Commit graph

452 commits

Author SHA1 Message Date
Emilio G. Cota 8f4f15e5f5
tcg: Introduce goto_ptr opcode and tcg_gen_lookup_and_goto_ptr
Instead of exporting goto_ptr directly to TCG frontends, export
tcg_gen_lookup_and_goto_ptr(), which calls goto_ptr with the pointer
returned by the lookup_tb_ptr() helper. This is the only use case
we have for goto_ptr and lookup_tb_ptr, so having this function is
very convenient. Furthermore, it trivially allows us to avoid calling
the lookup helper if goto_ptr is not implemented by the backend.

Backports commit cedbcb01529cb6cf9a2289cdbebbc63f6149fc18 from qemu
2018-03-02 21:05:18 -05:00
Richard Henderson 23d8f5fba2
qemu/atomic: Loosen restrictions for 64-bit ILP32 hosts
We need to coordinate with the TCG_OVERSIZED_GUEST test in cputlb.c,
and allow 64-bit atomics even though sizeof(void *) == 4.

Backports commit 374aae653499f4d405caf32b7fff0c8639113fe4 from qemu
2018-03-02 20:06:39 -05:00
Peter Xu fce1b469e5
memory: tune last param of iommu_ops.translate()
This patch converts the old "is_write" bool into IOMMUAccessFlags. The
difference is that "is_write" can only express either read/write, but
sometimes what we really want is "none" here (neither read nor write).
Replay is an good example - during replay, we should not check any RW
permission bits since thats not an actual IO at all.

Backports commit bf55b7afce53718ef96f4e6616da62c0ccac37dd from qemu
2018-03-02 18:59:12 -05:00
Gerd Hoffmann 108354cc4a
bitmap: add bitmap_copy_and_clear_atomic
Backports commit d6eb1413920affb7be3df9982682dd183a805dd7 from qemu
2018-03-02 18:59:11 -05:00
Peter Maydell b8b70dfcd2
Drop QEMU_GNUC_PREREQ() checks for gcc older than 4.1
We already require gcc 4.1 or newer (for the atomic
support), so the fallback codepaths for older gcc
versions than that are now dead code and we can
just delete them.

NB: clang reports itself as gcc 4.2 (regardless of
clang version), so clang won't be using the fallbacks
either.

Backports commit fa54abb8c298f892639ffc4bc2f61448ac3be4a1 from qemu
2018-03-02 18:59:05 -05:00
Paolo Bonzini c27870520a
exec: revert MemoryRegionCache
MemoryRegionCache did not know about virtio support for IOMMUs (because the
two features were developed at the same time). Revert MemoryRegionCache
to "normal" address_space_* operations for 2.9, as it is simpler than
undoing the virtio patches.

Backports commit 90c4fe5fc517a045e7a7cf2f23472e114042ca29 from qemu
2018-03-02 14:30:41 -05:00
Michael Davidsaver 2769c6ada0
armv7m: Fix reads of CONTROL register bit 1
The v7m CONTROL register bit 1 is SPSEL, which indicates
the stack being used. We were storing this information
not in v7m.control but in the separate v7m.other_sp
structure field. Unfortunately, the code handling reads
of the CONTROL register didn't take account of this, and
so if SPSEL was updated by an exception entry or exit then
a subsequent guest read of CONTROL would get the wrong value.

Using a separate structure field doesn't really gain us
anything in efficiency, so drop this unnecessary complexity
in favour of simply storing all the bits in v7m.control.

This is a migration compatibility break for M profile
CPUs only.

Backports commit abc24d86cc0364f402e438fae3acb14289b40734 from qemu
2018-03-02 13:26:38 -05:00
Dr. David Alan Gilbert 55d79cf4c0
RAMBlocks: qemu_ram_is_shared
Provide a helper to say whether a RAMBlock was created as a
shared mapping.

Backports commit 463a4ac23bcf0f0b65c850fa66f5ae6e43edd243 from qemu
2018-03-02 13:05:35 -05:00
Dr. David Alan Gilbert 5dfbee8930
memory_region: Fix name comments
The 'name' parameter to memory_region_init_* had been marked as debug
only, however vmstate_region_ram uses it as a parameter to
qemu_ram_set_idstr to set RAMBlock names and these form part of the
migration stream.

