x86/iommu: extract useful utilities into x86_iommu.c

related to the page tables page allocation and mapping.

Sponsored by: The FreeBSD Foundation
Sponsored by: Advanced Micro Devices (AMD)
MFC after: 1 week

sys: Automated cleanup of cdefs and other formatting

Apply the following automated changes to try to eliminate
no-longer-needed sys/cdefs.h includes as well as now-empty
blank lines in a row.

Remove /^#if.*\n#endif.*\n#include\s+<sys/cdefs.h>.*\n/
Remove /\n+#include\s+<sys/cdefs.h>.*\n+#if.*\n#endif.*\n+/
Remove /\n+#if.*\n#endif.*\n+/
Remove /^#if.*\n#endif.*\n/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/types.h>/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/param.h>/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/capsicum.h>/

Sponsored by: Netflix

sys: Remove $FreeBSD$: one-line .c pattern

Remove /^[\s*]*__FBSDID\("\$FreeBSD\$"\);?\s*\n/

spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD

The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of BSD-2-Clause.

Discussed with: pfg
MFC After: 3 days
Sponsored by: Netflix

DMAR: clean up warnings about write-only variables

For some of them, used only when KTR or KMSAN are configured, apply
__unused attribute directly.

Sponsored by: The FreeBSD Foundation
MFC after: 1 week

Remove "All Rights Reserved" from FreeBSD Foundation sys/ copyrights

These ones were unambiguous cases where the Foundation was the only
listed copyright holder (in the associated license block).

Sponsored by: The FreeBSD Foundation

x86: clean up empty lines in .c and .h files

Add iommu_domain constructor and destructor.

Reviewed by: kib
Sponsored by: DARPA/AFRL
Differential Revision: https://reviews.freebsd.org/D25956

Add a few macroses for conversion between DMAR unit, domain, ctx
and IOMMU unit, domain, ctx.

Reviewed by: kib
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D25926

Add iommu_domain_map_ops virtual table with map/unmap methods
so x86 can support Intel DMAR and AMD IOMMU simultaneously.

Reviewed by: kib
Sponsored by: DARPA/AFRL
Differential Revision: https://reviews.freebsd.org/D25894

o Don't include headers from iommu.h, include them from the header
consumers instead;
o Order includes properly.

Reviewed by: kib
Sponsored by: DARPA/AFRL
Differential Revision: https://reviews.freebsd.org/D25878

Rename DMAR flags:
o DMAR_DOMAIN_* -> IOMMU_DOMAIN_*
o DMAR_PGF_* -> IOMMU_PGF_*

Reviewed by: kib
Sponsored by: DARPA/AFRL
Differential Revision: https://reviews.freebsd.org/D25812

Split-out the Intel GAS (Guest Address Space) management component
from Intel DMAR support, so it can be used on other IOMMU systems.

Reviewed by: kib
Sponsored by: DARPA/AFRL
Differential Revision: https://reviews.freebsd.org/D25743

Move the Intel DMAR busdma backend to a generic place so
it can be used on other IOMMU systems.

Reviewed by: kib
Sponsored by: DARPA/AFRL
Differential Revision: https://reviews.freebsd.org/D25720

Start splitting-out the Intel DMAR busdma backend to a generic place,
so it can be used on other IOMMU systems.

Provide MI iommu_unit, iommu_domain and iommu_ctx structs in sys/iommu.h;
use them as a first member of MD dmar_unit, dmar_domain and dmar_ctx.

Change the namespace in DMAR backend: use iommu_ prefix instead of dmar_.

Move some macroses and function prototypes to sys/iommu.h.

Reviewed by: kib
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D25574

bus_dma_dmar_set_buswide(9): KPI to indicate that the whole dmar
context should share page tables.

Practically it means that dma requests from any device on the bus are
translated according to the entries loaded for the bus:0:0 device.
KPI requires that the slot and function of the device be 0:0, and that
no tags for other devices on the bus were used.

The intended use are NTBs which pass TLPs from the downstream to the
host with slot:func of the downstream originator.

Reviewed and tested by: mav
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D22434

Complete the removal of the "wire_count" field from struct vm_page.

Convert all remaining references to that field to "ref_count" and update
comments accordingly. No functional change intended.

Reviewed by: alc, kib
Sponsored by: Intel, Netflix
Differential Revision: https://reviews.freebsd.org/D21768

sys/x86: further adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

Comment only change, fix grammar and somewhat clarify the action.

Sponsored by: The FreeBSD Foundation
MFC after: 3 days

Typo in comment.

Split the DMAR unit domains and contexts. Domains carry address space
and related data structures. Contexts attach requests initiators to
domains. There is still 1:1 correspondence between contexts and
domains on the running system, since only busdma currently allocates
them, using dmar_get_ctx_for_dev().

Large part of the change is formal rename of the ctx to domain, but
patch also reworks the context allocation and free to allow for
independent domain creation.

The helper dmar_move_ctx_to_domain() is introduced for future use, to
reassign request initiator from one domain to another. The hard issue
which is not yet resolved with the context move is proper handling (or
reserving) RMRR entries in the destination domain as required by ACPI
DMAR table for moved context.

Tested by: pho
Sponsored by: The FreeBSD Foundation

Remove several write-only variables, all reported by the gcc 4.9
buildkernel run.

Some of them were write-only under some kernel options, e.g. variables
keeping values only used by CTR() macros. It costs nothing to the
code readability and correctness to eliminate the warnings in those
cases too by removing the local cached values used only for
single-access.

