Commit Graph

89 Commits

Author SHA1 Message Date
Antoine Brodin
147d12a7d3 vmmdev: return EFAULT when trying to read beyond VM system memory max address
Currently, when using dd(1) to take a VM memory image, the capture never ends,
reading zeroes when it's beyond VM system memory max address.
Return EFAULT when trying to read beyond VM system memory max address.

Reviewed by:	imp, grehan, anish
Approved by:	grehan
Differential Revision:	https://reviews.freebsd.org/D15156
2018-05-15 17:20:58 +00:00
Tycho Nightingale
6ac73777ea Add SDT probes to vmexit on Intel.
Submitted by:	domagoj.stolfa_gmail.com
Reviewed by:	grehan, tychon
Sponsored by:	DARPA/AFRL
Differential Revision:	https://reviews.freebsd.org/D14656
2018-04-13 17:23:05 +00:00
Rodney W. Grimes
01d822d33b Add the ability to control the CPU topology of created VMs
from userland without the need to use sysctls, it allows the old
sysctls to continue to function, but deprecates them at
FreeBSD_version 1200060 (Relnotes for deprecate).

The command line of bhyve is maintained in a backwards compatible way.
The API of libvmmapi is maintained in a backwards compatible way.
The sysctl's are maintained in a backwards compatible way.

Added command option looks like:
bhyve -c [[cpus=]n][,sockets=n][,cores=n][,threads=n][,maxcpus=n]
The optional parts can be specified in any order, but only a single
integer invokes the backwards compatible parse.  [,maxcpus=n] is
hidden by #ifdef until kernel support is added, though the api
is put in place.

bhyvectl --get-cpu-topology option added.

Reviewed by:	grehan (maintainer, earlier version),
Reviewed by:	bcr (manpages)
Approved by:	bde (mentor), phk (mentor)
Tested by:	Oleg Ginzburg <olevole@olevole.ru> (cbsd)
MFC after:	1 week
Relnotes:	Y
Differential Revision:	https://reviews.freebsd.org/D9930
2018-04-08 19:24:49 +00:00
John Baldwin
fc276d92ae Add a way to temporarily suspend and resume virtual CPUs.
This is used as part of implementing run control in bhyve's debug
server.  The hypervisor now maintains a set of "debugged" CPUs.
Attempting to run a debugged CPU will fail to execute any guest
instructions and will instead report a VM_EXITCODE_DEBUG exit to
the userland hypervisor.  Virtual CPUs are placed into the debugged
state via vm_suspend_cpu() (implemented via a new VM_SUSPEND_CPU ioctl).
Virtual CPUs can be resumed via vm_resume_cpu() (VM_RESUME_CPU ioctl).

The debug server suspends virtual CPUs when it wishes them to stop
executing in the guest (for example, when a debugger attaches to the
server).  The debug server can choose to resume only a subset of CPUs
(for example, when single stepping) or it can choose to resume all
CPUs.  The debug server must explicitly mark a CPU as resumed via
vm_resume_cpu() before the virtual CPU will successfully execute any
guest instructions.

Reviewed by:	avg, grehan
Tested on:	Intel (jhb), AMD (avg)
Differential Revision:	https://reviews.freebsd.org/D14466
2018-04-06 22:03:43 +00:00
Tycho Nightingale
490768e24a Fix a lock recursion introduced in r327065.
Reported by:	kmacy
Reviewed by:	grehan, jhb
Sponsored by:	Dell EMC Isilon
Differential Revision:	https://reviews.freebsd.org/D14548
2018-03-07 18:03:22 +00:00
John Baldwin
65eefbe422 Save and restore guest debug registers.
Currently most of the debug registers are not saved and restored
during VM transitions allowing guest and host debug register values to
leak into the opposite context.  One result is that hardware
watchpoints do not work reliably within a guest under VT-x.

Due to differences in SVM and VT-x, slightly different approaches are
used.

