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

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

sys: Remove $FreeBSD$: two-line .h pattern

Remove /^\s*\*\n \*\s+\$FreeBSD\$$\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spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD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

libvmmapi: Add a struct vcpu and use it in most APIs.

This replaces the 'struct vm, int vcpuid' tuple passed to most API
calls and is similar to the changes recently made in vmm(4) in the
kernel.

struct vcpu is an opaque type managed by libvmmapi. For now it stores
a pointer to the VM context and an integer id.

As an immediate effect this removes the divergence between the kernel
and userland for the instruction emulation code introduced by the
recent vmm(4) changes.

Since this is a major change to the vmmapi API, bump VMMAPI_VERSION to
0x200 (2.0) and the shared library major version.

While here (and since the major version is bumped), remove unused
vcpu argument from vm_setup_pptdev_msi*().

Add new functions vm_suspend_all_cpus() and vm_resume_all_cpus() for
use by the debug server. The underyling ioctl (which uses a vcpuid of
-1) remains unchanged, but the userlevel API now uses separate
functions for global CPU suspend/resume.

Reviewed by: corvink, markj
Differential Revision: https://reviews.freebsd.org/D38124

vmm: Use struct vcpu in the instruction emulation code.

This passes struct vcpu down in place of struct vm and and integer
vcpu index through the in-kernel instruction emulation code. To
minimize userland disruption, helper macros are used for the vCPU
arguments passed into and through the shared instruction emulation
code.

A few other APIs used by the instruction emulation code have also been
updated to accept struct vcpu in the kernel including
vm_get/set_register and vm_inject_fault.

Reviewed by: corvink, markj
Differential Revision: https://reviews.freebsd.org/D37161

bhyve: Remove unused vm and vcpu arguments from vm_copy routines.

The arguments identifying the VM and vCPU are only needed for
vm_copy_setup.

Reviewed by: corvink, markj
Differential Revision: https://reviews.freebsd.org/D37158

bhyve: Address some signed/unsigned comparison warnings

MFC after: 1 week

bhyve: Annotate unused function parameters

MFC after: 1 week

vmm_instruction_emul.c: fix bhyve build

The __diagused macro was used to cure a "set but not used" warning. This
broke the build for bhyve since __diagused is only defined in the
kernel. Define __diagused when not building the kernel.

Fixes: 5241577a223d ("vmm: fix set but not used warning")
Reported by: Jenkins

vmm: fix set but not used warning

Add bhyve support for LA57 guest mode.

Noted and reviewed by: grehan
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D25273

bhyve(8): For prototyping, reattempt decode in userspace

If userspace has a newer bhyve than the kernel, it may be able to decode
and emulate some instructions vmm.ko is unaware of. In this scenario,
reset decoder state and try again.

Reviewed by: grehan
Differential Revision: https://reviews.freebsd.org/D24464

vmm(4): Decode and emulate BEXTR

Clang 10 -march=native kernels on znver1 emit BEXTR for APIC reads,
apparently. Decode and emulate the instruction.

Reviewed by: grehan
Differential Revision: https://reviews.freebsd.org/D24463

vmm(4): Decode 3-byte VEX-prefixed instructions

Reviewed by: grehan
Differential Revision: https://reviews.freebsd.org/D24462

vmm(4): Expose instruction decode to userspace build

Permit instruction decoding logic to be compiled outside of the kernel for
rapid iteration and validation.

Reviewed by: grehan
Differential Revision: https://reviews.freebsd.org/D24439

Emulate the "TEST r/m{16,32,64}, imm{16,32,32}" instructions (opcode F7H).

This adds emulation for:
test r/m16, imm16
test r/m32, imm32
test r/m64, imm32 sign-extended to 64

OpenBSD guests compiled with clang 8.0.0 use TEST directly against a
Local APIC register instead of separate read via MOV followed by a
TEST against the register.

PR: 238794
Submitted by: jhb
Reported by: Jason Tubnor jason@tubnor.net
Tested by: Jason Tubnor jason@tubnor.net
Reviewed by: markj, Patrick Mooney patrick.mooney@joyent.com
MFC after: 3 days
Differential Revision: https://reviews.freebsd.org/D20755

Emulate the "ADD reg, r/m" instruction (opcode 03H).

OVMF's flash variable storage is using add instructions when indexing
the variable store bootrom location.

