Commit b4436a0b authored by Cornelia Huck's avatar Cornelia Huck
Browse files

virtio-ccw: Wire up ioeventfd.



On hosts that support ioeventfd, make use of it for host-to-guest
notifications via diagnose 500.
Signed-off-by: default avatarCornelia Huck <cornelia.huck@de.ibm.com>
parent 6504a930
......@@ -68,7 +68,7 @@ int css_create_css_image(uint8_t cssid, bool default_image)
return 0;
}
static uint16_t css_build_subchannel_id(SubchDev *sch)
uint16_t css_build_subchannel_id(SubchDev *sch)
{
if (channel_subsys->max_cssid > 0) {
return (sch->cssid << 8) | (1 << 3) | (sch->ssid << 1) | 1;
......
......@@ -90,6 +90,7 @@ bool css_devno_used(uint8_t cssid, uint8_t ssid, uint16_t devno);
void css_subch_assign(uint8_t cssid, uint8_t ssid, uint16_t schid,
uint16_t devno, SubchDev *sch);
void css_sch_build_virtual_schib(SubchDev *sch, uint8_t chpid, uint8_t type);
uint16_t css_build_subchannel_id(SubchDev *sch);
void css_reset(void);
void css_reset_sch(SubchDev *sch);
void css_queue_crw(uint8_t rsc, uint8_t erc, int chain, uint16_t rsid);
......
......@@ -63,6 +63,90 @@ VirtIODevice *virtio_ccw_get_vdev(SubchDev *sch)
return vdev;
}
static int virtio_ccw_set_guest2host_notifier(VirtioCcwDevice *dev, int n,
bool assign, bool set_handler)
{
VirtQueue *vq = virtio_get_queue(dev->vdev, n);
EventNotifier *notifier = virtio_queue_get_host_notifier(vq);
int r = 0;
SubchDev *sch = dev->sch;
uint32_t sch_id = (css_build_subchannel_id(sch) << 16) | sch->schid;
if (assign) {
r = event_notifier_init(notifier, 1);
if (r < 0) {
error_report("%s: unable to init event notifier: %d", __func__, r);
return r;
}
virtio_queue_set_host_notifier_fd_handler(vq, true, set_handler);
r = s390_assign_subch_ioeventfd(event_notifier_get_fd(notifier), sch_id,
n, assign);
if (r < 0) {
error_report("%s: unable to assign ioeventfd: %d", __func__, r);
virtio_queue_set_host_notifier_fd_handler(vq, false, false);
event_notifier_cleanup(notifier);
return r;
}
} else {
virtio_queue_set_host_notifier_fd_handler(vq, false, false);
s390_assign_subch_ioeventfd(event_notifier_get_fd(notifier), sch_id,
n, assign);
event_notifier_cleanup(notifier);
}
return r;
}
static void virtio_ccw_start_ioeventfd(VirtioCcwDevice *dev)
{
int n, r;
if (!(dev->flags & VIRTIO_CCW_FLAG_USE_IOEVENTFD) ||
dev->ioeventfd_started) {
return;
}
for (n = 0; n < VIRTIO_PCI_QUEUE_MAX; n++) {
if (!virtio_queue_get_num(dev->vdev, n)) {
continue;
}
r = virtio_ccw_set_guest2host_notifier(dev, n, true, true);
if (r < 0) {
goto assign_error;
}
}
dev->ioeventfd_started = true;
return;
assign_error:
while (--n >= 0) {
if (!virtio_queue_get_num(dev->vdev, n)) {
continue;
}
r = virtio_ccw_set_guest2host_notifier(dev, n, false, false);
assert(r >= 0);
}
dev->ioeventfd_started = false;
/* Disable ioeventfd for this device. */
dev->flags &= ~VIRTIO_CCW_FLAG_USE_IOEVENTFD;
error_report("%s: failed. Fallback to userspace (slower).", __func__);
}
static void virtio_ccw_stop_ioeventfd(VirtioCcwDevice *dev)
{
int n, r;
if (!dev->ioeventfd_started) {
return;
}
for (n = 0; n < VIRTIO_PCI_QUEUE_MAX; n++) {
if (!virtio_queue_get_num(dev->vdev, n)) {
continue;
}
r = virtio_ccw_set_guest2host_notifier(dev, n, false, false);
assert(r >= 0);
}
dev->ioeventfd_started = false;
}
VirtualCssBus *virtual_css_bus_init(void)
{
VirtualCssBus *cbus;
......@@ -187,6 +271,7 @@ static int virtio_ccw_cb(SubchDev *sch, CCW1 ccw)
}
break;
case CCW_CMD_VDEV_RESET:
virtio_ccw_stop_ioeventfd(dev);
virtio_reset(dev->vdev);
ret = 0;
break;
......@@ -309,10 +394,16 @@ static int virtio_ccw_cb(SubchDev *sch, CCW1 ccw)
ret = -EFAULT;
} else {
status = ldub_phys(ccw.cda);
if (!(status & VIRTIO_CONFIG_S_DRIVER_OK)) {
