1 files changed, 665 insertions, 0 deletions
diff --git a/drivers/hv/mshv_synic.c b/drivers/hv/mshv_synic.c
new file mode 100644
index 000000000000..e6b6381b7c36
--- /dev/null
+++ b/drivers/hv/mshv_synic.c
@@ -0,0 +1,665 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2023, Microsoft Corporation.
+ *
+ * mshv_root module's main interrupt handler and associated functionality.
+ *
+ * Authors: Microsoft Linux virtualization team
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/mm.h>
+#include <linux/io.h>
+#include <linux/random.h>
+#include <asm/mshyperv.h>
+
+#include "mshv_eventfd.h"
+#include "mshv.h"
+
+static u32 synic_event_ring_get_queued_port(u32 sint_index)
+{
+	struct hv_synic_event_ring_page **event_ring_page;
+	volatile struct hv_synic_event_ring *ring;
+	struct hv_synic_pages *spages;
+	u8 **synic_eventring_tail;
+	u32 message;
+	u8 tail;
+
+	spages = this_cpu_ptr(mshv_root.synic_pages);
+	event_ring_page = &spages->synic_event_ring_page;
+	synic_eventring_tail = (u8 **)this_cpu_ptr(hv_synic_eventring_tail);
+
+	if (unlikely(!*synic_eventring_tail)) {
+		pr_debug("Missing synic event ring tail!\n");
+		return 0;
+	}
+	tail = (*synic_eventring_tail)[sint_index];
+
+	if (unlikely(!*event_ring_page)) {
+		pr_debug("Missing synic event ring page!\n");
+		return 0;
+	}
+
+	ring = &(*event_ring_page)->sint_event_ring[sint_index];
+
+	/*
+	 * Get the message.
+	 */
+	message = ring->data[tail];
+
+	if (!message) {
+		if (ring->ring_full) {
+			/*
+			 * Ring is marked full, but we would have consumed all
+			 * the messages. Notify the hypervisor that ring is now
+			 * empty and check again.
+			 */
+			ring->ring_full = 0;
+			hv_call_notify_port_ring_empty(sint_index);
+			message = ring->data[tail];
+		}
+
+		if (!message) {
+			ring->signal_masked = 0;
+			/*
+			 * Unmask the signal and sync with hypervisor
+			 * before one last check for any message.
+			 */
+			mb();
+			message = ring->data[tail];
+
+			/*
+			 * Ok, lets bail out.
+			 */
+			if (!message)
+				return 0;
+		}
+
+		ring->signal_masked = 1;
+	}
+
+	/*
+	 * Clear the message in the ring buffer.
+	 */
+	ring->data[tail] = 0;
+
+	if (++tail == HV_SYNIC_EVENT_RING_MESSAGE_COUNT)
+		tail = 0;
+
+	(*synic_eventring_tail)[sint_index] = tail;
+
+	return message;
+}
+
+static bool
+mshv_doorbell_isr(struct hv_message *msg)
+{
+	struct hv_notification_message_payload *notification;
+	u32 port;
+
+	if (msg->header.message_type != HVMSG_SYNIC_SINT_INTERCEPT)
+		return false;
+
+	notification = (struct hv_notification_message_payload *)msg->u.payload;
+	if (notification->sint_index != HV_SYNIC_DOORBELL_SINT_INDEX)
+		return false;
+
+	while ((port = synic_event_ring_get_queued_port(HV_SYNIC_DOORBELL_SINT_INDEX))) {
+		struct port_table_info ptinfo = { 0 };
+
+		if (mshv_portid_lookup(port, &ptinfo)) {
+			pr_debug("Failed to get port info from port_table!\n");
+			continue;
+		}
+
+		if (ptinfo.hv_port_type != HV_PORT_TYPE_DOORBELL) {
+			pr_debug("Not a doorbell port!, port: %d, port_type: %d\n",
+				 port, ptinfo.hv_port_type);
+			continue;
+		}
+
+		/* Invoke the callback */
+		ptinfo.hv_port_doorbell.doorbell_cb(port,
+						 ptinfo.hv_port_doorbell.data);
+	}
+
+	return true;
+}
+
+static bool mshv_async_call_completion_isr(struct hv_message *msg)
+{
+	bool handled = false;
+	struct hv_async_completion_message_payload *async_msg;
+	struct mshv_partition *partition;
+	u64 partition_id;
+
+	if (msg->header.message_type != HVMSG_ASYNC_CALL_COMPLETION)
+		goto out;
+
+	async_msg =
+		(struct hv_async_completion_message_payload *)msg->u.payload;
+
+	partition_id = async_msg->partition_id;
+
+	/*
+	 * Hold this lock for the rest of the isr, because the partition could
+	 * be released anytime.
