8c74ade848
The Windows virtio driver ignores the advertized seg_max field and assumes the host can accept up to 67 segments in indirect descriptors, triggering an assert in the bhyve process. This brings back r282922 but with a couple of changes: - It raises the block interface segment limit to 128 instead of 67. - Linux's virtio driver assumes that the segment limit is no larger than the ring size. To avoid breaking Linux guests, raise the VirtIO ring size to 128, and cap the VirtIO segment limit at ring size - 2 (effectively 126). Reviewed by: rgrimes, Patrick Mooney <pmooney@pfmooney.com> Obtained from: Joyent (Linux workaround) MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D18831
79 lines
3.1 KiB
C
79 lines
3.1 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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*
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* Copyright (c) 2013 Peter Grehan <grehan@freebsd.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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/*
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* The block API to be used by bhyve block-device emulations. The routines
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* are thread safe, with no assumptions about the context of the completion
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* callback - it may occur in the caller's context, or asynchronously in
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* another thread.
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*/
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#ifndef _BLOCK_IF_H_
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#define _BLOCK_IF_H_
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#include <sys/uio.h>
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#include <sys/unistd.h>
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/*
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* BLOCKIF_IOV_MAX is the maximum number of scatter/gather entries in
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* a single request. BLOCKIF_RING_MAX is the maxmimum number of
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* pending requests that can be queued.
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*/
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#define BLOCKIF_IOV_MAX 128 /* not practical to be IOV_MAX */
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#define BLOCKIF_RING_MAX 128
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struct blockif_req {
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int br_iovcnt;
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off_t br_offset;
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ssize_t br_resid;
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void (*br_callback)(struct blockif_req *req, int err);
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void *br_param;
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struct iovec br_iov[BLOCKIF_IOV_MAX];
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};
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struct blockif_ctxt;
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struct blockif_ctxt *blockif_open(const char *optstr, const char *ident);
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off_t blockif_size(struct blockif_ctxt *bc);
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void blockif_chs(struct blockif_ctxt *bc, uint16_t *c, uint8_t *h,
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uint8_t *s);
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int blockif_sectsz(struct blockif_ctxt *bc);
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void blockif_psectsz(struct blockif_ctxt *bc, int *size, int *off);
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int blockif_queuesz(struct blockif_ctxt *bc);
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int blockif_is_ro(struct blockif_ctxt *bc);
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int blockif_candelete(struct blockif_ctxt *bc);
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int blockif_read(struct blockif_ctxt *bc, struct blockif_req *breq);
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int blockif_write(struct blockif_ctxt *bc, struct blockif_req *breq);
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int blockif_flush(struct blockif_ctxt *bc, struct blockif_req *breq);
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int blockif_delete(struct blockif_ctxt *bc, struct blockif_req *breq);
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int blockif_cancel(struct blockif_ctxt *bc, struct blockif_req *breq);
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int blockif_close(struct blockif_ctxt *bc);
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#endif /* _BLOCK_IF_H_ */
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