hyper-v: Globalize vp_index

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>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Jork Loeser <Jork.Loeser@microsoft.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Simon Xiao <sixiao@microsoft.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: devel@linuxdriverproject.org
Link: http://lkml.kernel.org/r/20170802160921.21791-7-vkuznets@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

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_HYPERV_TSCPAGE
 
@@ -80,6 +82,20 @@ 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()] = msr_vp_index;
+
+	return 0;
+}
+
 /*
  * This function is to be invoked early in the boot sequence after the
  * hypervisor has been detected.
@@ -95,6 +111,16 @@ void hyperv_init(void)
 	if (x86_hyper != &x86_hyper_ms_hyperv)
 		return;
 
+	/* Allocate percpu VP index */
+	hv_vp_index = kmalloc_array(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
@@ -106,7 +132,7 @@ 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);
@@ -149,6 +175,12 @@ register_msr_cs:
 	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;
 }
 
 /*

arch/x86/include/asm/mshyperv.h

@@ -282,6 +282,30 @@ static inline u64 hv_do_rep_hypercall(u16 code, u16 rep_count, u16 varhead_size,
 	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 *hv_vp_index;
+
+/**
+ * hv_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 hv_cpu_number_to_vp_number(int cpu_number)
+{
+	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);

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 = hv_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 = hv_cpu_number_to_vp_number(cur_cpu);
 }
 
 static void vmbus_wait_for_unload(void)
@@ -1219,8 +1219,7 @@ 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 = hv_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)

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 =
+			hv_cpu_number_to_vp_number(smp_processor_id());
 		vmbus_connection.connect_cpu = smp_processor_id();
 	} else {
 		msg->target_vcpu = 0;

drivers/hv/hv.c

@@ -234,7 +234,6 @@ 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);
@@ -275,14 +274,6 @@ 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.
 	 */

drivers/hv/hyperv_vmbus.h

@@ -228,17 +228,6 @@ 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.

drivers/hv/vmbus_drv.c

@@ -1451,23 +1451,6 @@ 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;

drivers/pci/host/pci-hyperv.c

@@ -562,52 +562,6 @@ static void put_pcichild(struct hv_pci_dev *hv_pcidev,
 static void get_hvpcibus(struct hv_pcibus_device *hv_pcibus);
 static void put_hvpcibus(struct hv_pcibus_device *hv_pcibus);
 
-
-/*
- * Temporary CPU to vCPU mapping to address transitioning
- * vmbus_cpu_number_to_vp_number() being migrated to
- * hv_cpu_number_to_vp_number() in a separate patch. Once that patch
- * has been picked up in the main line, remove this code here and use
- * the official code.
- */
-static struct hv_tmpcpumap
-{
-	bool initialized;
-	u32 vp_index[NR_CPUS];
-} hv_tmpcpumap;
-
-static void hv_tmpcpumap_init_cpu(void *_unused)
-{
-	int cpu = smp_processor_id();
-	u64 vp_index;
-
-	hv_get_vp_index(vp_index);
-
-	hv_tmpcpumap.vp_index[cpu] = vp_index;
-}
-
-static void hv_tmpcpumap_init(void)
-{
-	if (hv_tmpcpumap.initialized)
-		return;
-
-	memset(hv_tmpcpumap.vp_index, -1, sizeof(hv_tmpcpumap.vp_index));
-	on_each_cpu(hv_tmpcpumap_init_cpu, NULL, true);
-	hv_tmpcpumap.initialized = true;
-}
-
-/**
- * hv_tmp_cpu_nr_to_vp_nr() - Convert Linux CPU nr to Hyper-V vCPU nr
- *
- * Remove once vmbus_cpu_number_to_vp_number() has been converted to
- * hv_cpu_number_to_vp_number() and replace callers appropriately.
- */
-static u32 hv_tmp_cpu_nr_to_vp_nr(int cpu)
-{
-	return hv_tmpcpumap.vp_index[cpu];
-}
-
-
 /**
  * devfn_to_wslot() - Convert from Linux PCI slot to Windows
  * @devfn:	The Linux representation of PCI slot
@@ -971,7 +925,7 @@ static void hv_irq_unmask(struct irq_data *data)
 		var_size = 1 + HV_VP_SET_BANK_COUNT_MAX;
 
 		for_each_cpu_and(cpu, dest, cpu_online_mask) {
-			cpu_vmbus = hv_tmp_cpu_nr_to_vp_nr(cpu);
+			cpu_vmbus = hv_cpu_number_to_vp_number(cpu);
 
 			if (cpu_vmbus >= HV_VP_SET_BANK_COUNT_MAX * 64) {
 				dev_err(&hbus->hdev->device,
@@ -986,7 +940,7 @@ static void hv_irq_unmask(struct irq_data *data)
 	} else {
 		for_each_cpu_and(cpu, dest, cpu_online_mask) {
 			params->int_target.vp_mask |=
-				(1ULL << hv_tmp_cpu_nr_to_vp_nr(cpu));
+				(1ULL << hv_cpu_number_to_vp_number(cpu));
 		}
 	}
 
@@ -1063,7 +1017,7 @@ static u32 hv_compose_msi_req_v2(
 	 */
 	cpu = cpumask_first_and(affinity, cpu_online_mask);
 	int_pkt->int_desc.processor_array[0] =
-		hv_tmp_cpu_nr_to_vp_nr(cpu);
+		hv_cpu_number_to_vp_number(cpu);
 	int_pkt->int_desc.processor_count = 1;
 
 	return sizeof(*int_pkt);
@@ -2490,8 +2444,6 @@ static int hv_pci_probe(struct hv_device *hdev,
 		return -ENOMEM;
 	hbus->state = hv_pcibus_init;
 
-	hv_tmpcpumap_init();
-
 	/*
 	 * The PCI bus "domain" is what is called "segment" in ACPI and
 	 * other specs.  Pull it from the instance ID, to get something

include/linux/hyperv.h

@@ -1173,7 +1173,6 @@ 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.