diff options
Diffstat (limited to 'kernel/arch/arm/kvm/mmio.c')
| -rw-r--r-- | kernel/arch/arm/kvm/mmio.c | 218 |
1 files changed, 218 insertions, 0 deletions
diff --git a/kernel/arch/arm/kvm/mmio.c b/kernel/arch/arm/kvm/mmio.c new file mode 100644 index 000000000..974b1c606 --- /dev/null +++ b/kernel/arch/arm/kvm/mmio.c @@ -0,0 +1,218 @@ +/* + * 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" + +static void mmio_write_buf(char *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); +} + +static unsigned long mmio_read_buf(char *buf, unsigned int len) +{ + unsigned long data = 0; + union { + u16 hword; + u32 word; + u64 dword; + } tmp; + + switch (len) { + case 1: + data = buf[0]; + 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 + * @vcpu: The VCPU pointer + * @run: The VCPU run struct containing the mmio data + * + * This should only be called after returning from userspace for MMIO load + * emulation. + */ +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 = 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_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_isextabt(vcpu)) { + /* cache operation on I/O addr, tell guest unsupported */ + kvm_inject_dabt(vcpu, kvm_vcpu_get_hfar(vcpu)); + return 1; + } + + 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_reg(vcpu, rt), len); + + trace_kvm_mmio(KVM_TRACE_MMIO_WRITE, len, fault_ipa, data); + 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, 0); + + 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; + memcpy(run->mmio.data, data_buf, len); + + if (!ret) { + /* We handled the access successfully in the kernel. */ + kvm_handle_mmio_return(vcpu, run); + return 1; + } + + run->exit_reason = KVM_EXIT_MMIO; + return 0; +} |