a697a334b3
Based on a patch from Mark McLoughlin, this patch introduces a new bottom half packet transmitter that avoids the latency imposed by the tx_timer approach. Rather than scheduling a timer when a TX packet comes in, schedule a bottom half to be run from the iothread. The bottom half handler first attempts to flush the queue with notification disabled (this is where we could race with a guest without txburst). If we flush a full burst, reschedule immediately. If we send short of a full burst, try to re-enable notification. To avoid a race with TXs that may have occurred, we must then flush again. If we find some packets to send, the guest it probably active, so we can reschedule again. tx_timer and tx_bh are mutually exclusive, so we can re-use the tx_waiting flag to indicate one or the other needs to be setup. This allows us to seamlessly migrate between timer and bh TX handling. The bottom half handler becomes the new default and we add a new tx= option to virtio-net-pci. Usage: -device virtio-net-pci,tx=timer # select timer mitigation vs "bh" Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
410 lines
11 KiB
C
410 lines
11 KiB
C
/*
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* QEMU S390 virtio target
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*
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* Copyright (c) 2009 Alexander Graf <agraf@suse.de>
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, see <http://www.gnu.org/licenses/>.
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*/
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#include "hw.h"
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#include "block.h"
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#include "sysemu.h"
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#include "net.h"
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#include "boards.h"
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#include "monitor.h"
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#include "loader.h"
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#include "elf.h"
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#include "hw/virtio.h"
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#include "hw/virtio-serial.h"
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#include "hw/virtio-net.h"
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#include "hw/sysbus.h"
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#include "kvm.h"
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#include "hw/s390-virtio-bus.h"
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/* #define DEBUG_S390 */
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#ifdef DEBUG_S390
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#define dprintf(fmt, ...) \
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do { fprintf(stderr, fmt, ## __VA_ARGS__); } while (0)
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#else
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#define dprintf(fmt, ...) \
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do { } while (0)
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#endif
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struct BusInfo s390_virtio_bus_info = {
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.name = "s390-virtio",
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.size = sizeof(VirtIOS390Bus),
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};
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typedef struct {
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DeviceInfo qdev;
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int (*init)(VirtIOS390Device *dev);
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} VirtIOS390DeviceInfo;
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static const VirtIOBindings virtio_s390_bindings;
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static ram_addr_t s390_virtio_device_num_vq(VirtIOS390Device *dev);
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VirtIOS390Bus *s390_virtio_bus_init(ram_addr_t *ram_size)
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{
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VirtIOS390Bus *bus;
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BusState *_bus;
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DeviceState *dev;
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/* Create bridge device */
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dev = qdev_create(NULL, "s390-virtio-bridge");
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qdev_init_nofail(dev);
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/* Create bus on bridge device */
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_bus = qbus_create(&s390_virtio_bus_info, dev, "s390-virtio");
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bus = DO_UPCAST(VirtIOS390Bus, bus, _bus);
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bus->dev_page = *ram_size;
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bus->dev_offs = bus->dev_page;
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bus->next_ring = bus->dev_page + TARGET_PAGE_SIZE;
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/* Allocate RAM for VirtIO device pages (descriptors, queues, rings) */
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*ram_size += S390_DEVICE_PAGES * TARGET_PAGE_SIZE;
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return bus;
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}
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static int s390_virtio_device_init(VirtIOS390Device *dev, VirtIODevice *vdev)
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{
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VirtIOS390Bus *bus;
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int dev_len;
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bus = DO_UPCAST(VirtIOS390Bus, bus, dev->qdev.parent_bus);
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dev->vdev = vdev;
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dev->dev_offs = bus->dev_offs;
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dev->feat_len = sizeof(uint32_t); /* always keep 32 bits features */
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dev_len = VIRTIO_DEV_OFFS_CONFIG;
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dev_len += s390_virtio_device_num_vq(dev) * VIRTIO_VQCONFIG_LEN;
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dev_len += dev->feat_len * 2;
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dev_len += vdev->config_len;
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bus->dev_offs += dev_len;
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virtio_bind_device(vdev, &virtio_s390_bindings, dev);
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dev->host_features = vdev->get_features(vdev, dev->host_features);
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s390_virtio_device_sync(dev);
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return 0;
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}
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static int s390_virtio_net_init(VirtIOS390Device *dev)
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{
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VirtIODevice *vdev;
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vdev = virtio_net_init((DeviceState *)dev, &dev->nic, &dev->net);
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if (!vdev) {
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return -1;
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}
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return s390_virtio_device_init(dev, vdev);
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}
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static int s390_virtio_blk_init(VirtIOS390Device *dev)
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{
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VirtIODevice *vdev;
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vdev = virtio_blk_init((DeviceState *)dev, &dev->block);
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if (!vdev) {
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return -1;
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}
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return s390_virtio_device_init(dev, vdev);
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}
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static int s390_virtio_serial_init(VirtIOS390Device *dev)
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{
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VirtIOS390Bus *bus;
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VirtIODevice *vdev;
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int r;
