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freebsd-nq/usr.sbin/bhyve/virtio.h
Alexander Motin 7315946b80 Fix networking problem after r280026. 
I've missed that network driver sometimes returns taken request back to
available queue without processing.  Add new helper function for that case.

Reported by:	flo
MFC after:	2 weeks
2015-03-15 16:09:39 +00:00

465 lines
17 KiB
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/*-
* Copyright (c) 2013 Chris Torek <torek @ torek net>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#ifndef _VIRTIO_H_
#define _VIRTIO_H_
/*
* These are derived from several virtio specifications.
*
* Some useful links:
* https://github.com/rustyrussell/virtio-spec
* http://people.redhat.com/pbonzini/virtio-spec.pdf
*/
/*
* A virtual device has zero or more "virtual queues" (virtqueue).
* Each virtqueue uses at least two 4096-byte pages, laid out thus:
*
* +-----------------------------------------------+
* | "desc": <N> descriptors, 16 bytes each |
* | ----------------------------------------- |
* | "avail": 2 uint16; <N> uint16; 1 uint16 |
* | ----------------------------------------- |
* | pad to 4k boundary |
* +-----------------------------------------------+
* | "used": 2 x uint16; <N> elems; 1 uint16 |
* | ----------------------------------------- |
* | pad to 4k boundary |
* +-----------------------------------------------+
*
* The number <N> that appears here is always a power of two and is
* limited to no more than 32768 (as it must fit in a 16-bit field).
* If <N> is sufficiently large, the above will occupy more than
* two pages. In any case, all pages must be physically contiguous
* within the guest's physical address space.
*
* The <N> 16-byte "desc" descriptors consist of a 64-bit guest
* physical address <addr>, a 32-bit length <len>, a 16-bit
* <flags>, and a 16-bit <next> field (all in guest byte order).
*
* There are three flags that may be set :
* NEXT descriptor is chained, so use its "next" field
* WRITE descriptor is for host to write into guest RAM
* (else host is to read from guest RAM)
* INDIRECT descriptor address field is (guest physical)
* address of a linear array of descriptors
*
* Unless INDIRECT is set, <len> is the number of bytes that may
* be read/written from guest physical address <addr>. If
* INDIRECT is set, WRITE is ignored and <len> provides the length
* of the indirect descriptors (and <len> must be a multiple of
* 16). Note that NEXT may still be set in the main descriptor
* pointing to the indirect, and should be set in each indirect
* descriptor that uses the next descriptor (these should generally
* be numbered sequentially). However, INDIRECT must not be set
* in the indirect descriptors. Upon reaching an indirect descriptor
* without a NEXT bit, control returns to the direct descriptors.
*
* Except inside an indirect, each <next> value must be in the
* range [0 .. N) (i.e., the half-open interval). (Inside an
* indirect, each <next> must be in the range [0 .. <len>/16).)
*
* The "avail" data structures reside in the same pages as the
* "desc" structures since both together are used by the device to
* pass information to the hypervisor's virtual driver. These
* begin with a 16-bit <flags> field and 16-bit index <idx>, then
* have <N> 16-bit <ring> values, followed by one final 16-bit
* field <used_event>. The <N> <ring> entries are simply indices
* indices into the descriptor ring (and thus must meet the same
* constraints as each <next> value). However, <idx> is counted
* up from 0 (initially) and simply wraps around after 65535; it
* is taken mod <N> to find the next available entry.
*
* The "used" ring occupies a separate page or pages, and contains
* values written from the virtual driver back to the guest OS.
* This begins with a 16-bit <flags> and 16-bit <idx>, then there
* are <N> "vring_used" elements, followed by a 16-bit <avail_event>.
* The <N> "vring_used" elements consist of a 32-bit <id> and a
* 32-bit <len> (vu_tlen below). The <id> is simply the index of
* the head of a descriptor chain the guest made available
* earlier, and the <len> is the number of bytes actually written,
* e.g., in the case of a network driver that provided a large
* receive buffer but received only a small amount of data.
*
* The two event fields, <used_event> and <avail_event>, in the
* avail and used rings (respectively -- note the reversal!), are
* always provided, but are used only if the virtual device
* negotiates the VIRTIO_RING_F_EVENT_IDX feature during feature
* negotiation. Similarly, both rings provide a flag --
* VRING_AVAIL_F_NO_INTERRUPT and VRING_USED_F_NO_NOTIFY -- in
* their <flags> field, indicating that the guest does not need an
* interrupt, or that the hypervisor driver does not need a
* notify, when descriptors are added to the corresponding ring.
* (These are provided only for interrupt optimization and need
* not be implemented.)
