/*- * Copyright (c) 2013 Chris Torek * 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. */ #include __FBSDID("$FreeBSD$"); #include #include #include #include #include #include #include "bhyverun.h" #include "pci_emul.h" #include "virtio.h" /* * Functions for dealing with generalized "virtual devices" as * defined by */ /* * In case we decide to relax the "virtio softc comes at the * front of virtio-based device softc" constraint, let's use * this to convert. */ #define DEV_SOFTC(vs) ((void *)(vs)) /* * Link a virtio_softc to its constants, the device softc, and * the PCI emulation. */ void vi_softc_linkup(struct virtio_softc *vs, struct virtio_consts *vc, void *dev_softc, struct pci_devinst *pi, struct vqueue_info *queues) { int i; /* vs and dev_softc addresses must match */ assert((void *)vs == dev_softc); vs->vs_vc = vc; vs->vs_pi = pi; pi->pi_arg = vs; vs->vs_queues = queues; for (i = 0; i < vc->vc_nvq; i++) { queues[i].vq_vs = vs; queues[i].vq_num = i; } } /* * Reset device (device-wide). This erases all queues, i.e., * all the queues become invalid (though we don't wipe out the * internal pointers, we just clear the VQ_ALLOC flag). * * It resets negotiated features to "none". * * If MSI-X is enabled, this also resets all the vectors to NO_VECTOR. */ void vi_reset_dev(struct virtio_softc *vs) { struct vqueue_info *vq; int i, nvq; if (vs->vs_mtx) assert(pthread_mutex_isowned_np(vs->vs_mtx)); nvq = vs->vs_vc->vc_nvq; for (vq = vs->vs_queues, i = 0; i < nvq; vq++, i++) { vq->vq_flags = 0; vq->vq_last_avail = 0; vq->vq_save_used = 0; vq->vq_pfn = 0; vq->vq_msix_idx = VIRTIO_MSI_NO_VECTOR; } vs->vs_negotiated_caps = 0; vs->vs_curq = 0; /* vs->vs_status = 0; -- redundant */ if (vs->vs_isr) pci_lintr_deassert(vs->vs_pi); vs->vs_isr = 0; vs->vs_msix_cfg_idx = VIRTIO_MSI_NO_VECTOR; } /* * Set I/O BAR (usually 0) to map PCI config registers. */ void vi_set_io_bar(struct virtio_softc *vs, int barnum) { size_t size; /* * ??? should we use CFG0 if MSI-X is disabled? * Existing code did not... */ size = VTCFG_R_CFG1 + vs->vs_vc->vc_cfgsize; pci_emul_alloc_bar(vs->vs_pi, barnum, PCIBAR_IO, size); } /* * Initialize MSI-X vector capabilities if we're to use MSI-X, * or MSI capabilities if not. * * We assume we want one MSI-X vector per queue, here, plus one * for the config vec. */ int vi_intr_init(struct virtio_softc *vs, int barnum, int use_msix) { int nvec; if (use_msix) { vs->vs_flags |= VIRTIO_USE_MSIX; VS_LOCK(vs); vi_reset_dev(vs); /* set all vectors to NO_VECTOR */ VS_UNLOCK(vs); nvec = vs->vs_vc->vc_nvq + 1; if (pci_emul_add_msixcap(vs->vs_pi, nvec, barnum)) return (1); } else vs->vs_flags &= ~VIRTIO_USE_MSIX; /* Only 1 MSI vector for bhyve */ pci_emul_add_msicap(vs->vs_pi, 1); return (0); } /* * Initialize the currently-selected virtio queue (vs->vs_curq). * The guest just gave us a page frame number, from which we can * calculate the addresses of the queue. */ void vi_vq_init(struct virtio_softc *vs, uint32_t pfn) { struct vqueue_info *vq; uint64_t phys; size_t size; char *base; vq = &vs->vs_queues[vs->vs_curq]; vq->vq_pfn = pfn; phys = (uint64_t)pfn << VRING_PFN; size = vring_size(vq->vq_qsize); base = paddr_guest2host(vs->vs_pi->pi_vmctx, phys, size); /* First page(s) are descriptors... */ vq->vq_desc = (struct virtio_desc *)base; base += vq->vq_qsize * sizeof(struct virtio_desc); /* ... immediately followed by "avail" ring (entirely uint16_t's) */ vq->vq_avail = (struct vring_avail *)base; base += (2 + vq->vq_qsize + 1) * sizeof(uint16_t); /* Then it's rounded up to the next page... */ base = (char *)roundup2((uintptr_t)base, VRING_ALIGN); /* ... and the last page(s) are the used ring. */ vq->vq_used = (struct vring_used *)base; /* Mark queue as allocated, and start at 0 when we use