Backports commit e8f5fe2de125a0bfbefbaa6a69af81f4817cb7a0 from qemu
2018-03-02 13:01:23 -05:00
Markus Armbruster 8a8dc93945
qapi: Improve qobject visitor documentation
Backports commit aa3a982e674b09ae32502940f93ba98b3a8ad50e from qemu
2018-03-02 12:24:21 -05:00
Markus Armbruster ac1a61af47
qapi: Make input visitors detect unvisited list tails
Fix the design flaw demonstrated in the previous commit: new method
check_list() lets input visitors report that unvisited input remains
for a list, exactly like check_struct() lets them report that
unvisited input remains for a struct or union.

Implement the method for the qobject input visitor (straightforward),
and the string input visitor (less so, due to the magic list syntax
there). The opts visitor's list magic is even more impenetrable, and
all I can do there today is a stub with a FIXME comment. No worse
than before.

Backports commit a4a1c70dc759e5b81627e96564f344ab43ea86eb from qemu
2018-03-02 12:21:04 -05:00
Markus Armbruster e0ee098c4a
qapi: Drop unused non-strict qobject input visitor
The split between tests/test-qobject-input-visitor.c and
tests/test-qobject-input-strict.c now makes less sense than ever. The
next commit will take care of that.

Backports commit 048abb7b20c9f822ad9d4b730bade73b3311a47a from qemu
2018-03-02 12:14:52 -05:00
Markus Armbruster 50e3cda49a
qapi: Drop string input visitor method optional()
visit_optional() is to be called only between visit_start_struct() and
visit_end_struct(). Visitors that don't support struct visits,
i.e. don't implement start_struct(), end_struct(), have no use for it.
Clarify documentation.

The string input visitor doesn't support struct visits. Its
parse_optional() is therefore useless. Drop it.

Backports commit a8aec6de2ac1a5e36989fdfba29067b361009b75 from qemu
2018-03-02 12:07:55 -05:00
Markus Armbruster 84e5261cdf
qapi: Improve qobject input visitor error reporting
Error messages refer to nodes of the QObject being visited by name.
Trouble is the names are sometimes less than helpful:

* The name of the root QObject is whatever @name argument got passed
to the visitor, except NULL gets mapped to "null". We commonly pass
NULL. Not good.

Avoiding errors "at the root" mitigates. For instance,
visit_start_struct() can only fail when the visited object is not a
dictionary, and we commonly ensure it is beforehand.

* The name of a QDict's member is the member key. Good enough only
when this happens to be unique.

* The name of a QList's member is "null". Not good.

Improve error messages by referring to nodes by path instead, as
follows:

* The path of the root QObject is whatever @name argument got passed
to the visitor, except NULL gets mapped to "<anonymous>".

* The path of a root QDict's member is the member key.

* The path of a root QList's member is "[%u]", where %u is the list
index, starting at zero.

* The path of a non-root QDict's member is the path of the QDict
concatenated with "." and the member key.

* The path of a non-root QList's member is the path of the QList
concatenated with "[%u]", where %u is the list index.

For example, the incorrect QMP command

{ "execute": "blockdev-add", "arguments": { "node-name": "foo", "driver": "raw", "file": {"driver": "file" } } }

now fails with

{"error": {"class": "GenericError", "desc": "Parameter 'file.filename' is missing"}}

instead of

{"error": {"class": "GenericError", "desc": "Parameter 'filename' is missing"}}

and

{ "execute": "input-send-event", "arguments": { "device": "bar", "events": [ [] ] } }

now fails with

{"error": {"class": "GenericError", "desc": "Invalid parameter type for 'events[0]', expected: object"}}

instead of

{"error": {"class": "GenericError", "desc": "Invalid parameter type for 'null', expected: QDict"}}

Aside: calling the thing "parameter" is suboptimal for QMP, because
the root object is "arguments" there.

The qobject output visitor doesn't have this problem because it should
not fail. Same for dealloc and clone visitors.

The string visitors don't have this problem because they visit just
one value, whose name needs to be passed to the visitor as @name. The
string output visitor shouldn't fail anyway.

The options visitor uses QemuOpts names. Their name space is flat, so
the use of QDict member keys as names is fine. NULL names used with
roots and lists could conceivably result in bad error messages. Left
for another day.

Backports commit a9fc37f6bc3f2ab90585cb16493da9f6dcfbfbcf from qemu
2018-03-02 12:05:53 -05:00
Markus Armbruster d07bcef231
qmp: Eliminate silly QERR_QMP_* macros
The QERR_ macros are leftovers from the days of "rich" error objects.