*/
#define VRING_ALIGN 4096
#define VRING_DESC_F_NEXT (1 << 0)
#define VRING_DESC_F_WRITE (1 << 1)
#define VRING_DESC_F_INDIRECT (1 << 2)
struct virtio_desc { /* AKA vring_desc */
uint64_t vd_addr; /* guest physical address */
uint32_t vd_len; /* length of scatter/gather seg */
uint16_t vd_flags; /* VRING_F_DESC_* */
uint16_t vd_next; /* next desc if F_NEXT */
} __packed;
struct virtio_used { /* AKA vring_used_elem */
uint32_t vu_idx; /* head of used descriptor chain */
uint32_t vu_tlen; /* length written-to */
} __packed;
#define VRING_AVAIL_F_NO_INTERRUPT 1
struct vring_avail {
uint16_t va_flags; /* VRING_AVAIL_F_* */
uint16_t va_idx; /* counts to 65535, then cycles */
uint16_t va_ring[]; /* size N, reported in QNUM value */
/* uint16_t va_used_event; -- after N ring entries */
} __packed;
#define VRING_USED_F_NO_NOTIFY 1
struct vring_used {
uint16_t vu_flags; /* VRING_USED_F_* */
uint16_t vu_idx; /* counts to 65535, then cycles */
struct virtio_used vu_ring[]; /* size N */
/* uint16_t vu_avail_event; -- after N ring entries */
} __packed;
/*
* The address of any given virtual queue is determined by a single
* Page Frame Number register. The guest writes the PFN into the
* PCI config space. However, a device that has two or more
* virtqueues can have a different PFN, and size, for each queue.
* The number of queues is determinable via the PCI config space
* VTCFG_R_QSEL register. Writes to QSEL select the queue: 0 means
* queue #0, 1 means queue#1, etc. Once a queue is selected, the
* remaining PFN and QNUM registers refer to that queue.
*
* QNUM is a read-only register containing a nonzero power of two
* that indicates the (hypervisor's) queue size. Or, if reading it
* produces zero, the hypervisor does not have a corresponding
* queue. (The number of possible queues depends on the virtual
* device. The block device has just one; the network device
* provides either two -- 0 = receive, 1 = transmit -- or three,
* with 2 = control.)
*
* PFN is a read/write register giving the physical page address of
* the virtqueue in guest memory (the guest must allocate enough space
* based on the hypervisor's provided QNUM).
*
* QNOTIFY is effectively write-only: when the guest writes a queue
* number to the register, the hypervisor should scan the specified
* virtqueue. (Reading QNOTIFY currently always gets 0).
*/
/*
* PFN register shift amount
*/
#define VRING_PFN 12
/*
* Virtio device types
*
* XXX Should really be merged with <dev/virtio/virtio.h> defines
*/
#define VIRTIO_TYPE_NET 1
#define VIRTIO_TYPE_BLOCK 2
#define VIRTIO_TYPE_CONSOLE 3
#define VIRTIO_TYPE_ENTROPY 4
#define VIRTIO_TYPE_BALLOON 5
#define VIRTIO_TYPE_IOMEMORY 6
#define VIRTIO_TYPE_RPMSG 7
#define VIRTIO_TYPE_SCSI 8
#define VIRTIO_TYPE_9P 9
/* experimental IDs start at 65535 and work down */
/*
* PCI vendor/device IDs
*/
#define VIRTIO_VENDOR 0x1AF4
#define VIRTIO_DEV_NET 0x1000
#define VIRTIO_DEV_BLOCK 0x1001
#define VIRTIO_DEV_RANDOM 0x1002
/*
* PCI config space constants.
*
* If MSI-X is enabled, the ISR register is generally not used,
* and the configuration vector and queue vector appear at offsets
* 20 and 22 with the remaining configuration registers at 24.
* If MSI-X is not enabled, those two registers disappear and
* the remaining configuration registers start at offset 20.
*/
#define VTCFG_R_HOSTCAP 0
#define VTCFG_R_GUESTCAP 4
#define VTCFG_R_PFN 8
#define VTCFG_R_QNUM 12
#define VTCFG_R_QSEL 14
#define VTCFG_R_QNOTIFY 16
#define VTCFG_R_STATUS 18
#define VTCFG_R_ISR 19
#define VTCFG_R_CFGVEC 20
#define VTCFG_R_QVEC 22
#define VTCFG_R_CFG0 20 /* No MSI-X */
#define VTCFG_R_CFG1 24 /* With MSI-X */
#define VTCFG_R_MSIX 20
/*
* Bits in VTCFG_R_STATUS. Guests need not actually set any of these,
* but a guest writing 0 to this register means "please reset".
