1 files changed, 442 insertions, 0 deletions
diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c
new file mode 100644
index 000000000..4d6480d57
--- /dev/null
+++ b/drivers/hv/hv.c
@@ -0,0 +1,442 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2009, Microsoft Corporation.
+ *
+ * Authors:
+ *   Haiyang Zhang <haiyangz@microsoft.com>
+ *   Hank Janssen  <hjanssen@microsoft.com>
+ */
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/hyperv.h>
+#include <linux/random.h>
+#include <linux/clockchips.h>
+#include <linux/delay.h>
+#include <linux/interrupt.h>
+#include <clocksource/hyperv_timer.h>
+#include <asm/mshyperv.h>
+#include "hyperv_vmbus.h"
+
+/* The one and only */
+struct hv_context hv_context;
+
+/*
+ * hv_init - Main initialization routine.
+ *
+ * This routine must be called before any other routines in here are called
+ */
+int hv_init(void)
+{
+	hv_context.cpu_context = alloc_percpu(struct hv_per_cpu_context);
+	if (!hv_context.cpu_context)
+		return -ENOMEM;
+	return 0;
+}
+
+/*
+ * Functions for allocating and freeing memory with size and
+ * alignment HV_HYP_PAGE_SIZE. These functions are needed because
+ * the guest page size may not be the same as the Hyper-V page
+ * size. We depend upon kmalloc() aligning power-of-two size
+ * allocations to the allocation size boundary, so that the
+ * allocated memory appears to Hyper-V as a page of the size
+ * it expects.
+ */
+
+void *hv_alloc_hyperv_page(void)
+{
+	BUILD_BUG_ON(PAGE_SIZE <  HV_HYP_PAGE_SIZE);
+
+	if (PAGE_SIZE == HV_HYP_PAGE_SIZE)
+		return (void *)__get_free_page(GFP_KERNEL);
+	else
+		return kmalloc(HV_HYP_PAGE_SIZE, GFP_KERNEL);
+}
+
+void *hv_alloc_hyperv_zeroed_page(void)
+{
+	if (PAGE_SIZE == HV_HYP_PAGE_SIZE)
+		return (void *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
+	else
+		return kzalloc(HV_HYP_PAGE_SIZE, GFP_KERNEL);
+}
+
+void hv_free_hyperv_page(unsigned long addr)
+{
+	if (PAGE_SIZE == HV_HYP_PAGE_SIZE)
+		free_page(addr);
+	else
+		kfree((void *)addr);
+}
+
+/*
+ * hv_post_message - Post a message using the hypervisor message IPC.
+ *
+ * This involves a hypercall.
+ */
+int hv_post_message(union hv_connection_id connection_id,
+		  enum hv_message_type message_type,
+		  void *payload, size_t payload_size)
+{
+	struct hv_input_post_message *aligned_msg;
+	struct hv_per_cpu_context *hv_cpu;
+	u64 status;
+
+	if (payload_size > HV_MESSAGE_PAYLOAD_BYTE_COUNT)
+		return -EMSGSIZE;
+
+	hv_cpu = get_cpu_ptr(hv_context.cpu_context);
+	aligned_msg = hv_cpu->post_msg_page;
+	aligned_msg->connectionid = connection_id;
+	aligned_msg->reserved = 0;
+	aligned_msg->message_type = message_type;
+	aligned_msg->payload_size = payload_size;
+	memcpy((void *)aligned_msg->payload, payload, payload_size);
+
+	if (hv_isolation_type_snp())
+		status = hv_ghcb_hypercall(HVCALL_POST_MESSAGE,
+				(void *)aligned_msg, NULL,
+				sizeof(*aligned_msg));
+	else
+		status = hv_do_hypercall(HVCALL_POST_MESSAGE,
+				aligned_msg, NULL);
+
+	/* Preemption must remain disabled until after the hypercall
+	 * so some other thread can't get scheduled onto this cpu and
+	 * corrupt the per-cpu post_msg_page
+	 */
+	put_cpu_ptr(hv_cpu);
+
+	return hv_result(status);
+}
+
+int hv_synic_alloc(void)
+{
+	int cpu;
+	struct hv_per_cpu_context *hv_cpu;
+
+	/*
+	 * First, zero all per-cpu memory areas so hv_synic_free() can
+	 * detect what memory has been allocated and cleanup properly
+	 * after any failures.
