Commit Graph

3274 Commits

Author SHA1 Message Date
Marc-André Lureau
f4b3c5d0bd
qobject: use a QObjectBase_ struct
By moving the base fields to a QObjectBase_, QObject can be a type
which also has a 'base' field. This allows writing a generic QOBJECT()
macro that will work with any QObject type, including QObject
itself. The container_of() macro ensures that the object to cast has a
QObjectBase_ base field, giving some type safety guarantees. QObject
must have no members but QObjectBase_ base, or else QOBJECT() breaks.

QObjectBase_ is not a typedef and uses a trailing underscore to make
it obvious it is not for normal use and to avoid potential abuse.

Backports commit 3d3eacaeccaab718ea0e2ddaa578bfae9e311c59 from qemu
2018-05-04 10:11:24 -04:00
Marc-André Lureau
2ca916e106
qobject: Ensure base is at offset 0
All QObject types have the base QObject as their first field. This
allows the simplification of qobject_to().

Backports commit 7ee9edfdb117da47c86c9764d90f0be11a648666 from qemu
2018-05-04 09:54:36 -04:00
Laurent Vivier
ec12091943
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.

Backports commit 6001f7729e12dd1d810291e4cbf83cee8e07441d from qemu
2018-05-03 15:09:07 -04:00
Richard Henderson
2150745db4
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.

Backports commit 5bfa803448638a45542441fd6b7cc1241403ea72 from qemu
2018-05-03 15:05:43 -04:00
Richard Henderson
4fa9ea2ae1
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.

Backports commit 9a938d86b04025ac605db0ea9819e5896bf576ec from qemu
2018-05-03 14:42:57 -04:00
Henry Wertz
090e2e9d0e
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.

Backports commit 3f814b803797c007abfe5c4041de754e01723031 from qemu
2018-05-03 14:41:36 -04:00
Richard Henderson
16a55143dc
tcg: Document INDEX_mul[us]h_*
Backports commit d103021269ca9307ed7ca0d845d2b9e6c387509a from qemu
2018-05-03 14:40:49 -04:00
Laurent Vivier
97c8507f00
m68k: remove dead code (Coverity CID1390617)
floatx80_sin() and floatx80_cos() are derived from one
sincos() function. They have both unused code coming from
their common origin. Remove it.

Backports commit 6361d2984ce88912976a34e1797a5ad5139c649b from qemu
2018-05-01 11:44:18 -04:00
Laurent Vivier
ebf0c8f9ca
m68k: Fix floatx80_lognp1 (Coverity CID1390587)
return the result of packFloatx80() instead of
dropping it.

Backports commit 981348af5c3c72335d95f6877abf702d80176eb3 from qemu
2018-05-01 11:41:07 -04:00
Pavel Dovgalyuk
bf16c6daee
m68k: fix subx mem, mem instruction
This patch fixes decrement of the pointers for subx mem, mem instructions.
Without the patch pointers are decremented by OS_* constant value instead of
retrieving the corresponding data size and using it as a decrement.

Backports commit 355d4d1c00e708907ff391c24ca708f1c9c06bf0 from qemu
2018-05-01 11:40:00 -04:00
Aaron Lindsay
d3e7bbffea
target/arm: Make PMOVSCLR and PMUSERENR 64 bits wide
This is a bug fix to ensure 64-bit reads of these registers don't read
adjacent data.

Backports commit e4e91a217c17fff4045dd4b423cdcb471b3d6a0e from qemu
2018-04-26 09:25:09 -04:00
Aaron Lindsay
4ed7524444
target/arm: Fix bitmask for PMCCFILTR writes
It was shifted to the left one bit too few.

Backports commit ac57fd24cd864d42e7551f82266bc0930bd39547 from qemu
2018-04-26 09:23:04 -04:00
Aaron Lindsay
99a0be89a8
target/arm: Add pre-EL change hooks
Because the design of the PMU requires that the counter values be
converted between their delta and guest-visible forms for mode
filtering, an additional hook which occurs before the EL is changed is
necessary.

