Consistently access u16.high with atomics to avoid
undefined behaviour in MTTCG.
Note that icount_decr.u16.low is only used in icount mode,
so regular accesses to it are OK.
Backports part of commit fff42f183ea4c3967405d4c1dce6d97dae4d64c8 from
qemu
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
both do nothing as for the first all callers
parse_cpu_model() and qmp_query_cpu_model_()
should provide non NULL value, so just abort if it's not so.
While at it drop cpu_common_class_by_name() which is not need
any more as every target has CPUClass::class_by_name callback
by now, though abort in case a new arch will forget to define one.
Backports commit 99193d8f2ef594648ad67cc3d007b0e4fb2f8cf8 from qemu
With all targets defining CPU_RESOLVING_TYPE, refactor
cpu_parse_cpu_model(type, cpu_model) to parse_cpu_model(cpu_model)
so that callers won't have to know internal resolving cpu
type. Place it in exec.c so it could be called from both
target independed vl.c and *-user/main.c.
That allows us to stop abusing cpu type from
MachineClass::default_cpu_type
as resolver class in vl.c which were confusing part of
cpu_parse_cpu_model().
Also with new parse_cpu_model(), the last users of cpu_init()
in null-machine.c and bsd/linux-user targets could be switched
to cpu_create() API and cpu_init() API will be removed by
follow up patch.
With no longer users left remove MachineState::cpu_model field,
new code should use MachineState::cpu_type instead and
leave cpu_model parsing to generic code in vl.c.
Backports commit 2278b93941d42c30e2950d4b8dff4943d064e7de from qemu
it would allow to reuse feature parsing part in various machines
that have CPU features instead of re-implementing the same feature
parsing each time.
Backports commit 3c72234c98004a01d79a24f78b07053cfebd0f22 from qemu
since commit ( 9262685 cpu: Factor out cpu_generic_init() )
features parsed by it were truncated only to the 1st feature
after CPU name due to fact that
featurestr = strtok(NULL, ",");
cc->parse_features(cpu, featurestr, &err);
would extract exactly one feature and parse_features() callback
would parse it and only it leaving the rest of features ignored.
Reuse approach from x86 custom impl. i.e. replace strtok() token
parsing with g_strsplit(), which would split feature string in
2 parts name and features list and pass the later to
parse_features() callback.
Backports commit 3e2cf187eb3954fc406f81247a3fa598437ce1de from qemu
Considering that features are converted to global properties and
global properties are automatically applied to every new instance
of created CPU (at object_new() time), there is no point in
parsing cpu_model string every time a CPU created. So move
parsing outside CPU creation loop and do it only once.
Parsing also should be done before any CPU is created so that
features would affect the first CPU a well.
Backports commit 6aff24c6a61c6fec31e555c7748ba6085b7b2c06 from qemu
Currently CPUClass->parse_features() is used to parse -cpu
features string and set properties on created CPU instances.
But considering that features specified by -cpu apply to every
created CPU instance, it doesn't make sense to parse the same
features string for every CPU created. It also makes every target
that cares about parsing features string explicitly call
CPUClass->parse_features() parser, which gets in a way if we
consider using generic device_add for CPU hotplug as device_add
has not a clue about CPU specific hooks.
Turns out we can use global properties mechanism to set
properties on every created CPU instance for a given type. That
way it's possible to convert CPU features into a set of global
properties for CPU type specified by -cpu cpu_model and common
Device.device_post_init() will apply them to CPU of given type
automatically regardless whether it's manually created CPU or CPU
created with help of device_add.
Backports commits 62a48a2a5798425997152dea3fc48708f9116c04 and
f313369fdb78f849ecbbd8e5d88f01ddf38786c8 from qemu
Define a new MachineClass field ignore_memory_transaction_failures.
If this is flag is true then the CPU will ignore memory transaction
failures which should cause the CPU to take an exception due to an
access to an unassigned physical address; the transaction will
instead return zero (for a read) or be ignored (for a write). This
should be set only by legacy board models which rely on the old
RAZ/WI behaviour for handling devices that QEMU does not yet model.
New board models should instead use "unimplemented-device" for all
memory ranges where the guest will attempt to probe for a device that
QEMU doesn't implement and a stub device is required.
We need this for ARM boards, where we're about to implement support for
generating external aborts on memory transaction failures. Too many
of our legacy board models rely on the RAZ/WI behaviour and we
would break currently working guests when their "probe for device"
code provoked an external abort rather than a RAZ.
Backports commit ed860129acd3fcd0b1e47884e810212aaca4d21b from qemu
The helper can be used for CPU object lookup using the CPU's
arch-specific ID (the one returned by CPUClass::get_arch_id()).
Backports commit 5ce46cb34eecec0bc94a4b1394763f9a1bbe20c3 from qemu
This reverts commit e2a7f28693aea7e194ec1435697ec4feb24f8a6f.
This was not supposed to go upstream yet. Reverting.
Backports commit cde0a63ad721dbb538419a00f9405587680be436 from qemu
When emulating various SSE4.1 instructions such as pinsrd, the address
of a memory operand is computed without allowing for the 8-bit
immediate operand located after the memory operand, meaning that the
memory operand uses the wrong address in the case where it is
rip-relative. This patch adds the required rip_offset setting for
those instructions, so fixing some GCC test failures (13 in the gcc
testsuite in my GCC 6-based testing) when testing with a default CPU
setting enabling those instructions.
