kernel - Fix serious bug in virtio

* virtio_blk.c was destroy the buffer cache base global
in vtblk_write_dump().

Located-by: gcc8, bcopy -> memcpy inline optimization complained.

virtio - Get rid of unused flags option in virtio_alloc_virtqueues().

virtio - Explicitly teardown interrupts in driver detach methods.

* This seems to be an easy way to avoid potential races during driver
detachements.

virtio - Move virtqueue_pending() checks into the child driver.

* This makes it easier for now, to deal with virtqueue locking, when
multiple virtqueues are mapped to a single interrupt vector.

virtio - Get rid of config_change devmethod, treat like vq interrupts.

virtio - Specify handler and argument in bind_intr, instead of vq alloc.

virtio - Refactor virtio bus API, to untangle virtuques from IRQ allocation.

* These API changes allow each virtio device driver to explicitly control
the assignment of virtqueues to IRQ vectors.

virtio - Refactor virtio bus API, to untangle virtuques from IRQ allocation.

* These API changes allow each virtio device driver to explicitly control
the assignment of virtqueues to IRQ vectors.

* This allows explicitly assigning IRQ vectors to cpus. And virtio device
drivers also get to know, on which cpu each virtqueue interrupt is
running.

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virtio_blk - Inline vtblk_complete into vtblk_vq_intr. Dedup sglist_reset.

virtio_blk - Fix capacity calculation, when host sets large disk block size.

* The disk capacity in the virtio configuration space is always specified
in 512 byte sectors, so info.d_media_blksize

virtio_blk - Fix capacity calculation, when host sets large disk block size.

* The disk capacity in the virtio configuration space is always specified
in 512 byte sectors, so info.d_media_blksize should be 512.

* Also check for VIRTIO_BLK_F_GEOMETRY feature before reading the disk
geometry from configuration space.

* Add some device_printf calls to report the disk size and (if available)
geometry during bootup.

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virtio_blk - No need to negotiate unused (and legacy) VIRTIO_BLK_F_BARRIER.

virtio_blk - Clean up some unneeded functionalities.

* Get rid of remaining code for handling the B_ORDERED flag.
B_ORDERED doesn't even exist anymore in DragonFly.

* Get rid of sc->vtblk_req_rea

virtio_blk - Clean up some unneeded functionalities.

* Get rid of remaining code for handling the B_ORDERED flag.
B_ORDERED doesn't even exist anymore in DragonFly.

* Get rid of sc->vtblk_req_ready request list. We can just use
bioqdisksort() to add a request - that we failed to enqueue ino the
virtqueue - back into the bioq.

* Rename req->vbr_bp field to req->vbr_bio.

* Switch vtblk_req_free list from TAILQ to SLIST. A small optimization,
none of the additional features of the TAILQ are needed here.

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virtio - Get rid of nop {vtblk/vtnet}_modevent methods.

virtio: Fix and activate PCI MSI-X support.

* Change pci_msi_blacklisted() test to always assume working MSI and MSI-X
interrupts on virtual-machines. We should assume that a hypervisor
without

virtio: Fix and activate PCI MSI-X support.

* Change pci_msi_blacklisted() test to always assume working MSI and MSI-X
interrupts on virtual-machines. We should assume that a hypervisor
without MSI or MSI-X support shouldn't even indicate supported MSI(-X)
via the PCI config space.

* Move vtblk_alloc_disk() to the end of virtio_blk's attach method.
This avoids a race between irq enabling in virtio, and the disk probing.

* Fix allocation and teardown of MSI-X interrupts.

* Get rid of rather confusing VIRTIO_PCI_FLAG_NO_MSI and
VIRTIO_PCI_FLAG_NO_MSIX flags. The VIRTIO_PCI_FLAG_NO_MSI is unneeded
when using pci_alloc_1intr() for MSI allocation, and
instead of VIRTIO_PCI_FLAG_NO_MSIX we can just check sc->vtpci_msix_res.

* For now, MSI-X vectors are simply assigned to subsequent cores (plus
adding the device_get_unit() value to shuffle things a bit), i.e.:
(device_get_unit(dev) + cnt) % ncpus

* For the if_vtnet network driver this means that the rx and tx queues run
on different cores, but both queues still use the same serializer for
now.

