- In a PF_LOCAL address, "hostname" must begins with '/' and "servname"
is always NULL. All of ai_flags are ignored.
- PF_UNSPEC matches PF_LOCAL. EAI_SERVICE is not returned to make
AF-independent programming easier; "servname" is always ignored
in PF_LOCAL. In practice, PF_INET* and PF_LOCAL are
mutually-exclusive because a hostname which begins with '/' is invalid
in PF_INET*. No domain name resolution is performed for a PF_LOCAL address.
Differential Revision: https://reviews.freebsd.org/D3634
Note that the mountlist manipulations are somewhat fragile, and not very
pretty. The reason for this is to avoid changing vfs_mountroot(), which
is (obviously) rather mission-critical, but not very well documented,
and thus hard to test properly. It might be possible to rework it to use
its own simple root mount mechanism instead of vfs_mountroot().
Reviewed by: kib@
MFC after: 1 month
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D2698
This silence a warning brought up by valgrind whenever if_nametoindex
is used. This was already discussed in PR 166483, but the code
committed in r234329 guards the initilization with #ifdef PURIFY.
Therefore, valgrind still complains. Since this code is not performance
critical, always zero out the local variable to silence valgrind.
PR: 166483
Discussed with: eadler@
MFC after: 4 weeks
calling thread is supposed to see accesses issued by the initializer.
This means that the read of the once_control->state variable should
have an acquire semantic. Use atomic_thread_fence_acq() when the
value read is ONCE_DONE, instead of straightforward atomic_load_acq(),
to only put a barrier when needed (*).
On the other hand, the updates of the once_control->state with the
intermediate progress state do not need to synchronize with other
state accesses, remove _acq suffix.
Reviewed by: alc (previous version)
Suggested by: alc (*)
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Coredump notes depend on being able to invoke dump routines twice; once
in a dry-run mode to get the size of the note, and another to actually
emit the note to the corefile.
When a note helper emits a different length section the second time
around than the length it requested the first time, the kernel produces
a corrupt coredump.
NT_PROCSTAT_FILES output length, when packing kinfo structs, is tied to
the length of filenames corresponding to vnodes in the process' fd table
via vn_fullpath. As vnodes may move around during dump, this is racy.
So:
- Detect badly behaved notes in putnote() and pad underfilled notes.
- Add a fail point, debug.fail_point.fill_kinfo_vnode__random_path to
exercise the NT_PROCSTAT_FILES corruption. It simply picks random
lengths to expand or truncate paths to in fo_fill_kinfo_vnode().
- Add a sysctl, kern.coredump_pack_fileinfo, to allow users to
disable kinfo packing for PROCSTAT_FILES notes. This should avoid
both FILES note corruption and truncation, even if filenames change,
at the cost of about 1 kiB in padding bloat per open fd. Document
the new sysctl in core.5.
- Fix note_procstat_files to self-limit in the 2nd pass. Since
sometimes this will result in a short write, pad up to our advertised
size. This addresses note corruption, at the risk of sometimes
truncating the last several fd info entries.
- Fix NT_PROCSTAT_FILES consumers libutil and libprocstat to grok the
zero padding.
With suggestions from: bjk, jhb, kib, wblock
Approved by: markj (mentor)
Relnotes: yes
Sponsored by: EMC / Isilon Storage Division
Differential Revision: https://reviews.freebsd.org/D3548
the buffer. (n == hostlen) also means the buffer length was
too short.
- Use sdl->sdl_data only when (sdl->sdl_nlen > 0 && sdl->sdl_alen == 0)
to prevent redundant output.
Connect it to the build.
The code assumed that SCHED_* constants form a contiguous set of
numbers, remove the assumption by using schedulers[] array in
get_different_scheduler(). This is no-op on FreeBSD, but improves
code portability.
The selection of different priority used the min/max priority range of
the current scheduler class, instead of the priority to be changed to.
The bug caused the test failure.
Remove duplication of POSIX_SPAWN_SETSIGDEF flag and now unused
duplications of MIN/MAX definitions.
Reviewed by: jilles, pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D3533
comment above, POSIX_SPAWN_SETSIGMASK and POSIX_SPAWN_SETSIGDEF
handlers used libthr interposed functions instead of syscalls.
