Merge tag 'hyperv-next-signed-20210831' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux

Pull hyperv updates from Wei Liu:

 - make Hyper-V code arch-agnostic (Michael Kelley)

 - fix sched_clock behaviour on Hyper-V (Ani Sinha)

 - fix a fault when Linux runs as the root partition on MSHV (Praveen
   Kumar)

 - fix VSS driver (Vitaly Kuznetsov)

 - cleanup (Sonia Sharma)

* tag 'hyperv-next-signed-20210831' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux:
  hv_utils: Set the maximum packet size for VSS driver to the length of the receive buffer
  Drivers: hv: Enable Hyper-V code to be built on ARM64
  arm64: efi: Export screen_info
  arm64: hyperv: Initialize hypervisor on boot
  arm64: hyperv: Add panic handler
  arm64: hyperv: Add Hyper-V hypercall and register access utilities
  x86/hyperv: fix root partition faults when writing to VP assist page MSR
  hv: hyperv.h: Remove unused inline functions
  drivers: hv: Decouple Hyper-V clock/timer code from VMbus drivers
  x86/hyperv: add comment describing TSC_INVARIANT_CONTROL MSR setting bit 0
  Drivers: hv: Move Hyper-V misc functionality to arch-neutral code
  Drivers: hv: Add arch independent default functions for some Hyper-V handlers
  Drivers: hv: Make portions of Hyper-V init code be arch neutral
  x86/hyperv: fix for unwanted manipulation of sched_clock when TSC marked unstable
  asm-generic/hyperv: Add missing #include of nmi.h

4 files changed, 224 insertions, 8 deletions

diff --git a/drivers/hv/Kconfig b/drivers/hv/Kconfig
index 66c794d92391..d1123ceb38f3 100644
--- a/drivers/hv/Kconfig
+++ b/drivers/hv/Kconfig
@@ -4,15 +4,16 @@ menu "Microsoft Hyper-V guest support"
 
 config HYPERV
 	tristate "Microsoft Hyper-V client drivers"
-	depends on X86 && ACPI && X86_LOCAL_APIC && HYPERVISOR_GUEST
+	depends on ACPI && ((X86 && X86_LOCAL_APIC && HYPERVISOR_GUEST) \
+		|| (ARM64 && !CPU_BIG_ENDIAN))
 	select PARAVIRT
-	select X86_HV_CALLBACK_VECTOR
+	select X86_HV_CALLBACK_VECTOR if X86
 	help
 	  Select this option to run Linux as a Hyper-V client operating
 	  system.
 
 config HYPERV_TIMER
-	def_bool HYPERV
+	def_bool HYPERV && X86
 
 config HYPERV_UTILS
 	tristate "Microsoft Hyper-V Utilities driver"
diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c
index 7f42da98d377..c0d9048a4112 100644
--- a/drivers/hv/hv_common.c
+++ b/drivers/hv/hv_common.c
@@ -13,11 +13,162 @@
  */
 
 #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>
 #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;
+
+	/*
+	 * 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
+	 * 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)
@@ -64,3 +215,71 @@ bool hv_query_ext_cap(u64 cap_query)
 	return hv_extended_cap & 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);
+
+/*
+ * Default function to read the Hyper-V reference counter, independent
+ * of whether Hyper-V enlightened clocks/timers are being used. But on
+ * architectures where it is used, Hyper-V enlightenment code in
+ * hyperv_timer.c may override this function.
+ */
+static u64 __hv_read_ref_counter(void)
+{
+	return hv_get_register(HV_REGISTER_TIME_REF_COUNT);
+}
+
+u64 (*hv_read_reference_counter)(void) = __hv_read_ref_counter;
+EXPORT_SYMBOL_GPL(hv_read_reference_counter);
+
+/* 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);
diff --git a/drivers/hv/hv_snapshot.c b/drivers/hv/hv_snapshot.c
index 2267bd4c3472..6018b9d1b1fb 100644
--- a/drivers/hv/hv_snapshot.c
+++ b/drivers/hv/hv_snapshot.c
@@ -375,6 +375,7 @@ hv_vss_init(struct hv_util_service *srv)
 	}
 	recv_buffer = srv->recv_buffer;
 	vss_transaction.recv_channel = srv->channel;
+	vss_transaction.recv_channel->max_pkt_size = HV_HYP_PAGE_SIZE * 2;
 
 	/*
 	 * When this driver loads, the user level daemon that
diff --git a/drivers/hv/hv_util.c b/drivers/hv/hv_util.c
index 136576cba26f..835e6039c186 100644
--- a/drivers/hv/hv_util.c
+++ b/drivers/hv/hv_util.c
@@ -17,7 +17,6 @@
 #include <linux/hyperv.h>
 #include <linux/clockchips.h>
 #include <linux/ptp_clock_kernel.h>
-#include <clocksource/hyperv_timer.h>
 #include <asm/mshyperv.h>
 
 #include "hyperv_vmbus.h"
@@ -735,10 +734,6 @@ static struct ptp_clock *hv_ptp_clock;
 
 static int hv_timesync_init(struct hv_util_service *srv)
 {
-	/* TimeSync requires Hyper-V clocksource. */
-	if (!hv_read_reference_counter)
-		return -ENODEV;
-
 	spin_lock_init(&host_ts.lock);
 
 	INIT_WORK(&adj_time_work, hv_set_host_time);