it. */ vq->vq_flags = VQ_ALLOC; vq->vq_last_avail = 0; vq->vq_save_used = 0; } /* * Helper inline for vq_getchain(): record the i'th "real" * descriptor. */ static inline void _vq_record(int i, volatile struct virtio_desc *vd, struct vmctx *ctx, struct iovec *iov, int n_iov, uint16_t *flags) { if (i >= n_iov) return; iov[i].iov_base = paddr_guest2host(ctx, vd->vd_addr, vd->vd_len); iov[i].iov_len = vd->vd_len; if (flags != NULL) flags[i] = vd->vd_flags; } #define VQ_MAX_DESCRIPTORS 512 /* see below */ /* * Examine the chain of descriptors starting at the "next one" to * make sure that they describe a sensible request. If so, return * the number of "real" descriptors that would be needed/used in * acting on this request. This may be smaller than the number of * available descriptors, e.g., if there are two available but * they are two separate requests, this just returns 1. Or, it * may be larger: if there are indirect descriptors involved, * there may only be one descriptor available but it may be an * indirect pointing to eight more. We return 8 in this case, * i.e., we do not count the indirect descriptors, only the "real" * ones. * * Basically, this vets the vd_flags and vd_next field of each * descriptor and tells you how many are involved. Since some may * be indirect, this also needs the vmctx (in the pci_devinst * at vs->vs_pi) so that it can find indirect descriptors. * * As we process each descriptor, we copy and adjust it (guest to * host address wise, also using the vmtctx) into the given iov[] * array (of the given size). If the array overflows, we stop * placing values into the array but keep processing descriptors, * up to VQ_MAX_DESCRIPTORS, before giving up and returning -1. * So you, the caller, must not assume that iov[] is as big as the * return value (you can process the same thing twice to allocate * a larger iov array if needed, or supply a zero length to find * out how much space is needed). * * If you want to verify the WRITE flag on each descriptor, pass a * non-NULL "flags" pointer to an array of "uint16_t" of the same size * as n_iov and we'll copy each vd_flags field after unwinding any * indirects. * * If some descriptor(s) are invalid, this prints a diagnostic message * and returns -1. If no descriptors are ready now it simply returns 0. * * You are assumed to have done a vq_ring_ready() if needed (note * that vq_has_descs() does one). */ int vq_getchain(struct vqueue_info *vq, uint16_t *pidx, struct iovec *iov, int n_iov, uint16_t *flags) { int i; u_int ndesc, n_indir; u_int idx, next; volatile struct virtio_desc *vdir, *vindir, *vp; struct vmctx *ctx; struct virtio_softc *vs; const char *name; vs = vq->vq_vs; name = vs->vs_vc->vc_name; /* * Note: it's the responsibility of the guest not to * update vq->vq_avail->va_idx until all of the descriptors * the guest has written are valid (including all their * vd_next fields and vd_flags). * * Compute (last_avail - va_idx) in integers mod 2**16. This is * the number of descriptors the device has made available * since the last time we updated vq->vq_last_avail. * * We just need to do the subtraction as an unsigned int, * then trim off excess bits. */ idx = vq->vq_last_avail; ndesc = (uint16_t)((u_int)vq->vq_avail->va_idx - idx); if (ndesc == 0) return (0); if (ndesc > vq->vq_qsize) { /* XXX need better way to diagnose issues */ fprintf(stderr, "%s: ndesc (%u) out of range, driver confused?\r\n", name, (u_int)ndesc); return (-1); } /* * Now count/parse "involved" descriptors starting from * the head of the chain. * * To prevent loops, we could be more complicated and * check whether we're re-visiting a previously visited * index, but we just abort if the count gets excessive. */ ctx = vs->vs_pi->pi_vmctx; *pidx = next = vq->vq_avail->va_ring[idx & (vq->vq_qsize - 1)]; vq->vq_last_avail++; for (i = 0; i < VQ_MAX_DESCRIPTORS; next = vdir->vd_next) { if (next >= vq->vq_qsize) { fprintf(stderr, "%s: descriptor index %u out of range, " "driver confused?