Commit Graph

1636 Commits

Author SHA1 Message Date
Emilio G. Cota 1d34982155 tcg: fix s/compliment/complement/ typos
Signed-off-by: Emilio G. Cota <cota@braap.org>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
2018-05-20 08:25:23 +03:00
Peter Maydell f5583c527f target-arm queue:
* hw/arm/iotkit.c: fix minor memory leak
  * softfloat: fix wrong-exception-flags bug for multiply-add corner case
  * arm: isolate and clean up DTB generation
  * implement Arm v8.1-Atomics extension
  * Fix some bugs and missing instructions in the v8.2-FP16 extension
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Merge remote-tracking branch 'remotes/pmaydell/tags/pull-target-arm-20180510' into staging

target-arm queue:
 * hw/arm/iotkit.c: fix minor memory leak
 * softfloat: fix wrong-exception-flags bug for multiply-add corner case
 * arm: isolate and clean up DTB generation
 * implement Arm v8.1-Atomics extension
 * Fix some bugs and missing instructions in the v8.2-FP16 extension

# gpg: Signature made Thu 10 May 2018 18:44:34 BST
# gpg:                using RSA key 3C2525ED14360CDE
# gpg: Good signature from "Peter Maydell <peter.maydell@linaro.org>"
# gpg:                 aka "Peter Maydell <pmaydell@gmail.com>"
# gpg:                 aka "Peter Maydell <pmaydell@chiark.greenend.org.uk>"
# Primary key fingerprint: E1A5 C593 CD41 9DE2 8E83  15CF 3C25 25ED 1436 0CDE

* remotes/pmaydell/tags/pull-target-arm-20180510: (21 commits)
  target/arm: Clear SVE high bits for FMOV
  target/arm: Fix float16 to/from int16
  target/arm: Implement vector shifted FCVT for fp16
  target/arm: Implement vector shifted SCVF/UCVF for fp16
  target/arm: Enable ARM_FEATURE_V8_ATOMICS for user-only
  target/arm: Implement CAS and CASP
  target/arm: Fill in disas_ldst_atomic
  target/arm: Introduce ARM_FEATURE_V8_ATOMICS and initial decode
  target/riscv: Use new atomic min/max expanders
  tcg: Use GEN_ATOMIC_HELPER_FN for opposite endian atomic add
  tcg: Introduce atomic helpers for integer min/max
  target/xtensa: Use new min/max expanders
  target/arm: Use new min/max expanders
  tcg: Introduce helpers for integer min/max
  atomic.h: Work around gcc spurious "unused value" warning
  make sure that we aren't overwriting mc->get_hotplug_handler by accident
  arm/boot: split load_dtb() from arm_load_kernel()
  platform-bus-device: use device plug callback instead of machine_done notifier
  pc: simplify MachineClass::get_hotplug_handler handling
  softfloat: Handle default NaN mode after pickNaNMulAdd, not before
  ...

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

# Conflicts:
#	target/riscv/translate.c
2018-05-11 17:41:54 +01:00
Richard Henderson 5507c2bf35 tcg: Introduce atomic helpers for integer min/max
Given that this atomic operation will be used by both risc-v
and aarch64, let's not duplicate code across the two targets.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20180508151437.4232-5-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2018-05-10 18:10:57 +01:00
Richard Henderson b87fb8cd9f tcg: Introduce helpers for integer min/max
These operations are re-invented by several targets so far.
Several supported hosts have insns for these, so place the
expanders out-of-line for a future introduction of tcg opcodes.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20180508151437.4232-2-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2018-05-10 18:10:57 +01:00
Richard Henderson abebf92597 tcg: Limit the number of ops in a TB
In 6001f7729e we partially attempt to address the branch
displacement overflow caused by 15fa08f845.