Review: https://reviews.freebsd.org/D2665
Reviewed by: rodrigc
Looked at by: bjk
Sponsored by: The FreeBSD Foundation
MFC after: 1 week

Assert that the mapping loop makes progress.

Sponsored by: The FreeBSD Foundation
MFC after: 1 week

Use VT-d interrupt remapping block (IR) to perform FSB messages
translation. In particular, despite IO-APICs only take 8bit apic id,
IR translation structures accept 32bit APIC Id, which allows x2APIC
mode to function properly. Extend msi_cpu of struct msi_intrsrc and
io_cpu of ioapic_intsrc to full int from one byte.

KPI of IR is isolated into the x86/iommu/iommu_intrmap.h, to avoid
bringing all dmar headers into interrupt code. The non-PCI(e) devices
which generate message interrupts on FSB require special handling. The
HPET FSB interrupts are remapped, while DMAR interrupts are not.

For each msi and ioapic interrupt source, the iommu cookie is added,
which is in fact index of the IRE (interrupt remap entry) in the IR
table. Cookie is made at the source allocation time, and then used at
the map time to fill both IRE and device registers. The MSI
address/data registers and IO-APIC redirection registers are
programmed with the special values which are recognized by IR and used
to restore the IRE index, to find proper delivery mode and target.
Map all MSI interrupts in the block when msi_map() is called.

Since an interrupt source setup and dismantle code are done in the
non-sleepable context, flushing interrupt entries cache in the IR
hardware, which is done async and ideally waits for the interrupt,
requires busy-wait for queue to drain. The dmar_qi_wait_for_seq() is
modified to take a boolean argument requesting busy-wait for the
written sequence number instead of waiting for interrupt.

Some interrupts are configured before IR is initialized, e.g. ACPI
SCI. Add intr_reprogram() function to reprogram all already
configured interrupts, and call it immediately before an IR unit is
enabled. There is still a small window after the IO-APIC redirection
entry is reprogrammed with cookie but before the unit is enabled, but
to fix this properly, IR must be started much earlier.

Add workarounds for 5500 and X58 northbridges, some revisions of which
have severe flaws in handling IR. Use the same identification methods
as employed by Linux.

Review: https://reviews.freebsd.org/D1892
Reviewed by: neel
Discussed with: jhb
Tested by: glebius, pho (previous versions)
Sponsored by: The FreeBSD Foundation
MFC after: 3 weeks

Right now, for non-coherent DMARs, page table update code flushes the
cache for whole page containing modified pte, and more, only last page
in the series of the consequtive pages is flushed (i.e. the affected
mappings should be larger than 2MB).

Avoid excessive flushing and do missed neccessary flushing, by
splitting invalidation and unmapping. For now, flush exactly the
range of the changed pte. This is still somewhat bigger than
neccessary, since pte is 8 bytes, while cache flush line is at least
32 bytes.

The originator of the issue reports that after the change,
'dmar_bus_dmamap_unload went from 13,288 cycles down to
3,257. dmar_bus_dmamap_load_buffer went from 9,686 cycles down to
3,517. and I am now able to get line 1GbE speed with Netperf TCP
(even with 1K message size).'

Diagnosed and tested by: Nadav Amit <nadav.amit@gmail.com>
Sponsored by: The FreeBSD Foundation
MFC after: 1 week

Fix (erroneous) gcc warnings about usage of uninitialized variables in
sys/x86/iommu/intel_idpgtbl.c.

Reviewed by: kib

Add support for queued invalidation.

Right now, the semaphore write is scheduled after each batch, which is
not optimal and must be tuned.

Discussed with: alc
Tested by: pho
MFC after: 1 month

Import the driver for VT-d DMAR hardware, as specified in the revision
1.3 of Intelб╝ Virtualization Technology for Directed I/O Architecture
Specification. The Extended Context and PASIDs from the rev. 2.2 are
not supported, but I am not aware of any released hardware which
implements them. Code does not use queued invalidation, see comments
for the reason, and does not provide interrupt remapping services.

Code implements the management of the guest address space per domain
and allows to establish and tear down arbitrary mappings, but not
partial unmapping. The superpages are created as needed, but not
promoted. Faults are recorded, fault records could be obtained
programmatically, and printed on the console.

Implement the busdma(9) using DMARs. This busdma backend avoids
bouncing and provides security against misbehaving hardware and driver
bad programming, preventing leaks and corruption of the memory by wild
DMA accesses.

By default, the implementation is compiled into amd64 GENERIC kernel
but disabled; to enable, set hw.dmar.enable=1 loader tunable. Code is
written to work on i386, but testing there was low priority, and
driver is not enabled in GENERIC. Even with the DMAR turned on,
individual devices could be directed to use the bounce busdma with the
hw.busdma.pci<domain>:<bus>:<device>:<function>.bounce=1 tunable. If
DMARs are capable of the pass-through translations, it is used,
otherwise, an identity-mapping page table is constructed.

The driver was tested on Xeon 5400/5500 chipset legacy machine,
Haswell desktop and E5 SandyBridge dual-socket boxes, with ahci(4),
ata(4), bce(4), ehci(4), mfi(4), uhci(4), xhci(4) devices. It also
works with em(4) and igb(4), but there some fixes are needed for
drivers, which are not committed yet. Intel GPUs do not work with
DMAR (yet).

Many thanks to John Baldwin, who explained me the newbus integration;
Peter Holm, who did all testing and helped me to discover and
understand several incredible bugs; and to Jim Harris for the access
to the EDS and BWG and for listening when I have to explain my
findings to somebody.

Sponsored by: The FreeBSD Foundation
MFC after: 1 month