\r\n", name, next); return (-1); } vdir = &vq->vq_desc[next]; if ((vdir->vd_flags & VRING_DESC_F_INDIRECT) == 0) { _vq_record(i, vdir, ctx, iov, n_iov, flags); i++; } else if ((vs->vs_negotiated_caps & VIRTIO_RING_F_INDIRECT_DESC) == 0) { fprintf(stderr, "%s: descriptor has forbidden INDIRECT flag, " "driver confused?\r\n", name); return (-1); } else { n_indir = vdir->vd_len / 16; if ((vdir->vd_len & 0xf) || n_indir == 0) { fprintf(stderr, "%s: invalid indir len 0x%x, " "driver confused?\r\n", name, (u_int)vdir->vd_len); return (-1); } vindir = paddr_guest2host(ctx, vdir->vd_addr, vdir->vd_len); /* * Indirects start at the 0th, then follow * their own embedded "next"s until those run * out. Each one's indirect flag must be off * (we don't really have to check, could just * ignore errors...). */ next = 0; for (;;) { vp = &vindir[next]; if (vp->vd_flags & VRING_DESC_F_INDIRECT) { fprintf(stderr, "%s: indirect desc has INDIR flag," " driver confused?\r\n", name); return (-1); } _vq_record(i, vp, ctx, iov, n_iov, flags); if (++i > VQ_MAX_DESCRIPTORS) goto loopy; if ((vp->vd_flags & VRING_DESC_F_NEXT) == 0) break; next = vp->vd_next; if (next >= n_indir) { fprintf(stderr, "%s: invalid next %u > %u, " "driver confused?\r\n", name, (u_int)next, n_indir); return (-1); } } } if ((vdir->vd_flags & VRING_DESC_F_NEXT) == 0) return (i); } loopy: fprintf(stderr, "%s: descriptor loop? count > %d - driver confused?\r\n", name, i); return (-1); } /* * Return the currently-first request chain back to the available queue. * * (This chain is the one you handled when you called vq_getchain() * and used its positive return value.) */ void vq_retchain(struct vqueue_info *vq) { vq->vq_last_avail--; } /* * Return specified request chain to the guest, setting its I/O length * to the provided value. * * (This chain is the one you handled when you called vq_getchain() * and used its positive return value.) */ void vq_relchain(struct vqueue_info *vq, uint16_t idx, uint32_t iolen) { uint16_t uidx, mask; volatile struct vring_used *vuh; volatile struct virtio_used *vue; /* * Notes: * - mask is N-1 where N is a power of 2 so computes x % N * - vuh points to the "used" data shared with guest * - vue points to the "used" ring entry we want to update * - head is the same value we compute in vq_iovecs(). * * (I apologize for the two fields named vu_idx; the * virtio spec calls the one that vue points to, "id"...) */ mask = vq->vq_qsize - 1; vuh = vq->vq_used; uidx = vuh->vu_idx; vue = &vuh->vu_ring[uidx++ & mask]; vue->vu_idx = idx; vue->vu_tlen = iolen; vuh->vu_idx = uidx; } /* * Driver has finished processing "available" chains and calling * vq_relchain on each one. If driver used all the available * chains, used_all should be set. * * If the "used" index moved we may need to inform the guest, i.e., * deliver an interrupt. Even if the used index did NOT move we * may need to deliver an interrupt, if the avail ring is empty and * we are supposed to interrupt on empty. * * Note that used_all_avail is provided by the caller because it's * a snapshot of the ring state when he decided to finish interrupt * processing -- it's possible that descriptors became available after * that point. (It's also typically a constant 1/True as well.) */ void vq_endchains(struct vqueue_info *vq, int used_all_avail) { struct virtio_softc *vs; uint16_t event_idx, new_idx, old_idx; int intr; /* * Interrupt generation: if we're using EVENT_IDX, * interrupt if we've crossed the event threshold. * Otherwise interrupt is