[REFACTOR] Move vCPU code to separate file
This is to facilitate having a better framework for controlling access to CPU
features and registers.
Bug: 144898870
Change-Id: I68d7f08a4cce8e6b0bf2aa0325254a8a26fbf7fc
diff --git a/src/vcpu.c b/src/vcpu.c
new file mode 100644
index 0000000..a637a5a
--- /dev/null
+++ b/src/vcpu.c
@@ -0,0 +1,174 @@
+/*
+ * Copyright 2019 The Hafnium Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "hf/vcpu.h"
+
+#include "hf/check.h"
+#include "hf/dlog.h"
+#include "hf/std.h"
+#include "hf/vm.h"
+
+/**
+ * Locks the given vCPU and updates `locked` to hold the newly locked vCPU.
+ */
+struct vcpu_locked vcpu_lock(struct vcpu *vcpu)
+{
+ struct vcpu_locked locked = {
+ .vcpu = vcpu,
+ };
+
+ sl_lock(&vcpu->lock);
+
+ return locked;
+}
+
+/**
+ * Unlocks a vCPU previously locked with vpu_lock, and updates `locked` to
+ * reflect the fact that the vCPU is no longer locked.
+ */
+void vcpu_unlock(struct vcpu_locked *locked)
+{
+ sl_unlock(&locked->vcpu->lock);
+ locked->vcpu = NULL;
+}
+
+void vcpu_init(struct vcpu *vcpu, struct vm *vm)
+{
+ memset_s(vcpu, sizeof(*vcpu), 0, sizeof(*vcpu));
+ sl_init(&vcpu->lock);
+ vcpu->regs_available = true;
+ vcpu->vm = vm;
+ vcpu->state = VCPU_STATE_OFF;
+}
+
+/**
+ * Initialise the registers for the given vCPU and set the state to
+ * VCPU_STATE_READY. The caller must hold the vCPU lock while calling this.
+ */
+void vcpu_on(struct vcpu_locked vcpu, ipaddr_t entry, uintreg_t arg)
+{
+ arch_regs_set_pc_arg(&vcpu.vcpu->regs, entry, arg);
+ vcpu.vcpu->state = VCPU_STATE_READY;
+}
+
+spci_vcpu_index_t vcpu_index(const struct vcpu *vcpu)
+{
+ size_t index = vcpu - vcpu->vm->vcpus;
+
+ CHECK(index < UINT16_MAX);
+ return index;
+}
+
+/**
+ * Check whether the given vcpu_state is an off state, for the purpose of
+ * turning vCPUs on and off. Note that aborted still counts as on in this
+ * context.
+ */
+bool vcpu_is_off(struct vcpu_locked vcpu)
+{
+ switch (vcpu.vcpu->state) {
+ case VCPU_STATE_OFF:
+ return true;
+ case VCPU_STATE_READY:
+ case VCPU_STATE_RUNNING:
+ case VCPU_STATE_BLOCKED_MAILBOX:
+ case VCPU_STATE_BLOCKED_INTERRUPT:
+ case VCPU_STATE_ABORTED:
+ /*
+ * Aborted still counts as ON for the purposes of PSCI,
+ * because according to the PSCI specification (section
+ * 5.7.1) a core is only considered to be off if it has
+ * been turned off with a CPU_OFF call or hasn't yet
+ * been turned on with a CPU_ON call.
+ */
+ return false;
+ }
+}
+
+/**
+ * Starts a vCPU of a secondary VM.
+ *
+ * Returns true if the secondary was reset and started, or false if it was
+ * already on and so nothing was done.
+ */
+bool vcpu_secondary_reset_and_start(struct vcpu *vcpu, ipaddr_t entry,
+ uintreg_t arg)
+{
+ struct vcpu_locked vcpu_locked;
+ struct vm *vm = vcpu->vm;
+ bool vcpu_was_off;
+
+ CHECK(vm->id != HF_PRIMARY_VM_ID);
+
+ vcpu_locked = vcpu_lock(vcpu);
+ vcpu_was_off = vcpu_is_off(vcpu_locked);
+ if (vcpu_was_off) {
+ /*
+ * Set vCPU registers to a clean state ready for boot. As this
+ * is a secondary which can migrate between pCPUs, the ID of the
+ * vCPU is defined as the index and does not match the ID of the
+ * pCPU it is running on.
+ */
+ arch_regs_reset(vcpu);
+ vcpu_on(vcpu_locked, entry, arg);
+ }
+ vcpu_unlock(&vcpu_locked);
+
+ return vcpu_was_off;
+}
+
+/**
+ * Handles a page fault. It does so by determining if it's a legitimate or
+ * spurious fault, and recovering from the latter.
+ *
+ * Returns true if the caller should resume the current vcpu, or false if its VM
+ * should be aborted.
+ */
+bool vcpu_handle_page_fault(const struct vcpu *current,
+ struct vcpu_fault_info *f)
+{
+ struct vm *vm = current->vm;
+ uint32_t mode;
+ uint32_t mask = f->mode | MM_MODE_INVALID;
+ bool resume;
+
+ sl_lock(&vm->lock);
+
+ /*
+ * Check if this is a legitimate fault, i.e., if the page table doesn't
+ * allow the access attempted by the VM.
+ *
+ * Otherwise, this is a spurious fault, likely because another CPU is
+ * updating the page table. It is responsible for issuing global TLB
+ * invalidations while holding the VM lock, so we don't need to do
+ * anything else to recover from it. (Acquiring/releasing the lock
+ * ensured that the invalidations have completed.)
+ */
+ resume = mm_vm_get_mode(&vm->ptable, f->ipaddr, ipa_add(f->ipaddr, 1),
+ &mode) &&
+ (mode & mask) == f->mode;
+
+ sl_unlock(&vm->lock);
+
+ if (!resume) {
+ dlog("Stage-2 page fault: pc=%#x, vmid=%u, vcpu=%u, "
+ "vaddr=%#x, ipaddr=%#x, mode=%#x\n",
+ f->pc, vm->id, vcpu_index(current), f->vaddr, f->ipaddr,
+ f->mode);
+ }
+
+ return resume;
+}