Backports commit b5c53d1b3886387874f8c8582b205aeb3e4c3df6 from qemu
2018-04-26 09:21:54 -04:00
Aaron Lindsay
8caf217d26
target/arm: Support multiple EL change hooks
Backports commit 08267487c99e8150382420936ab72c1e0ad74ce3 from qemu
2018-04-26 09:16:09 -04:00
Aaron Lindsay
dfe1f54920
target/arm: Fetch GICv3 state directly from CPUARMState
This eliminates the need for fetching it from el_change_hook_opaque, and
allows for supporting multiple el_change_hooks without having to hack
something together to find the registered opaque belonging to GICv3.

Backports commit d5a5e4c93dae0dc3feb402cf7ee78d846da1a7e1 from qemu
2018-04-26 09:10:32 -04:00
Aaron Lindsay
1228bcf45d
target/arm: Mask PMU register writes based on PMCR_EL0.N
This is in preparation for enabling counters other than PMCCNTR

Backports commit 7ece99b17e832065236c07a158dfac62619ef99b from qemu
2018-04-26 09:09:12 -04:00
Aaron Lindsay
e1d021ad74
target/arm: Treat PMCCNTR as alias of PMCCNTR_EL0
They share the same underlying state

Backports commit 169c893874977eee8303a6dad4a3f25c5464858f from qemu
2018-04-26 09:07:50 -04:00
Aaron Lindsay
e1bffbf7df
target/arm: Check PMCNTEN for whether PMCCNTR is enabled
Backports commit ccbc0e338486b21cb0eb52e52cd309bbbe6a7507 from qemu
2018-04-26 09:07:02 -04:00
Peter Maydell
43e7478d3f
target/arm: Use v7m_stack_read() for reading the frame signature
In commit 95695effe8caa552b8f2 we changed the v7M/v8M stack
pop code to use a new v7m_stack_read() function that checks
whether the read should fail due to an MPU or bus abort.
We missed one call though, the one which reads the signature
word for the callee-saved register part of the frame.

Correct the omission.

Backports commit 4818bad98c8212fbbb0525d10761b6b65279ab92 from qemu
2018-04-26 09:02:11 -04:00
Peter Maydell
bec50934ad
target/arm: Remove stale TODO comment
Remove a stale TODO comment -- we have now made the arm_ldl_ptw()
and arm_ldq_ptw() functions propagate physical memory read errors
out to their callers.

Backports commit 145772707fe80395b87c244ccf5699a756f1946b from qemu
2018-04-26 09:00:08 -04:00
Richard Henderson
76e343ef55
fpu: Bound increment for scalbn
Without bounding the increment, we can overflow exp either here
in scalbn_decomposed or when adding the bias in round_canonical.
This can result in e.g. underflowing to 0 instead of overflowing
to infinity.

The old softfloat code did bound the increment.

Backports commit ce8d4082054519f2eaac39958edde502860a7fc6 from qemu
2018-04-18 09:21:03 -04:00
Alex Bennée
af6a0b7c14
fpu/softfloat: check for Inf / x or 0 / x before /0
The re-factoring of div_floats changed the order of checking meaning
an operation like -inf/0 erroneously raises the divbyzero flag.
IEEE-754 (2008) specifies this should only occur for operations on
finite operands.

We fix this by moving the check on the dividend being Inf/0 to before
the divisor is zero check.

Backports commit 9cb4e398c2f95c1e837fe9c570e124a55259f725 from qemu
2018-04-18 09:19:28 -04:00
Pavel Dovgalyuk
fe353764e9
m68k: fix exception stack frame for 68000
68000 CPUs do not save format in the exception stack frame.
This patch adds feature checking to prevent format saving for 68000.
m68k_ret() already includes this modification, this patch fixes
the exception processing function too.