QERR_QMP_BAD_INPUT_OBJECT, QERR_QMP_BAD_INPUT_OBJECT_MEMBER,
QERR_QMP_EXTRA_MEMBER are used in just one place now, except for one
use that has crept into qobject-input-visitor.c.

Drop these macros, to make the (bad) error messages more visible.

Backports commit 99fb0c53c038105bae68b02a3d9f1cbf7951ba10 from qemu
2018-03-02 11:28:17 -05:00
Yongji Xie 23f5b17a08
memory: Introduce DEVICE_HOST_ENDIAN for ram device
At the moment ram device's memory regions are DEVICE_NATIVE_ENDIAN. It's
incorrect. This memory region is backed by a MMIO area in host, so the
uint64_t data that MemoryRegionOps read from/write to this area should be
host-endian rather than target-endian. Hence, current code does not work
when target and host endianness are different which is the most common case
on PPC64. To fix it, this introduces DEVICE_HOST_ENDIAN for the ram device.

This has been tested on PPC64 BE/LE host/guest in all possible combinations
including TCG.

Backports commit c99a29e702528698c0ce2590f06ca7ff239f7c39 from qemu
2018-03-02 11:24:32 -05:00
Alex Bennée 454932263c
cputlb and arm/sparc targets: convert mmuidx flushes from varg to bitmap
While the vargs approach was flexible the original MTTCG ended up
having munge the bits to a bitmap so the data could be used in
deferred work helpers. Instead of hiding that in cputlb we push the
change to the API to make it take a bitmap of MMU indexes instead.

For ARM some the resulting flushes end up being quite long so to aid
readability I've tended to move the index shifting to a new line so
all the bits being or-ed together line up nicely, for example:

tlb_flush_page_by_mmuidx(other_cs, pageaddr,
(1 << ARMMMUIdx_S1SE1) |
(1 << ARMMMUIdx_S1SE0));

Backports commit 0336cbf8532935d8e23c2aabf3e2ce2c0697b6ac from qemu
2018-03-02 10:12:40 -05:00
KONRAD Frederic c5730ff194
tcg: add options for enabling MTTCG
We know there will be cases where MTTCG won't work until additional work
is done in the front/back ends to support. It will however be useful to
be able to turn it on.

As a result MTTCG will default to off unless the combination is
supported. However the user can turn it on for the sake of testing.

Backports commit 8d4e9146b3568022ea5730d92841345d41275d66 from qemu
2018-03-02 09:25:01 -05:00
Markus Armbruster 89d8e58718
util/cutils: Change qemu_strtosz*() from int64_t to uint64_t
This will permit its use in parse_option_size().

Backports commit f46bfdbfc8f95cf65d7818ef68a801e063c40332 from qemu
2018-03-02 08:58:55 -05:00
Markus Armbruster 8650d0213c
util/cutils: Return qemu_strtosz*() error and value separately
This makes qemu_strtosz(), qemu_strtosz_mebi() and
qemu_strtosz_metric() similar to qemu_strtoi64(), except negative
values are rejected.

Backports commit f17fd4fdf0df3d2f3444399d04c38d22b9a3e1b7 from qemu
2018-03-02 08:57:16 -05:00
Markus Armbruster 858acd4142
util/cutils: New qemu_strtosz()
Most callers of qemu_strtosz_suffix() pass QEMU_STRTOSZ_DEFSUFFIX_B.
Capture the pattern in new qemu_strtosz().

Inline qemu_strtosz_suffix() into its only remaining caller.

Backports commit 466dea14e677555dd24465aca75d00a3537ad062 from qemu
2018-03-02 08:50:56 -05:00
Markus Armbruster a3358798d6
util/cutils: Rename qemu_strtosz() to qemu_strtosz_MiB()
With qemu_strtosz(), no suffix means mebibytes. It's used rarely.
I'm going to add a similar function where no suffix means bytes.
Rename qemu_strtosz() to qemu_strtosz_MiB() to make the name
qemu_strtosz() available for the new function.

Backports commit e591591b323772eea733de6027f5e8b50692d0ff from qemu
2018-03-02 08:49:26 -05:00
Markus Armbruster f656cd91ec
util/cutils: New qemu_strtosz_metric()
To parse numbers with metric suffixes, we use

qemu_strtosz_suffix_unit(nptr, &eptr, QEMU_STRTOSZ_DEFSUFFIX_B, 1000)

Capture this in a new function for legibility:

qemu_strtosz_metric(nptr, &eptr)

Replace test_qemu_strtosz_suffix_unit() by test_qemu_strtosz_metric().