*/
#define VTCFG_STATUS_ACK 0x01 /* guest OS has acknowledged dev */
#define VTCFG_STATUS_DRIVER 0x02 /* guest OS driver is loaded */
#define VTCFG_STATUS_DRIVER_OK 0x04 /* guest OS driver ready */
#define VTCFG_STATUS_FAILED 0x80 /* guest has given up on this dev */
/*
* Bits in VTCFG_R_ISR. These apply only if not using MSI-X.
*
* (We don't [yet?] ever use CONF_CHANGED.)
*/
#define VTCFG_ISR_QUEUES 0x01 /* re-scan queues */
#define VTCFG_ISR_CONF_CHANGED 0x80 /* configuration changed */
#define VIRTIO_MSI_NO_VECTOR 0xFFFF
/*
* Feature flags.
* Note: bits 0 through 23 are reserved to each device type.
*/
#define VIRTIO_F_NOTIFY_ON_EMPTY (1 << 24)
#define VIRTIO_RING_F_INDIRECT_DESC (1 << 28)
#define VIRTIO_RING_F_EVENT_IDX (1 << 29)
/* From section 2.3, "Virtqueue Configuration", of the virtio specification */
static inline size_t
vring_size(u_int qsz)
{
size_t size;
/* constant 3 below = va_flags, va_idx, va_used_event */
size = sizeof(struct virtio_desc) * qsz + sizeof(uint16_t) * (3 + qsz);
size = roundup2(size, VRING_ALIGN);
/* constant 3 below = vu_flags, vu_idx, vu_avail_event */
size += sizeof(uint16_t) * 3 + sizeof(struct virtio_used) * qsz;
size = roundup2(size, VRING_ALIGN);
return (size);
}
struct vmctx;
struct pci_devinst;
struct vqueue_info;
/*
* A virtual device, with some number (possibly 0) of virtual
* queues and some size (possibly 0) of configuration-space
* registers private to the device. The virtio_softc should come
* at the front of each "derived class", so that a pointer to the
* virtio_softc is also a pointer to the more specific, derived-
* from-virtio driver's softc.
*
* Note: inside each hypervisor virtio driver, changes to these
* data structures must be locked against other threads, if any.
* Except for PCI config space register read/write, we assume each
* driver does the required locking, but we need a pointer to the
* lock (if there is one) for PCI config space read/write ops.
*
* When the guest reads or writes the device's config space, the
* generic layer checks for operations on the special registers
* described above. If the offset of the register(s) being read
* or written is past the CFG area (CFG0 or CFG1), the request is
* passed on to the virtual device, after subtracting off the
* generic-layer size. (So, drivers can just use the offset as
* an offset into "struct config", for instance.)
*
* (The virtio layer also makes sure that the read or write is to/
* from a "good" config offset, hence vc_cfgsize, and on BAR #0.
* However, the driver must verify the read or write size and offset
* and that no one is writing a readonly register.)
*
* The BROKED flag ("this thing done gone and broked") is for future
* use.
*/
#define VIRTIO_USE_MSIX 0x01
#define VIRTIO_EVENT_IDX 0x02 /* use the event-index values */
#define VIRTIO_BROKED 0x08 /* ??? */
struct virtio_softc {
struct virtio_consts *vs_vc; /* constants (see below) */
int vs_flags; /* VIRTIO_* flags from above */
pthread_mutex_t *vs_mtx; /* POSIX mutex, if any */
struct pci_devinst *vs_pi; /* PCI device instance */
uint32_t vs_negotiated_caps; /* negotiated capabilities */
struct vqueue_info *vs_queues; /* one per vc_nvq */
int vs_curq; /* current queue */
uint8_t vs_status; /* value from last status write */
uint8_t vs_isr; /* ISR flags, if not MSI-X */
uint16_t vs_msix_cfg_idx; /* MSI-X vector for config event */
};
#define VS_LOCK(vs) \
do { \
if (vs->vs_mtx) \
pthread_mutex_lock(vs->vs_mtx); \
} while (0)
#define VS_UNLOCK(vs) \
do { \
if (vs->vs_mtx) \
pthread_mutex_unlock(vs->vs_mtx); \
} while (0)
struct virtio_consts {
const char *vc_name; /* name of driver (for diagnostics) */
int vc_nvq; /* number of virtual queues */
size_t vc_cfgsize; /* size of dev-specific config regs */
void (*vc_reset)(void *); /* called on virtual device reset */
void (*vc_qnotify)(void *, struct vqueue_info *);
/* called on QNOTIFY if no VQ notify */
int (*vc_cfgread)(void *, int, int, uint32_t *);
/* called to read config regs */
int (*vc_cfgwrite)(void *, int, int, uint32_t);
/* called to write config regs */
void (*vc_apply_features)(void *, uint64_t);
/* called to apply negotiated features */
uint64_t vc_hv_caps; /* hypervisor-provided capabilities */
};
/*
* Data structure allocated (statically) per virtual queue.
