Home Home > GIT Browse
summaryrefslogtreecommitdiff
blob: dac7ceb1a677746cadb086a2cf8a07d8e560373c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
/*
 * Copyright (C) 2012 - Virtual Open Systems and Columbia University
 * Author: Christoffer Dall <c.dall@virtualopensystems.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License, version 2, as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

#include <linux/kvm_host.h>
#include <asm/kvm_mmio.h>
#include <asm/kvm_emulate.h>
#include <trace/events/kvm.h>

#include "trace.h"

void kvm_mmio_write_buf(void *buf, unsigned int len, unsigned long data)
{
	void *datap = NULL;
	union {
		u8	byte;
		u16	hword;
		u32	word;
		u64	dword;
	} tmp;

	switch (len) {
	case 1:
		tmp.byte	= data;
		datap		= &tmp.byte;
		break;
	case 2:
		tmp.hword	= data;
		datap		= &tmp.hword;
		break;
	case 4:
		tmp.word	= data;
		datap		= &tmp.word;
		break;
	case 8:
		tmp.dword	= data;
		datap		= &tmp.dword;
		break;
	}

	memcpy(buf, datap, len);
}

unsigned long kvm_mmio_read_buf(const void *buf, unsigned int len)
{
	unsigned long data = 0;
	union {
		u16	hword;
		u32	word;
		u64	dword;
	} tmp;

	switch (len) {
	case 1:
		data = *(u8 *)buf;
		break;
	case 2:
		memcpy(&tmp.hword, buf, len);
		data = tmp.hword;
		break;
	case 4:
		memcpy(&tmp.word, buf, len);
		data = tmp.word;
		break;
	case 8:
		memcpy(&tmp.dword, buf, len);
		data = tmp.dword;
		break;
	}

	return data;
}

/**
 * kvm_handle_mmio_return -- Handle MMIO loads after user space emulation
 *			     or in-kernel IO emulation
 *
 * @vcpu: The VCPU pointer
 * @run:  The VCPU run struct containing the mmio data
 */
int kvm_handle_mmio_return(struct kvm_vcpu *vcpu, struct kvm_run *run)
{
	unsigned long data;
	unsigned int len;
	int mask;

	if (!run->mmio.is_write) {
		len = run->mmio.len;
		if (len > sizeof(unsigned long))
			return -EINVAL;

		data = kvm_mmio_read_buf(run->mmio.data, len);

		if (vcpu->arch.mmio_decode.sign_extend &&
		    len < sizeof(unsigned long)) {
			mask = 1U << ((len * 8) - 1);
			data = (data ^ mask) - mask;
		}

		trace_kvm_mmio(KVM_TRACE_MMIO_READ, len, run->mmio.phys_addr,
			       &data);
		data = vcpu_data_host_to_guest(vcpu, data, len);
		vcpu_set_reg(vcpu, vcpu->arch.mmio_decode.rt, data);
	}

	return 0;
}

static int decode_hsr(struct kvm_vcpu *vcpu, bool *is_write, int *len)
{
	unsigned long rt;
	int access_size;
	bool sign_extend;

	if (kvm_vcpu_dabt_iss1tw(vcpu)) {
		/* page table accesses IO mem: tell guest to fix its TTBR */
		kvm_inject_dabt(vcpu, kvm_vcpu_get_hfar(vcpu));
		return 1;
	}

	access_size = kvm_vcpu_dabt_get_as(vcpu);
	if (unlikely(access_size < 0))
		return access_size;

	*is_write = kvm_vcpu_dabt_iswrite(vcpu);
	sign_extend = kvm_vcpu_dabt_issext(vcpu);
	rt = kvm_vcpu_dabt_get_rd(vcpu);

	*len = access_size;
	vcpu->arch.mmio_decode.sign_extend = sign_extend;
	vcpu->arch.mmio_decode.rt = rt;

	/*
	 * The MMIO instruction is emulated and should not be re-executed
	 * in the guest.
	 */
	kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
	return 0;
}

int io_mem_abort(struct kvm_vcpu *vcpu, struct kvm_run *run,
		 phys_addr_t fault_ipa)
{
	unsigned long data;
	unsigned long rt;
	int ret;
	bool is_write;
	int len;
	u8 data_buf[8];

	/*
	 * Prepare MMIO operation. First decode the syndrome data we get
	 * from the CPU. Then try if some in-kernel emulation feels
	 * responsible, otherwise let user space do its magic.
	 */
	if (kvm_vcpu_dabt_isvalid(vcpu)) {
		ret = decode_hsr(vcpu, &is_write, &len);
		if (ret)
			return ret;
	} else {
		kvm_err("load/store instruction decoding not implemented\n");
		return -ENOSYS;
	}

	rt = vcpu->arch.mmio_decode.rt;

	if (is_write) {
		data = vcpu_data_guest_to_host(vcpu, vcpu_get_reg(vcpu, rt),
					       len);

		trace_kvm_mmio(KVM_TRACE_MMIO_WRITE, len, fault_ipa, &data);
		kvm_mmio_write_buf(data_buf, len, data);

		ret = kvm_io_bus_write(vcpu, KVM_MMIO_BUS, fault_ipa, len,
				       data_buf);
	} else {
		trace_kvm_mmio(KVM_TRACE_MMIO_READ_UNSATISFIED, len,
			       fault_ipa, NULL);

		ret = kvm_io_bus_read(vcpu, KVM_MMIO_BUS, fault_ipa, len,
				      data_buf);
	}

	/* Now prepare kvm_run for the potential return to userland. */
	run->mmio.is_write	= is_write;
	run->mmio.phys_addr	= fault_ipa;
	run->mmio.len		= len;

	if (!ret) {
		/* We handled the access successfully in the kernel. */
		if (!is_write)
			memcpy(run->mmio.data, data_buf, len);
		vcpu->stat.mmio_exit_kernel++;
		kvm_handle_mmio_return(vcpu, run);
		return 1;
	}

	if (is_write)
		memcpy(run->mmio.data, data_buf, len);
	vcpu->stat.mmio_exit_user++;
	run->exit_reason	= KVM_EXIT_MMIO;
	return 0;
}