}
-static int kvm_check_many_ioeventfds(void)
-{
- /* Userspace can use ioeventfd for io notification. This requires a host
- * that supports eventfd(2) and an I/O thread; since eventfd does not
- * support SIGIO it cannot interrupt the vcpu.
- *
- * Older kernels have a 6 device limit on the KVM io bus. Find out so we
- * can avoid creating too many ioeventfds.
- */
-#if defined(CONFIG_EVENTFD)
- int ioeventfds[7];
- int i, ret = 0;
- for (i = 0; i < ARRAY_SIZE(ioeventfds); i++) {
- ioeventfds[i] = eventfd(0, EFD_CLOEXEC);
- if (ioeventfds[i] < 0) {
- break;
- }
- ret = kvm_set_ioeventfd_pio(ioeventfds[i], 0, i, true, 2, true);
- if (ret < 0) {
- close(ioeventfds[i]);
- break;
- }
- }
-
- /* Decide whether many devices are supported or not */
- ret = i == ARRAY_SIZE(ioeventfds);
-
- while (i-- > 0) {
- kvm_set_ioeventfd_pio(ioeventfds[i], 0, i, false, 2, true);
- close(ioeventfds[i]);
- }
- return ret;
-#else
- return 0;
-#endif
-}
-
static const KVMCapabilityInfo *
kvm_check_extension_list(KVMState *s, const KVMCapabilityInfo *list)
{
memory_listener_register(&kvm_coalesced_pio_listener,
&address_space_io);
- s->many_ioeventfds = kvm_check_many_ioeventfds();
-
s->sync_mmu = !!kvm_vm_check_extension(kvm_state, KVM_CAP_SYNC_MMU);
if (!s->sync_mmu) {
ret = ram_block_discard_disable(true);
return kvm_state->max_nested_state_len;
}
-int kvm_has_many_ioeventfds(void)
-{
- if (!kvm_enabled()) {
- return 0;
- }
- return kvm_state->many_ioeventfds;
-}
-
int kvm_has_gsi_routing(void)
{
#ifdef KVM_CAP_IRQ_ROUTING
bool pcie_port = pci_bus_is_express(pci_get_bus(pci_dev)) &&
!pci_bus_is_root(pci_get_bus(pci_dev));
- if (kvm_enabled() && !kvm_has_many_ioeventfds()) {
- proxy->flags &= ~VIRTIO_PCI_FLAG_USE_IOEVENTFD;
- }
-
/* fd-based ioevents can't be synchronized in record/replay */
if (replay_mode != REPLAY_MODE_NONE) {
proxy->flags &= ~VIRTIO_PCI_FLAG_USE_IOEVENTFD;