Noted by: jilles
Sponsored by: The FreeBSD Foundation
MFC after: 6 days
are aliases for the syscall stubs and are plt-interposed, to the
libc-private aliases of internally interposed sigprocmask() etc.
Since e.g. _sigaction is not interposed by libthr, calling signal()
removes thr_sighandler() from the handler slot etc. The result was
breaking signal semantic and rtld locking.
The added __libc_sigprocmask and other symbols are hidden, they are
not exported and cannot be called through PLT. The setjmp/longjmp
functions for x86 were changed to use direct calls, and since
PIC_PROLOGUE only needed for functional PLT indirection on i386, it is
removed as well.
The PowerPC bug of calling the syscall directly in the setjmp/longjmp
implementation is kept as is.
Reported by: Pete French <petefrench@ingresso.co.uk>
Tested by: Michiel Boland <boland37@xs4all.nl>
Reviewed by: jilles (previous version)
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Go ahead and defined -D_STANDALONE for all targets (only strictly
needed for some architecture, but harmless on those it isn't required
for). Also add -msoft-float to all architectures uniformly rather
that higgley piggley like it is today.
Differential Revision: https://reviews.freebsd.org/D3496
- in mbrtowc() we need to disallow codepoints above 0x10ffff.
- In wcrtomb() we need to disallow codepoints between 0xd800 and 0xdfff.
Reviewed by: bapt
Differential Revision: https://reviews.freebsd.org/D3399
adjusted. This seems to be the case on all non-x86 architectures libproc
supports.
Reviewed by: kib
Obtained from: ABT Systems Ltd
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D3465
having some children, the children' reaper is not reset to the parent.
This allows for the situation where reaper has children but not
descendands and the too strict asserts in the reap_status() fire.
Remove the wrong asserts, add some clarification for the situation to
the procctl(2) REAP_STATUS.
Reported and tested by: feld
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
missing until it can be cleaned up.
Reviewed by: jhb
Approved by: ABT Systems Ltd
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D3319
Distinguish between WRDE_BADVAL and WRDE_SYNTAX based on when the error
occurred (parsing or execution), not based on whether WRDE_UNDEF was passed.
Also, return WRDE_NOSPACE for a few more unexpected results from sh.
- Remove the redundant _PATH_RSH definition (paths.h at r96194);
- Use pid_t for PIDs
- Note that we are at the same level of OpenBSD's counterpart of
revision 1.7 (r94757).
No functional changes.
MFC after: 2 weeks
Each issue has a PR open to track. This workaround allows us to run the
tests to investigate the failures and avoid any new regressions.
PR: 202304, 202305, 202307
Reviewed by: ngie
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D3378
The functionality of the wordexp builtin is easily replaced using normal
shell code, although performance is slightly worse.
This does not mean that wordexp() will remain shell-independent -- a fully
reliable implementation of WRDE_NOCMD is really only possible using
extensions to the shell, or by adding much of the shell's code to libc.
- Add
nvlist_{add,get,take,move,exists,free}_{number,bool,string,nvlist,
descriptor} functions.
- Add support for (un)packing arrays.
- Add the nvl_array_next field to the nvlist structure.
If an array is added by the nvlist_{move,add}_nvlist_array function
this field will contains next element in the array.
- Add the nitems field to the nvpair and nvpair_header structure.
This field contains number of elements in the array.
- Add special flag (NV_FLAG_IN_ARRAY) which is set if nvlist is a part of
an array.
- Add special type (NV_TYPE_NVLIST_ARRAY_NEXT).This type is used only
on packing/unpacking.
- Add new API for traversing arrays (nvlist_get_array_next).
- Add the nvlist_get_pararr function which combines the
nvlist_get_array_next and nvlist_get_parent functions. If nvlist is in
the array it will return next element from array. If nvlist is last
element in array or it isn't in array it will return his
container (parent). This function should simplify traveling over nvlist.
- Add tests for new features.
- Add documentation for new functions.
- Add my copyright.
- Regenerate the sys/cddl/compat/opensolaris/sys/nvpair.h file.