Submitted by: D Scott Phillips <d.scott.phillips@intel.com>
Reviewed by: rgrimes
MFC after: 1 week
Sponsored by: Intel Corporation
Differential Revision: https://reviews.freebsd.org/D19975

bhyve: emulate CLFLUSH and CLFLUSHOPT.

Apparently CLFLUSH on mmio can cause VM exit, as reported in the PR.
I do not see that anything useful can be done except emulating page
faults on invalid addresses.

Due to the instruction encoding pecularity, also emulate SFENCE.

PR: 232081
Reported by: phk
Reviewed by: araujo, avg, jhb (all: previous version)
Sponsored by: The FreeBSD Foundation
Approved by: re (gjb)
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D17482

Add a new variant of the GLA2GPA ioctl for use by the debug server.

Unlike the existing GLA2GPA ioctl, GLA2GPA_NOFAULT does not modify
the guest. In particular, it does not inject any faults or modify
PTEs in the guest when performing an address space translation.

This is used by bhyve's debug server to read and write memory for
the remote debugger.

Reviewed by: grehan
MFC after: 1 month
Differential Revision: https://reviews.freebsd.org/D14075

sys/amd64: 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.

Emulate the "OR reg, r/m" instruction (opcode 0BH).

This is needed for the HDA emulation with FreeBSD guests.

Reviewed by: marcelo
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D12832

vmm(4): Small spelling fixes.

Reviewed by: grehan

verify_gla() needs to account for non-zero segment base addresses.

Reviewed by: neel

Restructure memory allocation in bhyve to support "devmem".

devmem is used to represent MMIO devices like the boot ROM or a VESA framebuffer
where doing a trap-and-emulate for every access is impractical. devmem is a
hybrid of system memory (sysmem) and emulated device models.

devmem is mapped in the guest address space via nested page tables similar
to sysmem. However the address range where devmem is mapped may be changed
by the guest at runtime (e.g. by reprogramming a PCI BAR). Also devmem is
usually mapped RO or RW as compared to RWX mappings for sysmem.

Each devmem segment is named (e.g. "bootrom") and this name is used to
create a device node for the devmem segment (e.g. /dev/vmm/testvm.bootrom).
The device node supports mmap(2) and this decouples the host mapping of
devmem from its mapping in the guest address space (which can change).

Reviewed by: tychon
Discussed with: grehan
Differential Revision: https://reviews.freebsd.org/D2762
MFC after: 4 weeks

The 'verify_gla()' function is used to ensure that the effective address
after decoding the instruction matches the one provided by hardware.

Prior to r283293 'vie->num_valid' used to contain the actual length of
the instruction whereas now it contains the maximum instruction length
possible. This introduced a bug when calculating a RIP-relative base address.

Fix this by using 'vie->num_processed' rather than 'vie->num_valid' as the
length of the emulated instruction.

Reported and tested by: tychon
MFC after: 1 week

Remove the verification of instruction length after instruction decode. The
check has been bogus since r273375.

MFC after: 1 week

Emulate the "CMP r/m, reg" instruction (opcode 39H).

Reported and tested by: Leon Dang (ldang@nahannisys.com)
MFC after: 1 week

Deprecate the 3-way return values from vm_gla2gpa() and vm_copy_setup().

Prior to this change both functions returned 0 for success, -1 for failure
and +1 to indicate that an exception was injected into the guest.

The numerical value of ERESTART also happens to be -1 so when these functions
returned -1 it had to be translated to a positive errno value to prevent the
VM_RUN ioctl from being inadvertently restarted. This made it easy to introduce
bugs when writing emulation code.

Fix this by adding an 'int *guest_fault' parameter and setting it to '1' if
an exception was delivered to the guest. The return value is 0 or EFAULT so
no additional translation is needed.

Reviewed by: tychon
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D2428

Emulate the 'CMP r/m8, imm8' instruction encountered when booting a Windows
Vista guest.

Reported by: Leon Dang (ldang@nahannisys.com)
MFC after: 1 week

Emulate the 'bit test' instruction. Windows 7 uses 'bit test' to check the
'Delivery Status' bit in APIC ICR register.

Reported by: Leon Dang (ldang@nahannisys.com)
MFC after: 2 weeks

STOS/STOSB/STOSW/STOSD/STOSQ instruction emulation.

