- Add bhyve NVMe device emulation.

The initial work on bhyve NVMe device emulation was done by the GSoC student
Shunsuke Mie and was heavily modified in performan, functionality and
guest support by Leon Dang.

bhyve:
	-s <n>,nvme,devpath,maxq=#,qsz=#,ioslots=#,sectsz=#,ser=A-Z

	accepted devpath:
		/dev/blockdev
		/path/to/image
		ram=size_in_MiB

Tested with guest OS: FreeBSD Head, Linux Fedora fc27, Ubuntu 18.04,
                      OpenSuse 15.0, Windows Server 2016 Datacenter.
Tested with all accepted device paths: Real nvme, zdev and also with ram.
Tested on: AMD Ryzen Threadripper 1950X 16-Core Processor and
           Intel(R) Xeon(R) CPU E5-2609 v2 @ 2.50GHz.

Tests at: https://people.freebsd.org/~araujo/bhyve_nvme/nvme.txt

Submitted by:	Shunsuke Mie <sux2mfgj_gmail.com>,
		Leon Dang <leon_digitalmsx.com>
Reviewed by:	chuck (early version), grehan
Relnotes:	Yes
Sponsored by:	iXsystems Inc.
Differential Revision:	https://reviews.freebsd.org/D14022

usr.sbin/bhyve/Makefile

@@ -41,6 +41,7 @@ SRCS=	\
 	pci_hostbridge.c	\
 	pci_irq.c		\
 	pci_lpc.c		\
+	pci_nvme.c		\
 	pci_passthru.c		\
 	pci_virtio_block.c	\
 	pci_virtio_console.c	\

usr.sbin/bhyve/bhyve.8

@@ -24,7 +24,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd Jun 11, 2018
+.Dd Jul 05, 2018
 .Dt BHYVE 8
 .Os
 .Sh NAME
@@ -241,6 +241,8 @@ The LPC bridge emulation can only be configured on bus 0.
 Raw framebuffer device attached to VNC server.
 .It Li xhci
 eXtensible Host Controller Interface (xHCI) USB controller.
+.It Li nvme
+NVM Express (NVMe) controller.
 .El
 .It Op Ar conf
 This optional parameter describes the backend for device emulations.
@@ -433,6 +435,27 @@ xHCI USB devices:
 A USB tablet device which provides precise cursor synchronization
 when using VNC.
 .El
+.Pp
+NVMe devices:
+.Bl -tag -width 10n
+.It Li devpath
+Accepted device paths are:
+.Ar /dev/blockdev
+or
+.Ar /path/to/image
+or
+.Ar ram=size_in_MiB .
+.It Li maxq
+Max number of queues.
+.It Li qsz
+Max elements in each queue.
+.It Li ioslots
+Max number of concurrent I/O requests.
+.It Li sectsz
+Sector size (defaults to blockif sector size).
+.It Li ser
+Serial number with maximum 20 characters.
+.El
 .El
 .It Fl S
 Wire guest memory.

usr.sbin/bhyve/block_if.h

@@ -44,12 +44,12 @@
 #define BLOCKIF_IOV_MAX		33	/* not practical to be IOV_MAX */
 
 struct blockif_req {
-	struct iovec	br_iov[BLOCKIF_IOV_MAX];
 	int		br_iovcnt;
 	off_t		br_offset;
 	ssize_t		br_resid;
 	void		(*br_callback)(struct blockif_req *req, int err);
 	void		*br_param;
+	struct iovec	br_iov[BLOCKIF_IOV_MAX];
 };
 
 struct blockif_ctxt;