However, gcc/testsuite/gcc.target/aarch64/advsimd-intrinsics/vqtbX.c
is a testcase that contains a TB so large as to overflow anyway.
The limit here of 8000 ops produces a maximum output TB size of
24112 bytes on a ppc64le host with that test case.  This is still
much less than the maximum forward branch distance of 32764 bytes.

Cc: qemu-stable@nongnu.org
Fixes: 15fa08f845 ("tcg: Dynamically allocate TCGOps")
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-05-09 08:30:57 -07:00
Peter Maydell 7eb30ef0ba tcg/i386: Fix dup_vec in non-AVX2 codepath
The VPUNPCKLD* instructions are all "non-destructive source",
indicated by "NDS" in the encoding string in the x86 ISA manual.
This means that they take two source operands, one of which is
encoded in the VEX.vvvv field. We were incorrectly treating them
as if they were destructive-source and passing 0 as the 'v'
argument of tcg_out_vex_modrm(). This meant we were always
using %xmm0 as one of the source operands, causing incorrect
results if the register allocator happened to want to use
something else. For instance the input AArch64 insn:
 DUP v26.16b, w21
which becomes TCG IR ops:
 dup_vec v128,e8,tmp2,x21
 st_vec v128,e8,tmp2,env,$0xa40
was assembled to:
0x607c568c:  c4 c1 7a 7e 86 e8 00 00  vmovq    0xe8(%r14), %xmm0
0x607c5694:  00
0x607c5695:  c5 f9 60 c8              vpunpcklbw %xmm0, %xmm0, %xmm1
0x607c5699:  c5 f9 61 c9              vpunpcklwd %xmm1, %xmm0, %xmm1
0x607c569d:  c5 f9 70 c9 00           vpshufd  $0, %xmm1, %xmm1
0x607c56a2:  c4 c1 7a 7f 8e 40 0a 00  vmovdqu  %xmm1, 0xa40(%r14)
0x607c56aa:  00

when the vpunpcklwd insn should be "%xmm1, %xmm1, %xmm1".
This resulted in our incorrectly setting the output vector to
q26=0000320000003200:0000320000003200
when given an input of x21 == 0000000002803200
rather than the expected all-zeroes.

Pass the correct source register number to tcg_out_vex_modrm()
for these insns.

Fixes: 770c2fc7bb
Cc: qemu-stable@nongnu.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <20180504153431.5169-1-peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-05-09 08:30:57 -07:00
Laurent Vivier 6001f7729e tcg: workaround branch instruction overflow in tcg_out_qemu_ld/st
ppc64 uses a BC instruction to call the tcg_out_qemu_ld/st
slow path. BC instruction uses a relative address encoded
on 14 bits.

The slow path functions are added at the end of the generated
instructions buffer, in the reverse order of the callers.
So more we have slow path functions more the distance between
the caller (BC) and the function increases.

This patch changes the behavior to generate the functions in
the same order of the callers.

Cc: qemu-stable@nongnu.org
Fixes: 15fa08f845 ("tcg: Dynamically allocate TCGOps")
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Message-Id: <20180429235840.16659-1-lvivier@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-05-01 11:56:55 -07:00
Richard Henderson 5bfa803448 tcg: Improve TCGv_ptr support
Drop TCGV_PTR_TO_NAT and TCGV_NAT_TO_PTR internal macros.

Add tcg_temp_local_new_ptr, tcg_gen_brcondi_ptr, tcg_gen_ext_i32_ptr,
tcg_gen_trunc_i64_ptr, tcg_gen_extu_ptr_i64, tcg_gen_trunc_ptr_i32.

