MFStable-10 r259301

MFC r256657,r257018,r257347,r257423,r257729,r257767,
r257933,r258609,r258614,r258668,r258673,r258855

Pull in some minor bugfixes and functionality enhancements
from CURRENT. These are candidates to be moved to 10.0-release.

r258855
mdoc: quote string properly.

r258673
Don't create an initial value for the host filesystem of "/".

r258668
Allow bhyve and bhyveload to attach to tty devices.

r258614
The 22-bit Data Byte Count (DBC) field of a Physical Region Descriptor was
being read as a 32-bit quantity by the bhyve AHCI driver.

r258609
Fix discrepancy between the IOAPIC ID advertised by firmware tables and the
actual value read by the guest.

r257933
Route the legacy timer interrupt (IRQ0) to pin 2 of the IOAPIC.

r257767
Fix an off-by-one error when iterating over the emulated PCI BARs.

r257729
Add the VM name to the process name with setproctitle().

r257423
Make the virtual ioapic available unconditionally in a bhyve virtual machine.

r257347
Update copyright to include the author of the LPC bridge emulation code.

hand-merge r257018
Tidy usage messages for bhyve and bhyveload.

r256657
Add an option to bhyveload(8) that allows setting a loader environment variable
from the command line.

Approved by: re@ (gjb)

Remove svn:mergeinfo from the releng/10.0 branch.

After branch creation from stable/10, the stable/10 branch mergeinfo
was moved to the root of the branch.

Since there have not been any merges from stable/10 to releng/10.0
yet, we do not need to track any of the existing mergeinfo here.

Merges to releng/10.0 should now be done to the root of the branch.

For future branches during the release cycle, unless otherwise noted,
this change will be done as part of the stable/ and releng/ branch
creation.

Discussed with: peter
Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

- Copy stable/10 (r259064) to releng/10.0 as part of the
10.0-RELEASE cycle.
- Update __FreeBSD_version [1]
- Set branch name to -RC1

[1] 10.0-CURRENT __FreeBSD_version value ended at '55', so
start releng/10.0 at '100' so the branch is started with
a value ending in zero.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Fix missing .

Approved by: re (blanket)

Parse the memory size parameter using expand_number() to allow specifying
the memory size more intuitively (e.g. 512M, 4G etc).

Submitted by: rodrigc
Reviewed by: grehan
Approved by: re (blanket)

Merge projects/bhyve_npt_pmap into head.

Make the amd64/pmap code aware of nested page table mappings used by bhyve
guests. This allows bhyve to associate each guest with its own vmspace and
deal with nested page faults in the context of that vmspace. This also
enables features like accessed/dirty bit tracking, swapping to disk and
transparent superpage promotions of guest memory.

Guest vmspace:
Each bhyve guest has a unique vmspace to represent the physical memory
allocated to the guest. Each memory segment allocated by the guest is
mapped into the guest's address space via the 'vmspace->vm_map' and is
backed by an object of type OBJT_DEFAULT.

pmap types:
The amd64/pmap now understands two types of pmaps: PT_X86 and PT_EPT.

The PT_X86 pmap type is used by the vmspace associated with the host kernel
as well as user processes executing on the host. The PT_EPT pmap is used by
the vmspace associated with a bhyve guest.

Page Table Entries:
The EPT page table entries as mostly similar in functionality to regular
page table entries although there are some differences in terms of what
bits are used to express that functionality. For e.g. the dirty bit is
represented by bit 9 in the nested PTE as opposed to bit 6 in the regular
x86 PTE. Therefore the bitmask representing the dirty bit is now computed
at runtime based on the type of the pmap. Thus PG_M that was previously a
macro now becomes a local variable that is initialized at runtime using
'pmap_modified_bit(pmap)'.

An additional wrinkle associated with EPT mappings is that older Intel
processors don't have hardware support for tracking accessed/dirty bits in
the PTE. This means that the amd64/pmap code needs to emulate these bits to
provide proper accounting to the VM subsystem. This is achieved by using
the following mapping for EPT entries that need emulation of A/D bits:
Bit Position Interpreted By
PG_V 52 software (accessed bit emulation handler)
PG_RW 53 software (dirty bit emulation handler)
PG_A 0 hardware (aka EPT_PG_RD)
PG_M 1 hardware (aka EPT_PG_WR)

The idea to use the mapping listed above for A/D bit emulation came from
Alan Cox (alc@).

