qemu/include/hw/virtio/virtio-bus.h

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/*
* VirtioBus
*
* Copyright (C) 2012 : GreenSocs Ltd
* http://www.greensocs.com/ , email: info@greensocs.com
*
* Developed by :
* Frederic Konrad <fred.konrad@greensocs.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, see <http://www.gnu.org/licenses/>.
*
*/
#ifndef VIRTIO_BUS_H
#define VIRTIO_BUS_H
#include "hw/qdev.h"
#include "sysemu/sysemu.h"
#include "hw/virtio/virtio.h"
#define TYPE_VIRTIO_BUS "virtio-bus"
#define VIRTIO_BUS_GET_CLASS(obj) \
OBJECT_GET_CLASS(VirtioBusClass, obj, TYPE_VIRTIO_BUS)
#define VIRTIO_BUS_CLASS(klass) \
OBJECT_CLASS_CHECK(VirtioBusClass, klass, TYPE_VIRTIO_BUS)
#define VIRTIO_BUS(obj) OBJECT_CHECK(VirtioBusState, (obj), TYPE_VIRTIO_BUS)
typedef struct VirtioBusState VirtioBusState;
typedef struct VirtioBusClass {
/* This is what a VirtioBus must implement */
BusClass parent;
void (*notify)(DeviceState *d, uint16_t vector);
void (*save_config)(DeviceState *d, QEMUFile *f);
void (*save_queue)(DeviceState *d, int n, QEMUFile *f);
void (*save_extra_state)(DeviceState *d, QEMUFile *f);
int (*load_config)(DeviceState *d, QEMUFile *f);
int (*load_queue)(DeviceState *d, int n, QEMUFile *f);
int (*load_done)(DeviceState *d, QEMUFile *f);
int (*load_extra_state)(DeviceState *d, QEMUFile *f);
bool (*has_extra_state)(DeviceState *d);
bool (*query_guest_notifiers)(DeviceState *d);
int (*set_guest_notifiers)(DeviceState *d, int nvqs, bool assign);
void (*vmstate_change)(DeviceState *d, bool running);
/*
* Expose the features the transport layer supports before
* the negotiation takes place.
*/
void (*pre_plugged)(DeviceState *d, Error **errp);
/*
* transport independent init function.
* This is called by virtio-bus just after the device is plugged.
*/
void (*device_plugged)(DeviceState *d, Error **errp);
/*
* transport independent exit function.
* This is called by virtio-bus just before the device is unplugged.
*/
void (*device_unplugged)(DeviceState *d);
int (*query_nvectors)(DeviceState *d);
/*
* ioeventfd handling: if the transport implements ioeventfd_assign,
* it must implement ioeventfd_enabled as well.
*/
/* Returns true if the ioeventfd is enabled for the device. */
bool (*ioeventfd_enabled)(DeviceState *d);
/*
* Assigns/deassigns the ioeventfd backing for the transport on
* the device for queue number n. Returns an error value on
* failure.
*/
int (*ioeventfd_assign)(DeviceState *d, EventNotifier *notifier,
int n, bool assign);
/*
* Does the transport have variable vring alignment?
* (ie can it ever call virtio_queue_set_align()?)
* Note that changing this will break migration for this transport.
*/
bool has_variable_vring_alignment;
AddressSpace *(*get_dma_as)(DeviceState *d);
} VirtioBusClass;
struct VirtioBusState {
BusState parent_obj;
/*
* Set if ioeventfd has been started.
*/
bool ioeventfd_started;
virtio: introduce grab/release_ioeventfd to fix vhost Following the recent refactoring of virtio notifiers [1], more specifically the patch ed08a2a0b ("virtio: use virtio_bus_set_host_notifier to start/stop ioeventfd") that uses virtio_bus_set_host_notifier [2] by default, core virtio code requires 'ioeventfd_started' to be set to true/false when the host notifiers are configured. When vhost is stopped and started, however, there is a stop followed by another start. Since ioeventfd_started was never set to true, the 'stop' operation triggered by virtio_bus_set_host_notifier() will not result in a call to virtio_pci_ioeventfd_assign(assign=false). This leaves the memory regions with stale notifiers and results on the next start triggering the following assertion: kvm_mem_ioeventfd_add: error adding ioeventfd: File exists Aborted This patch reintroduces (hopefully in a cleaner way) the concept that was present with ioeventfd_disabled before the refactoring. When ioeventfd_grabbed>0, ioeventfd_started tracks whether ioeventfd should be enabled or not, but ioeventfd is actually not started at all until vhost releases the host notifiers. [1] http://lists.nongnu.org/archive/html/qemu-devel/2016-10/msg07748.html [2] http://lists.nongnu.org/archive/html/qemu-devel/2016-10/msg07760.html Reported-by: Felipe Franciosi <felipe@nutanix.com> Reported-by: Christian Borntraeger <borntraeger@de.ibm.com> Reported-by: Alex Williamson <alex.williamson@redhat.com> Fixes: ed08a2a0b ("virtio: use virtio_bus_set_host_notifier to start/stop ioeventfd") Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Tested-by: Alexey Kardashevskiy <aik@ozlabs.ru> Tested-by: Farhan Ali <alifm@linux.vnet.ibm.com> Tested-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2016-11-18 18:07:00 +03:00
/*
* Set if ioeventfd has been grabbed by vhost. When ioeventfd
* is grabbed by vhost, we track its started/stopped state (which
* depends in turn on the virtio status register), but do not
* register a handler for the ioeventfd. When ioeventfd is
* released, if ioeventfd_started is true we finally register
* the handler so that QEMU's device model can use ioeventfd.