Rename qemu_strtosz_suffix_unit() to do_strtosz() and give it internal
linkage.

Backports commit d2734d2629266006b0413433778474d5801c60be from qemu
2018-03-02 08:47:40 -05:00
Markus Armbruster 41c2e1168f
util/cutils: Rename qemu_strtoll(), qemu_strtoull()
The name qemu_strtoll() suggests conversion to long long, but it
actually converts to int64_t. Rename to qemu_strtoi64().

The name qemu_strtoull() suggests conversion to unsigned long long,
but it actually converts to uint64_t. Rename to qemu_strtou64().

Backports commit b30d188677456b17c1cd68969e08ddc634cef644 from qemu
2018-03-02 08:39:45 -05:00
Bharata B Rao 7fadaf0bc4
softfloat: Add float128_to_uint32_round_to_zero()
float128_to_uint32_round_to_zero() is needed by xscvqpuwz instruction
of PowerPC ISA 3.0.

Backports commit fd425037d25cecaaffdb3831697e0adc10ca2ba3 from qemu
2018-03-02 08:33:09 -05:00
Bharata B Rao 64d32a2237
softfloat: Add float128_to_uint64_round_to_zero()
Implement float128_to_uint64() and use that to implement
float128_to_uint64_round_to_zero()

This is required by xscvqpudz instruction of PowerPC ISA 3.0.

Backports commit 2e6d85683576c970c714c1cc071dca742835b9d4 from qemu
2018-03-02 08:32:02 -05:00
Bharata B Rao 80e522b499
softfloat: Add round-to-odd rounding mode
Power ISA 3.0 introduces a few quadruple precision floating point
instructions that support round-to-odd rounding mode. The
round-to-odd mode is explained as under:

Let Z be the intermediate arithmetic result or the operand of a convert
operation. If Z can be represented exactly in the target format, the
result is Z. Otherwise the result is either Z1 or Z2 whichever is odd.
Here Z1 and Z2 are the next larger and smaller numbers representable
in the target format respectively.

Backports commit 9ee6f678f473007e252934d6acd09c24490d9d42 from qemu
2018-03-02 08:25:00 -05:00
Julian Brown cc217b0c90
arm: Correctly handle watchpoints for BE32 CPUs
In BE32 mode, sub-word size watchpoints can fail to trigger because the
address of the access is adjusted in the opcode helpers before being
compared with the watchpoint registers. This patch reverses the address
adjustment before performing the comparison with the help of a new CPUClass
hook.

This version of the patch augments and tidies up comments a little.

Backports commit 40612000599e52e792d23c998377a0fa429c4036 from qemu
2018-03-02 00:24:33 -05:00
Michael S. Tsirkin 0455644974
ARRAY_SIZE: check that argument is an array
It's a familiar pattern: some code uses ARRAY_SIZE, then refactoring
changes the argument from an array to a pointer to a dynamically
allocated buffer. Code keeps compiling but any ARRAY_SIZE calls now
return the size of the pointer divided by element size.

Let's add build time checks to ARRAY_SIZE before we allow more
of these in the code-base.

Backports commit ed63ec0d22ccdce3b2222d9a514423b7fbba3a0d from qemu
2018-03-02 00:09:51 -05:00
Michael S. Tsirkin ac013df0a2
compiler: expression version of QEMU_BUILD_BUG_ON
QEMU_BUILD_BUG_ON uses a typedef in order to be safe
to use outside functions, but sometimes it's useful
to have a version that can be used within an expression.
Following what Linux does, introduce QEMU_BUILD_BUG_ON_ZERO
that return zero after checking condition at build time.

Backports commit d757573e69f2ef58a4a7b41f6c55d65fa1e1c5c2 from qemu
2018-03-02 00:07:33 -05:00
Michael S. Tsirkin 634a8094f1
compiler: rework BUG_ON using a struct
There are theoretical concerns that some compilers might not trigger
build failures on attempts to define an array of size (x ? -1 : 1) where
x is a variable and make it a variable sized array instead. Let rewrite
using a struct with a negative bit field size instead as there are no
dynamic bit field sizes. This is similar to what Linux does.

