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/*
* 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_warning(
"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;
}