PR: 191083
Reviewed by: allanjude (doc)
Approved by: pjd (mentor)
The comment in the libc/sys symbol map referenced the generated symbols
for the syscall trampolines. Such comment was out of place in the secure
symbol map so remove the stale comment and attempt to clarify the old one
to avoid risks of confusion.
Pointed out by: kib
As part of the code refactoring to support FORTIFY_SOURCE we want
a new subdirectory "secure" to keep the files related to security.
Move the stack protector functions to this new directory.
No functional change.
Differential Review: https://reviews.freebsd.org/D3333
as well as when it was removed from POSIX specification.
Reviewed by: theraven, wblock, bapt, rodrigc
Approved by: bapt, rodrigc (mentor)
Differential Revision: D3374
The option was added only to ease the transition from GNU Binutils to
ELF Tool Chain tools, and that process is now complete (for the viable
replacements). Noting the removal in UPDATING is sufficient as we have
not shipped a release with the option.
Reviewed by: brooks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D3240
Fix some phrases to make it more clear.
Differential Revision: D3378
Reported by: bde@
Reviewed by: wblock
Approved by: bapt, rodrigc (mentor)
Sponsored by: gandi.net
POSIX.1-2001 and removed from the specification in POSIX.1-2008.
New softwares shall use memcpy(3) or memmove(3).
Differential Revision: D3358
Reviewed by: wblock
Approved by: rodrigc
Sponsored by: gandi.net
avoids recursion into rtld when leaving libthr critical section for
the deferred signal delivery.
For the same reason, use syscall(2) instead of referencing
__sys_sigreturn(2). Syscall() is already pre-resolved for fork()
interceptor.
Tested by: Andre Meiser <ortadur@web.de>
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
In fact, it doesn't even work with single-byte codesets like ISO-8859-1.
The comparison blows up at index 128 (the range is 0 to UCHAR_MAX (255).
As a temporary workaround, all comparisons will be done in C locale
regardless of the environment setting. The regex library needs to be
updated to handle all codesets.
Obtained from: Dragonfly
packed LC_COLLATE binary formats. These were generated with the colldef
tool, but the new LC_COLLATE files are going to be generated by the new
localedef tool using CLDR POSIX files as input. The BSD-flavored
version of localedef identifies the format as "BSD 1.0". Any
LC_COLLATE file with a different version will simply not be loaded, and
all LC* categories will get set to "C" (aka "POSIX") locale.
This work is based off of Nexenta's contribution to Illumos.
The integration with xlocale is John Marino's work for Dragonfly.
The following commits will enable localedef tool, disable the colldef
tool, add generated colldef directory, and finally remove colldef from
base.
The only difference with Dragonfly are:
- a few fixes to build with clang
- And identification of the flavor as "BSD 1.0" instead of "Dragonfly 4.4"
Obtained from: Dragonfly
LLVM PR 24343. This fixes the graphics/png build on i386, which
otherwise failed during its tests because of floating point exceptions,
leading to >5000 skipped other ports.
Clang emits SSE instructions on amd64 in the common path of
pthread_mutex_unlock. If the thread does not otherwise use SSE,
this usage incurs a context-switch of the FPU/SSE state, which
reduces the performance of multiple real-world applications by a
non-trivial amount (3-5% in one application).
Instead of this change, I experimented with eagerly switching the
FPU state at context-switch time. This did not help. Most of the
cost seems to be in the read/write of memory--as kib@ stated--and
not in the #NM handling. I tested on machines with and without
XSAVEOPT.
One counter-argument to this change is that most applications already
use SIMD, and the number of applications and amount of SIMD usage
are only increasing. This is absolutely true. I agree that--in
general and in principle--this change is in the wrong direction.
However, there are applications that do not use enough SSE to offset
the extra context-switch cost. SSE does not provide a clear benefit
in the current libthr code with the current compiler, but it does
provide a clear loss in some cases. Therefore, disabling SSE in
libthr is a non-loss for most, and a gain for some.
I refrained from disabling SSE in libc--as was suggested--because
I can't make the above argument for libc. It provides a wide variety
of code; each case should be analyzed separately.
https://lists.freebsd.org/pipermail/freebsd-current/2015-March/055193.html
Suggestions from: dim, jmg, rpaulo
Approved by: kib (mentor)
MFC after: 2 weeks
Sponsored by: Dell Inc.
