freebsd-skq/usr.sbin/bhyve/virtio.c

747 lines
20 KiB
C
Raw Normal View History

/*-
* 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/uio.h>
#include <stdio.h>
#include <stdint.h>
#include <pthread.h>
#include "bhyverun.h"
#include "pci_emul.h"
#include "virtio.h"
/*
* Functions for dealing with generalized "virtual devices" as
* defined by <https://www.google.com/#output=search&q=virtio+spec>
*/
/*
* 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;
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_pfn = 0;
vq->vq_msix_idx = VIRTIO_MSI_NO_VECTOR;
}
vs->vs_negotiated_caps = 0;
vs->vs_curq = 0;
/* vs->vs_status = 0; -- redundant */
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;
vi_reset_dev(vs); /* set all vectors to NO_VECTOR */
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 = 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;
}
/*
* 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,
struct iovec *iov, int n_iov, uint16_t *flags)
{
int i;
u_int ndesc, n_indir;
u_int idx, head, 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;
head = vq->vq_avail->va_ring[idx & (vq->vq_qsize - 1)];
next = head;
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 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, uint32_t iolen)
{
uint16_t head, 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;
head = vq->vq_avail->va_ring[vq->vq_last_avail++ & mask];
uidx = vuh->vu_idx;
vue = &vuh->vu_ring[uidx++ & mask];
vue->vu_idx = head; /* ie, vue->id = head */
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;
new_idx = vq->vq_used->vu_idx;
old_idx = vq->vq_save_used;
if (used_all_avail &&
(vs->vs_negotiated_caps & VIRTIO_F_NOTIFY_ON_EMPTY))
intr = 1;
else if (vs->vs_flags & VIRTIO_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 */
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;
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);
}