path: root/arch/x86/kvm/hyperv.c

/*
 * KVM Microsoft Hyper-V emulation
 *
 * derived from arch/x86/kvm/x86.c
 *
 * Copyright (C) 2006 Qumranet, Inc.
 * Copyright (C) 2008 Qumranet, Inc.
 * Copyright IBM Corporation, 2008
 * Copyright 2010 Red Hat, Inc. and/or its affiliates.
 * Copyright (C) 2015 Andrey Smetanin <asmetanin@virtuozzo.com>
 *
 * Authors:
 *   Avi Kivity   <avi@qumranet.com>
 *   Yaniv Kamay  <yaniv@qumranet.com>
 *   Amit Shah    <amit.shah@qumranet.com>
 *   Ben-Ami Yassour <benami@il.ibm.com>
 *   Andrey Smetanin <asmetanin@virtuozzo.com>
 *
 * This work is licensed under the terms of the GNU GPL, version 2.  See
 * the COPYING file in the top-level directory.
 *
 */

#include "x86.h"
#include "lapic.h"
#include "ioapic.h"
#include "hyperv.h"

#include <linux/kvm_host.h>
#include <linux/highmem.h>
#include <asm/apicdef.h>
#include <trace/events/kvm.h>

#include "trace.h"

static inline u64 synic_read_sint(struct kvm_vcpu_hv_synic *synic, int sint)
{
	return atomic64_read(&synic->sint[sint]);
}

static inline int synic_get_sint_vector(u64 sint_value)
{
	if (sint_value & HV_SYNIC_SINT_MASKED)
		return -1;
	return sint_value & HV_SYNIC_SINT_VECTOR_MASK;
}

static bool synic_has_vector_connected(struct kvm_vcpu_hv_synic *synic,
				      int vector)
{
	int i;

	for (i = 0; i < ARRAY_SIZE(synic->sint); i++) {
		if (synic_get_sint_vector(synic_read_sint(synic, i)) == vector)
			return true;
	}
	return false;
}

static bool synic_has_vector_auto_eoi(struct kvm_vcpu_hv_synic *synic,
				     int vector)
{
	int i;
	u64 sint_value;

	for (i = 0; i < ARRAY_SIZE(synic->sint); i++) {
		sint_value = synic_read_sint(synic, i);
		if (synic_get_sint_vector(sint_value) == vector &&
		    sint_value & HV_SYNIC_SINT_AUTO_EOI)
			return true;
	}
	return false;
}

static int synic_set_sint(struct kvm_vcpu_hv_synic *synic, int sint,
			  u64 data, bool host)
{
	int vector;

	vector = data & HV_SYNIC_SINT_VECTOR_MASK;
	if (vector < 16 && !host)
		return 1;
	/*
	 * Guest may configure multiple SINTs to use the same vector, so
	 * we maintain a bitmap of vectors handled by synic, and a
	 * bitmap of vectors with auto-eoi behavior.  The bitmaps are
	 * updated here, and atomically queried on fast paths.
	 */

	atomic64_set(&synic->sint[sint], data);

	if (synic_has_vector_connected(synic, vector))
		__set_bit(vector, synic->vec_bitmap);
	else
		__clear_bit(vector, synic->vec_bitmap);

	if (synic_has_vector_auto_eoi(synic, vector))
		__set_bit(vector, synic->auto_eoi_bitmap);
	else
		__clear_bit(vector, synic->auto_eoi_bitmap);

	/* Load SynIC vectors into EOI exit bitmap */
	kvm_make_request(KVM_REQ_SCAN_IOAPIC, synic_to_vcpu(synic));
	return 0;
}

static struct kvm_vcpu_hv_synic *synic_get(struct kvm *kvm, u32 vcpu_id)
{
	struct kvm_vcpu *vcpu;
	struct kvm_vcpu_hv_synic *synic;

	if (vcpu_id >= atomic_read(&kvm->online_vcpus))
		return NULL;
	vcpu = kvm_get_vcpu(kvm, vcpu_id);
	if (!vcpu)
		return NULL;
	synic = vcpu_to_synic(vcpu);
	return (synic->active) ? synic : NULL;
}

static void synic_clear_sint_msg_pending(struct kvm_vcpu_hv_synic *synic,
					u32 sint)
{
	struct kvm_vcpu *vcpu = synic_to_vcpu(synic);
	struct page *page;
	gpa_t gpa;
	struct hv_message *msg;
	struct hv_message_page *msg_page;

	gpa = synic->msg_page & PAGE_MASK;
	page = kvm_vcpu_gfn_to_page(vcpu, gpa >> PAGE_SHIFT);
	if (is_error_page(page)) {
		vcpu_err(vcpu, "Hyper-V SynIC can't get msg page, gpa 0x%llx\n",
			 gpa);
		return;
	}
	msg_page = kmap_atomic(page);

	msg = &msg_page->sint_message[sint];
	msg->header.message_flags.msg_pending = 0;

	kunmap_atomic(msg_page);
	kvm_release_page_dirty(page);
	kvm_vcpu_mark_page_dirty(vcpu, gpa >> PAGE_SHIFT);
}

static void kvm_hv_notify_acked_sint(struct kvm_vcpu *vcpu, u32 sint)
{
	struct kvm *kvm = vcpu->kvm;
	struct kvm_vcpu_hv_synic *synic = vcpu_to_synic(vcpu);
	struct kvm_vcpu_hv *hv_vcpu = vcpu_to_hv_vcpu(vcpu);
	struct kvm_vcpu_hv_stimer *