virtio_ccw_stop_ioeventfd(dev);
}
virtio_set_status(dev->vdev, status);
if (dev->vdev->status == 0) {
virtio_reset(dev->vdev);
}
if (status & VIRTIO_CONFIG_S_DRIVER_OK) {
virtio_ccw_start_ioeventfd(dev);
}
sch->curr_status.scsw.count = ccw.count - sizeof(status);
ret = 0;
}
......@@ -540,6 +631,7 @@ static int virtio_ccw_exit(VirtioCcwDevice *dev)
{
SubchDev *sch = dev->sch;
virtio_ccw_stop_ioeventfd(dev);
if (sch) {
css_subch_assign(sch->cssid, sch->ssid, sch->schid, sch->devno, NULL);
g_free(sch);
......@@ -801,12 +893,24 @@ static void virtio_ccw_reset(DeviceState *d)
{
VirtioCcwDevice *dev = VIRTIO_CCW_DEVICE(d);
virtio_ccw_stop_ioeventfd(dev);
virtio_reset(dev->vdev);
css_reset_sch(dev->sch);
dev->indicators = 0;
dev->indicators2 = 0;
}
static void virtio_ccw_vmstate_change(DeviceState *d, bool running)
{
VirtioCcwDevice *dev = VIRTIO_CCW_DEVICE(d);
if (running) {
virtio_ccw_start_ioeventfd(dev);
} else {
virtio_ccw_stop_ioeventfd(dev);
}
}
/**************** Virtio-ccw Bus Device Descriptions *******************/
static Property virtio_ccw_net_properties[] = {
......@@ -814,6 +918,8 @@ static Property virtio_ccw_net_properties[] = {
DEFINE_VIRTIO_NET_FEATURES(VirtioCcwDevice, host_features[0]),
DEFINE_VIRTIO_NET_PROPERTIES(VirtIONetCcw, vdev.net_conf),
DEFINE_NIC_PROPERTIES(VirtIONetCcw, vdev.nic_conf),
DEFINE_PROP_BIT("ioeventfd", VirtioCcwDevice, flags,
VIRTIO_CCW_FLAG_USE_IOEVENTFD_BIT, true),
DEFINE_PROP_END_OF_LIST(),
};
......@@ -840,6 +946,8 @@ static Property virtio_ccw_blk_properties[] = {
DEFINE_PROP_STRING("devno", VirtioCcwDevice, bus_id),
DEFINE_VIRTIO_BLK_FEATURES(VirtioCcwDevice, host_features[0]),
DEFINE_VIRTIO_BLK_PROPERTIES(VirtIOBlkCcw, blk),
DEFINE_PROP_BIT("ioeventfd", VirtioCcwDevice, flags,
VIRTIO_CCW_FLAG_USE_IOEVENTFD_BIT, true),
DEFINE_PROP_END_OF_LIST(),
};
......@@ -866,6 +974,8 @@ static Property virtio_ccw_serial_properties[] = {
DEFINE_PROP_STRING("devno", VirtioCcwDevice, bus_id),
DEFINE_VIRTIO_SERIAL_PROPERTIES(VirtioSerialCcw, vdev.serial),
DEFINE_VIRTIO_COMMON_FEATURES(VirtioCcwDevice, host_features[0]),
DEFINE_PROP_BIT("ioeventfd", VirtioCcwDevice, flags,
VIRTIO_CCW_FLAG_USE_IOEVENTFD_BIT, true),
DEFINE_PROP_END_OF_LIST(),
};
......@@ -891,6 +1001,8 @@ static const TypeInfo virtio_ccw_serial = {
static Property virtio_ccw_balloon_properties[] = {
DEFINE_PROP_STRING("devno", VirtioCcwDevice, bus_id),
DEFINE_VIRTIO_COMMON_FEATURES(VirtioCcwDevice, host_features[0]),
DEFINE_PROP_BIT("ioeventfd", VirtioCcwDevice, flags,
VIRTIO_CCW_FLAG_USE_IOEVENTFD_BIT, true),
DEFINE_PROP_END_OF_LIST(),
};
......@@ -917,6 +1029,8 @@ static Property virtio_ccw_scsi_properties[] = {
DEFINE_PROP_STRING("devno", VirtioCcwDevice, bus_id),
DEFINE_VIRTIO_SCSI_PROPERTIES(VirtIOSCSICcw, vdev.parent_obj.conf),
DEFINE_VIRTIO_SCSI_FEATURES(VirtioCcwDevice, host_features[0]),
DEFINE_PROP_BIT("ioeventfd", VirtioCcwDevice, flags,
VIRTIO_CCW_FLAG_USE_IOEVENTFD_BIT, true),
DEFINE_PROP_END_OF_LIST(),
};
......@@ -980,6 +1094,8 @@ static Property virtio_ccw_rng_properties[] = {
DEFINE_PROP_STRING("devno", VirtioCcwDevice, bus_id),
DEFINE_VIRTIO_COMMON_FEATURES(VirtioCcwDevice, host_features[0]),
DEFINE_VIRTIO_RNG_PROPERTIES(VirtIORNGCcw, vdev.conf),
DEFINE_PROP_BIT("ioeventfd", VirtioCcwDevice, flags,
VIRTIO_CCW_FLAG_USE_IOEVENTFD_BIT, true),
DEFINE_PROP_END_OF_LIST(),
};
......@@ -1107,6 +1223,7 @@ static void virtio_ccw_bus_class_init(ObjectClass *klass, void *data)
bus_class->max_dev = 1;
k->notify = virtio_ccw_notify;
k->get_features = virtio_ccw_get_features;
k->vmstate_change = virtio_ccw_vmstate_change;
}
static const TypeInfo virtio_ccw_bus_info = {
......