Reviewed by: neel

Enhance the support for Group 1 Extended opcodes:

* Implemement the 0x81 and 0x83 CMP instructions.
* Implemement the 0x83 AND instruction.
* Implemement the 0x81 OR instruction.

Reviewed by: neel

Fix "MOVS" instruction memory to MMIO emulation. Currently updates to
%rdi, %rsi, etc are inadvertently bypassed along with the check to
see if the instruction needs to be repeated per the 'rep' prefix.

Add "MOVS" instruction support for the 'MMIO to MMIO' case.

Reviewed by: neel

When fetching an instruction in non-64bit mode, consider the value of the
code segment base address.

Also if an instruction doesn't support a mod R/M (modRM) byte, don't
be concerned if the CPU is in real mode.

Reviewed by: neel

MOVS instruction emulation.

These instructions are emitted by 'bus_space_read_region()' when accessing
MMIO regions.

Since MOVS can be used with a repeat prefix start decoding the REPZ and
REPNZ prefixes. Also start decoding the segment override prefix since MOVS
allows overriding the source operand segment register.

Tested by: tychon
MFC after: 1 week

Emulate "POP r/m".

This is needed to boot OpenBSD/i386 MP kernel in bhyve.

Reported by: grehan
MFC after: 1 week

AMD processors that have the SVM decode assist capability will store the
instruction bytes in the VMCB on a nested page fault. This is useful because
it saves having to walk the guest page tables to fetch the instruction.

vie_init() now takes two additional parameters 'inst_bytes' and 'inst_len'
that map directly to 'vie->inst[]' and 'vie->num_valid'.

The instruction emulation handler skips calling 'vmm_fetch_instruction()'
if 'vie->num_valid' is non-zero.

The use of this capability can be turned off by setting the sysctl/tunable
'hw.vmm.svm.disable_npf_assist' to '1'.

Reviewed by: Anish Gupta (akgupt3@gmail.com)
Discussed with: grehan

The "SUB" instruction used in getcc() actually does 'x -= y' so use the
proper constraint for 'x'. The "+r" constraint indicates that 'x' is an
input and output register operand.

While here generate code for different variants of getcc() using a macro
GETCC(sz) where 'sz' indicates the operand size.

Update the status bits in %rflags when emulating AND and OR opcodes.

Reviewed by: grehan

Implement the 0x2B SUB instruction, and the OR variant of 0x81.

Found with local APIC accesses from bitrig/amd64 bsd.rd, 07/15-snap.

Reviewed by: neel
MFC after: 3 days

Support PCI extended config space in bhyve.

Add the ACPI MCFG table to advertise the extended config memory window.

Introduce a new flag MEM_F_IMMUTABLE for memory ranges that cannot be deleted
or moved in the guest's address space. The PCI extended config space is an
example of an immutable memory range.

Add emulation for the "movzw" instruction. This instruction is used by FreeBSD
to read a 16-bit extended config space register.

CR: https://phabric.freebsd.org/D505
Reviewed by: jhb, grehan
Requested by: tychon

Don't return -1 from the push emulation handler. Negative return values are
interpreted specially on return from sys_ioctl() and may cause undesirable
side-effects like restarting the system call.

Fix a couple of issues in the PUSH emulation:

It is not possible to PUSH a 32-bit operand on the stack in 64-bit mode. The
default operand size for PUSH is 64-bits and the operand size override prefix
changes that to 16-bits.

vm_copy_setup() can return '1' if it encounters a fault when walking the
guest page tables. This is a guest issue and is now handled properly by
resuming the guest to handle the fault.

Emulate instructions emitted by OpenBSD/i386 version 5.5:
- CMP REG, r/m
- MOV AX/EAX/RAX, moffset
- MOV moffset, AX/EAX/RAX
- PUSH r/m

Add support for operand size and address size override prefixes in bhyve's
instruction emulation [1].

Fix bug in emulation of opcode 0x8A where the destination is a legacy high
byte register and the guest vcpu is in 32-bit mode. Prior to this change
instead of modifying %ah, %bh, %ch or %dh the emulation would end up
modifying %spl, %bpl, %sil or %dil instead.

Add support for moffsets by treating it as a 2, 4 or 8 byte immediate value
during instruction decoding.

Fix bug in verify_gla() where the linear address computed after decoding
the instruction was not being truncated to the effective address size [2].

Tested by: Leon Dang [1]
Reported by: Peter Grehan [2]
Sponsored by: Nahanni Systems

Use the correct offset when converting a logical address (segment:offset)
to a linear address.