+	 */
+	for_each_present_cpu(cpu) {
+		hv_cpu = per_cpu_ptr(hv_context.cpu_context, cpu);
+		memset(hv_cpu, 0, sizeof(*hv_cpu));
+	}
+
+	hv_context.hv_numa_map = kcalloc(nr_node_ids, sizeof(struct cpumask),
+					 GFP_KERNEL);
+	if (hv_context.hv_numa_map == NULL) {
+		pr_err("Unable to allocate NUMA map\n");
+		goto err;
+	}
+
+	for_each_present_cpu(cpu) {
+		hv_cpu = per_cpu_ptr(hv_context.cpu_context, cpu);
+
+		tasklet_init(&hv_cpu->msg_dpc,
+			     vmbus_on_msg_dpc, (unsigned long) hv_cpu);
+
+		/*
+		 * Synic message and event pages are allocated by paravisor.
+		 * Skip these pages allocation here.
+		 */
+		if (!hv_isolation_type_snp()) {
+			hv_cpu->synic_message_page =
+				(void *)get_zeroed_page(GFP_ATOMIC);
+			if (hv_cpu->synic_message_page == NULL) {
+				pr_err("Unable to allocate SYNIC message page\n");
+				goto err;
+			}
+
+			hv_cpu->synic_event_page =
+				(void *)get_zeroed_page(GFP_ATOMIC);
+			if (hv_cpu->synic_event_page == NULL) {
+				pr_err("Unable to allocate SYNIC event page\n");
+				goto err;
+			}
+		}
+
+		hv_cpu->post_msg_page = (void *)get_zeroed_page(GFP_ATOMIC);
+		if (hv_cpu->post_msg_page == NULL) {
+			pr_err("Unable to allocate post msg page\n");
+			goto err;
+		}
+	}
+
+	return 0;
+err:
+	/*
+	 * Any memory allocations that succeeded will be freed when
+	 * the caller cleans up by calling hv_synic_free()
+	 */
+	return -ENOMEM;
+}
+
+
+void hv_synic_free(void)
+{
+	int cpu;
+
+	for_each_present_cpu(cpu) {
+		struct hv_per_cpu_context *hv_cpu
+			= per_cpu_ptr(hv_context.cpu_context, cpu);
+
+		free_page((unsigned long)hv_cpu->synic_event_page);
+		free_page((unsigned long)hv_cpu->synic_message_page);
+		free_page((unsigned long)hv_cpu->post_msg_page);
+	}
+
+	kfree(hv_context.hv_numa_map);
+}
+
+/*
+ * hv_synic_init - Initialize the Synthetic Interrupt Controller.
+ *
+ * If it is already initialized by another entity (ie x2v shim), we need to
+ * retrieve the initialized message and event pages.  Otherwise, we create and
+ * initialize the message and event pages.
