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-rw-r--r--arch/arm64/kvm/mmio.c196
1 files changed, 196 insertions, 0 deletions
diff --git a/arch/arm64/kvm/mmio.c b/arch/arm64/kvm/mmio.c
new file mode 100644
index 000000000..3dd38a151
--- /dev/null
+++ b/arch/arm64/kvm/mmio.c
@@ -0,0 +1,196 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2012 - Virtual Open Systems and Columbia University
+ * Author: Christoffer Dall <c.dall@virtualopensystems.com>
+ */
+
+#include <linux/kvm_host.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
+ */
+int kvm_handle_mmio_return(struct kvm_vcpu *vcpu)
+{
+ unsigned long data;
+ unsigned int len;
+ int mask;
+
+ /* Detect an already handled MMIO return */
+ if (unlikely(!vcpu->mmio_needed))
+ return 0;
+
+ vcpu->mmio_needed = 0;
+
+ if (!kvm_vcpu_dabt_iswrite(vcpu)) {
+ struct kvm_run *run = vcpu->run;
+
+ len = kvm_vcpu_dabt_get_as(vcpu);
+ data = kvm_mmio_read_buf(run->mmio.data, len);
+
+ if (kvm_vcpu_dabt_issext(vcpu) &&
+ len < sizeof(unsigned long)) {
+ mask = 1U << ((len * 8) - 1);
+ data = (data ^ mask) - mask;
+ }
+
+ if (!kvm_vcpu_dabt_issf(vcpu))
+ data = data & 0xffffffff;
+
+ 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, kvm_vcpu_dabt_get_rd(vcpu), data);
+ }
+
+ /*
+ * The MMIO instruction is emulated and should not be re-executed
+ * in the guest.
+ */
+ kvm_incr_pc(vcpu);
+
+ return 0;
+}
+
+int io_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa)
+{
+ struct kvm_run *run = vcpu->run;
+ unsigned long data;
+ unsigned long rt;
+ int ret;
+ bool is_write;
+ int len;
+ u8 data_buf[8];
+
+ /*
+ * No valid syndrome? Ask userspace for help if it has
+ * volunteered to do so, and bail out otherwise.
+ */
+ if (!kvm_vcpu_dabt_isvalid(vcpu)) {
+ if (test_bit(KVM_ARCH_FLAG_RETURN_NISV_IO_ABORT_TO_USER,
+ &vcpu->kvm->arch.flags)) {
+ run->exit_reason = KVM_EXIT_ARM_NISV;
+ run->arm_nisv.esr_iss = kvm_vcpu_dabt_iss_nisv_sanitized(vcpu);
+ run->arm_nisv.fault_ipa = fault_ipa;
+ return 0;
+ }
+
+ kvm_pr_unimpl("Data abort outside memslots with no valid syndrome info\n");
+ return -ENOSYS;
+ }
+
+ /*
+ * 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.
+ */
+ is_write = kvm_vcpu_dabt_iswrite(vcpu);
+ len = kvm_vcpu_dabt_get_as(vcpu);
+ rt = kvm_vcpu_dabt_get_rd(vcpu);
+
+ 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;
+ vcpu->mmio_needed = 1;
+
+ 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);
+ 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;
+}