Use inlines instead of macros where possible.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-05-01 11:56:16 -07:00
Richard Henderson 9a938d86b0 tcg: Allow wider vectors for cmp and mul
In db432672, we allow wide inputs for operations such as add.
However, in 212be173 and 3774030a we didn't do the same for
compare and multiply.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-05-01 11:56:16 -07:00
Henry Wertz 3f814b8037 tcg/arm: Fix memory barrier encoding
I found with qemu 2.11.x or newer that I would get an illegal instruction
error running some Intel binaries on my ARM chromebook.  On investigation,
I found it was quitting on memory barriers.

qemu instruction:
mb $0x31
was translating as:
0x604050cc:  5bf07ff5  blpl     #0x600250a8

After patch it gives:
0x604050cc:  f57ff05b  dmb      ish

In short, I found INSN_DMB_ISH (memory barrier for ARMv7) appeared to be
correct based on online docs, but due to some endian-related shenanigans it
had to be byte-swapped to suit qemu; it appears INSN_DMB_MCR (memory
barrier for ARMv6) also should be byte swapped  (and this patch does so).
I have not checked for correctness of aarch64's barrier instruction.

Cc: qemu-stable@nongnu.org
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Henry Wertz <hwertz10@gmail.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-05-01 11:56:07 -07:00
Richard Henderson d103021269 tcg: Document INDEX_mul[us]h_*
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-05-01 11:41:56 -07:00
Peter Maydell 161dfd1e7f tcg/mips: Handle large offsets from target env to tlb_table
The MIPS TCG target makes the assumption that the offset from the
target env pointer to the tlb_table is less than about 64K. This
used to be true, but gradual addition of features to the Arm
target means that it's no longer true there. This results in
the build-time assertion failing:

In file included from /home/pm215/qemu/include/qemu/osdep.h:36:0,
                 from /home/pm215/qemu/tcg/tcg.c:28:
/home/pm215/qemu/tcg/mips/tcg-target.inc.c: In function ‘tcg_out_tlb_load’:
/home/pm215/qemu/include/qemu/compiler.h:90:36: error: static assertion failed: "not expecting: offsetof(CPUArchState, tlb_table[NB_MMU_MODES - 1][1]) > 0x7ff0 + 0x7fff"
 #define QEMU_BUILD_BUG_MSG(x, msg) _Static_assert(!(x), msg)
                                    ^
/home/pm215/qemu/include/qemu/compiler.h:98:30: note: in expansion of macro ‘QEMU_BUILD_BUG_MSG’
 #define QEMU_BUILD_BUG_ON(x) QEMU_BUILD_BUG_MSG(x, "not expecting: " #x)
                              ^
/home/pm215/qemu/tcg/mips/tcg-target.inc.c:1236:9: note: in expansion of macro ‘QEMU_BUILD_BUG_ON’
         QEMU_BUILD_BUG_ON(offsetof(CPUArchState,
         ^
/home/pm215/qemu/rules.mak:66: recipe for target 'tcg/tcg.o' failed

An ideal long term approach would be to rearrange the CPU state
so that the tlb_table was not so far along it, but this is tricky
because it would move it from the "not cleared on CPU reset" part
of the struct to the "cleared on CPU reset" part. As a simple fix
for the 2.12 release, make the MIPS TCG target handle an arbitrary
offset by emitting more add instructions. This will mean an extra
instruction in the fastpath for TCG loads and stores for the
affected guests (currently just aarch64-softmmu).

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Message-id: 20180413142336.32163-1-peter.maydell@linaro.org
2018-04-16 11:51:37 +01:00
Richard Henderson 9743cd5736 tcg: Introduce tcg_set_insn_start_param
The parameters for tcg_gen_insn_start are target_ulong, which may be split
into two TCGArg parameters for storage in the opcode on 32-bit hosts.

Fixes the ARM target and its direct use of tcg_set_insn_param, which would
set the wrong argument in the 64-on-32 case.

Cc: qemu-stable@nongnu.org
Reported-by: alarson@ddci.com
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20180410003558.2470-1-richard.henderson@linaro.org
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2018-04-10 13:02:26 +01:00
Richard Henderson f2f1dde751 tcg: Mark muluh_i64 and mulsh_i64 as 64-bit ops
Failure to do so results in the tcg optimizer sign-extending
any constant fold from 32-bits.  This turns out to be visible
in the RISC-V testsuite using a host that emits these opcodes
(e.g. any non-x86_64).