Add support for emulating the move instruction: "mov r/m8, imm8".

Reviewed by: neel

Add segment protection and limits violation checks in vie_calculate_gla()
for 32-bit x86 guests.

Tested using ins/outs executed in a FreeBSD/i386 guest.

Do the linear address calculation for the ins/outs emulation using a new
API function 'vie_calculate_gla()'.

While the current implementation is simplistic it forms the basis of doing
segmentation checks if the guest is in 32-bit protected mode.

Consolidate all the information needed by the guest page table walker into
'struct vm_guest_paging'.

Check for canonical addressing in vmm_gla2gpa() and inject a protection
fault into the guest if a violation is detected.

If the page table walk is restarted in vmm_gla2gpa() then reset 'ptpphys' to
point to the root of the page tables.

When injecting a page fault into the guest also update the guest's %cr2 to
indicate the faulting linear address.

If the guest PML4 entry has the PG_PS bit set then inject a page fault into
the guest with the PGEX_RSV bit set in the error_code.

Get rid of redundant checks for the PG_RW violations when walking the page
tables.

Check for alignment check violation when processing in/out string instructions.

Add emulation of the "outsb" instruction. NetBSD guests use this to write to
the UART FIFO.

The emulation is constrained in a number of ways: 64-bit only, doesn't check
for all exception conditions, limited to i/o ports emulated in userspace.

Some of these constraints will be relaxed in followup commits.

Requested by: grehan
Reviewed by: tychon (partially and a much earlier version)

Inject page fault into the guest if the page table walker detects an invalid
translation for the guest linear address.

Add PG_RW check when translating a guest linear to guest physical address.

Set the accessed and dirty bits in the page table entry. If it fails then
restart the page table walk from the beginning. This might happen if another
vcpu modifies the page tables simultaneously.

Reviewed by: alc, kib

Add PG_U (user/supervisor) checks when translating a guest linear address
to a guest physical address.

PG_PS (page size) field is valid only in a PDE or a PDPTE so it is now
checked only in non-terminal paging entries.

Ignore the upper 32-bits of the CR3 for PAE paging.

Add support for emulating the byte move and sign extend instructions:
"movsx r/m8, r32" and "movsx r/m8, r64".

Approved by: grehan (co-mentor)

Add support for FreeBSD/i386 guests under bhyve.
- Similar to the hack for bootinfo32.c in userboot, define
_MACHINE_ELF_WANT_32BIT in the load_elf32 file handlers in userboot.
This allows userboot to load 32-bit kernels and modules.
- Copy the SMAP generation code out of bootinfo64.c and into its own
file so it can be shared with bootinfo32.c to pass an SMAP to the i386
kernel.
- Use uint32_t instead of u_long when aligning module metadata in
bootinfo32.c in userboot, as otherwise the metadata used 64-bit
alignment which corrupted the layout.
- Populate the basemem and extmem members of the bootinfo struct passed
to 32-bit kernels.
- Fix the 32-bit stack in userboot to start at the top of the stack
instead of the bottom so that there is room to grow before the
kernel switches to its own stack.
- Push a fake return address onto the 32-bit stack in addition to the
arguments normally passed to exec() in the loader. This return
address is needed to convince recover_bootinfo() in the 32-bit
locore code that it is being invoked from a "new" boot block.
- Add a routine to libvmmapi to setup a 32-bit flat mode register state
including a GDT and TSS that is able to start the i386 kernel and
update bhyveload to use it when booting an i386 kernel.
- Use the guest register state to determine the CPU's current instruction
mode (32-bit vs 64-bit) and paging mode (flat, 32-bit, PAE, or long
mode) in the instruction emulation code. Update the gla2gpa() routine
used when fetching instructions to handle flat mode, 32-bit paging, and
PAE paging in addition to long mode paging. Don't look for a REX
prefix when the CPU is in 32-bit mode, and use the detected mode to
enable the existing 32-bit mode code when decoding the mod r/m byte.

Reviewed by: grehan, neel
MFC after: 1 month

Add support for emulating the byte move and zero extend instructions:
"mov r/m8, r32" and "mov r/m8, r64".

Approved by: neel (co-mentor)

Roll back botched partial MFC :(

Enable memory overcommit for AMD processors.