+	 * e.g. the MSHV_RUN_VP thread could wake on another cpu; it could
+	 * release the partition unless we hold this!
+	 */
+	rcu_read_lock();
+
+	partition = mshv_partition_find(partition_id);
+
+	if (unlikely(!partition)) {
+		pr_debug("failed to find partition %llu\n", partition_id);
+		goto unlock_out;
+	}
+
+	partition->async_hypercall_status = async_msg->status;
+	complete(&partition->async_hypercall);
+
+	handled = true;
+
+unlock_out:
+	rcu_read_unlock();
+out:
+	return handled;
+}
+
+static void kick_vp(struct mshv_vp *vp)
+{
+	atomic64_inc(&vp->run.vp_signaled_count);
+	vp->run.kicked_by_hv = 1;
+	wake_up(&vp->run.vp_suspend_queue);
+}
+
+static void
+handle_bitset_message(const struct hv_vp_signal_bitset_scheduler_message *msg)
+{
+	int bank_idx, vps_signaled = 0, bank_mask_size;
+	struct mshv_partition *partition;
+	const struct hv_vpset *vpset;
+	const u64 *bank_contents;
+	u64 partition_id = msg->partition_id;
+
+	if (msg->vp_bitset.bitset.format != HV_GENERIC_SET_SPARSE_4K) {
+		pr_debug("scheduler message format is not HV_GENERIC_SET_SPARSE_4K");
+		return;
+	}
+
+	if (msg->vp_count == 0) {
+		pr_debug("scheduler message with no VP specified");
+		return;
+	}
+
+	rcu_read_lock();
+
+	partition = mshv_partition_find(partition_id);
+	if (unlikely(!partition)) {
+		pr_debug("failed to find partition %llu\n", partition_id);
+		goto unlock_out;
+	}
+
+	vpset = &msg->vp_bitset.bitset;
+
+	bank_idx = -1;
+	bank_contents = vpset->bank_contents;
+	bank_mask_size = sizeof(vpset->valid_bank_mask) * BITS_PER_BYTE;
+
+	while (true) {
+		int vp_bank_idx = -1;
+		int vp_bank_size = sizeof(*bank_contents) * BITS_PER_BYTE;
+		int vp_index;
+
+		bank_idx = find_next_bit((unsigned long *)&vpset->valid_bank_mask,
+					 bank_mask_size, bank_idx + 1);
+		if (bank_idx == bank_mask_size)
+			break;
+
+		while (true) {
+			struct mshv_vp *vp;
+
+			vp_bank_idx = find_next_bit((unsigned long *)bank_contents,
+						    vp_bank_size, vp_bank_idx + 1);
+			if (vp_bank_idx == vp_bank_size)
+				break;
+
+			vp_index = (bank_idx * vp_bank_size) + vp_bank_idx;
+
+			/* This shouldn't happen, but just in case. */
+			if (unlikely(vp_index >= MSHV_MAX_VPS)) {
+				pr_debug("VP index %u out of bounds\n",
+					 vp_index);
+				goto unlock_out;
+			}
+
+			vp = partition->pt_vp_array[vp_index];
+			if (unlikely(!vp)) {
+				pr_debug("failed to find VP %u\n", vp_index);
+				goto unlock_out;
+			}
+
+			kick_vp(vp);
+			vps_signaled++;
+		}
+
+		bank_contents++;
+	}
+
+unlock_out:
+	rcu_read_unlock();
+
+	if (vps_signaled != msg->vp_count)
+		pr_debug("asked to signal %u VPs but only did %u\n",
+			 msg->vp_count, vps_signaled);
+}
+
+static void
