vmbus: vmbus implementation
Add the VMBus infrastructure -- bus, devices, root bridge, vmbus state
machine, vmbus channel interactions, etc.
VMBus is a collection of technologies. At its lowest layer, it's a message
passing and signaling mechanism, allowing efficient passing of messages to and
from guest VMs. A layer higher, it's a mechanism for defining channels of
communication, where each channel is tagged with a type (which implies a
protocol) and a instance ID. A layer higher than that, it's a bus driver,
serving as the basis of device enumeration within a VM, where a channel can
optionally be exposed as a paravirtual device. When a server-side (paravirtual
back-end) component wishes to offer a channel to a guest VM, it does so by
specifying a channel type, a mode, and an instance ID. VMBus then exposes this
in the guest.
More information about VMBus can be found in the file
vmbuskernelmodeclientlibapi.h in Microsoft's WDK.
TODO:
- split into smaller palatable pieces
- more comments
- check and handle corner cases
Kudos to Evgeny Yakovlev (formerly eyakovlev@virtuozzo.com) and Andrey
Smetatin (formerly asmetanin@virtuozzo.com) for research and
prototyping.
Signed-off-by: Roman Kagan <rkagan@virtuozzo.com>
Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Signed-off-by: Jon Doron <arilou@gmail.com>
Message-Id: <20200424123444.3481728-4-arilou@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-04-24 15:34:41 +03:00
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/*
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* QEMU Hyper-V VMBus
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*
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* Copyright (c) 2017-2018 Virtuozzo International GmbH.
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*
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* This work is licensed under the terms of the GNU GPL, version 2 or later.
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* See the COPYING file in the top-level directory.
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*/
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#ifndef HW_HYPERV_VMBUS_H
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#define HW_HYPERV_VMBUS_H
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#include "sysemu/sysemu.h"
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#include "sysemu/dma.h"
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#include "hw/qdev-core.h"
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#include "migration/vmstate.h"
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#include "hw/hyperv/vmbus-proto.h"
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#include "qemu/uuid.h"
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#define TYPE_VMBUS_DEVICE "vmbus-dev"
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#define VMBUS_DEVICE(obj) \
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OBJECT_CHECK(VMBusDevice, (obj), TYPE_VMBUS_DEVICE)
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#define VMBUS_DEVICE_CLASS(klass) \
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OBJECT_CLASS_CHECK(VMBusDeviceClass, (klass), TYPE_VMBUS_DEVICE)
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#define VMBUS_DEVICE_GET_CLASS(obj) \
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OBJECT_GET_CLASS(VMBusDeviceClass, (obj), TYPE_VMBUS_DEVICE)
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2020-08-25 22:20:30 +03:00
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#define TYPE_VMBUS "vmbus"
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typedef struct VMBus VMBus;
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#define VMBUS(obj) OBJECT_CHECK(VMBus, (obj), TYPE_VMBUS)
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vmbus: vmbus implementation
Add the VMBus infrastructure -- bus, devices, root bridge, vmbus state
machine, vmbus channel interactions, etc.
VMBus is a collection of technologies. At its lowest layer, it's a message
passing and signaling mechanism, allowing efficient passing of messages to and
from guest VMs. A layer higher, it's a mechanism for defining channels of
communication, where each channel is tagged with a type (which implies a
protocol) and a instance ID. A layer higher than that, it's a bus driver,
serving as the basis of device enumeration within a VM, where a channel can
optionally be exposed as a paravirtual device. When a server-side (paravirtual
back-end) component wishes to offer a channel to a guest VM, it does so by
specifying a channel type, a mode, and an instance ID. VMBus then exposes this
in the guest.
More information about VMBus can be found in the file
vmbuskernelmodeclientlibapi.h in Microsoft's WDK.
TODO:
- split into smaller palatable pieces
- more comments
- check and handle corner cases
Kudos to Evgeny Yakovlev (formerly eyakovlev@virtuozzo.com) and Andrey
Smetatin (formerly asmetanin@virtuozzo.com) for research and
prototyping.
Signed-off-by: Roman Kagan <rkagan@virtuozzo.com>
Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Signed-off-by: Jon Doron <arilou@gmail.com>
Message-Id: <20200424123444.3481728-4-arilou@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-04-24 15:34:41 +03:00
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/*
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* Object wrapping a GPADL -- GPA Descriptor List -- an array of guest physical
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* pages, to be used for various buffers shared between the host and the guest.
