2 * Copyright (C) 2012 - Virtual Open Systems and Columbia University
3 * Author: Christoffer Dall <c.dall@virtualopensystems.com>
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.
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.
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.
19 #include <linux/kvm_host.h>
20 #include <asm/kvm_mmio.h>
21 #include <asm/kvm_emulate.h>
22 #include <trace/events/kvm.h>
26 void kvm_mmio_write_buf(void *buf, unsigned int len, unsigned long data)
55 memcpy(buf, datap, len);
58 unsigned long kvm_mmio_read_buf(const void *buf, unsigned int len)
60 unsigned long data = 0;
72 memcpy(&tmp.hword, buf, len);
76 memcpy(&tmp.word, buf, len);
80 memcpy(&tmp.dword, buf, len);
89 * kvm_handle_mmio_return -- Handle MMIO loads after user space emulation
90 * or in-kernel IO emulation
92 * @vcpu: The VCPU pointer
93 * @run: The VCPU run struct containing the mmio data
95 int kvm_handle_mmio_return(struct kvm_vcpu *vcpu, struct kvm_run *run)
101 /* Detect an already handled MMIO return */
102 if (unlikely(!vcpu->mmio_needed))
105 vcpu->mmio_needed = 0;
107 if (!run->mmio.is_write) {
109 if (len > sizeof(unsigned long))
112 data = kvm_mmio_read_buf(run->mmio.data, len);
114 if (vcpu->arch.mmio_decode.sign_extend &&
115 len < sizeof(unsigned long)) {
116 mask = 1U << ((len * 8) - 1);
117 data = (data ^ mask) - mask;
120 trace_kvm_mmio(KVM_TRACE_MMIO_READ, len, run->mmio.phys_addr,
122 data = vcpu_data_host_to_guest(vcpu, data, len);
123 vcpu_set_reg(vcpu, vcpu->arch.mmio_decode.rt, data);
127 * The MMIO instruction is emulated and should not be re-executed
130 kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
135 static int decode_hsr(struct kvm_vcpu *vcpu, bool *is_write, int *len)
141 if (kvm_vcpu_dabt_iss1tw(vcpu)) {
142 /* page table accesses IO mem: tell guest to fix its TTBR */
143 kvm_inject_dabt(vcpu, kvm_vcpu_get_hfar(vcpu));
147 access_size = kvm_vcpu_dabt_get_as(vcpu);
148 if (unlikely(access_size < 0))
151 *is_write = kvm_vcpu_dabt_iswrite(vcpu);
152 sign_extend = kvm_vcpu_dabt_issext(vcpu);
153 rt = kvm_vcpu_dabt_get_rd(vcpu);
156 vcpu->arch.mmio_decode.sign_extend = sign_extend;
157 vcpu->arch.mmio_decode.rt = rt;
162 int io_mem_abort(struct kvm_vcpu *vcpu, struct kvm_run *run,
163 phys_addr_t fault_ipa)
173 * Prepare MMIO operation. First decode the syndrome data we get
174 * from the CPU. Then try if some in-kernel emulation feels
175 * responsible, otherwise let user space do its magic.
177 if (kvm_vcpu_dabt_isvalid(vcpu)) {
178 ret = decode_hsr(vcpu, &is_write, &len);
182 kvm_err("load/store instruction decoding not implemented\n");
186 rt = vcpu->arch.mmio_decode.rt;
189 data = vcpu_data_guest_to_host(vcpu, vcpu_get_reg(vcpu, rt),
192 trace_kvm_mmio(KVM_TRACE_MMIO_WRITE, len, fault_ipa, &data);
193 kvm_mmio_write_buf(data_buf, len, data);
195 ret = kvm_io_bus_write(vcpu, KVM_MMIO_BUS, fault_ipa, len,
198 trace_kvm_mmio(KVM_TRACE_MMIO_READ_UNSATISFIED, len,
201 ret = kvm_io_bus_read(vcpu, KVM_MMIO_BUS, fault_ipa, len,
205 /* Now prepare kvm_run for the potential return to userland. */
206 run->mmio.is_write = is_write;
207 run->mmio.phys_addr = fault_ipa;
209 vcpu->mmio_needed = 1;
212 /* We handled the access successfully in the kernel. */
214 memcpy(run->mmio.data, data_buf, len);
215 vcpu->stat.mmio_exit_kernel++;
216 kvm_handle_mmio_return(vcpu, run);
221 memcpy(run->mmio.data, data_buf, len);
222 vcpu->stat.mmio_exit_user++;
223 run->exit_reason = KVM_EXIT_MMIO;