Reported-by: Michael Clark <mjc@sifive.com>
Reviewed-by: Emilio G. Cota <cota@braap.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-03-28 12:45:16 +08:00
Richard Henderson adb196cbd5 tcg: Add choose_vector_size
This unifies 5 copies of checks for supported vector size,
and in the process fixes a missing check in tcg_gen_gvec_2s.

This lead to an assertion failure for 64-bit vector multiply,
which is not available in the AVX instruction set.

Suggested-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-03-16 00:55:04 +08:00
Richard Henderson 7f34ed4bcd tcg/i386: Support INDEX_op_dup2_vec for -m32
Unknown why -m32 was passing with gcc but not clang; it should have
failed for both.  This would be used for tcg_gen_dup_i64_vec, and
visible with the right TB and an aarch64 guest.

Reported-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-03-16 00:55:04 +08:00
Richard Henderson b2e3ae9452 tcg: Improve tcg_gen_muli_i32/i64
Convert multiplication by power of two to left shift.

Reviewed-by: Emilio G. Cota <cota@braap.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-03-16 00:55:04 +08:00
Richard Henderson 14e4c1e235 tcg/aarch64: Add vector operations
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-02-08 15:54:08 +00:00
Richard Henderson 770c2fc7bb tcg/i386: Add vector operations
The x86 vector instruction set is extremely irregular.  With newer
editions, Intel has filled in some of the blanks.  However, we don't
get many 64-bit operations until SSE4.2, introduced in 2009.

The subsequent edition was for AVX1, introduced in 2011, which added
three-operand addressing, and adjusts how all instructions should be
encoded.

Given the relatively narrow 2 year window between possible to support
and desirable to support, and to vastly simplify code maintainence,
I am only planning to support AVX1 and later cpus.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-02-08 15:54:08 +00:00
Richard Henderson 170ba88f45 tcg/optimize: Handle vector opcodes during optimize
Trivial move and constant propagation.  Some identity and constant
function folding, but nothing that requires knowledge of the size
of the vector element.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-02-08 15:54:06 +00:00
Richard Henderson 22fc352703 tcg: Add generic vector helpers with a scalar operand
Use dup to convert a non-constant scalar to a third vector.

Add addition, multiplication, and logical operations with an immediate.
Add addition, subtraction, multiplication, and logical operations with
a non-constant scalar.  Allow for the front-end to build operations in
which the scalar operand comes first.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-02-08 15:54:06 +00:00
Richard Henderson f49b12c6e6 tcg: Add generic helpers for saturating arithmetic
No vector ops as yet.  SSE only has direct support for 8- and 16-bit
saturation; handling 32- and 64-bit saturation is much more expensive.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-02-08 15:54:06 +00:00
Richard Henderson 3774030a3e tcg: Add generic vector ops for multiplication
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-02-08 15:54:06 +00:00
Richard Henderson 212be173f0 tcg: Add generic vector ops for comparisons
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-02-08 15:54:05 +00:00
Richard Henderson d0ec97967f tcg: Add generic vector ops for constant shifts
Opcodes are added for scalar and vector shifts, but considering the
varied semantics of these do not expose them to the front ends.  Do
go ahead and provide them in case they are needed for backend expansion.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-02-08 15:54:05 +00:00
Richard Henderson db432672dc tcg: Add generic vector expanders
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-02-08 15:54:05 +00:00
Richard Henderson 474b2e8f0f tcg: Standardize integral arguments to expanders
Some functions use intN_t arguments, some use uintN_t, some just
used "unsigned".  To aid putting function pointers in tables, we
need consistency.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-02-08 15:54:05 +00:00
Richard Henderson d2fd745fe8 tcg: Add types and basic operations for host vectors
Nothing uses or enables them yet.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-02-08 15:54:04 +00:00
Richard Henderson da73a4abca tcg: Allow multiple word entries into the constant pool
This will be required for storing vector constants.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-02-08 15:53:34 +00:00
Richard Henderson 030ffe39dd tcg/ppc: Allow a 32-bit offset to the constant pool
We recently relaxed the limit of the number of opcodes that can
appear in a TranslationBlock.  In certain cases this has resulted
in relocation overflow.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-01-16 08:21:56 -08:00
Richard Henderson 4a64e0fd68 tcg/ppc: Support tlb offsets larger than 64k
AArch64 with SVE has an offset of 80k to the 8th TLB.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-01-16 08:21:56 -08:00
Richard Henderson 71f9cee9d0 tcg/arm: Support tlb offsets larger than 64k
AArch64 with SVE has an offset of 80k to the 8th TLB.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-01-16 08:21:56 -08:00
Richard Henderson 7170ac3313 tcg/arm: Fix double-word comparisons
The code sequence we were generating was only good for unsigned
comparisons.  For signed comparisions, use the sequence from gcc.