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*/
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typedef struct VMBusGpadl VMBusGpadl;
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/*
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* VMBus channel -- a pair of ring buffers for either direction, placed within
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* one GPADL, and the associated notification means.
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*/
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typedef struct VMBusChannel VMBusChannel;
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/*
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* Base class for VMBus devices. Includes one or more channels. Identified by
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* class GUID and instance GUID.
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*/
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typedef struct VMBusDevice VMBusDevice;
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typedef void(*VMBusChannelNotifyCb)(struct VMBusChannel *chan);
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typedef struct VMBusDeviceClass {
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DeviceClass parent;
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QemuUUID classid;
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QemuUUID instanceid; /* Fixed UUID for singleton devices */
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uint16_t channel_flags;
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uint16_t mmio_size_mb;
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/* Extentions to standard device callbacks */
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void (*vmdev_realize)(VMBusDevice *vdev, Error **errp);
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void (*vmdev_unrealize)(VMBusDevice *vdev);
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void (*vmdev_reset)(VMBusDevice *vdev);
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/*
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* Calculate the number of channels based on the device properties. Called
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* at realize time.
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**/
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uint16_t (*num_channels)(VMBusDevice *vdev);
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/*
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* Device-specific actions to complete the otherwise successful process of
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* opening a channel.
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* Return 0 on success, -errno on failure.
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*/
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int (*open_channel)(VMBusChannel *chan);
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/*
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* Device-specific actions to perform before closing a channel.
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*/
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void (*close_channel)(VMBusChannel *chan);
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/*
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* Main device worker; invoked in response to notifications from either
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* side, when there's work to do with the data in the channel ring buffers.
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*/
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VMBusChannelNotifyCb chan_notify_cb;
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} VMBusDeviceClass;
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struct VMBusDevice {
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DeviceState parent;
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QemuUUID instanceid;
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uint16_t num_channels;
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VMBusChannel *channels;
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AddressSpace *dma_as;
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};
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extern const VMStateDescription vmstate_vmbus_dev;
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/*
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* A unit of work parsed out of a message in the receive (i.e. guest->host)
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* ring buffer of a channel. It's supposed to be subclassed (through
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* embedding) by the specific devices.
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*/
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typedef struct VMBusChanReq {
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VMBusChannel *chan;
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uint16_t pkt_type;
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uint32_t msglen;
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void *msg;
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uint64_t transaction_id;
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bool need_comp;
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QEMUSGList sgl;
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} VMBusChanReq;
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VMBusDevice *vmbus_channel_device(VMBusChannel *chan);
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VMBusChannel *vmbus_device_channel(VMBusDevice *dev, uint32_t chan_idx);
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uint32_t vmbus_channel_idx(VMBusChannel *chan);
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bool vmbus_channel_is_open(VMBusChannel *chan);
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/*
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* Notify (on guest's behalf) the host side of the channel that there's data in
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* the ringbuffer to process.
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*/
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void vmbus_channel_notify_host(VMBusChannel *chan);
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/*
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* Reserve space for a packet in the send (i.e. host->guest) ringbuffer. If
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* there isn't enough room, indicate that to the guest, to be notified when it
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* becomes available.
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* Return 0 on success, negative errno on failure.
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* The ringbuffer indices are NOT updated, the requested space indicator may.
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*/
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int vmbus_channel_reserve(VMBusChannel *chan,
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uint32_t desclen, uint32_t msglen);
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/*
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* Send a packet to the guest. The space for the packet MUST be reserved
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* first.
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* Return total number of bytes placed in the send ringbuffer on success,
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* negative errno on failure.
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* The ringbuffer indices are updated on success, and the guest is signaled if
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* needed.
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*/
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ssize_t vmbus_channel_send(VMBusChannel *chan, uint16_t pkt_type,
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void *desc, uint32_t desclen,
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void *msg, uint32_t msglen,
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bool need_comp, uint64_t transaction_id);
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/*
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* Prepare to fetch a batch of packets from the receive ring buffer.
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* Return 0 on success, negative errno on failure.
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*/
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int vmbus_channel_recv_start(VMBusChannel *chan);
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/*
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* Shortcut for a common case of sending a simple completion packet with no
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* auxiliary descriptors.
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*/
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ssize_t vmbus_channel_send_completion(VMBusChanReq *req,
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void *msg, uint32_t msglen);
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/*
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* Peek at the receive (i.e. guest->host) ring buffer and extract a unit of
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* work (a device-specific subclass of VMBusChanReq) from a packet if there's
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* one.