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bus = DO_UPCAST(VirtIOS390Bus, bus, dev->qdev.parent_bus);
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vdev = virtio_serial_init((DeviceState *)dev, dev->max_virtserial_ports);
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if (!vdev) {
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return -1;
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}
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r = s390_virtio_device_init(dev, vdev);
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if (!r) {
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bus->console = dev;
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}
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return r;
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}
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static uint64_t s390_virtio_device_vq_token(VirtIOS390Device *dev, int vq)
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{
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ram_addr_t token_off;
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token_off = (dev->dev_offs + VIRTIO_DEV_OFFS_CONFIG) +
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(vq * VIRTIO_VQCONFIG_LEN) +
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VIRTIO_VQCONFIG_OFFS_TOKEN;
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return ldq_phys(token_off);
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}
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static ram_addr_t s390_virtio_device_num_vq(VirtIOS390Device *dev)
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{
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VirtIODevice *vdev = dev->vdev;
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int num_vq;
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for (num_vq = 0; num_vq < VIRTIO_PCI_QUEUE_MAX; num_vq++) {
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if (!virtio_queue_get_num(vdev, num_vq)) {
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break;
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}
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}
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return num_vq;
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}
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static ram_addr_t s390_virtio_next_ring(VirtIOS390Bus *bus)
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{
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ram_addr_t r = bus->next_ring;
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bus->next_ring += VIRTIO_RING_LEN;
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return r;
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}
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void s390_virtio_device_sync(VirtIOS390Device *dev)
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{
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VirtIOS390Bus *bus = DO_UPCAST(VirtIOS390Bus, bus, dev->qdev.parent_bus);
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ram_addr_t cur_offs;
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uint8_t num_vq;
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int i;
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virtio_reset(dev->vdev);
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/* Sync dev space */
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stb_phys(dev->dev_offs + VIRTIO_DEV_OFFS_TYPE, dev->vdev->device_id);
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stb_phys(dev->dev_offs + VIRTIO_DEV_OFFS_NUM_VQ, s390_virtio_device_num_vq(dev));
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stb_phys(dev->dev_offs + VIRTIO_DEV_OFFS_FEATURE_LEN, dev->feat_len);
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stb_phys(dev->dev_offs + VIRTIO_DEV_OFFS_CONFIG_LEN, dev->vdev->config_len);
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num_vq = s390_virtio_device_num_vq(dev);
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stb_phys(dev->dev_offs + VIRTIO_DEV_OFFS_NUM_VQ, num_vq);
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/* Sync virtqueues */
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for (i = 0; i < num_vq; i++) {
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ram_addr_t vq = (dev->dev_offs + VIRTIO_DEV_OFFS_CONFIG) +
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(i * VIRTIO_VQCONFIG_LEN);
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ram_addr_t vring;
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vring = s390_virtio_next_ring(bus);
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virtio_queue_set_addr(dev->vdev, i, vring);
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virtio_queue_set_vector(dev->vdev, i, i);
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stq_phys(vq + VIRTIO_VQCONFIG_OFFS_ADDRESS, vring);
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stw_phys(vq + VIRTIO_VQCONFIG_OFFS_NUM, virtio_queue_get_num(dev->vdev, i));
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}
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cur_offs = dev->dev_offs;
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cur_offs += VIRTIO_DEV_OFFS_CONFIG;
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cur_offs += num_vq * VIRTIO_VQCONFIG_LEN;
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/* Sync feature bitmap */
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stl_phys(cur_offs, dev->host_features);
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dev->feat_offs = cur_offs + dev->feat_len;
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cur_offs += dev->feat_len * 2;
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/* Sync config space */
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if (dev->vdev->get_config) {
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dev->vdev->get_config(dev->vdev, dev->vdev->config);
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}
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cpu_physical_memory_rw(cur_offs, dev->vdev->config, dev->vdev->config_len, 1);
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cur_offs += dev->vdev->config_len;
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}
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void s390_virtio_device_update_status(VirtIOS390Device *dev)
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{
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VirtIODevice *vdev = dev->vdev;
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uint32_t features;
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virtio_set_status(vdev, ldub_phys(dev->dev_offs + VIRTIO_DEV_OFFS_STATUS));
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/* Update guest supported feature bitmap */
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features = ldl_phys(dev->feat_offs);
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if (vdev->set_features) {
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vdev->set_features(vdev, features);
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}
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vdev->guest_features = features;
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}
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VirtIOS390Device *s390_virtio_bus_console(VirtIOS390Bus *bus)
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{
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return bus->console;
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}
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/* Find a device by vring address */
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VirtIOS390Device *s390_virtio_bus_find_vring(VirtIOS390Bus *bus,
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ram_addr_t mem,
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int *vq_num)
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{
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VirtIOS390Device *_dev;
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DeviceState *dev;
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int i;
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QLIST_FOREACH(dev, &bus->bus.children, sibling) {
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_dev = (VirtIOS390Device *)dev;
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for(i = 0; i < VIRTIO_PCI_QUEUE_MAX; i++) {
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if (!virtio_queue_get_addr(_dev->vdev, i))
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break;
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if (virtio_queue_get_addr(_dev->vdev, i) == mem) {
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if (vq_num) {
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*vq_num = i;
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}
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return _dev;