Backports commit f291887e8eef5d37d31484638f6e62401b4b99a2 from qemu
2018-03-02 00:05:07 -05:00
Michael S. Tsirkin 7f9fb3395c
QEMU_BUILD_BUG_ON: use __COUNTER__
Some headers use QEMU_BUILD_BUG_ON. This causes a problem
if the C file including that header happens to have
QEMU_BUILD_BUG_ON at the same line number.

Fix using a widely available extension: __COUNTER__.
If unavailable, provide a stub.

Backports commit 60abf0a5e05134187e274ce5f32524ccf0cae1a6 from qemu
2018-03-02 00:03:44 -05:00
Michael S. Tsirkin beca05eb5f
compiler: drop ; after BUILD_BUG_ON
All users include the trailing ; anyway, let's require that -
it seems cleaner.

Backports commit f29831828441318c7916ae28e6e16e4a1c4a6795 from qemu
2018-03-02 00:01:44 -05:00
Sascha Silbe 11c66029b7
error: error_setg_errno(): errno gets preserved
C11 allows errno to be clobbered by pretty much any library function
call, so in general callers need to take care to save errno before
calling other functions.

However, for error reporting functions this is rather awkward and can
make the code on the caller side more complicated than
necessary. error_setg_errno() already takes care of preserving errno
and some functions rely on that, so just promise that we continue to
do so in the future.

Backports commit 98cb89af4df7e1776ce418ed6167b6e214a64435 from qemu
2018-03-01 23:38:25 -05:00
Thomas Huth b2f1326437
Move target-* CPU file into a target/ folder
We've currently got 18 architectures in QEMU, and thus 18 target-xxx
folders in the root folder of the QEMU source tree. More architectures
(e.g. RISC-V, AVR) are likely to be included soon, too, so the main
folder of the QEMU sources slowly gets quite overcrowded with the
target-xxx folders.
To disburden the main folder a little bit, let's move the target-xxx
folders into a dedicated target/ folder, so that target-xxx/ simply
becomes target/xxx/ instead.

Backports commit fcf5ef2ab52c621a4617ebbef36bf43b4003f4c0 from qemu
2018-03-01 22:50:58 -05:00
Alex Bennée e3e57ca08e
cputlb: drop flush_global flag from tlb_flush
We have never has the concept of global TLB entries which would avoid
the flush so we never actually use this flag. Drop it and make clear
that tlb_flush is the sledge-hammer it has always been.

Backports commit  d10eb08f5d8389c814b554d01aa2882ac58221bf from qemu
2018-03-01 19:36:04 -05:00
Richard Henderson 5ca8ac1aeb
qemu/host-utils.h: Reduce the operation count in the fallback ctpop
Backports commit 7bdcecb7b2d79c292d1256f7d6cf0f1da50d381f from qemu
2018-03-01 18:35:51 -05:00
Jason Wang 29932d0719
memory: handle alias in memory_region_is_iommu()
Backports commit 12d37882f0c0def5dee1c21be5d8fea9c21baada from qemu
2018-03-01 13:06:18 -05:00
Jason Wang fdca6292a1
exec: introduce address_space_get_iotlb_entry()
This patch introduces a helper to query the iotlb entry for a
possible iova. This will be used by later device IOTLB API to enable
the capability for a dataplane (e.g vhost) to query the IOTLB.

Backports commit 052c8fa9983f553fdfa0d61034774070dd639c2b from qemu
2018-03-01 13:05:08 -05:00
Paolo Bonzini 81ad780e5e
exec: introduce MemoryRegionCache
Device models often have to perform multiple access to a single
memory region that is known in advance, but would to use "DMA-style"
functions instead of address_space_map/unmap. This can happen
for example when the data has to undergo endianness conversion.
Introduce a new data structure to cache the result of
address_space_translate without forcing usage of a host address
like address_space_map does.

Backports commit 1f4e496e1fc2eb6c8bf377a0f9695930c380bfd3 from qemu
2018-03-01 10:50:30 -05:00
Paolo Bonzini 88ad0f4f6e
exec: introduce memory_ldst.inc.c
Templatize the address_space_* and *_phys functions, so that we can add
similar functions in the next patch that work with a lightweight,
cache-like version of address_space_map/unmap.