Backports commit 000761dc0c97d70e7314db3e8f52783880325a22 from qemu
2018-04-16 13:49:56 -04:00
Alex Bennée
9517a002da
fpu/softfloat: raise float_invalid for NaN/Inf in round_to_int_and_pack
The re-factor broke the raising of INVALID when NaN/Inf is passed to
the float_to_int conversion functions. round_to_uint_and_pack got this
right for NaN but also missed out the Inf handling.

Fixes https://bugs.launchpad.net/qemu/+bug/1759264

Backports commit 801bc56336a127d9b351b3a2cc0336e4d0cb2686 from qemu
2018-04-16 13:48:17 -04:00
Emilio G. Cota
74b7fe484c
softfloat: fix {min, max}nummag for same-abs-value inputs
Before 8936006 ("fpu/softfloat: re-factor minmax", 2018-02-21),
we used to return +Zero for maxnummag(-Zero,+Zero); after that
commit, we return -Zero.

Fix it by making {min,max}nummag consistent with {min,max}num,
deferring to the latter when the absolute value of the operands
is the same.

With this fix we now pass fp-test.

Backports commit 6245327a367292b354489c54e965646823023919 from qemu
2018-04-16 13:46:29 -04:00
Peter Maydell
778d0c47df
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"
^
/home/pm215/qemu/include/qemu/compiler.h:98:30: note: in expansion of macro ‘QEMU_BUILD_BUG_MSG’
^
/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)

Backports commit 161dfd1e7fad1203840c0390f235030eba3fd23c from qemu
2018-04-16 13:44:39 -04:00
Pavel Dovgalyuk
b4bf3c776b
icount: fix cpu_restore_state_from_tb for non-tb-exit cases
In icount mode, instructions that access io memory spaces in the middle
of the translation block invoke TB recompilation. After recompilation,
such instructions become last in the TB and are allowed to access io
memory spaces.

When the code includes instruction like i386 'xchg eax, 0xffffd080'
which accesses APIC, QEMU goes into an infinite loop of the recompilation.

This instruction includes two memory accesses - one read and one write.
After the first access, APIC calls cpu_report_tpr_access, which restores
the CPU state to get the current eip. But cpu_restore_state_from_tb
resets the cpu->can_do_io flag which makes the second memory access invalid.
Therefore the second memory access causes a recompilation of the block.
Then these operations repeat again and again.

This patch moves resetting cpu->can_do_io flag from
cpu_restore_state_from_tb to cpu_loop_exit* functions.

It also adds a parameter for cpu_restore_state which controls restoring
icount. There is no need to restore icount when we only query CPU state
without breaking the TB. Restoring it in such cases leads to the
incorrect flow of the virtual time.

In most cases new parameter is true (icount should be recalculated).
But there are two cases in i386 and openrisc when the CPU state is only
queried without the need to break the TB. This patch fixes both of
these cases.

Backports commit afd46fcad2dceffda35c0586f5723c127b6e09d8 from qemu
2018-04-11 20:05:40 -04:00
Alex Bennée
4074587775
accel/tcg/translate-all: expand cpu_restore_state addr check
We are still seeing signals during translation time when we walk over
a page protection boundary. This expands the check to ensure the host
PC is inside the code generation buffer. The original suggestion was
to check versus tcg_ctx.code_gen_ptr but as we now segment the
translation buffer we have to settle for just a general check for
being inside.

I've also fixed up the declaration to make it clear it can deal with
invalid addresses. A later patch will fix up the call sites.

Backports commit d25f2a72272b9ffe0d06710d6217d1169bc2cc7d from qemu
2018-04-11 19:53:57 -04:00
Richard Henderson
bc8e85a1c5
fpu: Fix rounding mode for floatN_to_uintM_round_to_zero
We incorrectly passed in the current rounding mode
instead of float_round_to_zero.

Backports commit bd49e6027cbc207c87633c7add3ebd7d3474cd35 from qemu
2018-04-11 19:36:12 -04:00
Richard Henderson
49476ebf5e
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.