*
* Drivers may change vq_qsize after a reset. When the guest OS
* requests a device reset, the hypervisor first calls
* vs->vs_vc->vc_reset(); then the data structure below is
* reinitialized (for each virtqueue: vs->vs_vc->vc_nvq).
*
* The remaining fields should only be fussed-with by the generic
* code.
*
* Note: the addresses of vq_desc, vq_avail, and vq_used are all
* computable from each other, but it's a lot simpler if we just
* keep a pointer to each one. The event indices are similarly
* (but more easily) computable, and this time we'll compute them:
* they're just XX_ring[N].
*/
#define VQ_ALLOC 0x01 /* set once we have a pfn */
#define VQ_BROKED 0x02 /* ??? */
struct vqueue_info {
uint16_t vq_qsize; /* size of this queue (a power of 2) */
void (*vq_notify)(void *, struct vqueue_info *);
/* called instead of vc_notify, if not NULL */
struct virtio_softc *vq_vs; /* backpointer to softc */
uint16_t vq_num; /* we're the num'th queue in the softc */
uint16_t vq_flags; /* flags (see above) */
uint16_t vq_last_avail; /* a recent value of vq_avail->va_idx */
uint16_t vq_save_used; /* saved vq_used->vu_idx; see vq_endchains */
uint16_t vq_msix_idx; /* MSI-X index, or VIRTIO_MSI_NO_VECTOR */
uint32_t vq_pfn; /* PFN of virt queue (not shifted!) */
volatile struct virtio_desc *vq_desc; /* descriptor array */
volatile struct vring_avail *vq_avail; /* the "avail" ring */
volatile struct vring_used *vq_used; /* the "used" ring */
};
/* as noted above, these are sort of backwards, name-wise */
#define VQ_AVAIL_EVENT_IDX(vq) \
(*(volatile uint16_t *)&(vq)->vq_used->vu_ring[(vq)->vq_qsize])
#define VQ_USED_EVENT_IDX(vq) \
((vq)->vq_avail->va_ring[(vq)->vq_qsize])
/*
* Is this ring ready for I/O?
*/
static inline int
vq_ring_ready(struct vqueue_info *vq)
{
return (vq->vq_flags & VQ_ALLOC);
}
/*
* Are there "available" descriptors? (This does not count
* how many, just returns True if there are some.)
*/
static inline int
vq_has_descs(struct vqueue_info *vq)
{
return (vq_ring_ready(vq) && vq->vq_last_avail !=
vq->vq_avail->va_idx);
}
/*
* Deliver an interrupt to guest on the given virtual queue
* (if possible, or a generic MSI interrupt if not using MSI-X).
*/
static inline void
vq_interrupt(struct virtio_softc *vs, struct vqueue_info *vq)
{
if (pci_msix_enabled(vs->vs_pi))
pci_generate_msix(vs->vs_pi, vq->vq_msix_idx);
else {
VS_LOCK(vs);
vs->vs_isr |= VTCFG_ISR_QUEUES;
pci_generate_msi(vs->vs_pi, 0);
pci_lintr_assert(vs->vs_pi);
VS_UNLOCK(vs);
}
}
struct iovec;
void vi_softc_linkup(struct virtio_softc *vs, struct virtio_consts *vc,
void *dev_softc, struct pci_devinst *pi,
struct vqueue_info *queues);
int vi_intr_init(struct virtio_softc *vs, int barnum, int use_msix);
void vi_reset_dev(struct virtio_softc *);
void vi_set_io_bar(struct virtio_softc *, int);
int vq_getchain(struct vqueue_info *vq, uint16_t *pidx,
struct iovec *iov, int n_iov, uint16_t *flags);
void vq_retchain(struct vqueue_info *vq);
void vq_relchain(struct vqueue_info *vq, uint16_t idx, uint32_t iolen);
void vq_endchains(struct vqueue_info *vq, int used_all_avail);
uint64_t vi_pci_read(struct vmctx *ctx, int vcpu, struct pci_devinst *pi,
int baridx, uint64_t offset, int size);
void vi_pci_write(struct vmctx *ctx, int vcpu, struct pci_devinst *pi,
int baridx, uint64_t offset, int size, uint64_t value);
#endif /* _VIRTIO_H_ */
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