Backports commit 0ce265ffef87f19f4dd1ff0663e09a63d66ae408 from qemu
2018-03-01 09:59:34 -05:00
Paolo Bonzini 9404dbf74e
cpu-exec: fix icount out-of-bounds access
When icount is active, tb_add_jump is surprisingly called with an
out of bounds basic block index. I have no idea how that can work,
but it does not seem like a good idea. Clear *last_tb for all
TB_EXIT_ICOUNT_EXPIRED cases, even when all you have to do is
refill icount_extra.

Backports commit d8dea6fbcbed177ca5d23ab77b3834a9437f0e88 from qemu
2018-03-01 09:17:26 -05:00
Bobby Bingham d46e52d9d0
cpu_ldst.h: use correct guest address parameter
In the user emulation code path, tlb_vaddr_to_host erronesously passed
vaddr as the guest address to be translated, instead of addr, the parameter
which actually contained the guest address.

This resulted in incorrect addresses being used when emulating block copy
(mvc/mvpg) and block clear (xc) instructions for the s390x target.

Backports commit c2a85316902e67530da9d6548139fcce73c0cac6 from qemu
2018-03-01 08:56:37 -05:00
Paolo Bonzini 9d64a89acf
tcg: comment on which functions have to be called with tb_lock held
softmmu requires more functions to be thread-safe, because translation
blocks can be invalidated from e.g. notdirty callbacks. Probably the
same holds for user-mode emulation, it's just that no one has ever
tried to produce a coherent locking there.

This patch will guide the introduction of more tb_lock and tb_unlock
calls for system emulation.

Note that after this patch some (most) of the mentioned functions are
still called outside tb_lock/tb_unlock. The next one will rectify this.

Backports commit 7d7500d99895f888f97397ef32bb536bb0df3b74 from qemu
2018-02-28 10:26:28 -05:00
Alex Bennée 7aab0bd9a6
translate-all: add DEBUG_LOCKING asserts
This adds asserts to check the locking on the various translation
engines structures. There are two sets of structures that are protected
by locks.

The first the l1map and PageDesc structures used to track which
translation blocks are associated with which physical addresses. In
user-mode this is covered by the mmap_lock.

The second case are TB context related structures which are protected by
tb_lock which is also user-mode only.

Currently the asserts do nothing in SoftMMU mode but this will change
for MTTCG.

Backports commit 301e40ed8005306c009978be295ed9a4b725178b from qemu
2018-02-28 08:56:15 -05:00
Richard Henderson da01e53757
tcg: Add atomic128 helpers
Force the use of cmpxchg16b on x86_64.

Wikipedia suggests that only very old AMD64 (circa 2004) did not have
this instruction. Further, it's required by Windows 8 so no new cpus
will ever omit it.

If we truely care about these, then we could check this at startup time
and then avoid executing paths that use it.

Backports commit 7ebee43ee3e2fcd7b5063058b7ef74bc43216733 from qemu
2018-02-27 21:43:48 -05:00
Richard Henderson 5c0ce1b99c
tcg: Add atomic helpers
Add all of cmpxchg, op_fetch, fetch_op, and xchg.
Handle both endian-ness, and sizes up to 8.
Handle expanding non-atomically, when emulating in serial.

Backports commit c482cb117cc418115ca9c6d21a7a2315414c0a40 from qemu
2018-02-27 15:57:47 -05:00
Yongbok Kim 79e4c001a9
softmmu: Add probe_write()
Probe for whether the specified guest write access is permitted.
If it is not permitted then an exception will be taken in the same
way as if this were a real write access (and we will not return).
Otherwise the function will return, and there will be a valid
entry in the TLB for this access.

Backports commit 3b4afc9e75ab1a95f33e41f462921093f8a109c4 from qemu
2018-02-27 12:20:50 -05:00
Richard Henderson e35aacd5ae
tcg: Add EXCP_ATOMIC
When we cannot emulate an atomic operation within a parallel
context, this exception allows us to stop the world and try
again in a serial context.

Backports commit fdbc2b5722f6092e47181a947c90fd4bdcc1c121 from qemu

Also backports parts of commit 02d57ea115b7669f588371c86484a2e8ebc369be
2018-02-27 11:57:58 -05:00
Richard Henderson d5510a546f
int128: Add int128_make128
Allows Int128 to be used more generally, rather than having to
begin with 64-bit inputs and accumulate.

Backports commit 1edaeee0955fba7d834b7c8f4e372e7eae030745 from qemu
2018-02-27 11:06:33 -05:00