......@@ -69,6 +69,11 @@ typedef struct VirtIOCCWDeviceClass {
/* Change here if we want to support more feature bits. */
#define VIRTIO_CCW_FEATURE_SIZE 1
/* Performance improves when virtqueue kick processing is decoupled from the
* vcpu thread using ioeventfd for some devices. */
#define VIRTIO_CCW_FLAG_USE_IOEVENTFD_BIT 1
#define VIRTIO_CCW_FLAG_USE_IOEVENTFD (1 << VIRTIO_CCW_FLAG_USE_IOEVENTFD_BIT)
struct VirtioCcwDevice {
DeviceState parent_obj;
SubchDev *sch;
......@@ -76,6 +81,8 @@ struct VirtioCcwDevice {
char *bus_id;
uint32_t host_features[VIRTIO_CCW_FEATURE_SIZE];
VirtioBusState bus;
bool ioeventfd_started;
uint32_t flags;
/* Guest provided values: */
hwaddr indicators;
hwaddr indicators2;
......
......@@ -1081,6 +1081,7 @@ void kvm_s390_io_interrupt(S390CPU *cpu, uint16_t subchannel_id,
void kvm_s390_crw_mchk(S390CPU *cpu);
void kvm_s390_enable_css_support(S390CPU *cpu);
int kvm_s390_get_registers_partial(CPUState *cpu);
int kvm_s390_assign_subch_ioeventfd(int fd, uint32_t sch, int vq, bool assign);
#else
static inline void kvm_s390_io_interrupt(S390CPU *cpu,
uint16_t subchannel_id,
......@@ -1099,6 +1100,11 @@ static inline int kvm_s390_get_registers_partial(CPUState *cpu)
{
return -ENOSYS;
}
static inline int kvm_s390_assign_subch_ioeventfd(int fd, uint32_t sch, int vq,
bool assign)
{
return -ENOSYS;
}
#endif
static inline void s390_io_interrupt(S390CPU *cpu,
......@@ -1125,4 +1131,14 @@ static inline void s390_crw_mchk(S390CPU *cpu)
}
}
static inline int s390_assign_subch_ioeventfd(int fd, uint32_t sch_id, int vq,
bool assign)
{
if (kvm_enabled()) {
return kvm_s390_assign_subch_ioeventfd(fd, sch_id, vq, assign);
} else {
return -ENOSYS;
}
}
#endif
......@@ -932,3 +932,22 @@ void kvm_s390_enable_css_support(S390CPU *cpu)
void kvm_arch_init_irq_routing(KVMState *s)
{
}
int kvm_s390_assign_subch_ioeventfd(int fd, uint32_t sch, int vq, bool assign)
{
struct kvm_ioeventfd kick = {
.flags = KVM_IOEVENTFD_FLAG_VIRTIO_CCW_NOTIFY |
KVM_IOEVENTFD_FLAG_DATAMATCH,
.fd = fd,
.datamatch = vq,
.addr = sch,
.len = 8,
};
if (!kvm_check_extension(kvm_state, KVM_CAP_IOEVENTFD)) {
return -ENOSYS;
}
if (!assign) {
kick.flags |= KVM_IOEVENTFD_FLAG_DEASSIGN;
}
return kvm_vm_ioctl(kvm_state, KVM_IOEVENTFD, &kick);
}
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