Fixes booting of ppc64 firmware, with a patch changing the code
sequence for ppc comparisons.

Tested-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-01-16 08:20:39 -08:00
Richard Henderson 1df3caa946 tcg: Allow 6 arguments to TCG helpers
We already handle this in the backends, and the lifetime datum
for the TCGOp is already large enough.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2017-12-29 12:43:40 -08:00
Richard Henderson 923ed17501 tcg: Add tcg_signed_cond
Complimenting the existing tcg_unsigned_cond.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2017-12-29 12:43:40 -08:00
Richard Henderson cd9090aa9d tcg: Generalize TCGOp parameters
We had two fields specific to INDEX_op_call.  Rename these and
add some macros so that the fields may be reused for other opcodes.

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2017-12-29 12:43:39 -08:00
Richard Henderson 15fa08f845 tcg: Dynamically allocate TCGOps
With no fixed array allocation, we can't overflow a buffer.
This will be important as optimizations related to host vectors
may expand the number of ops used.

Use QTAILQ to link the ops together.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2017-12-29 12:43:39 -08:00
Richard Henderson f764718d0c tcg: Remove TCGV_UNUSED* and TCGV_IS_UNUSED*
These are now trivial sets and tests against NULL.  Unwrap.

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2017-12-29 12:43:39 -08:00
Richard Henderson ba2c747992 tcg/s390x: Use constant pool for prologue
Rather than have separate code only used for guest_base,
rely on a recent change to handle constant pool entries.

Cc: qemu-s390x@nongnu.org
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2017-11-03 09:33:45 +01:00
Richard Henderson 5b38ee3161 tcg: Allow constant pool entries in the prologue
Both ARMv6 and AArch64 currently may drop complex guest_base values
into the constant pool.  But generic code wasn't expecting that, and
the pool is not emitted.  Correct that.

Tested-by: Emilio G. Cota <cota@braap.org>
Tested-by: Laurent Desnogues <laurent.desnogues@gmail.com>
Reported-by: Laurent Desnogues <laurent.desnogues@gmail.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2017-11-03 09:33:45 +01:00
Richard Henderson 1c2adb958f tcg: Initialize cpu_env generically
This is identical for each target.  So, move the initialization to
common code.  Move the variable itself out of tcg_ctx and name it
cpu_env to minimize changes within targets.

This also means we can remove tcg_global_reg_new_{ptr,i32,i64},
since there are no longer global-register temps created by targets.

Reviewed-by: Emilio G. Cota <cota@braap.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2017-10-24 13:53:42 -07:00
Emilio G. Cota 3468b59e18 tcg: enable multiple TCG contexts in softmmu
This enables parallel TCG code generation. However, we do not take
advantage of it yet since tb_lock is still held during tb_gen_code.