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* Return an allocated buffer, containing the request of @size with filled
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* VMBusChanReq at the beginning, followed by the message payload, or NULL on
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* failure.
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* The ringbuffer indices are NOT updated, nor is the private copy of the read
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* index.
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*/
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void *vmbus_channel_recv_peek(VMBusChannel *chan, uint32_t size);
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/*
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* Update the private copy of the read index once the preceding peek is deemed
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* successful.
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* The ringbuffer indices are NOT updated.
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*/
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void vmbus_channel_recv_pop(VMBusChannel *chan);
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/*
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* Propagate the private copy of the read index into the receive ring buffer,
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* and thus complete the reception of a series of packets. Notify guest if
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* needed.
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* Return the number of bytes popped off the receive ring buffer by the
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* preceding recv_peek/recv_pop calls on success, negative errno on failure.
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*/
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ssize_t vmbus_channel_recv_done(VMBusChannel *chan);
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/*
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* Free the request allocated by vmbus_channel_recv_peek, together with its
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* fields.
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*/
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void vmbus_free_req(void *req);
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/*
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* Find and reference a GPADL by @gpadl_id.
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* If not found return NULL.
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*/
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VMBusGpadl *vmbus_get_gpadl(VMBusChannel *chan, uint32_t gpadl_id);
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/*
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* Unreference @gpadl. If the reference count drops to zero, free it.
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* @gpadl may be NULL, in which case nothing is done.
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*/
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void vmbus_put_gpadl(VMBusGpadl *gpadl);
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/*
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* Calculate total length in bytes of @gpadl.
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* @gpadl must be valid.
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*/
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uint32_t vmbus_gpadl_len(VMBusGpadl *gpadl);
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/*
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* Copy data from @iov to @gpadl at offset @off.
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* Return the number of bytes copied, or a negative status on failure.
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*/
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ssize_t vmbus_iov_to_gpadl(VMBusChannel *chan, VMBusGpadl *gpadl, uint32_t off,
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const struct iovec *iov, size_t iov_cnt);
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/*
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* Map SGList contained in the request @req, at offset @off and no more than
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* @len bytes, for io in direction @dir, and populate @iov with the mapped
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* iovecs.
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* Return the number of iovecs mapped, or negative status on failure.
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*/
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int vmbus_map_sgl(VMBusChanReq *req, DMADirection dir, struct iovec *iov,
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unsigned iov_cnt, size_t len, size_t off);
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/*
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* Unmap *iov mapped with vmbus_map_sgl, marking the number of bytes @accessed.
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*/
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void vmbus_unmap_sgl(VMBusChanReq *req, DMADirection dir, struct iovec *iov,
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unsigned iov_cnt, size_t accessed);
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2020-04-24 15:34:44 +03:00
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void vmbus_save_req(QEMUFile *f, VMBusChanReq *req);
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void *vmbus_load_req(QEMUFile *f, VMBusDevice *dev, uint32_t size);
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vmbus: vmbus implementation
Add the VMBus infrastructure -- bus, devices, root bridge, vmbus state
machine, vmbus channel interactions, etc.
VMBus is a collection of technologies. At its lowest layer, it's a message
passing and signaling mechanism, allowing efficient passing of messages to and
from guest VMs. A layer higher, it's a mechanism for defining channels of
communication, where each channel is tagged with a type (which implies a
protocol) and a instance ID. A layer higher than that, it's a bus driver,
serving as the basis of device enumeration within a VM, where a channel can
optionally be exposed as a paravirtual device. When a server-side (paravirtual
back-end) component wishes to offer a channel to a guest VM, it does so by
specifying a channel type, a mode, and an instance ID. VMBus then exposes this
in the guest.
More information about VMBus can be found in the file
vmbuskernelmodeclientlibapi.h in Microsoft's WDK.
TODO:
- split into smaller palatable pieces
- more comments
- check and handle corner cases
Kudos to Evgeny Yakovlev (formerly eyakovlev@virtuozzo.com) and Andrey
Smetatin (formerly asmetanin@virtuozzo.com) for research and
prototyping.
Signed-off-by: Roman Kagan <rkagan@virtuozzo.com>
Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Signed-off-by: Jon Doron <arilou@gmail.com>
Message-Id: <20200424123444.3481728-4-arilou@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-04-24 15:34:41 +03:00
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#endif
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