tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * Copyright (C) 2012 - Virtual Open Systems and Columbia University
3 * Author: Christoffer Dall <c.dall@virtualopensystems.com>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License, version 2, as
7 * published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
17 */
18
19#include <linux/kvm_host.h>
20#include <asm/kvm_mmio.h>
21#include <asm/kvm_emulate.h>
22#include <trace/events/kvm.h>
23
24#include "trace.h"
25
26/**
27 * kvm_handle_mmio_return -- Handle MMIO loads after user space emulation
28 * @vcpu: The VCPU pointer
29 * @run: The VCPU run struct containing the mmio data
30 *
31 * This should only be called after returning from userspace for MMIO load
32 * emulation.
33 */
34int kvm_handle_mmio_return(struct kvm_vcpu *vcpu, struct kvm_run *run)
35{
36 __u32 *dest;
37 unsigned int len;
38 int mask;
39
40 if (!run->mmio.is_write) {
41 dest = vcpu_reg(vcpu, vcpu->arch.mmio_decode.rt);
42 memset(dest, 0, sizeof(int));
43
44 len = run->mmio.len;
45 if (len > 4)
46 return -EINVAL;
47
48 memcpy(dest, run->mmio.data, len);
49
50 trace_kvm_mmio(KVM_TRACE_MMIO_READ, len, run->mmio.phys_addr,
51 *((u64 *)run->mmio.data));
52
53 if (vcpu->arch.mmio_decode.sign_extend && len < 4) {
54 mask = 1U << ((len * 8) - 1);
55 *dest = (*dest ^ mask) - mask;
56 }
57 }
58
59 return 0;
60}
61
62static int decode_hsr(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
63 struct kvm_exit_mmio *mmio)
64{
65 unsigned long rt, len;
66 bool is_write, sign_extend;
67
68 if ((vcpu->arch.hsr >> 8) & 1) {
69 /* cache operation on I/O addr, tell guest unsupported */
70 kvm_inject_dabt(vcpu, vcpu->arch.hxfar);
71 return 1;
72 }
73
74 if ((vcpu->arch.hsr >> 7) & 1) {
75 /* page table accesses IO mem: tell guest to fix its TTBR */
76 kvm_inject_dabt(vcpu, vcpu->arch.hxfar);
77 return 1;
78 }
79
80 switch ((vcpu->arch.hsr >> 22) & 0x3) {
81 case 0:
82 len = 1;
83 break;
84 case 1:
85 len = 2;
86 break;
87 case 2:
88 len = 4;
89 break;
90 default:
91 kvm_err("Hardware is weird: SAS 0b11 is reserved\n");
92 return -EFAULT;
93 }
94
95 is_write = vcpu->arch.hsr & HSR_WNR;
96 sign_extend = vcpu->arch.hsr & HSR_SSE;
97 rt = (vcpu->arch.hsr & HSR_SRT_MASK) >> HSR_SRT_SHIFT;
98
99 if (kvm_vcpu_reg_is_pc(vcpu, rt)) {
100 /* IO memory trying to read/write pc */
101 kvm_inject_pabt(vcpu, vcpu->arch.hxfar);
102 return 1;
103 }
104
105 mmio->is_write = is_write;
106 mmio->phys_addr = fault_ipa;
107 mmio->len = len;
108 vcpu->arch.mmio_decode.sign_extend = sign_extend;
109 vcpu->arch.mmio_decode.rt = rt;
110
111 /*
112 * The MMIO instruction is emulated and should not be re-executed
113 * in the guest.
114 */
115 kvm_skip_instr(vcpu, (vcpu->arch.hsr >> 25) & 1);
116 return 0;
117}
118
119int io_mem_abort(struct kvm_vcpu *vcpu, struct kvm_run *run,
120 phys_addr_t fault_ipa)
121{
122 struct kvm_exit_mmio mmio;
123 unsigned long rt;
124 int ret;
125
126 /*
127 * Prepare MMIO operation. First stash it in a private
128 * structure that we can use for in-kernel emulation. If the
129 * kernel can't handle it, copy it into run->mmio and let user
130 * space do its magic.
131 */
132
133 if (vcpu->arch.hsr & HSR_ISV) {
134 ret = decode_hsr(vcpu, fault_ipa, &mmio);
135 if (ret)
136 return ret;
137 } else {
138 kvm_err("load/store instruction decoding not implemented\n");
139 return -ENOSYS;
140 }
141
142 rt = vcpu->arch.mmio_decode.rt;
143 trace_kvm_mmio((mmio.is_write) ? KVM_TRACE_MMIO_WRITE :
144 KVM_TRACE_MMIO_READ_UNSATISFIED,
145 mmio.len, fault_ipa,
146 (mmio.is_write) ? *vcpu_reg(vcpu, rt) : 0);
147
148 if (mmio.is_write)
149 memcpy(mmio.data, vcpu_reg(vcpu, rt), mmio.len);
150
151 if (vgic_handle_mmio(vcpu, run, &mmio))
152 return 1;
153
154 kvm_prepare_mmio(run, &mmio);
155 return 0;
156}