For VT-x:

- Enable debug register save/restore for VM entry/exit in the VMCS for
  DR7 and MSR_DEBUGCTL.
- Explicitly save DR0-3,6 of the guest.
- Explicitly save DR0-3,6-7, MSR_DEBUGCTL, and the trap flag from
  %rflags for the host.  Note that because DR6 is "software" managed
  and not stored in the VMCS a kernel debugger which single steps
  through VM entry could corrupt the guest DR6 (since a single step
  trap taken after loading the guest DR6 could alter the DR6
  register).  To avoid this, explicitly disable single-stepping via
  the trace flag before loading the guest DR6.  A determined debugger
  could still defeat this by setting a breakpoint after the guest DR6
  was loaded and then single-stepping.

For SVM:
- Enable debug register caching in the VMCB for DR6/DR7.
- Explicitly save DR0-3 of the guest.
- Explicitly save DR0-3,6-7, and MSR_DEBUGCTL for the host.  Since SVM
  saves the guest DR6 in the VMCB, the race with single-stepping
  described for VT-x does not exist.

For both platforms, expose all of the guest DRx values via --get-drX
and --set-drX flags to bhyvectl.

Discussed with:	avg, grehan
Tested by:	avg (SVM), myself (VT-x)
MFC after:	1 month
Differential Revision:	https://reviews.freebsd.org/D13229
2018-01-17 23:11:25 +00:00
Pedro F. Giffuni
c49761dd57 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.
2017-11-27 15:03:07 +00:00
Pedro F. Giffuni
edafb5a327 sys/amd64: Small spelling fixes.
No functional change.
2016-05-03 22:13:04 +00:00
Neel Natu
9b1aa8d622 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
2015-06-18 06:00:17 +00:00
Neel Natu
248e6799e9 Fix non-deterministic delays when accessing a vcpu that was in "running" or
"sleeping" state. This is done by forcing the vcpu to transition to "idle"
by returning to userspace with an exit code of VM_EXITCODE_REQIDLE.

MFC after:      2 weeks
2015-05-28 17:37:01 +00:00
Neel Natu
ede0403309 Check 'td_owepreempt' and yield the vcpu thread if it is set.
This is done explicitly because a vcpu thread can be in a critical section
for the entire time slice alloted to it. This in turn can delay the handling
of the 'td_owepreempt'.

Reviewed by:	jhb
MFC after:	1 week
Differential Revision:	https://reviews.freebsd.org/D2430
2015-05-06 23:40:24 +00:00
Neel Natu
9c4d547896 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
2015-05-06 16:25:20 +00:00
Neel Natu
8325ce5c7e Don't require <sys/cpuset.h> to be always included before <machine/vmm.h>.
Only a subset of source files that include <machine/vmm.h> need to use the
APIs that require the inclusion of <sys/cpuset.h>.

MFC after:	1 week
2015-04-30 22:23:22 +00:00
Tycho Nightingale
e4f605ee81 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
2015-03-24 17:12:36 +00:00
Neel Natu
7534635359 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
2015-01-19 06:53:31 +00:00
Neel Natu
c9c75df48c 'struct vm_exception' was intended to be used only as the collateral for the
VM_INJECT_EXCEPTION ioctl. However it morphed into other uses like keeping
track pending exceptions for a vcpu. This in turn causes confusion because
some fields in 'struct vm_exception' like 'vcpuid' make sense only in the
ioctl context. It also makes it harder to add or remove structure fields.

Fix this by using 'struct vm_exception' only to communicate information
from userspace to vmm.ko when injecting an exception.

Also, add a field 'restart_instruction' to 'struct vm_exception'. This
field is set to '1' for exceptions where the faulting instruction is
restarted after the exception is handled.

MFC after:      1 week
2015-01-13 22:00:47 +00:00
Neel Natu
0dafa5cd4b Replace bhyve's minimal RTC emulation with a fully featured one in vmm.ko.
The new RTC emulation supports all interrupt modes: periodic, update ended
and alarm. It is also capable of maintaining the date/time and NVRAM contents
across virtual machine reset. Also, the date/time fields can now be modified
by the guest.

Since bhyve now emulates both the PIT and the RTC there is no need for
"Legacy Replacement Routing" in the HPET so get rid of it.