It looks like EVFILT_READ and EVFILT_WRITE trigger under the same
conditions as poll()'s POLLRDNORM and POLLWRNORM as described by POSIX.
The only difference is that POLLRDNORM has to be triggered on regular
files unconditionally, whereas EVFILT_READ only triggers when not EOF.
Introduce a new flag, NOTE_FILE_POLL, that can be used to make
EVFILT_READ and EVFILT_WRITE behave identically to poll(). This flag
will be used by cloudlibc's poll() function.
Reviewed by: jmg
Differential Revision: https://reviews.freebsd.org/D3303
of the timehands, from the kern_tc.c implementation to vdso. Add
comments giving hints where to look for the algorithm explanation.
To compensate the removal of rmb() in userspace binuptime(), add
explicit lfence instruction before rdtsc. On i386, add usual
complications to detect SSE2 presence; assume that old CPUs which do
not implement SSE2 also execute rdtsc almost in order.
Reviewed by: alc, bde (previous version)
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Summary:
Back in 2005, maxim@ attempted to fix shutdown() to return ENOTCONN in case the socket was not connected (r150152). This had to be rolled back (r150155), as it broke some of the existing programs that depend on this behavior. I reapplied this change on my system and indeed, syslogd failed to start up. I fixed this back in February (279016) and MFC'ed it to the supported stable branches. Apart from that, things seem to work out all right.
Since at least Linux and Mac OS X do the right thing, I'd like to go ahead and give this another try. To keep old copies of syslogd working, only start returning ENOTCONN for recent binaries.
I took a look at the XNU sources and they seem to test against both SS_ISCONNECTED, SS_ISCONNECTING and SS_ISDISCONNECTING, instead of just SS_ISCONNECTED. That seams reasonable, so let's do the same.
Test Plan:
This issue was uncovered while writing tests for shutdown() in CloudABI:
https://github.com/NuxiNL/cloudlibc/blob/master/src/libc/sys/socket/shutdown_test.c#L26
Reviewers: glebius, rwatson, #manpages, gnn, #network
Reviewed By: gnn, #network
Subscribers: bms, mjg, imp
Differential Revision: https://reviews.freebsd.org/D3039
This is required by our FORTIFY_SOURCE implementation as it
does more inlining. As a rule of thumb, FORTIFY_SOURCE doubles
the number of inlines except that in grep inlining
blows up for some reason.
to no longer claim they are experimental.
Reviewed by: rwatson@, wblock@
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D2985
Fix a warning triggered by the gcc + FORTIFY_SOURCE patches:
In function 'libusb20_parse_config_desc': lib/libusb/libusb20_desc.c:141:
warning: passing argument 1 of 'memcpy' discards qualifiers from pointer
target type
Submitted by: hselansky
We want to ensure we always use libarchive from ports in the ports tree.
It simplifies ports maintainance and anyway libarchive.pc was not reflecting the
different way libarchive can be built in base
SIGCHLD signal, should keep full 32 bits of the status passed to the
_exit(2).
Split the combined p_xstat of the struct proc into the separate exit
status p_xexit for normal process exit, and signalled termination
information p_xsig. Kernel-visible macro KW_EXITCODE() reconstructs
old p_xstat from p_xexit and p_xsig. p_xexit contains complete status
and copied out into si_status.
Requested by: Joerg Schilling
Reviewed by: jilles (previous version), pho
Tested by: pho
Sponsored by: The FreeBSD Foundation
This is based on work done by jeff@ and jhb@, as well as the numa.diff
patch that has been circulating when someone asks for first-touch NUMA
on -10 or -11.
* Introduce a simple set of VM policy and iterator types.
* tie the policy types into the vm_phys path for now, mirroring how
the initial first-touch allocation work was enabled.
* add syscalls to control changing thread and process defaults.
* add a global NUMA VM domain policy.
* implement a simple cascade policy order - if a thread policy exists, use it;
if a process policy exists, use it; use the default policy.
* processes inherit policies from their parent processes, threads inherit
policies from their parent threads.
* add a simple tool (numactl) to query and modify default thread/process
policities.
* add documentation for the new syscalls, for numa and for numactl.