Backports commit 9743cd5736263e90d312b2c33bd739ffe1eae70d from qemu
2018-04-11 19:34:18 -04:00
Peter Maydell
8f26d8e556
target/arm: Report unsupported MPU region sizes more clearly
Currently our PMSAv7 and ARMv7M MPU implementation cannot handle
MPU region sizes smaller than our TARGET_PAGE_SIZE. However we
report that in a slightly confusing way:

DRSR[3]: No support for MPU (sub)region alignment of 9 bits. Minimum is 10

The problem is not the alignment of the region, but its size;
tweak the error message to say so:
DRSR[3]: No support for MPU (sub)region size of 512 bytes. Minimum is 1024.

Backports commit 8aec759b45fa6986c0b159cb27353d6abb0d5d73 from qemu
2018-04-11 19:32:16 -04:00
Onur Sahin
18e6b1549f
target-arm: Check undefined opcodes for SWP in A32 decoder
Make sure we are not treating architecturally Undefined instructions
as a SWP, by verifying the opcodes as per section A8.8.229 of ARMv7-A
specification. Bits [21:20] must be zero for this to be a SWP or SWPB.
We also choose to UNDEF for the architecturally UNPREDICTABLE case of
bits [11:8] not being zero.

Backports commit c4869ca630a57f4269bb932ec7f719cef5bc79b8 from qemu
2018-04-11 19:30:50 -04:00
Eugene Minibaev
87180dd231
Add missing bit for SSE instr in VEX decoding
The 2-byte VEX prefix imples a leading 0Fh opcode byte.

Backports commit e0014d4b3a955cfd8d517674703bfa87f340290a from qemu
2018-04-10 08:49:15 -04:00
Alexandro Sanchez Bach
4a1de154ef
target/i386: Fix andn instruction
In commit 7073fbada733c8d10992f00772c9b9299d740e9b, the `andn` instruction
was implemented via `tcg_gen_andc` but passes the operands in the wrong
order:
- X86 defines `andn dest,src1,src2` as: dest = ~src1 & src2
- TCG defines `andc dest,src1,src2` as: dest = src1 & ~src2

The following simple test shows the issue:

int main(void) {
uint32_t ret = 0;
__asm (
"mov $0xFF00, %%ecx\n"
"mov $0x0F0F, %%eax\n"
"andn %%ecx, %%eax, %%ecx\n"
"mov %%ecx, %0\n"
: "=r" (ret));
printf("%08X\n", ret);
return 0;
}

This patch fixes the problem by simply swapping the order of the two last
arguments in `tcg_gen_andc_tl`.

Backports commit 5cd10051c2e02b7a86eae49919d6c65a87dbea46 from qemu
2018-04-10 08:48:05 -04:00
Richard Henderson
e0903adacf
tcg: Fix out-of-line generic vector compares
A mistake in the type passed to sizeof, that happens to work
when the out-of-line fallback itself is using host vectors,
but fails when using only the base types.

Backports commit 6cb1d3b8517572031a22675280ec642972cdb395 from qemu
2018-04-07 23:05:19 -04:00
Laurent Vivier
b25de410a9
tcg: fix 16-byte vector operations detection
configure tries to detect if the compiler
supports 16-byte vector operations.

As stated in the comment of the detection
program, there is a problem with the system
compiler on GCC on Centos 7.

This program doesn't actually detect the problem
with GCC on RHEL7 on PPC64LE (Red Hat 4.8.5-28).

This patch updates the test to look more like
it is in QEMU helpers, and now detects the problem.

The error reported is:

CC ppc64-softmmu/accel/tcg/tcg-runtime-gvec.o
..//accel/tcg/tcg-runtime-gvec.c: In function ‘helper_gvec_shl8i’:
../accel/tcg/tcg-runtime-gvec.c:558:26: internal compiler error: in emit_move_insn, at expr.c:3495
*(vec8 *)(d + i) = *(vec8 *)(a + i) << shift;
^
Fixes: db43267 "tcg: Add generic vector expanders"

Backports commit 74912f6dad207bfdd5bfa8c6012c364ea9405fc7 from qemu
2018-04-07 23:03:11 -04:00
Richard Henderson
c2e46f2931
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).