The RTC device state can be inspected via bhyvectl as follows:
bhyvectl --vm=vm --get-rtc-time
bhyvectl --vm=vm --set-rtc-time=<unix_time_secs>
bhyvectl --vm=vm --rtc-nvram-offset=<offset> --get-rtc-nvram
bhyvectl --vm=vm --rtc-nvram-offset=<offset> --set-rtc-nvram=<value>

Reviewed by:	tychon
Discussed with:	grehan
Differential Revision:	https://reviews.freebsd.org/D1385
MFC after:	2 weeks
2014-12-30 22:19:34 +00:00
Neel Natu
b053814333 Allow ktr(4) tracing of all guest exceptions via the tunable
"hw.vmm.trace_guest_exceptions".  To enable this feature set the tunable
to "1" before loading vmm.ko.

Tracing the guest exceptions can be useful when debugging guest triple faults.

Note that there is a performance impact when exception tracing is enabled
since every exception will now trigger a VM-exit.

Also, handle machine check exceptions that happen during guest execution
by vectoring to the host's machine check handler via "int $18".

Discussed with:	grehan
MFC after:	2 weeks
2014-12-23 02:14:49 +00:00
Neel Natu
160ef77abf Move the ACPI PM timer emulation into vmm.ko.
This reduces variability during timer calibration by keeping the emulation
"close" to the guest. Additionally having all timer emulations in the kernel
will ease the transition to a per-VM clock source (as opposed to using the
host's uptime keep track of time).

Discussed with:	grehan
2014-10-26 04:44:28 +00:00
Neel Natu
ed6aacb51f IFC @r272887 2014-10-10 23:52:56 +00:00
Neel Natu
65145c7f50 Inject #UD into the guest when it executes either 'MONITOR' or 'MWAIT'.
The hypervisor hides the MONITOR/MWAIT capability by unconditionally setting
CPUID.01H:ECX[3] to 0 so the guest should not expect these instructions to
be present anyways.

Discussed with:	grehan
2014-10-06 20:48:01 +00:00
Neel Natu
8f02c5e456 IFC r271888.
Restructure MSR emulation so it is all done in processor-specific code.
2014-09-20 21:46:31 +00:00
Neel Natu
c3498942a5 Restructure the MSR handling so it is entirely handled by processor-specific
code. There are only a handful of MSRs common between the two so there isn't
too much duplicate functionality.

The VT-x code has the following types of MSRs:

- MSRs that are unconditionally saved/restored on every guest/host context
  switch (e.g., MSR_GSBASE).

- MSRs that are restored to guest values on entry to vmx_run() and saved
  before returning. This is an optimization for MSRs that are not used in
  host kernel context (e.g., MSR_KGSBASE).

- MSRs that are emulated and every access by the guest causes a trap into
  the hypervisor (e.g., MSR_IA32_MISC_ENABLE).

Reviewed by:	grehan
2014-09-20 02:35:21 +00:00
Neel Natu
4e27d36d38 IFC @r271694 2014-09-17 18:46:51 +00:00
Neel Natu
bbadcde418 Set the 'vmexit->inst_length' field properly depending on the type of the
VM-exit and ultimately on whether nRIP is valid. This allows us to update
the %rip after the emulation is finished so any exceptions triggered during
the emulation will point to the right instruction.

Don't attempt to handle INS/OUTS VM-exits unless the DecodeAssist capability
is available. The effective segment field in EXITINFO1 is not valid without
this capability.

Add VM_EXITCODE_SVM to flag SVM VM-exits that cannot be handled. Provide the
VMCB fields exitinfo1 and exitinfo2 as collateral to help with debugging.

Provide a SVM VM-exit handler to dump the exitcode, exitinfo1 and exitinfo2
fields in bhyve(8).

Reviewed by:	Anish Gupta (akgupt3@gmail.com)
Reviewed by:	grehan
2014-09-14 04:39:04 +00:00
Neel Natu
d181963296 Optimize the common case of injecting an interrupt into a vcpu after a HLT
by explicitly moving it out of the interrupt shadow. The hypervisor is done
"executing" the HLT and by definition this moves the vcpu out of the
1-instruction interrupt shadow.

Prior to this change the interrupt would be held pending because the VMCS
guest-interruptibility-state would indicate that "blocking by STI" was in
effect. This resulted in an unnecessary round trip into the guest before
the pending interrupt could be injected.

Reviewed by:	grehan
2014-09-12 06:15:20 +00:00
Peter Grehan
7f21538b6e Change __inline style to be consistent with FreeBSD usage,
and also fix gcc build (on STABLE, when MFCd).