+handle_pair_message(const struct hv_vp_signal_pair_scheduler_message *msg)
+{
+	struct mshv_partition *partition = NULL;
+	struct mshv_vp *vp;
+	int idx;
+
+	rcu_read_lock();
+
+	for (idx = 0; idx < msg->vp_count; idx++) {
+		u64 partition_id = msg->partition_ids[idx];
+		u32 vp_index = msg->vp_indexes[idx];
+
+		if (idx == 0 || partition->pt_id != partition_id) {
+			partition = mshv_partition_find(partition_id);
+			if (unlikely(!partition)) {
+				pr_debug("failed to find partition %llu\n",
+					 partition_id);
+				break;
+			}
+		}
+
+		/* This shouldn't happen, but just in case. */
+		if (unlikely(vp_index >= MSHV_MAX_VPS)) {
+			pr_debug("VP index %u out of bounds\n", vp_index);
+			break;
+		}
+
+		vp = partition->pt_vp_array[vp_index];
+		if (!vp) {
+			pr_debug("failed to find VP %u\n", vp_index);
+			break;
+		}
+
+		kick_vp(vp);
+	}
+
+	rcu_read_unlock();
+}
+
+static bool
+mshv_scheduler_isr(struct hv_message *msg)
+{
+	if (msg->header.message_type != HVMSG_SCHEDULER_VP_SIGNAL_BITSET &&
+	    msg->header.message_type != HVMSG_SCHEDULER_VP_SIGNAL_PAIR)
+		return false;
+
+	if (msg->header.message_type == HVMSG_SCHEDULER_VP_SIGNAL_BITSET)
+		handle_bitset_message((struct hv_vp_signal_bitset_scheduler_message *)
+				      msg->u.payload);
+	else
+		handle_pair_message((struct hv_vp_signal_pair_scheduler_message *)
+				    msg->u.payload);
+
+	return true;
+}
+
+static bool
+mshv_intercept_isr(struct hv_message *msg)
+{
+	struct mshv_partition *partition;
+	bool handled = false;
+	struct mshv_vp *vp;
+	u64 partition_id;
+	u32 vp_index;
+
+	partition_id = msg->header.sender;
+
+	rcu_read_lock();
+
+	partition = mshv_partition_find(partition_id);
+	if (unlikely(!partition)) {
+		pr_debug("failed to find partition %llu\n",
+			 partition_id);
+		goto unlock_out;
+	}
+
+	if (msg->header.message_type == HVMSG_X64_APIC_EOI) {
+		/*
+		 * Check if this gsi is registered in the
+		 * ack_notifier list and invoke the callback
+		 * if registered.
+		 */
+
+		/*
+		 * If there is a notifier, the ack callback is supposed
+		 * to handle the VMEXIT. So we need not pass this message
+		 * to vcpu thread.
+		 */
+		struct hv_x64_apic_eoi_message *eoi_msg =
+			(struct hv_x64_apic_eoi_message *)&msg->u.payload[0];
+
+		if (mshv_notify_acked_gsi(partition, eoi_msg->interrupt_vector)) {
+			handled = true;
+			goto unlock_out;
+		}
+	}
+
+	/*
+	 * We should get an opaque intercept message here for all intercept
+	 * messages, since we're using the mapped VP intercept message page.
+	 *
+	 * The intercept message will have been placed in intercept message
+	 * page at this point.
+	 *
+	 * Make sure the message type matches our expectation.
