Subject: [PATCH v5 6/8] arm64: hyperv: Initialize hypervisor on boot

From: Michael Kelley <[email-masked]>
Date: Thu, 3 Oct 2019 19:03:24 +0000

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-masked]>
---
 arch/arm64/hyperv/hv_init.c | 153 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 153 insertions(+)

diff --git a/arch/arm64/hyperv/hv_init.c b/arch/arm64/hyperv/hv_init.c
index 67350ec..86e4621 100644
--- a/arch/arm64/hyperv/hv_init.c
+++ b/arch/arm64/hyperv/hv_init.c
@@ -13,15 +13,48 @@
 #include <linux/types.h>
 #include <linux/version.h>
 #include <linux/export.h>
+#include <linux/vmalloc.h>
 #include <linux/mm.h>
+#include <linux/acpi.h>
+#include <linux/module.h>
 #include <linux/hyperv.h>
 #include <linux/spinlock.h>
 #include <linux/list.h>
 #include <linux/string.h>
+#include <linux/slab.h>
+#include <linux/cpuhotplug.h>
+#include <linux/psci.h>
+#include <linux/sched_clock.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;
+
+	hv_get_vp_index(msr_vp_index);
+
+	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
@@ -88,6 +121,120 @@ void hv_free_hyperv_page(unsigned long addr)

 /*
+ * 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_register_output result;
+	u32	a, b, c, d;
+	u64	guest_id;
+	int	i;
+
+	/*
+	 * 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_PRIVILEGES_AND_FEATURES, &result);
+	ms_hyperv.features = lower_32_bits(result.registervaluelow);
+	ms_hyperv.misc_features = upper_32_bits(result.registervaluehigh);
+
+	hv_get_vpreg_128(HV_REGISTER_FEATURES, &result);
+	ms_hyperv.hints = lower_32_bits(result.registervaluelow);
+
+	pr_info("Hyper-V: Features 0x%x, hints 0x%x\n",
+		ms_hyperv.features, ms_hyperv.hints);
+
+	/*
+	 * Direct mode is the only option for STIMERs provided Hyper-V
+	 * on ARM64, so Hyper-V doesn't actually set the flag.  But add
+	 * the flag so the architecture independent code in
+	 * drivers/clocksource/hyperv_timer.c will correctly use that mode.
+	 */
+	ms_hyperv.misc_features |= HV_STIMER_DIRECT_MODE_AVAILABLE;
+
+	/*
+	 * Hyper-V on ARM64 doesn't support AutoEOI.  Add the hint
+	 * that tells architecture independent code not to use this
+	 * feature.
+	 */
+	ms_hyperv.hints |= HV_DEPRECATING_AEOI_RECOMMENDED;
+
+	/* Get information about the Hyper-V host version */
+	hv_get_vpreg_128(HV_REGISTER_HYPERVISOR_VERSION, &result);
+	a = lower_32_bits(result.registervaluelow);
+	b = upper_32_bits(result.registervaluelow);
+	c = lower_32_bits(result.registervaluehigh);
+	d = upper_32_bits(result.registervaluehigh);
+	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;
+
+	if (cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "arm64/hyperv_init:online",
+			      hv_cpu_init, NULL) < 0)
+		goto free_vp_index;
+
+	hv_init_clocksource();
+
+	hyperv_initialized = true;
+	return 0;
+
+free_vp_index:
+	kfree(hv_vp_index);
+	hv_vp_index = NULL;
+	return -EINVAL;
+}
+TIMER_ACPI_DECLARE(hyperv, ACPI_SIG_GTDT, hyperv_init);
+
+
+/*
+ * Called from hv_init_clocksource() to do ARM64
+ * specific initialization of the sched clock
+ */
+void __init hv_setup_sched_clock(void *sched_clock)
+{
+	sched_clock_register(sched_clock, 64, HV_CLOCK_HZ);
+}
+
+/*
+ * 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
  */
 u64 hv_do_hypercall(u64 control, void *input, void *output)
@@ -260,3 +407,9 @@ 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);
-- 
1.8.3.1

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