+ */
+void hv_synic_enable_regs(unsigned int cpu)
+{
+	struct hv_per_cpu_context *hv_cpu
+		= per_cpu_ptr(hv_context.cpu_context, cpu);
+	union hv_synic_simp simp;
+	union hv_synic_siefp siefp;
+	union hv_synic_sint shared_sint;
+	union hv_synic_scontrol sctrl;
+
+	/* Setup the Synic's message page */
+	simp.as_uint64 = hv_get_register(HV_REGISTER_SIMP);
+	simp.simp_enabled = 1;
+
+	if (hv_isolation_type_snp()) {
+		hv_cpu->synic_message_page
+			= memremap(simp.base_simp_gpa << HV_HYP_PAGE_SHIFT,
+				   HV_HYP_PAGE_SIZE, MEMREMAP_WB);
+		if (!hv_cpu->synic_message_page)
+			pr_err("Fail to map syinc message page.\n");
+	} else {
+		simp.base_simp_gpa = virt_to_phys(hv_cpu->synic_message_page)
+			>> HV_HYP_PAGE_SHIFT;
+	}
+
+	hv_set_register(HV_REGISTER_SIMP, simp.as_uint64);
+
+	/* Setup the Synic's event page */
+	siefp.as_uint64 = hv_get_register(HV_REGISTER_SIEFP);
+	siefp.siefp_enabled = 1;
+
+	if (hv_isolation_type_snp()) {
+		hv_cpu->synic_event_page =
+			memremap(siefp.base_siefp_gpa << HV_HYP_PAGE_SHIFT,
+				 HV_HYP_PAGE_SIZE, MEMREMAP_WB);
+
+		if (!hv_cpu->synic_event_page)
+			pr_err("Fail to map syinc event page.\n");
+	} else {
+		siefp.base_siefp_gpa = virt_to_phys(hv_cpu->synic_event_page)
+			>> HV_HYP_PAGE_SHIFT;
+	}
+
+	hv_set_register(HV_REGISTER_SIEFP, siefp.as_uint64);
+
+	/* Setup the shared SINT. */
+	if (vmbus_irq != -1)
+		enable_percpu_irq(vmbus_irq, 0);
+	shared_sint.as_uint64 = hv_get_register(HV_REGISTER_SINT0 +
+					VMBUS_MESSAGE_SINT);
+
+	shared_sint.vector = vmbus_interrupt;
+	shared_sint.masked = false;
+
+	/*
+	 * On architectures where Hyper-V doesn't support AEOI (e.g., ARM64),
+	 * it doesn't provide a recommendation flag and AEOI must be disabled.
+	 */
+#ifdef HV_DEPRECATING_AEOI_RECOMMENDED
+	shared_sint.auto_eoi =
+			!(ms_hyperv.hints & HV_DEPRECATING_AEOI_RECOMMENDED);
+#else
+	shared_sint.auto_eoi = 0;
+#endif
+	hv_set_register(HV_REGISTER_SINT0 + VMBUS_MESSAGE_SINT,
+				shared_sint.as_uint64);
+
+	/* Enable the global synic bit */
+	sctrl.as_uint64 = hv_get_register(HV_REGISTER_SCONTROL);
+	sctrl.enable = 1;
+
+	hv_set_register(HV_REGISTER_SCONTROL, sctrl.as_uint64);
+}
+
+int hv_synic_init(unsigned int cpu)
+{
+	hv_synic_enable_regs(cpu);
+
+	hv_stimer_legacy_init(cpu, VMBUS_MESSAGE_SINT);
+
+	return 0;
+}
+
+/*
+ * hv_synic_cleanup - Cleanup routine for hv_synic_init().
+ */
+void hv_synic_disable_regs(unsigned int cpu)
+{
+	struct hv_per_cpu_context *hv_cpu
+		= per_cpu_ptr(hv_context.cpu_context, cpu);
+	union hv_synic_sint shared_sint;
+	union hv_synic_simp simp;
+	union hv_synic_siefp siefp;
+	union hv_synic_scontrol sctrl;
+
+	shared_sint.as_uint64 = hv_get_register(HV_REGISTER_SINT0 +
+					VMBUS_MESSAGE_SINT);
+
+	shared_sint.masked = 1;
+
+	/* Need to correctly cleanup in the case of SMP!!! */
+	/* Disable the interrupt */
+	hv_set_register(HV_REGISTER_SINT0 + VMBUS_MESSAGE_SINT,
+				shared_sint.as_uint64);
+
+	simp.as_uint64 = hv_get_register(HV_REGISTER_SIMP);
+	/*
+	 * In Isolation VM, sim and sief pages are allocated by
+	 * paravisor. These pages also will be used by kdump
+	 * kernel. So just reset enable bit here and keep page
+	 * addresses.
