summaryrefslogtreecommitdiff
path: root/arch/arm/kvm/mmio.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/arm/kvm/mmio.c')
-rw-r--r--arch/arm/kvm/mmio.c218
1 files changed, 218 insertions, 0 deletions
diff --git a/arch/arm/kvm/mmio.c b/arch/arm/kvm/mmio.c
new file mode 100644
index 000000000..974b1c606
--- /dev/null
+++ b/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;
+}