 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 49 insertions(+), 8 deletions(-)

diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index 5cc0c0f..e87a029 100644
--- a/arch/x86/hyperv/hv_init.c
+++ b/arch/x86/hyperv/hv_init.c
@@ -468,7 +468,6 @@ void hyperv_cleanup(void)
 	hypercall_msr.as_uint64 = 0;
 	wrmsrl(HV_X64_MSR_REFERENCE_TSC, hypercall_msr.as_uint64);
 }
-EXPORT_SYMBOL_GPL(hyperv_cleanup);
 
 void hyperv_report_panic(struct pt_regs *regs, long err, bool in_die)
 {
@@ -542,4 +541,3 @@ bool hv_is_isolation_supported(void)
 {
 	return hv_get_isolation_type() != HV_ISOLATION_TYPE_NONE;
 }
-EXPORT_SYMBOL_GPL(hv_is_isolation_supported);
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index 4e78643..4e1491c 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -62,14 +62,12 @@ void hv_setup_vmbus_handler(void (*handler)(void))
 {
 	vmbus_handler = handler;
 }
-EXPORT_SYMBOL_GPL(hv_setup_vmbus_handler);
 
 void hv_remove_vmbus_handler(void)
 {
 	/* We have no way to deallocate the interrupt gate */
 	vmbus_handler = NULL;
 }
-EXPORT_SYMBOL_GPL(hv_remove_vmbus_handler);
 
 /*
  * Routines to do per-architecture handling of stimer0
@@ -104,25 +102,21 @@ void hv_setup_kexec_handler(void (*handler)(void))
 {
 	hv_kexec_handler = handler;
 }
-EXPORT_SYMBOL_GPL(hv_setup_kexec_handler);
 
 void hv_remove_kexec_handler(void)
 {
 	hv_kexec_handler = NULL;
 }
-EXPORT_SYMBOL_GPL(hv_remove_kexec_handler);
 
 void hv_setup_crash_handler(void (*handler)(struct pt_regs *regs))
 {
 	hv_crash_handler = handler;
 }
-EXPORT_SYMBOL_GPL(hv_setup_crash_handler);
 
 void hv_remove_crash_handler(void)
 {
 	hv_crash_handler = NULL;
 }
-EXPORT_SYMBOL_GPL(hv_remove_crash_handler);
 
 #ifdef CONFIG_KEXEC_CORE
 static void hv_machine_shutdown(void)
diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c
index e836002b..fe333f4 100644
--- a/drivers/hv/hv_common.c
+++ b/drivers/hv/hv_common.c
@@ -16,6 +16,7 @@
 #include <linux/export.h>
 #include <linux/bitfield.h>
 #include <linux/cpumask.h>
+#include <linux/ptrace.h>
 #include <linux/slab.h>
 #include <asm/hyperv-tlfs.h>
 #include <asm/mshyperv.h>
@@ -202,3 +203,51 @@ bool hv_query_ext_cap(u64 cap_query)
 	return hv_extended_cap & cap_query;
 }
 EXPORT_SYMBOL_GPL(hv_query_ext_cap);
+
+/* These __weak functions provide default "no-op" behavior and
+ * may be overridden by architecture specific versions. Architectures
+ * for which the default "no-op" behavior is sufficient can leave
+ * them unimplemented and not be cluttered with a bunch of stub
+ * functions in arch-specific code.
+ */
+
+bool __weak hv_is_isolation_supported(void)
+{
+	return false;
+}
+EXPORT_SYMBOL_GPL(hv_is_isolation_supported);
+
+void __weak hv_setup_vmbus_handler(void (*handler)(void))
+{
+}
+EXPORT_SYMBOL_GPL(hv_setup_vmbus_handler);
+
+void __weak hv_remove_vmbus_handler(void)
+{
+}
+EXPORT_SYMBOL_GPL(hv_remove_vmbus_handler);
+
+void __weak hv_setup_kexec_handler(void (*handler)(void))
+{
+}
+EXPORT_SYMBOL_GPL(hv_setup_kexec_handler);
+
+void __weak hv_remove_kexec_handler(void)
+{
+}
+EXPORT_SYMBOL_GPL(hv_remove_kexec_handler);
+
+void __weak hv_setup_crash_handler(void (*handler)(struct pt_regs *regs))
+{
+}
+EXPORT_SYMBOL_GPL(hv_setup_crash_handler);
+
+void __weak hv_remove_crash_handler(void)
+{
+}
+EXPORT_SYMBOL_GPL(hv_remove_crash_handler);
+
+void __weak hyperv_cleanup(void)
+{
+}
+EXPORT_SYMBOL_GPL(hyperv_cleanup);
-- 
1.8.3.1

[PATCH v2 3/3] Drivers: hv: Move Hyper-V misc functionality to arch-neutral code

[Michael Kelley]

The check for whether hibernation is possible, and the enabling of
Hyper-V panic notification during kexec, are both architecture neutral.
Move the code from under arch/x86 and into drivers/hv/hv_common.c where
it can also be used for ARM64.

No functional change.

