kvm_arch_vcpu_ioctl_run
前回MMIOが原因でguestが中断していれば、userlandでそのemulationをした結果を、書き戻す
vcpu_load
kvm_riscv_stage2_vmid_update
kvm_riscv_check_vcpu_request
preempt_disable, local_irq_disable
kvm_riscv_vcpu_flush_interrups
kvm_riscv_update_vsip
__kvm_riscv_switch_to
csr_read(CSR_SCAUSE)
csr_read(CSR_STVAL)
kvm_riscv_vcpu_sync_interrups
kvm_riscv_vcpu_exit
code:arch/riscv/kvm/vcpu.c
int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
{
int ret;
unsigned long scause, stval;
/* Mark this VCPU ran atleast once */
vcpu->arch.ran_atleast_once = true;
vcpu->arch.srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
/* Process MMIO value returned from user-space */
if (run->exit_reason == KVM_EXIT_MMIO) {
ret = kvm_riscv_vcpu_mmio_return(vcpu, vcpu->run);
if (ret) {
srcu_read_unlock(&vcpu->kvm->srcu, vcpu->arch.srcu_idx);
return ret;
}
}
if (run->immediate_exit) {
srcu_read_unlock(&vcpu->kvm->srcu, vcpu->arch.srcu_idx);
return -EINTR;
}
vcpu_load(vcpu);
kvm_sigset_activate(vcpu);
ret = 1;
run->exit_reason = KVM_EXIT_UNKNOWN;
while (ret > 0) {
/* Check conditions before entering the guest */
cond_resched();
kvm_riscv_stage2_vmid_update(vcpu);
kvm_riscv_check_vcpu_requests(vcpu);
preempt_disable();
local_irq_disable();
/*
* Exit if we have a signal pending so that we can deliver
* the signal to user space.
*/
if (signal_pending(current)) {
ret = -EINTR;
run->exit_reason = KVM_EXIT_INTR;
}
/*
* Ensure we set mode to IN_GUEST_MODE after we disable
* interrupts and before the final VCPU requests check.
* See the comment in kvm_vcpu_exiting_guest_mode() and
* Documentation/virtual/kvm/vcpu-requests.rst
*/
vcpu->mode = IN_GUEST_MODE;
srcu_read_unlock(&vcpu->kvm->srcu, vcpu->arch.srcu_idx);
smp_mb__after_srcu_read_unlock();
/*
* We might have got VCPU interrupts updated asynchronously
* so update it in HW.
*/
kvm_riscv_vcpu_flush_interrupts(vcpu);
/* Update VSIP CSR for current CPU */
kvm_riscv_update_vsip(vcpu);
if (ret <= 0 ||
kvm_riscv_stage2_vmid_ver_changed(&vcpu->kvm->arch.vmid) ||
kvm_request_pending(vcpu)) {
vcpu->mode = OUTSIDE_GUEST_MODE;
local_irq_enable();
preempt_enable();
vcpu->arch.srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
continue;
}
guest_enter_irqoff();
__kvm_riscv_switch_to(&vcpu->arch);
vcpu->mode = OUTSIDE_GUEST_MODE;
vcpu->stat.exits++;
/* Save SCAUSE and STVAL because we might get an interrupt
* between __kvm_riscv_switch_to() and local_irq_enable()
* which can potentially overwrite SCAUSE and STVAL.
*/
scause = csr_read(CSR_SCAUSE);
stval = csr_read(CSR_STVAL);
/* Syncup interrupts state with HW */
kvm_riscv_vcpu_sync_interrupts(vcpu);
/*
* We may have taken a host interrupt in VS/VU-mode (i.e.
* while executing the guest). This interrupt is still
* pending, as we haven't serviced it yet!
*
* We're now back in HS-mode with interrupts disabled
* so enabling the interrupts now will have the effect
* of taking the interrupt again, in HS-mode this time.
*/
local_irq_enable();
/*
* We do local_irq_enable() before calling guest_exit() so
* that if a timer interrupt hits while running the guest
* we account that tick as being spent in the guest. We
* enable preemption after calling guest_exit() so that if
* we get preempted we make sure ticks after that is not
* counted as guest time.
*/
guest_exit();
preempt_enable();
vcpu->arch.srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
ret = kvm_riscv_vcpu_exit(vcpu, run, scause, stval);
}
kvm_sigset_deactivate(vcpu);
vcpu_put(vcpu);
srcu_read_unlock(&vcpu->kvm->srcu, vcpu->arch.srcu_idx);
return ret;
}