Backports commit f2f1dde75160cac6ede330f3db50dc817d01a2d6 from qemu
2018-03-29 14:03:00 -04:00
Peter Maydell
92b5817d92
target/arm: Always set FAR to a known unknown value for debug exceptions
For debug exceptions due to breakpoints or the BKPT instruction which
are taken to AArch32, the Fault Address Register is architecturally
UNKNOWN. We were using that as license to simply not set
env->exception.vaddress, but this isn't correct, because it will
expose to the guest whatever old value was in that field when
arm_cpu_do_interrupt_aarch32() writes it to the guest IFSR. That old
value might be a FAR for a previous guest EL2 or secure exception, in
which case we shouldn't show it to an EL1 or non-secure exception
handler. It might also be a non-deterministic value, which is bad
for record-and-replay.

Clear env->exception.vaddress before taking breakpoint debug
exceptions, to avoid this minor information leak.

Backports commit 548f514cf89dd9ab39c0cb4c063097bccf141fdd from qemu
2018-03-25 16:38:14 -04:00
Peter Maydell
d6eafe5982
target/arm: Set FSR for BKPT, BRK when raising exception
Now that we have a helper function specifically for the BRK and
BKPT instructions, we can set the exception.fsr there rather
than in arm_cpu_do_interrupt_aarch32(). This allows us to
use our new arm_debug_exception_fsr() helper.

In particular this fixes a bug where we were hardcoding the
short-form IFSR value, which is wrong if the target exception
level has LPAE enabled.

Fixes: https://bugs.launchpad.net/qemu/+bug/1756927

Backports commit 62b94f31d0df75187bb00684fc29e8639eacc0c5 from qemu
2018-03-25 16:36:51 -04:00
Peter Maydell
16c0c2d253
target/arm: Factor out code to calculate FSR for debug exceptions
When a debug exception is taken to AArch32, it appears as a Prefetch
Abort, and the Instruction Fault Status Register (IFSR) must be set.
The IFSR has two possible formats, depending on whether LPAE is in
use. Factor out the code in arm_debug_excp_handler() which picks
an FSR value into its own utility function, update it to use
arm_fi_to_lfsc() and arm_fi_to_sfsc() rather than hard-coded constants,
and use the correct condition to select long or short format.

In particular this fixes a bug where we could select the short
format because we're at EL0 and the EL1 translation regime is
not using LPAE, but then route the debug exception to EL2 because
of MDCR_EL2.TDE and hand EL2 the wrong format FSR.

Backports commit 81621d9ab8a0f07956e67850b15eebf6d6992eec from qemu
2018-03-25 16:35:27 -04:00
Peter Maydell
7a3ee5fd95
target/arm: Honour MDCR_EL2.TDE when routing exceptions due to BKPT/BRK
The MDCR_EL2.TDE bit allows the exception level targeted by debug
exceptions to be set to EL2 for code executing at EL0. We handle
this in the arm_debug_target_el() function, but this is only used for
hardware breakpoint and watchpoint exceptions, not for the exception
generated when the guest executes an AArch32 BKPT or AArch64 BRK
instruction. We don't have enough information for a translate-time
equivalent of arm_debug_target_el(), so instead make BKPT and BRK
call a special purpose helper which can do the routing, rather than
the generic exception_with_syndrome helper.