In user-mode we use a single TCG context; see the documentation
added to tcg_region_init for the rationale.

Note that targets do not need any conversion: targets initialize a
TCGContext (e.g. defining TCG globals), and after this initialization
has finished, the context is cloned by the vCPU threads, each of
them keeping a separate copy.

TCG threads claim one entry in tcg_ctxs[] by atomically increasing
n_tcg_ctxs. Do not be too annoyed by the subsequent atomic_read's
of that variable and tcg_ctxs; they are there just to play nice with
analysis tools such as thread sanitizer.

Note that we do not allocate an array of contexts (we allocate
an array of pointers instead) because when tcg_context_init
is called, we do not know yet how many contexts we'll use since
the bool behind qemu_tcg_mttcg_enabled() isn't set yet.

Previous patches folded some TCG globals into TCGContext. The non-const
globals remaining are only set at init time, i.e. before the TCG
threads are spawned. Here is a list of these set-at-init-time globals
under tcg/:

Only written by tcg_context_init:
- indirect_reg_alloc_order
- tcg_op_defs
Only written by tcg_target_init (called from tcg_context_init):
- tcg_target_available_regs
- tcg_target_call_clobber_regs
- arm: arm_arch, use_idiv_instructions
- i386: have_cmov, have_bmi1, have_bmi2, have_lzcnt,
        have_movbe, have_popcnt
- mips: use_movnz_instructions, use_mips32_instructions,
        use_mips32r2_instructions, got_sigill (tcg_target_detect_isa)
- ppc: have_isa_2_06, have_isa_3_00, tb_ret_addr
- s390: tb_ret_addr, s390_facilities
- sparc: qemu_ld_trampoline, qemu_st_trampoline (build_trampolines),
         use_vis3_instructions

Only written by tcg_prologue_init:
- 'struct jit_code_entry one_entry'
- aarch64: tb_ret_addr
- arm: tb_ret_addr
- i386: tb_ret_addr, guest_base_flags
- ia64: tb_ret_addr
- mips: tb_ret_addr, bswap32_addr, bswap32u_addr, bswap64_addr

Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Emilio G. Cota <cota@braap.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2017-10-24 13:53:42 -07:00
Emilio G. Cota e8feb96fcc tcg: introduce regions to split code_gen_buffer
This is groundwork for supporting multiple TCG contexts.

The naive solution here is to split code_gen_buffer statically
among the TCG threads; this however results in poor utilization
if translation needs are different across TCG threads.

What we do here is to add an extra layer of indirection, assigning
regions that act just like pages do in virtual memory allocation.
(BTW if you are wondering about the chosen naming, I did not want
to use blocks or pages because those are already heavily used in QEMU).

We use a global lock to serialize allocations as well as statistics
reporting (we now export the size of the used code_gen_buffer with
tcg_code_size()). Note that for the allocator we could just use
a counter and atomic_inc; however, that would complicate the gathering
of tcg_code_size()-like stats. So given that the region operations are
not a fast path, a lock seems the most reasonable choice.

The effectiveness of this approach is clear after seeing some numbers.
I used the bootup+shutdown of debian-arm with '-tb-size 80' as a benchmark.
Note that I'm evaluating this after enabling per-thread TCG (which
is done by a subsequent commit).

* -smp 1, 1 region (entire buffer):
    qemu: flush code_size=83885014 nb_tbs=154739 avg_tb_size=357
    qemu: flush code_size=83884902 nb_tbs=153136 avg_tb_size=363
    qemu: flush code_size=83885014 nb_tbs=152777 avg_tb_size=364
    qemu: flush code_size=83884950 nb_tbs=150057 avg_tb_size=373
    qemu: flush code_size=83884998 nb_tbs=150234 avg_tb_size=373
    qemu: flush code_size=83885014 nb_tbs=154009 avg_tb_size=360
    qemu: flush code_size=83885014 nb_tbs=151007 avg_tb_size=370
    qemu: flush code_size=83885014 nb_tbs=151816 avg_tb_size=367

That is, 8 flushes.