PR:	192880
Reviewed by:	neel
Reported by:	ngie
MFC after:	1 day
2014-08-24 02:07:34 +00:00
Neel Natu
f008d1571d If a vcpu has issued a HLT instruction with interrupts disabled then it sleeps
forever in vm_handle_hlt().

This is usually not an issue as long as one of the other vcpus properly resets
or powers off the virtual machine. However, if the bhyve(8) process is killed
with a signal the halted vcpu cannot be woken up because it's sleep cannot be
interrupted.

Fix this by waking up periodically and returning from vm_handle_hlt() if
TDF_ASTPENDING is set.

Reported by:	Leon Dang
Sponsored by:	Nahanni Systems
2014-07-26 02:53:51 +00:00
Neel Natu
d37f2adb38 Fix fault injection in bhyve.
The faulting instruction needs to be restarted when the exception handler
is done handling the fault. bhyve now does this correctly by setting
'vmexit[vcpu].inst_length' to zero so the %rip is not advanced.

A minor complication is that the fault injection APIs are used by instruction
emulation code that is shared by vmm.ko and bhyve. Thus the argument that
refers to 'struct vm *' in kernel or 'struct vmctx *' in userspace needs to
be loosely typed as a 'void *'.
2014-07-24 01:38:11 +00:00
Neel Natu
d665d229ce 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
2014-07-23 04:28:51 +00:00
Neel Natu
091d453222 Handle nested exceptions in bhyve.
A nested exception condition arises when a second exception is triggered while
delivering the first exception. Most nested exceptions can be handled serially
but some are converted into a double fault. If an exception is generated during
delivery of a double fault then the virtual machine shuts down as a result of
a triple fault.

vm_exit_intinfo() is used to record that a VM-exit happened while an event was
being delivered through the IDT. If an exception is triggered while handling
the VM-exit it will be treated like a nested exception.

vm_entry_intinfo() is used by processor-specific code to get the event to be
injected into the guest on the next VM-entry. This function is responsible for
deciding the disposition of nested exceptions.
2014-07-19 20:59:08 +00:00
Neel Natu
3d5444c864 Add emulation for legacy x86 task switching mechanism.
FreeBSD/i386 uses task switching to handle double fault exceptions and this
change enables that to work.

Reported by:	glebius
2014-07-16 21:26:26 +00:00
Neel Natu
f7a9f1784f 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
2014-07-15 17:37:17 +00:00
Neel Natu
b301b9e28f Accurately identify the vcpu's operating mode as 64-bit, compatibility,
protected or real.
2014-07-08 21:48:57 +00:00
Tycho Nightingale
5ebc578ba6 Replace enum forward declarations with complete definitions.
Reviewed by:	neel
2014-06-10 18:46:00 +00:00
Neel Natu
404874659f Add helper functions to populate VM exit information for rendezvous and
astpending exits. This is to reduce code duplication between VT-x and
SVM implementations.
2014-06-10 16:45:58 +00:00
Neel Natu
5fcf252f41 Add ioctl(VM_REINIT) to reinitialize the virtual machine state maintained
by vmm.ko. This allows the virtual machine to be restarted without having
to destroy it first.

Reviewed by:	grehan
2014-06-07 21:36:52 +00:00
Neel Natu
95ebc360ef Activate vcpus from bhyve(8) using the ioctl VM_ACTIVATE_CPU instead of doing
it implicitly in vmm.ko.

Add ioctl VM_GET_CPUS to get the current set of 'active' and 'suspended' cpus
and display them via /usr/sbin/bhyvectl using the "--get-active-cpus" and
"--get-suspended-cpus" options.

This is in preparation for being able to reset virtual machine state without
having to destroy and recreate it.
2014-05-31 23:37:34 +00:00
Neel Natu
65ffa035a7 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.
2014-05-27 04:26:22 +00:00
Neel Natu
5382c19d81 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.
2014-05-25 00:57:24 +00:00
Neel Natu
da11f4aa1d Add libvmmapi functions vm_copyin() and vm_copyout() to copy into and out
of the guest linear address space. These APIs in turn use a new ioctl
'VM_GLA2GPA' to convert the guest linear address to guest physical.

