arm64: hyperv: Initialize hypervisor on boot

Add ARM64-specific code to initialize the Hyper-V
hypervisor when booting as a guest VM. Provide functions
and data structures indicating hypervisor status that
are needed by VMbus driver.

This code is built only when CONFIG_HYPERV is enabled.

Signed-off-by: Michael Kelley <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>

Author: kelleymh

arch/arm64/hyperv/hv_core.c

@@ -18,10 +18,41 @@
 #include <linux/slab.h>
 #include <linux/hyperv.h>
 #include <linux/arm-smccc.h>
+#include <linux/vmalloc.h>
+#include <linux/acpi.h>
+#include <linux/module.h>
+#include <linux/cpuhotplug.h>
+#include <linux/psci.h>
 #include <asm-generic/bug.h>
 #include <asm/hyperv-tlfs.h>
 #include <asm/mshyperv.h>
+#include <asm/sysreg.h>
+#include <clocksource/hyperv_timer.h>
 
+static bool    hyperv_initialized;
+
+struct         ms_hyperv_info ms_hyperv __ro_after_init;
+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);
+
+static int hv_cpu_init(unsigned int cpu)
+{
+	u64 msr_vp_index;
+
+	msr_vp_index = hv_get_vpreg(HV_REGISTER_VPINDEX);
+
+	hv_vp_index[smp_processor_id()] = msr_vp_index;
+
+	if (msr_vp_index > hv_max_vp_index)
+		hv_max_vp_index = msr_vp_index;
+
+	return 0;
+}
 
 /*
  * Functions for allocating and freeing memory with size and
@@ -66,6 +97,107 @@ void hv_free_hyperv_page(unsigned long addr)
 EXPORT_SYMBOL_GPL(hv_free_hyperv_page);
 
 
+/*
+ * This function is invoked via the ACPI clocksource probe mechanism. We
+ * don't actually use any values from the ACPI GTDT table, but we set up
+ * the Hyper-V synthetic clocksource and do other initialization for
+ * interacting with Hyper-V the first time.  Using early_initcall to invoke
+ * this function is too late because interrupts are already enabled at that
+ * point, and hv_init_clocksource() must run before interrupts are enabled.
+ *
+ * 1. Setup the guest ID.
+ * 2. Get features and hints info from Hyper-V
+ * 3. Setup per-cpu VP indices.
+ * 4. Initialize the Hyper-V clocksource.
+ */
+
+static int __init hyperv_init(struct acpi_table_header *table)
+{
+	struct hv_get_vp_registers_output result;
+	u32	a, b, c, d;
+	u64	guest_id;
+	int	i, cpuhp;
+
+	/*
+	 * If we're in a VM on Hyper-V, the ACPI hypervisor_id field will
+	 * have the string "MsHyperV".
+	 */
+	if (strncmp((char *)&acpi_gbl_FADT.hypervisor_id, "MsHyperV", 8))
+		return -EINVAL;
+
+	/* Setup the guest ID */
+	guest_id = generate_guest_id(0, LINUX_VERSION_CODE, 0);
+	hv_set_vpreg(HV_REGISTER_GUEST_OSID, guest_id);
+
+	/* Get the features and hints from Hyper-V */
+	hv_get_vpreg_128(HV_REGISTER_FEATURES, &result);
+	ms_hyperv.features = result.as32.a;
+	ms_hyperv.misc_features = result.as32.c;
+
+	hv_get_vpreg_128(HV_REGISTER_ENLIGHTENMENTS, &result);
+	ms_hyperv.hints = result.as32.a;
+
+	pr_info("Hyper-V: Features 0x%x, hints 0x%x, misc 0x%x\n",
+		ms_hyperv.features, ms_hyperv.hints, ms_hyperv.misc_features);
+
+	/*
+	 * If Hyper-V has crash notifications, set crash_kexec_post_notifiers
+	 * so that we will report the panic to Hyper-V before running kdump.
+	 */
+	if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE)
+		crash_kexec_post_notifiers = true;
+
+	/* Get information about the Hyper-V host version */
+	hv_get_vpreg_128(HV_REGISTER_HYPERVISOR_VERSION, &result);
+	a = result.as32.a;
+	b = result.as32.b;
+	c = result.as32.c;
+	d = result.as32.d;
+	pr_info("Hyper-V: Host Build %d.%d.%d.%d-%d-%d\n",
+		b >> 16, b & 0xFFFF, a,	d & 0xFFFFFF, c, d >> 24);
+
+	/* Allocate and initialize percpu VP index array */
+	hv_vp_index = kmalloc_array(num_possible_cpus(), sizeof(*hv_vp_index),
+				    GFP_KERNEL);
+	if (!hv_vp_index)
+		return -ENOMEM;
+
+	for (i = 0; i < num_possible_cpus(); i++)
+		hv_vp_index[i] = VP_INVAL;
+
+	cpuhp = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN,
+			"arm64/hyperv_init:online", hv_cpu_init, NULL);
+	if (cpuhp < 0)
+		goto free_vp_index;
+
+	hv_init_clocksource();
+	if (hv_stimer_alloc())
+		goto remove_cpuhp_state;
+
+	hyperv_initialized = true;
+	return 0;
+
+remove_cpuhp_state:
+	cpuhp_remove_state(cpuhp);
+free_vp_index:
+	kfree(hv_vp_index);
+	hv_vp_index = NULL;
+	return -EINVAL;
+}
+TIMER_ACPI_DECLARE(hyperv, ACPI_SIG_GTDT, hyperv_init);
+
+/*
+ * This routine is called before kexec/kdump, it does the required cleanup.
+ */
+void hyperv_cleanup(void)
+{
+	/* Reset our OS id */
+	hv_set_vpreg(HV_REGISTER_GUEST_OSID, 0);
+
+}
+EXPORT_SYMBOL_GPL(hyperv_cleanup);
+
+
 /*
  * hv_do_hypercall- Invoke the specified hypercall
  */
@@ -291,3 +423,15 @@ void hyperv_report_panic_msg(phys_addr_t pa, size_t size)
 	       (HV_CRASH_CTL_CRASH_NOTIFY | HV_CRASH_CTL_CRASH_NOTIFY_MSG));
 }
 EXPORT_SYMBOL_GPL(hyperv_report_panic_msg);
+
+bool hv_is_hyperv_initialized(void)
+{
+	return hyperv_initialized;
+}
+EXPORT_SYMBOL_GPL(hv_is_hyperv_initialized);
+
+bool hv_is_hibernation_supported(void)
+{
+	return false;
+}
+EXPORT_SYMBOL_GPL(hv_is_hibernation_supported);