Signed-off-by: Michael Kelley <mikelley@microsoft.com>
---
 arch/x86/hyperv/hv_init.c      |  8 +-------
 arch/x86/kernel/cpu/mshyperv.c | 11 -----------
 drivers/hv/hv_common.c         | 18 ++++++++++++++++++
 3 files changed, 19 insertions(+), 18 deletions(-)

diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index e87a029..6f247e7 100644
--- a/arch/x86/hyperv/hv_init.c
+++ b/arch/x86/hyperv/hv_init.c
@@ -7,10 +7,10 @@
  * Author : K. Y. Srinivasan <kys@microsoft.com>
  */
 
-#include <linux/acpi.h>
 #include <linux/efi.h>
 #include <linux/types.h>
 #include <linux/bitfield.h>
+#include <linux/io.h>
 #include <asm/apic.h>
 #include <asm/desc.h>
 #include <asm/hypervisor.h>
@@ -523,12 +523,6 @@ bool hv_is_hyperv_initialized(void)
 }
 EXPORT_SYMBOL_GPL(hv_is_hyperv_initialized);
 
-bool hv_is_hibernation_supported(void)
-{
-	return !hv_root_partition && acpi_sleep_state_supported(ACPI_STATE_S4);
-}
-EXPORT_SYMBOL_GPL(hv_is_hibernation_supported);
-
 enum hv_isolation_type hv_get_isolation_type(void)
 {
 	if (!(ms_hyperv.priv_high & HV_ISOLATION))
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index 4e1491c..7639036 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -17,7 +17,6 @@
 #include <linux/irq.h>
 #include <linux/kexec.h>
 #include <linux/i8253.h>
-#include <linux/panic_notifier.h>
 #include <linux/random.h>
 #include <asm/processor.h>
 #include <asm/hypervisor.h>
@@ -326,16 +325,6 @@ static void __init ms_hyperv_init_platform(void)
 			ms_hyperv.nested_features);
 	}
 
-	/*
-	 * Hyper-V expects to get crash register data or kmsg when
-	 * crash enlightment is available and system crashes. Set
-	 * crash_kexec_post_notifiers to be true to make sure that
-	 * calling crash enlightment interface before running kdump
-	 * kernel.
-	 */
-	if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE)
-		crash_kexec_post_notifiers = true;
-
 #ifdef CONFIG_X86_LOCAL_APIC
 	if (ms_hyperv.features & HV_ACCESS_FREQUENCY_MSRS &&
 	    ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE) {
diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c
index fe333f4..46658de 100644
--- a/drivers/hv/hv_common.c
+++ b/drivers/hv/hv_common.c
@@ -13,9 +13,11 @@
  */
 
 #include <linux/types.h>
+#include <linux/acpi.h>
 #include <linux/export.h>
 #include <linux/bitfield.h>
 #include <linux/cpumask.h>
+#include <linux/panic_notifier.h>
 #include <linux/ptrace.h>
 #include <linux/slab.h>
 #include <asm/hyperv-tlfs.h>
@@ -71,6 +73,16 @@ int __init hv_common_init(void)
 	int i;
 
 	/*
+	 * Hyper-V expects to get crash register data or kmsg when
+	 * crash enlightment is available and system crashes. Set
+	 * crash_kexec_post_notifiers to be true to make sure that
+	 * calling crash enlightment interface before running kdump
+	 * kernel.
+	 */
+	if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE)
+		crash_kexec_post_notifiers = true;
+
+	/*
 	 * Allocate the per-CPU state for the hypercall input arg.
 	 * If this allocation fails, we will not be able to setup
 	 * (per-CPU) hypercall input page and thus this failure is
@@ -204,6 +216,12 @@ bool hv_query_ext_cap(u64 cap_query)
 }
 EXPORT_SYMBOL_GPL(hv_query_ext_cap);
 
+bool hv_is_hibernation_supported(void)
+{
+	return !hv_root_partition && acpi_sleep_state_supported(ACPI_STATE_S4);
+}
+EXPORT_SYMBOL_GPL(hv_is_hibernation_supported);
+
 /* These __weak functions provide default "no-op" behavior and
  * may be overridden by architecture specific versions. Architectures
  * for which the default "no-op" behavior is sufficient can leave
-- 
1.8.3.1

Re: [PATCH v2 0/3] Additional refactoring of Hyper-V arch specific code

[Wei Liu]

On Wed, Jul 14, 2021 at 11:34:44AM -0700, Michael Kelley wrote:
> This patch set moves additional Hyper-V code under arch/x86 into
> arch-neutral hv_common.c where it can be shared by x86 and
> and ARM64 implementations.  The move reduces the overall lines
> of code across both architectures, and removes code under
> arch/ that isn't really architecture-specific.
> 
> The code is moved into hv_common.c because it must be
> built-in to the kernel image, and not be part of a module.
> 
> No functional changes are intended.
> 
> ---
> Changes in v2:
> * Fixed problem when building with CONFIG_HYPERV=n
>   (reported by kernel test robot <lkp@intel.com>)
> 

Thanks for the quick turnaround. I've pushed these three patches to
hyperv-next.

Wei.

> 
> Michael Kelley (3):
>   Drivers: hv: Make portions of Hyper-V init code be arch neutral
>   Drivers: hv: Add arch independent default functions for some Hyper-V
>     handlers
>   Drivers: hv: Move Hyper-V misc functionality to arch-neutral code
> 
>  arch/x86/hyperv/hv_init.c       | 101 +++-----------------
>  arch/x86/include/asm/mshyperv.h |   4 -
>  arch/x86/kernel/cpu/mshyperv.c  |  20 ----
>  drivers/hv/hv_common.c          | 205 ++++++++++++++++++++++++++++++++++++++++
>  include/asm-generic/mshyperv.h  |  10 ++
>  5 files changed, 226 insertions(+), 114 deletions(-)
> 
> -- 
> 1.8.3.1
>