[PATCH 5/7] hyper-v: globalize vp_index

[Vitaly Kuznetsov <vkuznets@redhat.com>]

To support implementing remote TLB flushing on Hyper-V with a hypercall
we need to make vp_index available outside of vmbus module. Rename and
globalize.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
 arch/x86/hyperv/hv_init.c       | 34 +++++++++++++++++++++++++++++++++-
 arch/x86/include/asm/mshyperv.h | 26 ++++++++++++++++++++++++++
 drivers/hv/channel_mgmt.c       |  7 +++----
 drivers/hv/connection.c         |  3 ++-
 drivers/hv/hv.c                 |  9 ---------
 drivers/hv/hyperv_vmbus.h       | 11 -----------
 drivers/hv/vmbus_drv.c          | 17 -----------------
 include/linux/hyperv.h          |  1 -
 8 files changed, 64 insertions(+), 44 deletions(-)

diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index 7d961d4..1c14088 100644
--- a/arch/x86/hyperv/hv_init.c
+++ b/arch/x86/hyperv/hv_init.c
@@ -26,6 +26,8 @@
 #include <linux/mm.h>
 #include <linux/clockchips.h>
 #include <linux/hyperv.h>
+#include <linux/slab.h>
+#include <linux/cpuhotplug.h>
 
 #ifdef CONFIG_X86_64
 
@@ -103,6 +105,20 @@ EXPORT_SYMBOL_GPL(hv_hypercall_pg);
 struct clocksource *hyperv_cs;
 EXPORT_SYMBOL_GPL(hyperv_cs);
 
+u32 *hv_vp_index;
+EXPORT_SYMBOL_GPL(hv_vp_index);
+
+static int hv_cpu_init(unsigned int cpu)
+{
+	u64 msr_vp_index;
+
+	hv_get_vp_index(msr_vp_index);
+
+	hv_vp_index[smp_processor_id()] = (u32)msr_vp_index;
+
+	return 0;
+}
+
 /*
  * This function is to be invoked early in the boot sequence after the
  * hypervisor has been detected.
@@ -118,6 +134,16 @@ void hyperv_init(void)
 	if (x86_hyper != &x86_hyper_ms_hyperv)
 		return;
 
+	/* Allocate percpu VP index */
+	hv_vp_index = kcalloc(num_possible_cpus(), sizeof(*hv_vp_index),
+			      GFP_KERNEL);
+	if (!hv_vp_index)
+		return;
+
+	if (cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/hyperv_init:online",
+			      hv_cpu_init, NULL) < 0)
+		goto free_vp_index;
+
 	/*
 	 * Setup the hypercall page and enable hypercalls.
 	 * 1. Register the guest ID
@@ -129,7 +155,7 @@ void hyperv_init(void)
 	hv_hypercall_pg  = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL_RX);
 	if (hv_hypercall_pg == NULL) {
 		wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);
-		return;
+		goto free_vp_index;
 	}
 
 	rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
@@ -169,6 +195,12 @@ void hyperv_init(void)
 	hyperv_cs = &hyperv_cs_msr;
 	if (ms_hyperv.features & HV_X64_MSR_TIME_REF_COUNT_AVAILABLE)
 		clocksource_register_hz(&hyperv_cs_msr, NSEC_PER_SEC/100);
+
+	return;
+
+free_vp_index:
+	kfree(hv_vp_index);
+	hv_vp_index = NULL;
 }
 
 /*
diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index a2c996b..1293c84 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -274,6 +274,32 @@ static inline u64 hv_do_rep_hypercall(u16 code, u16 rep_count, void *input,
 	return status;
 }
 
+/*
+ * Hypervisor's notion of virtual processor ID is different from
+ * Linux' notion of CPU ID. This information can only be retrieved
+ * in the context of the calling CPU. Setup a map for easy access
+ * to this information.
+ */
+extern u32 __percpu *hv_vp_index;
+
+/**
+ * vmbus_cpu_number_to_vp_number() - Map CPU to VP.
+ * @cpu_number: CPU number in Linux terms
+ *
+ * This function returns the mapping between the Linux processor
+ * number and the hypervisor's virtual processor number, useful
+ * in making hypercalls and such that talk about specific
+ * processors.
+ *
+ * Return: Virtual processor number in Hyper-V terms
+ */
+static inline int vmbus_cpu_number_to_vp_number(int cpu_number)
+{
+	WARN_ON(hv_vp_index[cpu_number] == -1);
+
+	return hv_vp_index[cpu_number];
+}
+
 void hyperv_init(void);
 void hyperv_report_panic(struct pt_regs *regs);
 bool hv_is_hypercall_page_setup(void);
diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
index 6cfa297..9969c82 100644
--- a/drivers/hv/channel_mgmt.c
+++ b/drivers/hv/channel_mgmt.c
@@ -599,7 +599,7 @@ static void init_vp_index(struct vmbus_channel *channel, u16 dev_type)
 		 */
 		channel->numa_node = 0;
 		channel->target_cpu = 0;
-		channel->target_vp = hv_context.vp_index[0];
+		channel->target_vp = vmbus_cpu_number_to_vp_number(0);
 		return;
 	}
 