- No emulation of A/D bits is required since AMD-V RVI
supports A/D bits.
- Enable pmap PT_RVI support(w/o PAT) which is required for
memory over-commit support.
- Other minor fixes:
* Make use of VMCB EXITINTINFO field. If a #VMEXIT happens while
delivering an interrupt, EXITINTINFO has all the details that bhyve
needs to inject the same interrupt.
* SVM h/w decode assist code was incomplete - removed for now.
* Some minor code clean-up (more coming).

Submitted by: Anish Gupta (akgupt3@gmail.com)

Remove unnecessary includes of <machine/pmap.h>

Requested by: alc@

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

Fix a bug in decoding an instruction that has an SIB byte as well as an
immediate operand. The presence of an SIB byte in decoding the ModR/M field
would cause 'imm_bytes' to not be set to the correct value.

Fix this by initializing 'imm_bytes' independent of the ModR/M decoding.

Reported by: grehan@
Approved by: re@

Add support for emulating the byte move instruction "mov r/m8, r8".

This emulation is required when dumping MMIO space via the ddb "examine"
command.

Add in last remaining files to get AMD-SVM operational.

Submitted by: Anish Gupta (akgupt3@gmail.com)

Add support for emulation of the "or r/m, imm8" instruction.

Submitted by: Zhixiang Yu (zxyu.core@gmail.com)
Obtained from: GSoC 2013 (AHCI device emulation for bhyve)

Verify that all bytes in the instruction buffer are consumed during decoding.

Suggested by: grehan

Switch to standard copyright license text

The initial version of this came from Sandvine but had "PROVIDED BY NETAPP,
INC" in the copyright text, presuambly because the license block was copied
from another file. Replace it with standard "AUTHOR AND CONTRIBUTORS" form.

Approvided by: grehan@

Add RIP-relative addressing to the instruction decoder.
Rework the guest register fetch code to allow the RIP to
be extracted from the VMCS while the kernel decoder is
functioning.

Hit by the OpenBSD local-apic code.

Submitted by: neel
Reviewed by: grehan
Obtained from: NetApp

Allow caller to skip 'guest linear address' validation when doing instruction
decode. This is to accomodate hardware assist implementations that do not
provide the 'guest linear address' as part of nested page fault collateral.

Submitted by: Anish Gupta (akgupt3 at gmail dot com)

Add emulation support for instruction "88/r: mov r/m8, r8".

This instruction moves a byte from a register to a memory location.

Tested by: tycho nightingale at pluribusnetworks com

Properly screen for the AND 0x81 instruction from the set
of group1 0x81 instructions that use the reg bits as an
extended opcode.

Still todo: properly update rflags.

Pointed out by: jilles@

Remove debug printf.

Pointed out by: emaste

Add support for the 0x81 AND instruction, now generated
by clang in the local APIC code.

0x81 is a read-modify-write instruction - the EPT check
that only allowed read or write and not both has been
relaxed to allow read and write.

Reviewed by: neel
Obtained from: NetApp

Revamp the x86 instruction emulation in bhyve.

On a nested page table fault the hypervisor will:
- fetch the instruction using the guest %rip and %cr3
- decode the instruction in 'struct vie'
- emulate the instruction in host kernel context for local apic accesses
- any other type of mmio access is punted up to user-space (e.g. ioapic)

The decoded instruction is passed as collateral to the user-space process
that is handling the PAGING exit.

The emulation code is fleshed out to include more addressing modes (e.g. SIB)
and more types of operands (e.g. imm8). The source code is unified into a
single file (vmm_instruction_emul.c) that is compiled into vmm.ko as well
as /usr/sbin/bhyve.

Reviewed by: grehan
Obtained from: NetApp

Get rid of assumptions in the hypervisor that the host physical memory
associated with guest physical memory is contiguous.

Add check to vm_gpa2hpa() that the range indicated by [gpa,gpa+len) is all
contained within a single 4KB page.

Intel VT-x provides the length of the instruction at the time of the nested
page table fault. Use this when fetching the instruction bytes from the guest
memory.

Also modify the lapic_mmio() API so that a decoded instruction is fed into it
instead of having it fetch the instruction bytes from the guest. This is
useful for hardware assists like SVM that provide the faulting instruction
as part of the vmexit.

Add support for trapping MMIO writes to local apic registers and emulating them.

The default behavior is still to present the local apic to the guest in the
x2apic mode.