+	 */
+	simp.simp_enabled = 0;
+	if (hv_isolation_type_snp())
+		memunmap(hv_cpu->synic_message_page);
+	else
+		simp.base_simp_gpa = 0;
+
+	hv_set_register(HV_REGISTER_SIMP, simp.as_uint64);
+
+	siefp.as_uint64 = hv_get_register(HV_REGISTER_SIEFP);
+	siefp.siefp_enabled = 0;
+
+	if (hv_isolation_type_snp())
+		memunmap(hv_cpu->synic_event_page);
+	else
+		siefp.base_siefp_gpa = 0;
+
+	hv_set_register(HV_REGISTER_SIEFP, siefp.as_uint64);
+
+	/* Disable the global synic bit */
+	sctrl.as_uint64 = hv_get_register(HV_REGISTER_SCONTROL);
+	sctrl.enable = 0;
+	hv_set_register(HV_REGISTER_SCONTROL, sctrl.as_uint64);
+
+	if (vmbus_irq != -1)
+		disable_percpu_irq(vmbus_irq);
+}
+
+#define HV_MAX_TRIES 3
+/*
+ * Scan the event flags page of 'this' CPU looking for any bit that is set.  If we find one
+ * bit set, then wait for a few milliseconds.  Repeat these steps for a maximum of 3 times.
+ * Return 'true', if there is still any set bit after this operation; 'false', otherwise.
+ *
+ * If a bit is set, that means there is a pending channel interrupt.  The expectation is
+ * that the normal interrupt handling mechanism will find and process the channel interrupt
+ * "very soon", and in the process clear the bit.
+ */
+static bool hv_synic_event_pending(void)
+{
+	struct hv_per_cpu_context *hv_cpu = this_cpu_ptr(hv_context.cpu_context);
+	union hv_synic_event_flags *event =
+		(union hv_synic_event_flags *)hv_cpu->synic_event_page + VMBUS_MESSAGE_SINT;
+	unsigned long *recv_int_page = event->flags; /* assumes VMBus version >= VERSION_WIN8 */
+	bool pending;
+	u32 relid;
+	int tries = 0;
+
+retry:
+	pending = false;
+	for_each_set_bit(relid, recv_int_page, HV_EVENT_FLAGS_COUNT) {
+		/* Special case - VMBus channel protocol messages */
+		if (relid == 0)
+			continue;
+		pending = true;
+		break;
+	}
+	if (pending && tries++ < HV_MAX_TRIES) {
+		usleep_range(10000, 20000);
+		goto retry;
+	}
+	return pending;
+}
+
+int hv_synic_cleanup(unsigned int cpu)
+{
+	struct vmbus_channel *channel, *sc;
+	bool channel_found = false;
+
+	if (vmbus_connection.conn_state != CONNECTED)
+		goto always_cleanup;
+
+	/*
+	 * Hyper-V does not provide a way to change the connect CPU once
+	 * it is set; we must prevent the connect CPU from going offline
+	 * while the VM is running normally. But in the panic or kexec()
+	 * path where the vmbus is already disconnected, the CPU must be
+	 * allowed to shut down.
+	 */
+	if (cpu == VMBUS_CONNECT_CPU)
+		return -EBUSY;
+
+	/*
+	 * Search for channels which are bound to the CPU we're about to
+	 * cleanup.  In case we find one and vmbus is still connected, we
+	 * fail; this will effectively prevent CPU offlining.
+	 *
+	 * TODO: Re-bind the channels to different CPUs.
+	 */
+	mutex_lock(&vmbus_connection.channel_mutex);
+	list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
+		if (channel->target_cpu == cpu) {
+			channel_found = true;
+			break;
+		}
+		list_for_each_entry(sc, &channel->sc_list, sc_list) {
+			if (sc->target_cpu == cpu) {
+				channel_found = true;
+				break;
+			}
+		}
+		if (channel_found)
+			break;
+	}
+	mutex_unlock(&vmbus_connection.channel_mutex);
+
+	if (channel_found)
+		return -EBUSY;
+
+	/*
+	 * channel_found == false means that any channels that were previously
+	 * assigned to the CPU have been reassigned elsewhere with a call of
+	 * vmbus_send_modifychannel().  Scan the event flags page looking for
+	 * bits that are set and waiting with a timeout for vmbus_chan_sched()
+	 * to process such bits.  If bits are still set after this operation
+	 * and VMBus is connected, fail the CPU offlining operation.
+	 */
+	if (vmbus_proto_version >= VERSION_WIN10_V4_1 && hv_synic_event_pending())
+		return -EBUSY;
+
+always_cleanup:
+	hv_stimer_legacy_cleanup(cpu);
+
+	hv_synic_disable_regs(cpu);
+
+	return 0;
+}