6a284cacb1
Most of these arguments were unused. Device models which do need access to the vmctx in one of these methods can obtain it from the pi_vmctx member of the pci_devinst argument instead. Reviewed by: corvink, markj Differential Revision: https://reviews.freebsd.org/D38096
438 lines
16 KiB
C
438 lines
16 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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*
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* Copyright (c) 2013 Chris Torek <torek @ torek net>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#ifndef _BHYVE_VIRTIO_H_
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#define _BHYVE_VIRTIO_H_
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#include <machine/atomic.h>
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#include <dev/virtio/virtio.h>
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#include <dev/virtio/virtio_ring.h>
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#include <dev/virtio/pci/virtio_pci_var.h>
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/*
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* These are derived from several virtio specifications.
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*
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* Some useful links:
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* https://github.com/rustyrussell/virtio-spec
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* http://people.redhat.com/pbonzini/virtio-spec.pdf
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*/
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/*
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* A virtual device has zero or more "virtual queues" (virtqueue).
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* Each virtqueue uses at least two 4096-byte pages, laid out thus:
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*
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* +-----------------------------------------------+
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* | "desc": <N> descriptors, 16 bytes each |
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* | ----------------------------------------- |
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* | "avail": 2 uint16; <N> uint16; 1 uint16 |
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* | ----------------------------------------- |
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* | pad to 4k boundary |
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* +-----------------------------------------------+
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* | "used": 2 x uint16; <N> elems; 1 uint16 |
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* | ----------------------------------------- |
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* | pad to 4k boundary |
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* +-----------------------------------------------+
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*
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* The number <N> that appears here is always a power of two and is
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* limited to no more than 32768 (as it must fit in a 16-bit field).
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* If <N> is sufficiently large, the above will occupy more than
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* two pages. In any case, all pages must be physically contiguous
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* within the guest's physical address space.
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*
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* The <N> 16-byte "desc" descriptors consist of a 64-bit guest
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* physical address <addr>, a 32-bit length <len>, a 16-bit
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* <flags>, and a 16-bit <next> field (all in guest byte order).
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*
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* There are three flags that may be set :
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* NEXT descriptor is chained, so use its "next" field
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* WRITE descriptor is for host to write into guest RAM
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* (else host is to read from guest RAM)
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* INDIRECT descriptor address field is (guest physical)
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* address of a linear array of descriptors
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*
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* Unless INDIRECT is set, <len> is the number of bytes that may
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* be read/written from guest physical address <addr>. If
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* INDIRECT is set, WRITE is ignored and <len> provides the length
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* of the indirect descriptors (and <len> must be a multiple of
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* 16). Note that NEXT may still be set in the main descriptor
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* pointing to the indirect, and should be set in each indirect
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* descriptor that uses the next descriptor (these should generally
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* be numbered sequentially). However, INDIRECT must not be set
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* in the indirect descriptors. Upon reaching an indirect descriptor
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* without a NEXT bit, control returns to the direct descriptors.
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*
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* Except inside an indirect, each <next> value must be in the
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* range [0 .. N) (i.e., the half-open interval). (Inside an
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* indirect, each <next> must be in the range [0 .. <len>/16).)
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*
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* The "avail" data structures reside in the same pages as the
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* "desc" structures since both together are used by the device to
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* pass information to the hypervisor's virtual driver. These
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* begin with a 16-bit <flags> field and 16-bit index <idx>, then
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* have <N> 16-bit <ring> values, followed by one final 16-bit
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* field <used_event>. The <N> <ring> entries are simply indices
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* indices into the descriptor ring (and thus must meet the same
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* constraints as each <next> value). However, <idx> is counted
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* up from 0 (initially) and simply wraps around after 65535; it
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* is taken mod <N> to find the next available entry.
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*
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* The "used" ring occupies a separate page or pages, and contains
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* values written from the virtual driver back to the guest OS.
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* This begins with a 16-bit <flags> and 16-bit <idx>, then there
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* are <N> "vring_used" elements, followed by a 16-bit <avail_event>.
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* The <N> "vring_used" elements consist of a 32-bit <id> and a
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* 32-bit <len> (vu_tlen below). The <id> is simply the index of
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* the head of a descriptor chain the guest made available
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* earlier, and the <len> is the number of bytes actually written,
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* e.g., in the case of a network driver that provided a large
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* receive buffer but received only a small amount of data.