* re-enable first touch NUMA again by default, as now policies can be
set in a variety of methods.
This is only relevant for very specific workloads.
This doesn't pretend to be a final NUMA solution.
The previous defaults in -HEAD (with MAXMEMDOM set) can be achieved by
'sysctl vm.default_policy=rr'.
This is only relevant if MAXMEMDOM is set to something other than 1.
Ie, if you're using GENERIC or a modified kernel with non-NUMA, then
this is a glorified no-op for you.
Thank you to Norse Corp for giving me access to rather large
(for FreeBSD!) NUMA machines in order to develop and verify this.
Thank you to Dell for providing me with dual socket sandybridge
and westmere v3 hardware to do NUMA development with.
Thank you to Scott Long at Netflix for providing me with access
to the two-socket, four-domain haswell v3 hardware.
Thank you to Peter Holm for running the stress testing suite
against the NUMA branch during various stages of development!
Tested:
* MIPS (regression testing; non-NUMA)
* i386 (regression testing; non-NUMA GENERIC)
* amd64 (regression testing; non-NUMA GENERIC)
* westmere, 2 socket (thankyou norse!)
* sandy bridge, 2 socket (thankyou dell!)
* ivy bridge, 2 socket (thankyou norse!)
* westmere-EX, 4 socket / 1TB RAM (thankyou norse!)
* haswell, 2 socket (thankyou norse!)
* haswell v3, 2 socket (thankyou dell)
* haswell v3, 2x18 core (thankyou scott long / netflix!)
* Peter Holm ran a stress test suite on this work and found one
issue, but has not been able to verify it (it doesn't look NUMA
related, and he only saw it once over many testing runs.)
* I've tested bhyve instances running in fixed NUMA domains and cpusets;
all seems to work correctly.
Verified:
* intel-pcm - pcm-numa.x and pcm-memory.x, whilst selecting different
NUMA policies for processes under test.
Review:
This was reviewed through phabricator (https://reviews.freebsd.org/D2559)
as well as privately and via emails to freebsd-arch@. The git history
with specific attributes is available at https://github.com/erikarn/freebsd/
in the NUMA branch (https://github.com/erikarn/freebsd/compare/local/adrian_numa_policy).
This has been reviewed by a number of people (stas, rpaulo, kib, ngie,
wblock) but not achieved a clear consensus. My hope is that with further
exposure and testing more functionality can be implemented and evaluated.
Notes:
* The VM doesn't handle unbalanced domains very well, and if you have an overly
unbalanced memory setup whilst under high memory pressure, VM page allocation
may fail leading to a kernel panic. This was a problem in the past, but it's
much more easily triggered now with these tools.
* This work only controls the path through vm_phys; it doesn't yet strongly/predictably
affect contigmalloc, KVA placement, UMA, etc. So, driver placement of memory
isn't really guaranteed in any way. That's next on my plate.
Sponsored by: Norse Corp, Inc.; Dell
Some external tools just do a 'ls /dev/vmm' to figure out the bhyve virtual
machines on the host. These tools break if the devmem device nodes also
appear in /dev/vmm.
Requested by: grehan
the 'user' sysctl tree, which have all been coming back 0 or empty
since r240176.
Differential Revision: https://reviews.freebsd.org/D2945
Reviewed by: sbruno
Approved by: jmallett (mentor)
MFC after: 3 days
This function is equivalent to fclose(3) function except that it
does not close the underlying file descriptor.
fdclose(3) is step forward to make FILE structure private.
Reviewed by: wblock, jilles, jhb, pjd
Approved by: pjd (mentor)
Differential Revision: https://reviews.freebsd.org/D2697
directory sys/contrib/libnv.
The goal of this operation is to NOT install header files which shouldn't
be used outside the nvlist library.