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}
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}
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}
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return NULL;
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}
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/* Find a device by device descriptor location */
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VirtIOS390Device *s390_virtio_bus_find_mem(VirtIOS390Bus *bus, ram_addr_t mem)
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{
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VirtIOS390Device *_dev;
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DeviceState *dev;
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QLIST_FOREACH(dev, &bus->bus.children, sibling) {
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_dev = (VirtIOS390Device *)dev;
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if (_dev->dev_offs == mem) {
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return _dev;
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}
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}
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return NULL;
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}
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static void virtio_s390_notify(void *opaque, uint16_t vector)
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{
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VirtIOS390Device *dev = (VirtIOS390Device*)opaque;
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uint64_t token = s390_virtio_device_vq_token(dev, vector);
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/* XXX kvm dependency! */
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kvm_s390_virtio_irq(s390_cpu_addr2state(0), 0, token);
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}
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static unsigned virtio_s390_get_features(void *opaque)
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{
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VirtIOS390Device *dev = (VirtIOS390Device*)opaque;
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return dev->host_features;
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}
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/**************** S390 Virtio Bus Device Descriptions *******************/
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static const VirtIOBindings virtio_s390_bindings = {
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.notify = virtio_s390_notify,
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.get_features = virtio_s390_get_features,
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};
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static VirtIOS390DeviceInfo s390_virtio_net = {
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.init = s390_virtio_net_init,
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.qdev.name = "virtio-net-s390",
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.qdev.size = sizeof(VirtIOS390Device),
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.qdev.props = (Property[]) {
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DEFINE_NIC_PROPERTIES(VirtIOS390Device, nic),
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DEFINE_PROP_UINT32("x-txtimer", VirtIOS390Device,
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net.txtimer, TX_TIMER_INTERVAL),
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DEFINE_PROP_INT32("x-txburst", VirtIOS390Device,
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net.txburst, TX_BURST),
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DEFINE_PROP_STRING("tx", VirtIOS390Device, net.tx),
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DEFINE_PROP_END_OF_LIST(),
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},
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};
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static VirtIOS390DeviceInfo s390_virtio_blk = {
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.init = s390_virtio_blk_init,
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.qdev.name = "virtio-blk-s390",
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.qdev.size = sizeof(VirtIOS390Device),
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.qdev.props = (Property[]) {
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DEFINE_BLOCK_PROPERTIES(VirtIOS390Device, block),
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DEFINE_PROP_END_OF_LIST(),
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},
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};
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static VirtIOS390DeviceInfo s390_virtio_serial = {
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.init = s390_virtio_serial_init,
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.qdev.name = "virtio-serial-s390",
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.qdev.alias = "virtio-serial",
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.qdev.size = sizeof(VirtIOS390Device),
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.qdev.props = (Property[]) {
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DEFINE_PROP_UINT32("max_ports", VirtIOS390Device, max_virtserial_ports,
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31),
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DEFINE_PROP_END_OF_LIST(),
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},
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};
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static int s390_virtio_busdev_init(DeviceState *dev, DeviceInfo *info)
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{
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VirtIOS390DeviceInfo *_info = (VirtIOS390DeviceInfo *)info;
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VirtIOS390Device *_dev = (VirtIOS390Device *)dev;
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return _info->init(_dev);
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}
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static void s390_virtio_bus_register_withprop(VirtIOS390DeviceInfo *info)
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{
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info->qdev.init = s390_virtio_busdev_init;
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info->qdev.bus_info = &s390_virtio_bus_info;
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assert(info->qdev.size >= sizeof(VirtIOS390Device));
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qdev_register(&info->qdev);
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}
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static void s390_virtio_register(void)
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{
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s390_virtio_bus_register_withprop(&s390_virtio_serial);
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s390_virtio_bus_register_withprop(&s390_virtio_blk);
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s390_virtio_bus_register_withprop(&s390_virtio_net);
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}
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device_init(s390_virtio_register);
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/***************** S390 Virtio Bus Bridge Device *******************/
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/* Only required to have the virtio bus as child in the system bus */
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static int s390_virtio_bridge_init(SysBusDevice *dev)
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{
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/* nothing */
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return 0;
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}
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static SysBusDeviceInfo s390_virtio_bridge_info = {
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.init = s390_virtio_bridge_init,
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.qdev.name = "s390-virtio-bridge",
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.qdev.size = sizeof(SysBusDevice),
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.qdev.no_user = 1,
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};
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static void s390_virtio_register_devices(void)
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{
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sysbus_register_withprop(&s390_virtio_bridge_info);
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}
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device_init(s390_virtio_register_devices)
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