+	 */
+	if (msg->header.message_type != HVMSG_OPAQUE_INTERCEPT) {
+		pr_debug("wrong message type %d", msg->header.message_type);
+		goto unlock_out;
+	}
+
+	/*
+	 * Since we directly index the vp, and it has to exist for us to be here
+	 * (because the vp is only deleted when the partition is), no additional
+	 * locking is needed here
+	 */
+	vp_index =
+	       ((struct hv_opaque_intercept_message *)msg->u.payload)->vp_index;
+	vp = partition->pt_vp_array[vp_index];
+	if (unlikely(!vp)) {
+		pr_debug("failed to find VP %u\n", vp_index);
+		goto unlock_out;
+	}
+
+	kick_vp(vp);
+
+	handled = true;
+
+unlock_out:
+	rcu_read_unlock();
+
+	return handled;
+}
+
+void mshv_isr(void)
+{
+	struct hv_synic_pages *spages = this_cpu_ptr(mshv_root.synic_pages);
+	struct hv_message_page **msg_page = &spages->synic_message_page;
+	struct hv_message *msg;
+	bool handled;
+
+	if (unlikely(!(*msg_page))) {
+		pr_debug("Missing synic page!\n");
+		return;
+	}
+
+	msg = &((*msg_page)->sint_message[HV_SYNIC_INTERCEPTION_SINT_INDEX]);
+
+	/*
+	 * If the type isn't set, there isn't really a message;
+	 * it may be some other hyperv interrupt
+	 */
+	if (msg->header.message_type == HVMSG_NONE)
+		return;
+
+	handled = mshv_doorbell_isr(msg);
+
+	if (!handled)
+		handled = mshv_scheduler_isr(msg);
+
+	if (!handled)
+		handled = mshv_async_call_completion_isr(msg);
+
+	if (!handled)
+		handled = mshv_intercept_isr(msg);
+
+	if (handled) {
+		/*
+		 * Acknowledge message with hypervisor if another message is
+		 * pending.
+		 */
+		msg->header.message_type = HVMSG_NONE;
+		/*
+		 * Ensure the write is complete so the hypervisor will deliver
+		 * the next message if available.
+		 */
+		mb();
+		if (msg->header.message_flags.msg_pending)
+			hv_set_non_nested_msr(HV_MSR_EOM, 0);
+
+#ifdef HYPERVISOR_CALLBACK_VECTOR
+		add_interrupt_randomness(HYPERVISOR_CALLBACK_VECTOR);
+#endif
+	} else {
+		pr_warn_once("%s: unknown message type 0x%x\n", __func__,
+			     msg->header.message_type);
+	}
+}
+
+int mshv_synic_init(unsigned int cpu)
+{
+	union hv_synic_simp simp;
+	union hv_synic_siefp siefp;
+	union hv_synic_sirbp sirbp;
+#ifdef HYPERVISOR_CALLBACK_VECTOR
+	union hv_synic_sint sint;
+#endif
+	union hv_synic_scontrol sctrl;
+	struct hv_synic_pages *spages = this_cpu_ptr(mshv_root.synic_pages);
+	struct hv_message_page **msg_page = &spages->synic_message_page;
+	struct hv_synic_event_flags_page **event_flags_page =
+			&spages->synic_event_flags_page;
+	struct hv_synic_event_ring_page **event_ring_page =
+			&spages->synic_event_ring_page;
+
+	/* Setup the Synic's message page */
+	simp.as_uint64 = hv_get_non_nested_msr(HV_MSR_SIMP);
+	simp.simp_enabled = true;
+	*msg_page = memremap(simp.base_simp_gpa << HV_HYP_PAGE_SHIFT,
+			     HV_HYP_PAGE_SIZE,
+			     MEMREMAP_WB);
+
+	if (!(*msg_page))
+		return -EFAULT;
+
+	hv_set_non_nested_msr(HV_MSR_SIMP, simp.as_uint64);
+
+	/* Setup the Synic's event flags page */