Use the new copyin/copyout APIs when emulating ins/outs instruction in
bhyve(8).
2014-05-24 23:12:30 +00:00
Neel Natu
e813a87350 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.
2014-05-24 20:26:57 +00:00
Neel Natu
37a723a5b3 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.
2014-05-24 19:13:25 +00:00
Neel Natu
d17b5104a9 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)
2014-05-23 05:15:17 +00:00
Neel Natu
fd949af642 Inject page fault into the guest if the page table walker detects an invalid
translation for the guest linear address.
2014-05-22 03:14:54 +00:00
Neel Natu
e4c8a13d61 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.
2014-05-19 03:50:07 +00:00
John Baldwin
b3e9732a76 Implement a PCI interrupt router to route PCI legacy INTx interrupts to
the legacy 8259A PICs.
- Implement an ICH-comptabile PCI interrupt router on the lpc device with
  8 steerable pins configured via config space access to byte-wide
  registers at 0x60-63 and 0x68-6b.
- For each configured PCI INTx interrupt, route it to both an I/O APIC
  pin and a PCI interrupt router pin.  When a PCI INTx interrupt is
  asserted, ensure that both pins are asserted.
- Provide an initial routing of PCI interrupt router (PIRQ) pins to
  8259A pins (ISA IRQs) and initialize the interrupt line config register
  for the corresponding PCI function with the ISA IRQ as this matches
  existing hardware.
- Add a global _PIC method for OSPM to select the desired interrupt routing
  configuration.
- Update the _PRT methods for PCI bridges to provide both APIC and legacy
  PRT tables and return the appropriate table based on the configured
  routing configuration.  Note that if the lpc device is not configured, no
  routing information is provided.
- When the lpc device is enabled, provide ACPI PCI link devices corresponding
  to each PIRQ pin.
- Add a VMM ioctl to adjust the trigger mode (edge vs level) for 8259A
  pins via the ELCR.
- Mark the power management SCI as level triggered.
- Don't hardcode the number of elements in Packages in the source for
  the DSDT.  iasl(8) will fill in the actual number of elements, and
  this makes it simpler to generate a Package with a variable number of
  elements.

Reviewed by:	tycho
2014-05-15 14:16:55 +00:00
Neel Natu
e50ce2aa06 Add logic in the HLT exit handler to detect if the guest has put all vcpus
to sleep permanently by executing a HLT with interrupts disabled.

When this condition is detected the guest with be suspended with a reason of
VM_SUSPEND_HALT and the bhyve(8) process will exit.

Tested by executing "halt" inside a RHEL7-beta guest.

Discussed with:	grehan@
Reviewed by:	jhb@, tychon@
2014-05-02 00:33:56 +00:00
Neel Natu
c6a0cc2e21 Some Linux guests will implement a 'halt' by disabling the APIC and executing
the 'HLT' instruction. This condition was detected by 'vm_handle_hlt()' and
converted into the SPINDOWN_CPU exitcode . The bhyve(8) process would exit
the vcpu thread in response to a SPINDOWN_CPU and when the last vcpu was
spun down it would reset the virtual machine via vm_suspend(VM_SUSPEND_RESET).

This functionality was broken in r263780 in a way that made it impossible
to kill the bhyve(8) process because it would loop forever in
vm_handle_suspend().

Unbreak this by removing the code to spindown vcpus. Thus a 'halt' from
a Linux guest will appear to be hung but this is consistent with the
behavior on bare metal. The guest can be rebooted by using the bhyvectl
options '--force-reset' or '--force-poweroff'.

Reviewed by:	grehan@
2014-04-29 18:42:56 +00:00
Neel Natu
f0fdcfe247 Allow a virtual machine to be forcibly reset or powered off. This is done
by adding an argument to the VM_SUSPEND ioctl that specifies how the virtual
machine should be suspended, viz. VM_SUSPEND_RESET or VM_SUSPEND_POWEROFF.

The disposition of VM_SUSPEND is also made available to the exit handler
via the 'u.suspended' member of 'struct vm_exit'.

This capability is exposed via the '--force-reset' and '--force-poweroff'
arguments to /usr/sbin/bhyvectl.

Discussed with:	grehan@
2014-04-28 22:06:40 +00:00