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*
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* The two event fields, <used_event> and <avail_event>, in the
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* avail and used rings (respectively -- note the reversal!), are
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* always provided, but are used only if the virtual device
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* negotiates the VIRTIO_RING_F_EVENT_IDX feature during feature
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* negotiation. Similarly, both rings provide a flag --
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* VRING_AVAIL_F_NO_INTERRUPT and VRING_USED_F_NO_NOTIFY -- in
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* their <flags> field, indicating that the guest does not need an
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* interrupt, or that the hypervisor driver does not need a
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* notify, when descriptors are added to the corresponding ring.
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* (These are provided only for interrupt optimization and need
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* not be implemented.)
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*/
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#define VRING_ALIGN 4096
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/*
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* The address of any given virtual queue is determined by a single
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* Page Frame Number register. The guest writes the PFN into the
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* PCI config space. However, a device that has two or more
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* virtqueues can have a different PFN, and size, for each queue.
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* The number of queues is determinable via the PCI config space
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* VTCFG_R_QSEL register. Writes to QSEL select the queue: 0 means
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* queue #0, 1 means queue#1, etc. Once a queue is selected, the
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* remaining PFN and QNUM registers refer to that queue.
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*
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* QNUM is a read-only register containing a nonzero power of two
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* that indicates the (hypervisor's) queue size. Or, if reading it
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* produces zero, the hypervisor does not have a corresponding
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* queue. (The number of possible queues depends on the virtual
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* device. The block device has just one; the network device
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* provides either two -- 0 = receive, 1 = transmit -- or three,
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* with 2 = control.)
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*
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* PFN is a read/write register giving the physical page address of
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* the virtqueue in guest memory (the guest must allocate enough space
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* based on the hypervisor's provided QNUM).
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*
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* QNOTIFY is effectively write-only: when the guest writes a queue
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* number to the register, the hypervisor should scan the specified
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* virtqueue. (Reading QNOTIFY currently always gets 0).
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*/
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/*
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* PFN register shift amount
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*/
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#define VRING_PFN 12
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/*
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* PCI vendor/device IDs
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*/
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#define VIRTIO_VENDOR 0x1AF4
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#define VIRTIO_DEV_NET 0x1000
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#define VIRTIO_DEV_BLOCK 0x1001
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#define VIRTIO_DEV_CONSOLE 0x1003
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#define VIRTIO_DEV_SCSI 0x1004
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#define VIRTIO_DEV_RANDOM 0x1005
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#define VIRTIO_DEV_9P 0x1009
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#define VIRTIO_DEV_INPUT 0x1052
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/*
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* PCI revision IDs
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*/
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#define VIRTIO_REV_INPUT 1
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/*
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* PCI subvendor IDs
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*/
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#define VIRTIO_SUBVEN_INPUT 0x108E
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/*
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* PCI subdevice IDs
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*/
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#define VIRTIO_SUBDEV_INPUT 0x1100
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/* From section 2.3, "Virtqueue Configuration", of the virtio specification */
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static inline int
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vring_size_aligned(u_int qsz)
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{
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return (roundup2(vring_size(qsz, VRING_ALIGN), VRING_ALIGN));
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}
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struct pci_devinst;
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struct vqueue_info;
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struct vm_snapshot_meta;
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/*
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* A virtual device, with some number (possibly 0) of virtual
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* queues and some size (possibly 0) of configuration-space
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* registers private to the device. The virtio_softc should come
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* at the front of each "derived class", so that a pointer to the
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* virtio_softc is also a pointer to the more specific, derived-
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* from-virtio driver's softc.
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*
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* Note: inside each hypervisor virtio driver, changes to these
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* data structures must be locked against other threads, if any.
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* Except for PCI config space register read/write, we assume each
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* driver does the required locking, but we need a pointer to the
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* lock (if there is one) for PCI config space read/write ops.
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*
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* When the guest reads or writes the device's config space, the
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* generic layer checks for operations on the special registers
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* described above. If the offset of the register(s) being read
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* or written is past the CFG area (CFG0 or CFG1), the request is
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* passed on to the virtual device, after subtracting off the
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* generic-layer size. (So, drivers can just use the offset as
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* an offset into "struct config", for instance.)