generated if we added "used" entries, * but suppressed by VRING_AVAIL_F_NO_INTERRUPT. * * In any case, though, if NOTIFY_ON_EMPTY is set and the * entire avail was processed, we need to interrupt always. */ vs = vq->vq_vs; old_idx = vq->vq_save_used; vq->vq_save_used = new_idx = vq->vq_used->vu_idx; if (used_all_avail && (vs->vs_negotiated_caps & VIRTIO_F_NOTIFY_ON_EMPTY)) intr = 1; else if (vs->vs_negotiated_caps & VIRTIO_RING_F_EVENT_IDX) { event_idx = VQ_USED_EVENT_IDX(vq); /* * This calculation is per docs and the kernel * (see src/sys/dev/virtio/virtio_ring.h). */ intr = (uint16_t)(new_idx - event_idx - 1) < (uint16_t)(new_idx - old_idx); } else { intr = new_idx != old_idx && !(vq->vq_avail->va_flags & VRING_AVAIL_F_NO_INTERRUPT); } if (intr) vq_interrupt(vs, vq); } /* Note: these are in sorted order to make for a fast search */ static struct config_reg { uint16_t cr_offset; /* register offset */ uint8_t cr_size; /* size (bytes) */ uint8_t cr_ro; /* true => reg is read only */ const char *cr_name; /* name of reg */ } config_regs[] = { { VTCFG_R_HOSTCAP, 4, 1, "HOSTCAP" }, { VTCFG_R_GUESTCAP, 4, 0, "GUESTCAP" }, { VTCFG_R_PFN, 4, 0, "PFN" }, { VTCFG_R_QNUM, 2, 1, "QNUM" }, { VTCFG_R_QSEL, 2, 0, "QSEL" }, { VTCFG_R_QNOTIFY, 2, 0, "QNOTIFY" }, { VTCFG_R_STATUS, 1, 0, "STATUS" }, { VTCFG_R_ISR, 1, 0, "ISR" }, { VTCFG_R_CFGVEC, 2, 0, "CFGVEC" }, { VTCFG_R_QVEC, 2, 0, "QVEC" }, }; static inline struct config_reg * vi_find_cr(int offset) { u_int hi, lo, mid; struct config_reg *cr; lo = 0; hi = sizeof(config_regs) / sizeof(*config_regs) - 1; while (hi >= lo) { mid = (hi + lo) >> 1; cr = &config_regs[mid]; if (cr->cr_offset == offset) return (cr); if (cr->cr_offset < offset) lo = mid + 1; else hi = mid - 1; } return (NULL); } /* * Handle pci config space reads. * If it's to the MSI-X info, do that. * If it's part of the virtio standard stuff, do that. * Otherwise dispatch to the actual driver. */ uint64_t vi_pci_read(struct vmctx *ctx, int vcpu, struct pci_devinst *pi, int baridx, uint64_t offset, int size) { struct virtio_softc *vs = pi->pi_arg; struct virtio_consts *vc; struct config_reg *cr; uint64_t virtio_config_size, max; const char *name; uint32_t newoff; uint32_t value; int error; if (vs->vs_flags & VIRTIO_USE_MSIX) { if (baridx == pci_msix_table_bar(pi) || baridx == pci_msix_pba_bar(pi)) { return (pci_emul_msix_tread(pi, offset, size)); } } /* XXX probably should do something better than just assert() */ assert(baridx == 0); if (vs->vs_mtx) pthread_mutex_lock(vs->vs_mtx); vc = vs->vs_vc; name = vc->vc_name; value = size == 1 ? 0xff : size == 2 ? 0xffff : 0xffffffff; if (size != 1 && size != 2 && size != 4) goto bad; if (pci_msix_enabled(pi)) virtio_config_size = VTCFG_R_CFG1; else virtio_config_size = VTCFG_R_CFG0; if (offset >= virtio_config_size) { /* * Subtract off the standard size (including MSI-X * registers if enabled) and dispatch to underlying driver. * If that fails, fall into general code. */ newoff = offset - virtio_config_size; max = vc->vc_cfgsize ? vc->vc_cfgsize : 0x100000000; if (newoff + size > max) goto bad; error = (*vc->vc_cfgread)(DEV_SOFTC(vs), newoff, size, &value); if (!error) goto done; } bad: cr = vi_find_cr(offset); if (cr == NULL || cr->cr_size != size) { if (cr != NULL) { /* offset must be OK, so size must be bad */ fprintf(stderr, "%s: read from %s: bad size %d\r\n", name, cr->cr_name, size); } else { fprintf(stderr, "%s: read from bad offset/size %jd/%d\r\n", name, (uintmax_t)offset, size); } goto done; } switch (offset) { case VTCFG_R_HOSTCAP: value = vc->vc_hv_caps; break; case VTCFG_R_GUESTCAP: value = vs->vs_negotiated_caps; break; case VTCFG_R_PFN: if (vs->vs_curq < vc->vc_nvq) value = vs->vs_queues[vs->vs_curq].vq_pfn; break; case VTCFG_R_QNUM: value = vs->vs_curq < vc->vc_nvq ? vs->vs_queues[vs->vs_curq].vq_qsize : 0; break; case VTCFG_R_QSEL: value = vs->vs_curq; break; case VTCFG_R_QNOTIFY: value = 0; /* XXX */ break; case VTCFG_R_STATUS: value = vs->vs_status; break; case VTCFG_R_ISR: value = vs->vs_isr; vs->vs_isr = 0; /* a read clears this flag */ if (value) pci_lintr_deassert(pi); break; case VTCFG_R_CFGVEC: value = vs->vs_msix_cfg_idx; break; case VTCFG_R_QVEC: value = vs->vs_curq < vc->vc_nvq ? vs->vs_queues[vs->vs_curq].vq_msix_idx : VIRTIO_MSI_NO_VECTOR; break; } done: if (vs->vs_mtx) pthread_mutex_unlock(vs->vs_mtx); return (value); } /* * Handle pci config space writes. * If it's to the MSI-X info, do that. * If it's part of the virtio standard stuff, do that. * Otherwise dispatch to the actual driver. */ void vi_pci_write(struct vmctx *ctx, int vcpu, struct pci_devinst *pi, int baridx, uint64_t offset, int size, uint64_t value) { struct virtio_softc *vs = pi->pi_arg; struct vqueue_info *vq; struct virtio_consts *vc; struct config_reg *cr; uint64_t virtio_config_size, max; const char *name; uint32_t newoff; int error; if (vs->vs_flags & VIRTIO_USE_MSIX) { if (baridx == pci_msix_table_bar(pi) || baridx == pci_msix_pba_bar(pi)) { pci_emul_msix_twrite(pi, offset, size, value); return; } } /* XXX probably should do something better than just assert() */ assert(baridx == 0); if (vs->vs_mtx) pthread_mutex_lock(vs->vs_mtx); vc = vs->vs_vc; name = vc->vc_name; if (size != 1 && size != 2 && size != 4) goto bad; if (pci_msix_enabled(pi)) virtio_config_size = VTCFG_R_CFG1; else virtio_config_size = VTCFG_R_CFG0; if (offset >= virtio_config_size) { /* * Subtract off the standard size (including MSI-X * registers if enabled) and dispatch to underlying driver. */ newoff = offset - virtio_config_size; max = vc->vc_cfgsize ? vc->vc_cfgsize : 0x100000000; if (newoff + size > max) goto bad; error = (*vc->vc_cfgwrite)(DEV_SOFTC(vs), newoff, size, value); if (!error) goto done; } bad: cr = vi_find_cr(offset); if (cr == NULL || cr->cr_size != size || cr->cr_ro) { if (cr != NULL) { /* offset must be OK, wrong size and/or reg is R/O */ if (cr->cr_size != size) fprintf(stderr, "%s: write to %s: bad size %d\r\n", name, cr->cr_name, size); if (cr->cr_ro) fprintf(stderr, "%s: write to read-only reg %s\r\n", name, cr->cr_name); } else { fprintf(stderr, "%s: write to bad offset/size %jd/%d\r\n", name, (uintmax_t)offset, size); } goto done; } switch (offset) { case VTCFG_R_GUESTCAP: vs->vs_negotiated_caps = value & vc->vc_hv_caps; if (vc->vc_apply_features) (*vc->vc_apply_features)(DEV_SOFTC(vs), vs->vs_negotiated_caps); break; case VTCFG_R_PFN: if (vs->vs_curq >= vc->vc_nvq) goto bad_qindex; vi_vq_init(vs, value); break; case VTCFG_R_QSEL: /* * Note that the guest is allowed to select an * invalid queue; we just need to return a QNUM * of 0 while the bad queue is selected. */ vs->vs_curq = value; break; case VTCFG_R_QNOTIFY: if (value >= vc->vc_nvq) { fprintf(stderr, "%s: queue %d notify out of range\r\n", name, (int)value); goto done; } vq = &vs->vs_queues[value]; if (vq->vq_notify) (*vq->vq_notify)(DEV_SOFTC(vs), vq); else if (vc->vc_qnotify) (*vc->vc_qnotify)(DEV_SOFTC(vs), vq); else fprintf(stderr, "%s: qnotify queue %d: missing vq/vc notify\r\n", name, (int)value); break; case VTCFG_R_STATUS: vs->vs_status = value; if (value == 0) (*vc->vc_reset)(DEV_SOFTC(vs)); break; case VTCFG_R_CFGVEC: vs->vs_msix_cfg_idx = value; break; case VTCFG_R_QVEC: if (vs->vs_curq >= vc->vc_nvq) goto bad_qindex; vq = &vs->vs_queues[vs->vs_curq]; vq->vq_msix_idx = value; break; } goto done; bad_qindex: fprintf(stderr, "%s: write config reg %s: curq %d >= max %d\r\n", name, cr->cr_name, vs->vs_curq, vc->vc_nvq); done: if (vs->vs_mtx) pthread_mutex_unlock(vs->vs_mtx); }