+	siefp.as_uint64 = hv_get_non_nested_msr(HV_MSR_SIEFP);
+	siefp.siefp_enabled = true;
+	*event_flags_page = memremap(siefp.base_siefp_gpa << PAGE_SHIFT,
+				     PAGE_SIZE, MEMREMAP_WB);
+
+	if (!(*event_flags_page))
+		goto cleanup;
+
+	hv_set_non_nested_msr(HV_MSR_SIEFP, siefp.as_uint64);
+
+	/* Setup the Synic's event ring page */
+	sirbp.as_uint64 = hv_get_non_nested_msr(HV_MSR_SIRBP);
+	sirbp.sirbp_enabled = true;
+	*event_ring_page = memremap(sirbp.base_sirbp_gpa << PAGE_SHIFT,
+				    PAGE_SIZE, MEMREMAP_WB);
+
+	if (!(*event_ring_page))
+		goto cleanup;
+
+	hv_set_non_nested_msr(HV_MSR_SIRBP, sirbp.as_uint64);
+
+#ifdef HYPERVISOR_CALLBACK_VECTOR
+	/* Enable intercepts */
+	sint.as_uint64 = 0;
+	sint.vector = HYPERVISOR_CALLBACK_VECTOR;
+	sint.masked = false;
+	sint.auto_eoi = hv_recommend_using_aeoi();
+	hv_set_non_nested_msr(HV_MSR_SINT0 + HV_SYNIC_INTERCEPTION_SINT_INDEX,
+			      sint.as_uint64);
+
+	/* Doorbell SINT */
+	sint.as_uint64 = 0;
+	sint.vector = HYPERVISOR_CALLBACK_VECTOR;
+	sint.masked = false;
+	sint.as_intercept = 1;
+	sint.auto_eoi = hv_recommend_using_aeoi();
+	hv_set_non_nested_msr(HV_MSR_SINT0 + HV_SYNIC_DOORBELL_SINT_INDEX,
+			      sint.as_uint64);
+#endif
+
+	/* Enable global synic bit */
+	sctrl.as_uint64 = hv_get_non_nested_msr(HV_MSR_SCONTROL);
+	sctrl.enable = 1;
+	hv_set_non_nested_msr(HV_MSR_SCONTROL, sctrl.as_uint64);
+
+	return 0;
+
+cleanup:
+	if (*event_ring_page) {
+		sirbp.sirbp_enabled = false;
+		hv_set_non_nested_msr(HV_MSR_SIRBP, sirbp.as_uint64);
+		memunmap(*event_ring_page);
+	}
+	if (*event_flags_page) {
+		siefp.siefp_enabled = false;
+		hv_set_non_nested_msr(HV_MSR_SIEFP, siefp.as_uint64);
+		memunmap(*event_flags_page);
+	}
+	if (*msg_page) {
+		simp.simp_enabled = false;
+		hv_set_non_nested_msr(HV_MSR_SIMP, simp.as_uint64);
+		memunmap(*msg_page);
+	}
+
+	return -EFAULT;
+}
+
+int mshv_synic_cleanup(unsigned int cpu)
+{
+	union hv_synic_sint sint;
+	union hv_synic_simp simp;
+	union hv_synic_siefp siefp;
+	union hv_synic_sirbp sirbp;
+	union hv_synic_scontrol sctrl;
+	struct hv_synic_pages *spages = this_cpu_ptr(mshv_root.synic_pages);
+	struct hv_message_page **msg_page = &spages->synic_message_page;
+	struct hv_synic_event_flags_page **event_flags_page =
+		&spages->synic_event_flags_page;
+	struct hv_synic_event_ring_page **event_ring_page =
+		&spages->synic_event_ring_page;
+
+	/* Disable the interrupt */
+	sint.as_uint64 = hv_get_non_nested_msr(HV_MSR_SINT0 + HV_SYNIC_INTERCEPTION_SINT_INDEX);
+	sint.masked = true;
+	hv_set_non_nested_msr(HV_MSR_SINT0 + HV_SYNIC_INTERCEPTION_SINT_INDEX,
+			      sint.as_uint64);
+
+	/* Disable Doorbell SINT */
+	sint.as_uint64 = hv_get_non_nested_msr(HV_MSR_SINT0 + HV_SYNIC_DOORBELL_SINT_INDEX);
+	sint.masked = true;
+	hv_set_non_nested_msr(HV_MSR_SINT0 + HV_SYNIC_DOORBELL_SINT_INDEX,
+			      sint.as_uint64);
+
+	/* Disable Synic's event ring page */