* One major advantages in using MSI-X interrupts instead of the legacy
IRQ is, that this avoids interrupt sharing in many virtual-machine
configurations.

* Tested on qemu with TCG (unaccelerated emulation) and 1 core, and with
KVM acceleration and 2 cores, with both virtio network and disk devices.

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buf - Remove B_ORDERED, Incidental CAM MPSAFE

* Remove support for B_ORDERED. Most drivers ignore it, and it is basically
unusable.

* The CAM "xpt", "pass", and "sg" devices are MPSAFE, flag the

buf - Remove B_ORDERED, Incidental CAM MPSAFE

* Remove support for B_ORDERED. Most drivers ignore it, and it is basically
unusable.

* The CAM "xpt", "pass", and "sg" devices are MPSAFE, flag them
appropriately.

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virtio - vtblk_finish_bio() called with serializer held

* vtblk_finish_bio() was being improperly called with the
serializer held in the strategy error path.

* Note that biodone() is properly cal

virtio - vtblk_finish_bio() called with serializer held

* vtblk_finish_bio() was being improperly called with the
serializer held in the strategy error path.

* Note that biodone() is properly called without the
serializer held in the normal completion path.

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virtio - Fix a few porting issues and bugs

* vtblk_maximum_segments() was really buggy. It was
adding the base min segments to blkcfg->seg_max,
miscalculating values for the case where the F_SE

virtio - Fix a few porting issues and bugs

* vtblk_maximum_segments() was really buggy. It was
adding the base min segments to blkcfg->seg_max,
miscalculating values for the case where the F_SEG_MAX
feature is not in the feature list.

This could result in virtio imploding on a too-small
sglist.

* Fix situations where M_NOWAIT is improperly used.

* At least use 16-byte alignment for contigmalloc()'s.

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virtio_blk: Add support for indirect buffers.

Taken-From: FreeBSD

virtio_blk: Use contigmalloc/contigfree for vtblk_request allocations.

This should fix the "panic: header spanned multiple segments: 2" panic
occuring for some users when running in qemu.

Reported-

virtio_blk: Use contigmalloc/contigfree for vtblk_request allocations.

This should fix the "panic: header spanned multiple segments: 2" panic
occuring for some users when running in qemu.

Reported-By: Jim B.

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virtio_blk: Enable dump support. Partial sync with FreeBSD up to r252707.

* Adds support for dumping to the virtio_blk driver.

* The dev.vtblk.X.writecache_mode sysctl can now be used to toggle wri

virtio_blk: Enable dump support. Partial sync with FreeBSD up to r252707.

* Adds support for dumping to the virtio_blk driver.

* The dev.vtblk.X.writecache_mode sysctl can now be used to toggle write
caching by the virtual-machine host.

* Add a workaround in sys/dev/virtual/virtio/virtio/virtqueue.c to avoid
a serializer exit/enter pair while dumping.

* Reduce diff relative to FreeBSD's virtio_blk.c version.

* Adapt manpage, comment out description of the hw.vtblk.no_ident tunable.

* Updates are taken from FreeBSD's r252707, r252703 and r247829.

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kernel: Use DEVMETHOD_END in the drivers.

kernel/virtio: Remove some unneeded inclusions of <sys/cdefs.h>.

kernel/virtio: Remove some unused variables.

kernel -- virtio: Implement virtio-layer lwkt_serializer for devices

* Switch virtio device targets (currently only -blk) to use a
serializer for synchronizing per-target state. Thread the
seria

kernel -- virtio: Implement virtio-layer lwkt_serializer for devices

* Switch virtio device targets (currently only -blk) to use a
serializer for synchronizing per-target state. Thread the
serializer through virtqueue_notify (release around kick) and
into the bus interrupt setup code.

* Remove dump support from virtio-blk for now; it doesn't work and
results in further panics from an incorrectly setup bio.

* Other cleanups of virtio-blk (de-indirect locks).

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Build fixes.

kernel/virtio: Some cleanup (Makefiles and gcc47 warnings).