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Diffstat (limited to 'usr/src/cmd/bhyve/virtio.h')
| -rw-r--r-- | usr/src/cmd/bhyve/virtio.h | 484 |
1 files changed, 484 insertions, 0 deletions
diff --git a/usr/src/cmd/bhyve/virtio.h b/usr/src/cmd/bhyve/virtio.h new file mode 100644 index 0000000000..a2c3362ec2 --- /dev/null +++ b/usr/src/cmd/bhyve/virtio.h @@ -0,0 +1,484 @@ +/*- + * SPDX-License-Identifier: BSD-2-Clause-FreeBSD + * + * 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_ + +#include <pthread_np.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_CONSOLE 0x1003 +#define VIRTIO_DEV_RANDOM 0x1005 +#define VIRTIO_DEV_SCSI 0x1008 + +/* + * 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 { +#ifndef __FreeBSD__ + boolean_t unlock = B_FALSE; + + if (vs->vs_mtx && !pthread_mutex_isowned_np(vs->vs_mtx)) { + unlock = B_TRUE; + pthread_mutex_lock(vs->vs_mtx); + } +#else + VS_LOCK(vs); +#endif + vs->vs_isr |= VTCFG_ISR_QUEUES; + pci_generate_msi(vs->vs_pi, 0); + pci_lintr_assert(vs->vs_pi); +#ifndef __FreeBSD__ + if (unlock) + pthread_mutex_unlock(vs->vs_mtx); +#else + VS_UNLOCK(vs); +#endif + } +} + +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_ */ |