@@ -683,7 +683,7 @@ static void init_vp_index(struct vmbus_channel *channel, u16 dev_type)
 	}
 
 	channel->target_cpu = cur_cpu;
-	channel->target_vp = hv_context.vp_index[cur_cpu];
+	channel->target_vp = vmbus_cpu_number_to_vp_number(cur_cpu);
 }
 
 static void vmbus_wait_for_unload(void)
@@ -1187,8 +1187,7 @@ struct vmbus_channel *vmbus_get_outgoing_channel(struct vmbus_channel *primary)
 		return outgoing_channel;
 	}
 
-	cur_cpu = hv_context.vp_index[get_cpu()];
-	put_cpu();
+	cur_cpu = vmbus_cpu_number_to_vp_number(smp_processor_id());
 	list_for_each_safe(cur, tmp, &primary->sc_list) {
 		cur_channel = list_entry(cur, struct vmbus_channel, sc_list);
 		if (cur_channel->state != CHANNEL_OPENED_STATE)
diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c
index 545f2a4..7026d13 100644
--- a/drivers/hv/connection.c
+++ b/drivers/hv/connection.c
@@ -96,7 +96,8 @@ static int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo,
 	 * the CPU attempting to connect may not be CPU 0.
 	 */
 	if (version >= VERSION_WIN8_1)
-		msg->target_vcpu = hv_context.vp_index[smp_processor_id()];
+		msg->target_vcpu =
+			vmbus_cpu_number_to_vp_number(smp_processor_id());
 	else
 		msg->target_vcpu = 0;
 
diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c
index 12e7bae..7e67ef4 100644
--- a/drivers/hv/hv.c
+++ b/drivers/hv/hv.c
@@ -229,7 +229,6 @@ int hv_synic_init(unsigned int cpu)
 	union hv_synic_siefp siefp;
 	union hv_synic_sint shared_sint;
 	union hv_synic_scontrol sctrl;
-	u64 vp_index;
 
 	/* Setup the Synic's message page */
 	hv_get_simp(simp.as_uint64);
@@ -271,14 +270,6 @@ int hv_synic_init(unsigned int cpu)
 	hv_context.synic_initialized = true;
 
 	/*
-	 * Setup the mapping between Hyper-V's notion
-	 * of cpuid and Linux' notion of cpuid.
-	 * This array will be indexed using Linux cpuid.
-	 */
-	hv_get_vp_index(vp_index);
-	hv_context.vp_index[cpu] = (u32)vp_index;
-
-	/*
 	 * Register the per-cpu clockevent source.
 	 */
 	if (ms_hyperv.features & HV_X64_MSR_SYNTIMER_AVAILABLE)
diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h
index 6113e91..d624526 100644
--- a/drivers/hv/hyperv_vmbus.h
+++ b/drivers/hv/hyperv_vmbus.h
@@ -229,17 +229,6 @@ struct hv_context {
 	struct hv_per_cpu_context __percpu *cpu_context;
 
 	/*
-	 * Hypervisor's notion of virtual processor ID is different from
-	 * Linux' notion of CPU ID. This information can only be retrieved
-	 * in the context of the calling CPU. Setup a map for easy access
-	 * to this information:
-	 *
-	 * vp_index[a] is the Hyper-V's processor ID corresponding to
-	 * Linux cpuid 'a'.
-	 */
-	u32 vp_index[NR_CPUS];
-
-	/*
 	 * To manage allocations in a NUMA node.
 	 * Array indexed by numa node ID.
 	 */
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 0087b49..63e743d 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -1455,23 +1455,6 @@ void vmbus_free_mmio(resource_size_t start, resource_size_t size)
 }
 EXPORT_SYMBOL_GPL(vmbus_free_mmio);
 
-/**
- * vmbus_cpu_number_to_vp_number() - Map CPU to VP.
- * @cpu_number: CPU number in Linux terms
- *
- * This function returns the mapping between the Linux processor
- * number and the hypervisor's virtual processor number, useful
- * in making hypercalls and such that talk about specific
- * processors.
- *
- * Return: Virtual processor number in Hyper-V terms
- */
-int vmbus_cpu_number_to_vp_number(int cpu_number)
-{
-	return hv_context.vp_index[cpu_number];
-}
-EXPORT_SYMBOL_GPL(vmbus_cpu_number_to_vp_number);
-
 static int vmbus_acpi_add(struct acpi_device *device)
 {
 	acpi_status result;
diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index 5d6777c..2450e07 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -1184,7 +1184,6 @@ int vmbus_allocate_mmio(struct resource **new, struct hv_device *device_obj,
 			resource_size_t size, resource_size_t align,
 			bool fb_overlap_ok);
 void vmbus_free_mmio(resource_size_t start, resource_size_t size);
-int vmbus_cpu_number_to_vp_number(int cpu_number);
 
 /*
  * GUID definitions of various offer types - services offered to the guest.
-- 
2.9.3