* -smp 8, 32 regions (80/32 MB per region) [i.e. this patch]:

    qemu: flush code_size=76328008 nb_tbs=141040 avg_tb_size=356
    qemu: flush code_size=75366534 nb_tbs=138000 avg_tb_size=361
    qemu: flush code_size=76864546 nb_tbs=140653 avg_tb_size=361
    qemu: flush code_size=76309084 nb_tbs=135945 avg_tb_size=375
    qemu: flush code_size=74581856 nb_tbs=132909 avg_tb_size=375
    qemu: flush code_size=73927256 nb_tbs=135616 avg_tb_size=360
    qemu: flush code_size=78629426 nb_tbs=142896 avg_tb_size=365
    qemu: flush code_size=76667052 nb_tbs=138508 avg_tb_size=368

Again, 8 flushes. Note how buffer utilization is not 100%, but it
is close. Smaller region sizes would yield higher utilization,
but we want region allocation to be rare (it acquires a lock), so
we do not want to go too small.

* -smp 8, static partitioning of 8 regions (10 MB per region):
    qemu: flush code_size=21936504 nb_tbs=40570 avg_tb_size=354
    qemu: flush code_size=11472174 nb_tbs=20633 avg_tb_size=370
    qemu: flush code_size=11603976 nb_tbs=21059 avg_tb_size=365
    qemu: flush code_size=23254872 nb_tbs=41243 avg_tb_size=377
    qemu: flush code_size=28289496 nb_tbs=52057 avg_tb_size=358
    qemu: flush code_size=43605160 nb_tbs=78896 avg_tb_size=367
    qemu: flush code_size=45166552 nb_tbs=82158 avg_tb_size=364
    qemu: flush code_size=63289640 nb_tbs=116494 avg_tb_size=358
    qemu: flush code_size=51389960 nb_tbs=93937 avg_tb_size=362
    qemu: flush code_size=59665928 nb_tbs=107063 avg_tb_size=372
    qemu: flush code_size=38380824 nb_tbs=68597 avg_tb_size=374
    qemu: flush code_size=44884568 nb_tbs=79901 avg_tb_size=376
    qemu: flush code_size=50782632 nb_tbs=90681 avg_tb_size=374
    qemu: flush code_size=39848888 nb_tbs=71433 avg_tb_size=372
    qemu: flush code_size=64708840 nb_tbs=119052 avg_tb_size=359
    qemu: flush code_size=49830008 nb_tbs=90992 avg_tb_size=362
    qemu: flush code_size=68372408 nb_tbs=123442 avg_tb_size=368
    qemu: flush code_size=33555560 nb_tbs=59514 avg_tb_size=378
    qemu: flush code_size=44748344 nb_tbs=80974 avg_tb_size=367
    qemu: flush code_size=37104248 nb_tbs=67609 avg_tb_size=364

That is, 20 flushes. Note how a static partitioning approach uses
the code buffer poorly, leading to many unnecessary flushes.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Emilio G. Cota <cota@braap.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2017-10-24 13:53:42 -07:00
Emilio G. Cota 34184b0718 tcg: allocate optimizer temps with tcg_malloc
Groundwork for supporting multiple TCG contexts.

While at it, also allocate temps_used directly as a bitmap of the
required size, instead of using a bitmap of TCG_MAX_TEMPS via
TCGTempSet.