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*
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* (The virtio layer also makes sure that the read or write is to/
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* from a "good" config offset, hence vc_cfgsize, and on BAR #0.
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* However, the driver must verify the read or write size and offset
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* and that no one is writing a readonly register.)
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*
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* The BROKED flag ("this thing done gone and broked") is for future
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* use.
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*/
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#define VIRTIO_USE_MSIX 0x01
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#define VIRTIO_EVENT_IDX 0x02 /* use the event-index values */
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#define VIRTIO_BROKED 0x08 /* ??? */
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struct virtio_softc {
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struct virtio_consts *vs_vc; /* constants (see below) */
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int vs_flags; /* VIRTIO_* flags from above */
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pthread_mutex_t *vs_mtx; /* POSIX mutex, if any */
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struct pci_devinst *vs_pi; /* PCI device instance */
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uint32_t vs_negotiated_caps; /* negotiated capabilities */
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struct vqueue_info *vs_queues; /* one per vc_nvq */
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int vs_curq; /* current queue */
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uint8_t vs_status; /* value from last status write */
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uint8_t vs_isr; /* ISR flags, if not MSI-X */
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uint16_t vs_msix_cfg_idx; /* MSI-X vector for config event */
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};
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#define VS_LOCK(vs) \
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do { \
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if (vs->vs_mtx) \
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pthread_mutex_lock(vs->vs_mtx); \
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} while (0)
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#define VS_UNLOCK(vs) \
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do { \
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if (vs->vs_mtx) \
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pthread_mutex_unlock(vs->vs_mtx); \
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} while (0)
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struct virtio_consts {
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const char *vc_name; /* name of driver (for diagnostics) */
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int vc_nvq; /* number of virtual queues */
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size_t vc_cfgsize; /* size of dev-specific config regs */
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void (*vc_reset)(void *); /* called on virtual device reset */
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void (*vc_qnotify)(void *, struct vqueue_info *);
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/* called on QNOTIFY if no VQ notify */
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int (*vc_cfgread)(void *, int, int, uint32_t *);
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/* called to read config regs */
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int (*vc_cfgwrite)(void *, int, int, uint32_t);
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/* called to write config regs */
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void (*vc_apply_features)(void *, uint64_t);
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/* called to apply negotiated features */
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uint64_t vc_hv_caps; /* hypervisor-provided capabilities */
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void (*vc_pause)(void *); /* called to pause device activity */
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void (*vc_resume)(void *); /* called to resume device activity */
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int (*vc_snapshot)(void *, struct vm_snapshot_meta *);
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/* called to save / restore device state */
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};
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/*
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* Data structure allocated (statically) per virtual queue.
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*
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* Drivers may change vq_qsize after a reset. When the guest OS
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* requests a device reset, the hypervisor first calls
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* vs->vs_vc->vc_reset(); then the data structure below is
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* reinitialized (for each virtqueue: vs->vs_vc->vc_nvq).
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*
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* The remaining fields should only be fussed-with by the generic
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* code.
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*
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* Note: the addresses of vq_desc, vq_avail, and vq_used are all
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* computable from each other, but it's a lot simpler if we just
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* keep a pointer to each one. The event indices are similarly
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* (but more easily) computable, and this time we'll compute them:
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* they're just XX_ring[N].
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*/
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#define VQ_ALLOC 0x01 /* set once we have a pfn */
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#define VQ_BROKED 0x02 /* ??? */
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struct vqueue_info {
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uint16_t vq_qsize; /* size of this queue (a power of 2) */
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void (*vq_notify)(void *, struct vqueue_info *);
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/* called instead of vc_notify, if not NULL */
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struct virtio_softc *vq_vs; /* backpointer to softc */
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uint16_t vq_num; /* we're the num'th queue in the softc */
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uint16_t vq_flags; /* flags (see above) */
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uint16_t vq_last_avail; /* a recent value of vq_avail->idx */
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uint16_t vq_next_used; /* index of the next used slot to be filled */
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uint16_t vq_save_used; /* saved vq_used->idx; see vq_endchains */
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uint16_t vq_msix_idx; /* MSI-X index, or VIRTIO_MSI_NO_VECTOR */
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uint32_t vq_pfn; /* PFN of virt queue (not shifted!) */
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struct vring_desc *vq_desc; /* descriptor array */
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struct vring_avail *vq_avail; /* the "avail" ring */
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struct vring_used *vq_used; /* the "used" ring */
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};
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/* as noted above, these are sort of backwards, name-wise */
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#define VQ_AVAIL_EVENT_IDX(vq) \
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(*(uint16_t *)&(vq)->vq_used->ring[(vq)->vq_qsize])
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#define VQ_USED_EVENT_IDX(vq) \
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((vq)->vq_avail->ring[(vq)->vq_qsize])
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/*
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* Is this ring ready for I/O?