The final difference with respect to x86 PTEs is that some EPT implementations
do not support superpage mappings. This is recorded in the 'pm_flags' field
of the pmap.

TLB invalidation:
The amd64/pmap code has a number of ways to do invalidation of mappings
that may be cached in the TLB: single page, multiple pages in a range or the
entire TLB. All of these funnel into a single EPT invalidation routine called
'pmap_invalidate_ept()'. This routine bumps up the EPT generation number and
sends an IPI to the host cpus that are executing the guest's vcpus. On a
subsequent entry into the guest it will detect that the EPT has changed and
invalidate the mappings from the TLB.

Guest memory access:
Since the guest memory is no longer wired we need to hold the host physical
page that backs the guest physical page before we can access it. The helper
functions 'vm_gpa_hold()/vm_gpa_release()' are available for this purpose.

PCI passthru:
Guest's with PCI passthru devices will wire the entire guest physical address
space. The MMIO BAR associated with the passthru device is backed by a
vm_object of type OBJT_SG. An IOMMU domain is created only for guest's that
have one or more PCI passthru devices attached to them.

Limitations:
There isn't a way to map a guest physical page without execute permissions.
This is because the amd64/pmap code interprets the guest physical mappings as
user mappings since they are numerically below VM_MAXUSER_ADDRESS. Since PG_U
shares the same bit position as EPT_PG_EXECUTE all guest mappings become
automatically executable.

Thanks to Alan Cox and Konstantin Belousov for their rigorous code reviews
as well as their support and encouragement.

Thanks for John Baldwin for reviewing the use of OBJT_SG as the backing
object for pci passthru mmio regions.

Special thanks to Peter Holm for testing the patch on short notice.

Approved by: re
Discussed with: grehan
Reviewed by: alc, kib
Tested by: pho

mdoc: remove superfluous paragraph macro.

Simplify the assignment of memory to virtual machines by requiring a single
command line option "-m <memsize in MB>" to specify the memory size.

Prior to this change the user needed to explicitly specify the amount of
memory allocated below 4G (-m <lowmem>) and the amount above 4G (-M <highmem>).

The "-M" option is no longer supported by 'bhyveload' and 'bhyve'.

The start of the PCI hole is fixed at 3GB and cannot be directly changed
using command line options. However it is still possible to change this in
special circumstances via the 'vm_set_lowmem_limit()' API provided by
libvmmapi.

Submitted by: Dinakar Medavaram (initial version)
Reviewed by: grehan
Obtained from: NetApp

Remove EOL whitespace.

Minor mdoc fixes.

Merge projects/bhyve to head.

'bhyve' was developed by grehan@ and myself at NetApp (thanks!).

Special thanks to Peter Snyder, Joe Caradonna and Michael Dexter for their
support and encouragement.

Obtained from: NetApp

Add the 'bhyveload(8)' man page.

Obtained from: NetApp
Reviewed by: grehan

Reduce the default memory allocation for a VM from 768MB to 128MB.

Obtained from: NetApp

IFC @ r242684

Use the new userboot 'getenv' callback to set a couple of environment variables
in the guest.

The variables are: smbios.bios.vendor=BHYVE and boot_serial=1

The FreeBSD guest uses the "smbios.bios.vendor" environment variable to
detect whether or not it is running as a guest inside a hypervisor.

The "boot_serial=1" is temporary and will be dropped when bhyve can do VGA
emulation.

Obtained from: NetApp

IFC @ r234692

sys/amd64/include/cpufunc.h
sys/amd64/include/fpu.h
sys/amd64/amd64/fpu.c
sys/amd64/vmm/vmm.c

- Add API to allow vmm FPU state init/save/restore.

FP stuff discussed with: kib

'bhyveload' is a userspace FreeBSD loader that can load the kernel + metadata
inside a BHyVe-based virtual machine.

It is a thin wrapper on top of userboot.so which is a variant of the FreeBSD
loader packaged as a shared library. 'bhyveload' provides callbacks that are
utilized by userboot.so to do things like console i/o, disk i/o,
set virtual machine registers etc.

Thanks for Doug Rabson (dfr@) for making this happen.