*/
int ioeventfd_grabbed;
};
void virtio_bus_device_plugged(VirtIODevice *vdev, Error **errp);
void virtio_bus_reset(VirtioBusState *bus);
void virtio_bus_device_unplugged(VirtIODevice *bus);
/* Get the device id of the plugged device. */
uint16_t virtio_bus_get_vdev_id(VirtioBusState *bus);
/* Get the config_len field of the plugged device. */
size_t virtio_bus_get_vdev_config_len(VirtioBusState *bus);
/* Get bad features of the plugged device. */
uint32_t virtio_bus_get_vdev_bad_features(VirtioBusState *bus);
/* Get config of the plugged device. */
void virtio_bus_get_vdev_config(VirtioBusState *bus, uint8_t *config);
/* Set config of the plugged device. */
void virtio_bus_set_vdev_config(VirtioBusState *bus, uint8_t *config);
static inline VirtIODevice *virtio_bus_get_device(VirtioBusState *bus)
{
BusState *qbus = &bus->parent_obj;
BusChild *kid = QTAILQ_FIRST(&qbus->children);
DeviceState *qdev = kid ? kid->child : NULL;
/* This is used on the data path, the cast is guaranteed
* to succeed by the qdev machinery.
*/
return (VirtIODevice *)qdev;
}
/* Return whether the proxy allows ioeventfd. */
bool virtio_bus_ioeventfd_enabled(VirtioBusState *bus);
/* Start the ioeventfd. */
int virtio_bus_start_ioeventfd(VirtioBusState *bus);
/* Stop the ioeventfd. */
void virtio_bus_stop_ioeventfd(VirtioBusState *bus);
virtio: introduce grab/release_ioeventfd to fix vhost Following the recent refactoring of virtio notifiers [1], more specifically the patch ed08a2a0b ("virtio: use virtio_bus_set_host_notifier to start/stop ioeventfd") that uses virtio_bus_set_host_notifier [2] by default, core virtio code requires 'ioeventfd_started' to be set to true/false when the host notifiers are configured. When vhost is stopped and started, however, there is a stop followed by another start. Since ioeventfd_started was never set to true, the 'stop' operation triggered by virtio_bus_set_host_notifier() will not result in a call to virtio_pci_ioeventfd_assign(assign=false). This leaves the memory regions with stale notifiers and results on the next start triggering the following assertion: kvm_mem_ioeventfd_add: error adding ioeventfd: File exists Aborted This patch reintroduces (hopefully in a cleaner way) the concept that was present with ioeventfd_disabled before the refactoring. When ioeventfd_grabbed>0, ioeventfd_started tracks whether ioeventfd should be enabled or not, but ioeventfd is actually not started at all until vhost releases the host notifiers. [1] http://lists.nongnu.org/archive/html/qemu-devel/2016-10/msg07748.html [2] http://lists.nongnu.org/archive/html/qemu-devel/2016-10/msg07760.html Reported-by: Felipe Franciosi <felipe@nutanix.com> Reported-by: Christian Borntraeger <borntraeger@de.ibm.com> Reported-by: Alex Williamson <alex.williamson@redhat.com> Fixes: ed08a2a0b ("virtio: use virtio_bus_set_host_notifier to start/stop ioeventfd") Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Tested-by: Alexey Kardashevskiy <aik@ozlabs.ru> Tested-by: Farhan Ali <alifm@linux.vnet.ibm.com> Tested-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2016-11-18 18:07:00 +03:00
/* Tell the bus that vhost is grabbing the ioeventfd. */
int virtio_bus_grab_ioeventfd(VirtioBusState *bus);
/* bus that vhost is not using the ioeventfd anymore. */
void virtio_bus_release_ioeventfd(VirtioBusState *bus);
/* Switch from/to the generic ioeventfd handler */
int virtio_bus_set_host_notifier(VirtioBusState *bus, int n, bool assign);
#endif /* VIRTIO_BUS_H */