+	sirbp.as_uint64 = hv_get_non_nested_msr(HV_MSR_SIRBP);
+	sirbp.sirbp_enabled = false;
+	hv_set_non_nested_msr(HV_MSR_SIRBP, sirbp.as_uint64);
+	memunmap(*event_ring_page);
+
+	/* Disable Synic's event flags page */
+	siefp.as_uint64 = hv_get_non_nested_msr(HV_MSR_SIEFP);
+	siefp.siefp_enabled = false;
+	hv_set_non_nested_msr(HV_MSR_SIEFP, siefp.as_uint64);
+	memunmap(*event_flags_page);
+
+	/* Disable Synic's message page */
+	simp.as_uint64 = hv_get_non_nested_msr(HV_MSR_SIMP);
+	simp.simp_enabled = false;
+	hv_set_non_nested_msr(HV_MSR_SIMP, simp.as_uint64);
+	memunmap(*msg_page);
+
+	/* Disable global synic bit */
+	sctrl.as_uint64 = hv_get_non_nested_msr(HV_MSR_SCONTROL);
+	sctrl.enable = 0;
+	hv_set_non_nested_msr(HV_MSR_SCONTROL, sctrl.as_uint64);
+
+	return 0;
+}
+
+int
+mshv_register_doorbell(u64 partition_id, doorbell_cb_t doorbell_cb, void *data,
+		       u64 gpa, u64 val, u64 flags)
+{
+	struct hv_connection_info connection_info = { 0 };
+	union hv_connection_id connection_id = { 0 };
+	struct port_table_info *port_table_info;
+	struct hv_port_info port_info = { 0 };
+	union hv_port_id port_id = { 0 };
+	int ret;
+
+	port_table_info = kmalloc(sizeof(*port_table_info), GFP_KERNEL);
+	if (!port_table_info)
+		return -ENOMEM;
+
+	port_table_info->hv_port_type = HV_PORT_TYPE_DOORBELL;
+	port_table_info->hv_port_doorbell.doorbell_cb = doorbell_cb;
+	port_table_info->hv_port_doorbell.data = data;
+	ret = mshv_portid_alloc(port_table_info);
+	if (ret < 0) {
+		kfree(port_table_info);
+		return ret;
+	}
+
+	port_id.u.id = ret;
+	port_info.port_type = HV_PORT_TYPE_DOORBELL;
+	port_info.doorbell_port_info.target_sint = HV_SYNIC_DOORBELL_SINT_INDEX;
+	port_info.doorbell_port_info.target_vp = HV_ANY_VP;
+	ret = hv_call_create_port(hv_current_partition_id, port_id, partition_id,
+				  &port_info,
+				  0, 0, NUMA_NO_NODE);
+
+	if (ret < 0) {
+		mshv_portid_free(port_id.u.id);
+		return ret;
+	}
+
+	connection_id.u.id = port_id.u.id;
+	connection_info.port_type = HV_PORT_TYPE_DOORBELL;
+	connection_info.doorbell_connection_info.gpa = gpa;
+	connection_info.doorbell_connection_info.trigger_value = val;
+	connection_info.doorbell_connection_info.flags = flags;
+
+	ret = hv_call_connect_port(hv_current_partition_id, port_id, partition_id,
+				   connection_id, &connection_info, 0, NUMA_NO_NODE);
+	if (ret < 0) {
+		hv_call_delete_port(hv_current_partition_id, port_id);
+		mshv_portid_free(port_id.u.id);
+		return ret;
+	}
+
+	// lets use the port_id as the doorbell_id
+	return port_id.u.id;
+}
+
+void
+mshv_unregister_doorbell(u64 partition_id, int doorbell_portid)
+{
+	union hv_port_id port_id = { 0 };
+	union hv_connection_id connection_id = { 0 };
+
+	connection_id.u.id = doorbell_portid;
+	hv_call_disconnect_port(partition_id, connection_id);
+
+	port_id.u.id = doorbell_portid;
+	hv_call_delete_port(hv_current_partition_id, port_id);
+
+	mshv_portid_free(doorbell_portid);
+}