Backports commit c900a2e62dd6dde11c8f5249b638caad05bb15be from qemu
2018-03-25 16:33:04 -04:00
Victor Kamensky
ecd2ecb590
arm/translate-a64: treat DISAS_UPDATE as variant of DISAS_EXIT
In OE project 4.15 linux kernel boot hang was observed under
single cpu aarch64 qemu. Kernel code was in a loop waiting for
vtimer arrival, spinning in TC generated blocks, while interrupt
was pending unprocessed. This happened because when qemu tried to
handle vtimer interrupt target had interrupts disabled, as
result flag indicating TCG exit, cpu->icount_decr.u16.high,
was cleared but arm_cpu_exec_interrupt function did not call
arm_cpu_do_interrupt to process interrupt. Later when target
reenabled interrupts, it happened without exit into main loop, so
following code that waited for result of interrupt execution
run in infinite loop.

To solve the problem instructions that operate on CPU sys state
(i.e enable/disable interrupt), and marked as DISAS_UPDATE,
should be considered as DISAS_EXIT variant, and should be
forced to exit back to main loop so qemu will have a chance
processing pending CPU state updates, including pending
interrupts.

This change brings consistency with how DISAS_UPDATE is treated
in aarch32 case.

Backports commit a75a52d62418dafe462be4fe30485501d1010bb9 from qemu
2018-03-25 16:27:27 -04:00
Lioncash
1c4c5a9403
softfloat-specialize: Perform comparison pass with qemu
Ensures code and formatting are similar
2018-03-21 13:27:59 -04:00
Lioncash
ba874ef639
softfloat: Perform comparison pass with qemu
Ensure that the code and formatting are similar.
2018-03-21 13:26:09 -04:00
Lioncash
2dc6364de9
object: Add assert to ensure uc is not null 2018-03-21 12:47:44 -04:00
Lioncash
a0c39b4996
translate-all: Fix missing #elif condition in alloc_code_gen_buffer 2018-03-21 12:46:03 -04:00
Lioncash
b65302b377
qemu-thread-win32: Prevent null pointer dereference in win32_start_routine 2018-03-21 12:42:44 -04:00
Lioncash
43fe0c8a1c
memory: Protect against use-after-free 2018-03-21 09:40:33 -04:00
Bharata B Rao
309b85548f
cpu: Convert cpu_index into a bitmap
Currently CPUState::cpu_index is monotonically increasing and a newly
created CPU always gets the next higher index. The next available
index is calculated by counting the existing number of CPUs. This is
fine as long as we only add CPUs, but there are architectures which
are starting to support CPU removal, too. For an architecture like PowerPC
which derives its CPU identifier (device tree ID) from cpu_index, the
existing logic of generating cpu_index values causes problems.

With the currently proposed method of handling vCPU removal by parking
the vCPU fd in QEMU
(Ref: http://lists.gnu.org/archive/html/qemu-devel/2015-02/msg02604.html),
generating cpu_index this way will not work for PowerPC.

This patch changes the way cpu_index is handed out by maintaining
a bit map of the CPUs that tracks both addition and removal of CPUs.

The CPU bitmap allocation logic is part of cpu_exec_init(), which is
called by instance_init routines of various CPU targets. Newly added
cpu_exec_exit() API handles the deallocation part and this routine is
called from generic CPU instance_finalize.

Note: This new CPU enumeration is for !CONFIG_USER_ONLY only.
CONFIG_USER_ONLY continues to have the old enumeration logic.

Backports commit b7bca7333411bd19c449147e8202ae6b0e4a8e09 from qemu
2018-03-21 08:06:07 -04:00
Bharata B Rao
e373c001fa
cpu: Add Error argument to cpu_exec_init()
Add an Error argument to cpu_exec_init() to let users collect the
error. This is in preparation to change the CPU enumeration logic
in cpu_exec_init(). With the new enumeration logic, cpu_exec_init()
can fail if cpu_index values corresponding to max_cpus have already
been handed out.

Since all current callers of cpu_exec_init() are from instance_init,
use error_abort Error argument to abort in case of an error.

Backports commit 5a790cc4b942e651fec7edc597c19b637fad5a76 from qemu
2018-03-21 07:50:33 -04:00