Performance-wise we lose about 1.12% in a translation-heavy workload
such as booting+shutting down debian-arm:

Performance counter stats for 'taskset -c 0 arm-softmmu/qemu-system-arm \
	-machine type=virt -nographic -smp 1 -m 4096 \
	-netdev user,id=unet,hostfwd=tcp::2222-:22 \
	-device virtio-net-device,netdev=unet \
	-drive file=die-on-boot.qcow2,id=myblock,index=0,if=none \
	-device virtio-blk-device,drive=myblock \
	-kernel kernel.img -append console=ttyAMA0 root=/dev/vda1 \
	-name arm,debug-threads=on -smp 1' (10 runs):

             exec time (s)  Relative slowdown wrt original (%)
---------------------------------------------------------------
 original     20.213321616                                  0.
 tcg_malloc   20.441130078                           1.1270214
 TCGContext   20.477846517                           1.3086662
 g_malloc     20.780527895                           2.8061013

The other two alternatives shown in the table are:
- TCGContext: embed temps[TCG_MAX_TEMPS] and TCGTempSet used_temps
  in TCGContext. This is simple enough but it isn't faster than using
  tcg_malloc; moreover, it wastes memory.
- g_malloc: allocate/deallocate both temps and used_temps every time
  tcg_optimize is executed.

Suggested-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Emilio G. Cota <cota@braap.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2017-10-24 13:53:42 -07:00
Emilio G. Cota c3fac1138e tcg: distribute profiling counters across TCGContext's
This is groundwork for supporting multiple TCG contexts.

To avoid scalability issues when profiling info is enabled, this patch
makes the profiling info counters distributed via the following changes:

1) Consolidate profile info into its own struct, TCGProfile, which
   TCGContext also includes. Note that tcg_table_op_count is brought
   into TCGProfile after dropping the tcg_ prefix.
2) Iterate over the TCG contexts in the system to obtain the total counts.

This change also requires updating the accessors to TCGProfile fields to
use atomic_read/set whenever there may be conflicting accesses (as defined
in C11) to them.

Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Emilio G. Cota <cota@braap.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2017-10-24 13:53:42 -07:00
Emilio G. Cota df2cce2968 tcg: introduce **tcg_ctxs to keep track of all TCGContext's
Groundwork for supporting multiple TCG contexts.

Note that having n_tcg_ctxs is unnecessary. However, it is
convenient to have it, since it will simplify iterating over the
array: we'll have just a for loop instead of having to iterate
over a NULL-terminated array (which would require n+1 elems)
or having to check with ifdef's for usermode/softmmu.

Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Emilio G. Cota <cota@braap.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2017-10-24 13:53:42 -07:00
Emilio G. Cota 26689780f8 gen-icount: fold exitreq_label into TCGContext
Groundwork for supporting multiple TCG contexts.

Reviewed-by: Richard Henderson <rth@twiddle.net>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Emilio G. Cota <cota@braap.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2017-10-24 13:53:42 -07:00
Emilio G. Cota b1311c4acf tcg: define tcg_init_ctx and make tcg_ctx a pointer
Groundwork for supporting multiple TCG contexts.

The core of this patch is this change to tcg/tcg.h:

> -extern TCGContext tcg_ctx;
> +extern TCGContext tcg_init_ctx;
> +extern TCGContext *tcg_ctx;

Note that for now we set *tcg_ctx to whatever TCGContext is passed
to tcg_context_init -- in this case &tcg_init_ctx.

Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Emilio G. Cota <cota@braap.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2017-10-24 13:53:42 -07:00
Emilio G. Cota 44ded3d048 tcg: take tb_ctx out of TCGContext
Groundwork for supporting multiple TCG contexts.

Reviewed-by: Richard Henderson <rth@twiddle.net>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Emilio G. Cota <cota@braap.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2017-10-24 13:53:42 -07:00
Emilio G. Cota e82d5a2460 tcg: check CF_PARALLEL instead of parallel_cpus
Thereby decoupling the resulting translated code from the current state
of the system.

The tb->cflags field is not passed to tcg generation functions. So
we add a field to TCGContext, storing there a copy of tb->cflags.

Most architectures have <= 32 registers, which results in a 4-byte hole
in TCGContext. Use this hole for the new field.

Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Emilio G. Cota <cota@braap.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2017-10-24 13:53:42 -07:00