Approved by: pjd (mentor)
Notable upstream commits (upstream revision in parens):
- Add a JSON producer to LLDB (228636)
- Don't crash on bad DWARF expression (228729)
- Add support of DWARFv3 DW_OP_form_tls_address (231342)
- Assembly profiler for MIPS64 (232619)
- Handle FreeBSD/arm64 core files (233273)
- Read/Write register for MIPS64 (233685)
- Rework LLDB system initialization (233758)
- SysV ABI for aarch64 (236098)
- MIPS software single stepping (236696)
- FreeBSD/arm live debugging support (237303)
- Assembly profiler for mips32 (237420)
- Parse function name from DWARF DW_AT_abstract_origin (238307)
- Improve LLDB prompt handling (238313)
- Add real time signals support to FreeBSDSignals (238316)
- Fix race in IOHandlerProcessSTDIO (238423)
- MIPS64 Branch instruction emulation for SW single stepping (238820)
- Improve OSType initialization in elf object file's arch_spec (239148)
- Emulation of MIPS64 floating-point branch instructions (239996)
- ABI Plugin for MIPS32 (239997)
- ABI Plugin for MIPS64 (240123)
- MIPS32 branch emulation and single stepping (240373)
- Improve instruction emulation based stack unwinding on ARM (240533)
- Add branch emulation to aarch64 instruction emulator (240769)
Update setkey and libipsec to understand aes-gcm-16 as an
encryption method.
A partial commit of the work in review D2936.
Submitted by: eri
Reviewed by: jmg
MFC after: 2 weeks
Sponsored by: Rubicon Communications (Netgate)
temporary file is created and then a rename() call move it to official file.
This operation didn't have any check to make sure data was written to disk
and if a power cycle happens system could end up with a 0 length passwd
or group database.
There is a pfSense bug with more infor about it:
https://redmine.pfsense.org/issues/4523
The following changes were made to protect passwd and group operations:
* lib/libutil/gr_util.c:
- Replace mkstemp() by mkostemp() with O_SYNC flag to create temp file
- After rename(), fsync() call on directory for faster result
* lib/libutil/pw_util.c
- Replace mkstemp() by mkostemp() with O_SYNC flag to create temp file
* usr.sbin/pwd_mkdb/pwd_mkdb.c
- Added O_SYNC flag on dbopen() calls
- After rename(), fsync() call on directory for faster result
* lib/libutil/pw_util.3
- pw_lock() returns a file descriptor to master password file on success
Differential Revision: https://reviews.freebsd.org/D2978
Approved by: bapt
Sponsored by: Netgate
point support. The fenv-vfp.c file overrides -mfloat-abi so it can use
floating point instructions if it detects support at runtime. Make it also
override -mfpu in case the user has set -mfpu=none.
to be before the lavel, otherwise an extra word may be added between the
label and the data.
Obtained from: ABT Systems Ltd
Sponsored by: The FReeBSD Foundation
CLANG WARNINGS.
BUMP SHLIB_MAJOR version as the ABI potentially changed.
Also run an 'exp run' to double check if any external project are using
those functions. Thanks antoine@.
PR: 200807
Differential Revision: D2775
Reviewed by: kib, ngie
This symbol can sometimes be emitted by clang++, and was not yet
exported from libcxxrt. Attempt to be compatible with libsupc++ by
using the same CXXABI_1.3.6 symbol version.
Reported by: yuri@rawbw.com
PR: 200863
Reviewed by: emaste
MFC after: 3 days
Differential Revision: https://reviews.freebsd.org/D2850
When enough time has passed for users to update their userland the kernel
fix will be applied. This will change the ABI to have x0 point to the args
and sp be correctly aligned.
It is expected this compatibility code can be removed when the kernel and
qemu usermode emulation have both been updated for the new ABI.
This fixes clang failures, and most likely other crashes.
Obtained from: ABT Systems Ltd
Sponsored by: The FreeBSD Foundation
due to a change in behavior of the 'vm_map_gpa()'.
Prior to r284539 if 'vm_map_gpa()' was called to map an address range in the
guest MMIO region then it would return NULL. This was used by the "movs"
emulation to detect if the 'src' or 'dst' operand was in MMIO space.
Post r284539 'vm_map_gpa()' started returning a non-NULL pointer even when
mapping the guest MMIO region.
Fix this by returning non-NULL only if [gaddr, gaddr+len) is entirely
within the 'lowmem' or 'highmem' regions and NULL otherwise.
Pointy hat to: neel
Reviewed by: grehan
Reported by: tychon, Ben Perrault (ben.perrault@gmail.com)
MFC after: 1 week