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*/
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static inline int
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vq_ring_ready(struct vqueue_info *vq)
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{
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return (vq->vq_flags & VQ_ALLOC);
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}
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/*
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* Are there "available" descriptors? (This does not count
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* how many, just returns True if there are some.)
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*/
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static inline int
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vq_has_descs(struct vqueue_info *vq)
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{
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return (vq_ring_ready(vq) && vq->vq_last_avail !=
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vq->vq_avail->idx);
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}
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/*
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* Deliver an interrupt to the guest for a specific MSI-X queue or
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* event.
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*/
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static inline void
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vi_interrupt(struct virtio_softc *vs, uint8_t isr, uint16_t msix_idx)
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{
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if (pci_msix_enabled(vs->vs_pi))
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pci_generate_msix(vs->vs_pi, msix_idx);
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else {
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VS_LOCK(vs);
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vs->vs_isr |= isr;
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pci_generate_msi(vs->vs_pi, 0);
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pci_lintr_assert(vs->vs_pi);
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VS_UNLOCK(vs);
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}
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}
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/*
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* Deliver an interrupt to the guest on the given virtual queue (if
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* possible, or a generic MSI interrupt if not using MSI-X).
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*/
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static inline void
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vq_interrupt(struct virtio_softc *vs, struct vqueue_info *vq)
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{
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vi_interrupt(vs, VIRTIO_PCI_ISR_INTR, vq->vq_msix_idx);
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}
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static inline void
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vq_kick_enable(struct vqueue_info *vq)
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{
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vq->vq_used->flags &= ~VRING_USED_F_NO_NOTIFY;
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/*
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* Full memory barrier to make sure the store to vq_used->flags
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* happens before the load from vq_avail->idx, which results from a
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* subsequent call to vq_has_descs().
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*/
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atomic_thread_fence_seq_cst();
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}
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static inline void
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vq_kick_disable(struct vqueue_info *vq)
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{
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vq->vq_used->flags |= VRING_USED_F_NO_NOTIFY;
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}
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struct iovec;
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/*
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* Request description returned by vq_getchain.
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*
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* Writable iovecs start at iov[req.readable].
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*/
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struct vi_req {
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int readable; /* num of readable iovecs */
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int writable; /* num of writable iovecs */
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unsigned int idx; /* ring index */
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};
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void vi_softc_linkup(struct virtio_softc *vs, struct virtio_consts *vc,
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void *dev_softc, struct pci_devinst *pi,
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struct vqueue_info *queues);
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int vi_intr_init(struct virtio_softc *vs, int barnum, int use_msix);
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void vi_reset_dev(struct virtio_softc *);
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void vi_set_io_bar(struct virtio_softc *, int);
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int vq_getchain(struct vqueue_info *vq, struct iovec *iov, int niov,
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struct vi_req *reqp);
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void vq_retchains(struct vqueue_info *vq, uint16_t n_chains);
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void vq_relchain_prepare(struct vqueue_info *vq, uint16_t idx,
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uint32_t iolen);
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void vq_relchain_publish(struct vqueue_info *vq);
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void vq_relchain(struct vqueue_info *vq, uint16_t idx, uint32_t iolen);
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void vq_endchains(struct vqueue_info *vq, int used_all_avail);
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uint64_t vi_pci_read(struct pci_devinst *pi, int baridx, uint64_t offset,
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int size);
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void vi_pci_write(struct pci_devinst *pi, int baridx, uint64_t offset,
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int size, uint64_t value);
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#ifdef BHYVE_SNAPSHOT
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int vi_pci_snapshot(struct vm_snapshot_meta *meta);
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int vi_pci_pause(struct pci_devinst *pi);
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int vi_pci_resume(struct pci_devinst *pi);
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#endif
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#endif /* _BHYVE_VIRTIO_H_ */
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