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Differential D29433 Diff 86355 usr.sbin/bhyve/pci_virtio_block.c

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usr.sbin/bhyve/pci_virtio_block.c

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pci_vtblk_proc(struct pci_vtblk_softc *sc, struct vqueue_info *vq) pci_vtblk_proc(struct pci_vtblk_softc *sc, struct vqueue_info *vq)
{ {
struct virtio_blk_hdr *vbh; struct virtio_blk_hdr *vbh;
struct pci_vtblk_ioreq *io; struct pci_vtblk_ioreq *io;
int i, n; int i, n;
int err; int err;
ssize_t iolen; ssize_t iolen;
int writeop, type; int writeop, type;
struct vi_req req;
struct iovec iov[BLOCKIF_IOV_MAX + 2]; struct iovec iov[BLOCKIF_IOV_MAX + 2];
uint16_t idx, flags[BLOCKIF_IOV_MAX + 2];
struct virtio_blk_discard_write_zeroes *discard; struct virtio_blk_discard_write_zeroes *discard;
n = vq_getchain(vq, &idx, iov, BLOCKIF_IOV_MAX + 2, flags); n = vq_getchain(vq, iov, BLOCKIF_IOV_MAX + 2, &req);
/* /*
* The first descriptor will be the read-only fixed header, * The first descriptor will be the read-only fixed header,
* and the last is for status (hence +2 above and below). * and the last is for status (hence +2 above and below).
* The remaining iov's are the actual data I/O vectors. * The remaining iov's are the actual data I/O vectors.
* *
* XXX - note - this fails on crash dump, which does a * XXX - note - this fails on crash dump, which does a
* VIRTIO_BLK_T_FLUSH with a zero transfer length * VIRTIO_BLK_T_FLUSH with a zero transfer length
*/ */
assert(n >= 2 && n <= BLOCKIF_IOV_MAX + 2); assert(n >= 2 && n <= BLOCKIF_IOV_MAX + 2);
io = &sc->vbsc_ios[idx]; io = &sc->vbsc_ios[req.idx];
assert((flags[0] & VRING_DESC_F_WRITE) == 0); assert(req.rd_niov != 0);
assert(iov[0].iov_len == sizeof(struct virtio_blk_hdr)); assert(req.rd_iov[0].iov_len == sizeof(struct virtio_blk_hdr));
vbh = (struct virtio_blk_hdr *)iov[0].iov_base; vbh = (struct virtio_blk_hdr *)iov[0].iov_base;
memcpy(&io->io_req.br_iov, &iov[1], sizeof(struct iovec) * (n - 2)); memcpy(&io->io_req.br_iov, &iov[1], sizeof(struct iovec) * (n - 2));
io->io_req.br_iovcnt = n - 2; io->io_req.br_iovcnt = n - 2;
io->io_req.br_offset = vbh->vbh_sector * VTBLK_BSIZE; io->io_req.br_offset = vbh->vbh_sector * VTBLK_BSIZE;
io->io_status = (uint8_t *)iov[--n].iov_base; io->io_status = (uint8_t *)iov[--n].iov_base;
assert(iov[n].iov_len == 1); assert(req.wr_niov != 0);
assert(flags[n] & VRING_DESC_F_WRITE); assert(req.wr_iov[req.wr_niov - 1].iov_len == 1);
/* /*
* XXX * XXX
* The guest should not be setting the BARRIER flag because * The guest should not be setting the BARRIER flag because
* we don't advertise the capability. * we don't advertise the capability.
*/ */
type = vbh->vbh_type & ~VBH_FLAG_BARRIER; type = vbh->vbh_type & ~VBH_FLAG_BARRIER;
writeop = (type == VBH_OP_WRITE || type == VBH_OP_DISCARD); writeop = (type == VBH_OP_WRITE || type == VBH_OP_DISCARD);
assert(n == (writeop ? req.rd_niov : req.wr_niov));
iolen = 0; iolen = 0;
for (i = 1; i < n; i++) { for (i = 1; i < n; i++) {
philipUnsubmitted
Done
Inline Actions

The previous comment inside the loop (deleted lines 348-354 in this diff) was a little clearer. I agree that the assertion should be outside the loop but the comment could be a little clearer. To a casual reader, the assertion is inverted.

philip: The previous comment inside the loop (deleted lines 348-354 in this diff) was a little clearer.
/*
* - write op implies read-only descriptor,
* - read/ident op implies write-only descriptor,
* therefore test the inverse of the descriptor bit
* to the op.
*/
assert(((flags[i] & VRING_DESC_F_WRITE) == 0) == writeop);
iolen += iov[i].iov_len; iolen += iov[i].iov_len;
} }
io->io_req.br_resid = iolen; io->io_req.br_resid = iolen;
DPRINTF(("virtio-block: %s op, %zd bytes, %d segs, offset %ld", DPRINTF(("virtio-block: %s op, %zd bytes, %d segs, offset %ld",
writeop ? "write/discard" : "read/ident", iolen, i - 1, writeop ? "write/discard" : "read/ident", iolen, i - 1,
io->io_req.br_offset)); io->io_req.br_offset));
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