This means general bitops, like those documented in [atomic-ops]_ could
also be used, e.g. ::
- clear_bit(KVM_REQ_UNHALT & KVM_REQUEST_MASK, &vcpu->requests);
+ clear_bit(KVM_REQ_UNBLOCK & KVM_REQUEST_MASK, &vcpu->requests);
However, VCPU request users should refrain from doing so, as it would
break the abstraction. The first 8 bits are reserved for architecture
or in order to update the interrupt routing and ensure that assigned
devices will wake up the vCPU.
-KVM_REQ_UNHALT
-
- This request may be made from the KVM common function kvm_vcpu_block(),
- which is used to emulate an instruction that causes a CPU to halt until
- one of an architectural specific set of events and/or interrupts is
- received (determined by checking kvm_arch_vcpu_runnable()). When that
- event or interrupt arrives kvm_vcpu_block() makes the request. This is
- in contrast to when kvm_vcpu_block() returns due to any other reason,
- such as a pending signal, which does not indicate the VCPU's halt
- emulation should stop, and therefore does not make the request.
-
KVM_REQ_OUTSIDE_GUEST_MODE
This "request" ensures the target vCPU has exited guest mode prior to the
to check if it should awaken. One reason to do so is to provide
architectures a function where requests may be checked if necessary.
-Clearing Requests
------------------
-
-Generally it only makes sense for the receiving VCPU thread to clear a
-request. However, in some circumstances, such as when the requesting
-thread and the receiving VCPU thread are executed serially, such as when
-they are the same thread, or when they are using some form of concurrency
-control to temporarily execute synchronously, then it's possible to know
-that the request may be cleared immediately, rather than waiting for the
-receiving VCPU thread to handle the request in VCPU RUN. The only current
-examples of this are kvm_vcpu_block() calls made by VCPUs to block
-themselves. A possible side-effect of that call is to make the
-KVM_REQ_UNHALT request, which may then be cleared immediately when the
-VCPU returns from the call.
-
References
==========
kvm_vcpu_halt(vcpu);
vcpu_clear_flag(vcpu, IN_WFIT);
- kvm_clear_request(KVM_REQ_UNHALT, vcpu);
preempt_disable();
vgic_v4_load(vcpu);
* We are runnable, then definitely go off to user space to
* check if any I/O interrupts are pending.
*/
- kvm_clear_request(KVM_REQ_UNHALT, vcpu);
if (kvm_arch_vcpu_runnable(vcpu))
vcpu->run->exit_reason = KVM_EXIT_IRQ_WINDOW_OPEN;
}
if (msr & MSR_POW) {
if (!vcpu->arch.pending_exceptions) {
kvm_vcpu_halt(vcpu);
- kvm_clear_request(KVM_REQ_UNHALT, vcpu);
vcpu->stat.generic.halt_wakeup++;
/* Unset POW bit after we woke up */
case H_CEDE:
kvmppc_set_msr_fast(vcpu, kvmppc_get_msr(vcpu) | MSR_EE);
kvm_vcpu_halt(vcpu);
- kvm_clear_request(KVM_REQ_UNHALT, vcpu);
vcpu->stat.generic.halt_wakeup++;
return EMULATE_DONE;
case H_LOGICAL_CI_LOAD:
if (vcpu->arch.shared->msr & MSR_WE) {
local_irq_enable();
kvm_vcpu_halt(vcpu);
- kvm_clear_request(KVM_REQ_UNHALT, vcpu);
hard_irq_disable();
kvmppc_set_exit_type(vcpu, EMULATED_MTMSRWE_EXITS);
case EV_HCALL_TOKEN(EV_IDLE):
r = EV_SUCCESS;
kvm_vcpu_halt(vcpu);
- kvm_clear_request(KVM_REQ_UNHALT, vcpu);
break;
default:
r = EV_UNIMPLEMENTED;
kvm_vcpu_srcu_read_unlock(vcpu);
kvm_vcpu_halt(vcpu);
kvm_vcpu_srcu_read_lock(vcpu);
- kvm_clear_request(KVM_REQ_UNHALT, vcpu);
}
}
goto retry;
}
- /* nothing to do, just clear the request */
- kvm_clear_request(KVM_REQ_UNHALT, vcpu);
/* we left the vsie handler, nothing to do, just clear the request */
kvm_clear_request(KVM_REQ_VSIE_RESTART, vcpu);
if (hv_timer)
kvm_lapic_switch_to_hv_timer(vcpu);
- kvm_clear_request(KVM_REQ_UNHALT, vcpu);
-
/*
* If the vCPU is not runnable, a signal or another host event
* of some kind is pending; service it without changing the
r = 0;
goto out;
}
- kvm_clear_request(KVM_REQ_UNHALT, vcpu);
r = -EAGAIN;
if (signal_pending(current)) {
r = -EINTR;
del_timer(&vcpu->arch.xen.poll_timer);
vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE;
- kvm_clear_request(KVM_REQ_UNHALT, vcpu);
}
vcpu->arch.xen.poll_evtchn = 0;
#define KVM_REQUEST_NO_ACTION BIT(10)
/*
* Architecture-independent vcpu->requests bit members
- * Bits 4-7 are reserved for more arch-independent bits.
+ * Bits 3-7 are reserved for more arch-independent bits.
*/
#define KVM_REQ_TLB_FLUSH (0 | KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP)
#define KVM_REQ_VM_DEAD (1 | KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP)
#define KVM_REQ_UNBLOCK 2
-#define KVM_REQ_UNHALT 3
#define KVM_REQUEST_ARCH_BASE 8
/*
int ret = -EINTR;
int idx = srcu_read_lock(&vcpu->kvm->srcu);
- if (kvm_arch_vcpu_runnable(vcpu)) {
- kvm_make_request(KVM_REQ_UNHALT, vcpu);
+ if (kvm_arch_vcpu_runnable(vcpu))
goto out;
- }
if (kvm_cpu_has_pending_timer(vcpu))
goto out;
if (signal_pending(current))