Backports commit ab6ab3e9972a49a359f59895a88bed311472ca97 from qemu
Commit 1f5c00cfdb8114c ("qom/cpu: move tlb_flush to cpu_common_reset")
moved the call to tlb_flush() from the target-specific reset handlers
into the common code qom/cpu.c file, and protected the call with
"#ifdef CONFIG_SOFTMMU" to avoid that it is called for linux-user
only targets. But since qom/cpu.c is common code, CONFIG_SOFTMMU is
*never* defined here, so the tlb_flush() was simply never executed
anymore. Fix it by introducing a wrapper for tlb_flush() in a file
that is re-compiled for each target, i.e. in translate-all.c.
Backports commit 2cd53943115be5118b5b2d4b80ee0a39c94c4f73 from qemu
Some code paths can lead to atomic accesses racing with memset()
on cpu->tb_jmp_cache, which can result in torn reads/writes
and is undefined behaviour in C11.
These torn accesses are unlikely to show up as bugs, but from code
inspection they seem possible. For example, tb_phys_invalidate does:
/* remove the TB from the hash list */
h = tb_jmp_cache_hash_func(tb->pc);
CPU_FOREACH(cpu) {
if (atomic_read(&cpu->tb_jmp_cache[h]) == tb) {
atomic_set(&cpu->tb_jmp_cache[h], NULL);
}
}
Here atomic_set might race with a concurrent memset (such as the
ones scheduled via "unsafe" async work, e.g. tlb_flush_page) and
therefore we might end up with a torn pointer (or who knows what,
because we are under undefined behaviour).
This patch converts parallel accesses to cpu->tb_jmp_cache to use
atomic primitives, thereby bringing these accesses back to defined
behaviour. The price to pay is to potentially execute more instructions
when clearing cpu->tb_jmp_cache, but given how infrequently they happen
and the small size of the cache, the performance impact I have measured
is within noise range when booting debian-arm.
Note that under "safe async" work (e.g. do_tb_flush) we could use memset
because no other vcpus are running. However I'm keeping these accesses
atomic as well to keep things simple and to avoid confusing analysis
tools such as ThreadSanitizer.
Backports commit f3ced3c59287dabc253f83f0c70aa4934470c15e from qemu
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
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
Both the cpu->tb_jmp_cache and SoftMMU TLB structures are only used
when running TCG code so we might as well skip them for anything else.
Backports commit ba7d3d1858c257e39b47f7f12fa2016ffd960b11 from qemu
It is a common thing amongst the various cpu reset functions want to
flush the SoftMMU's TLB entries. This is done either by calling
tlb_flush directly or by way of a general memset of the CPU
structure (sometimes both).
This moves the tlb_flush call to the common reset function and
additionally ensures it is only done for the CONFIG_SOFTMMU case and
when tcg is enabled.
In some target cases we add an empty end_of_reset_fields structure to the
target vCPU structure so have a clear end point for any memset which
is resetting value in the structure before CPU_COMMON (where the TLB
structures are).
While this is a nice clean-up in general it is also a precursor for
changes coming to cputlb for MTTCG where the clearing of entries
can't be done arbitrarily across vCPUs. Currently the cpu_reset
function is usually called from the context of another vCPU as the
architectural power up sequence is run. By using the cputlb API
functions we can ensure the right behaviour in the future.
Backports commit 1f5c00cfdb8114c1e3a13426588ceb64f82c9ddb from qemu
ThreadSanitizer picks up potential races although we already use
barriers to ensure things are in the correct order when processing exit
requests. For true C11 defined behaviour across threads we need to use
relaxed atomic_set/atomic_read semantics to reassure tsan.
Backports commit 027d9a7d2911e993cdcbd21c7c35d1dd058f05bb from qemu
The ThreadSanitizer rightly complains that something initialised with a
normal access is later updated and read atomically.
Backports commit ce7cf6a973f4b614162b9518954d441fa5e32fc6 from qemu
This field was used for telling cpu_interrupt() to unlink a chain of TBs
being executed when it worked that way. Now, cpu_interrupt() don't do
this anymore. So we don't need this field anymore.
Backports commit 3213525f8ab48742db09dab18cb9ae6f36a6c921 from qemu
Commit 57cb38b included qapi/error.h into qemu/osdep.h to get the
Error typedef. Since then, we've moved to include qemu/osdep.h
everywhere. Its file comment explains: "To avoid getting into
possible circular include dependencies, this file should not include
any other QEMU headers, with the exceptions of config-host.h,
compiler.h, os-posix.h and os-win32.h, all of which are doing a
similar job to this file and are under similar constraints."
qapi/error.h doesn't do a similar job, and it doesn't adhere to
similar constraints: it includes qapi-types.h. That's in excess of
100KiB of crap most .c files don't actually need.
Add the typedef to qemu/typedefs.h, and include that instead of
qapi/error.h. Include qapi/error.h in .c files that need it and don't
get it now. Include qapi-types.h in qom/object.h for uint16List.
Update scripts/clean-includes accordingly. Update it further to match
reality: replace config.h by config-target.h, add sysemu/os-posix.h,
sysemu/os-win32.h. Update the list of includes in the qemu/osdep.h
comment quoted above similarly.
This reduces the number of objects depending on qapi/error.h from "all
of them" to less than a third. Unfortunately, the number depending on
qapi-types.h shrinks only a little. More work is needed for that one.
Backports commit da34e65cb4025728566d6504a99916f6e7e1dd6a from qemu
When QEMU watchpoint matches, that is not definitely an architectural
watchpoint match yet. If it is a stop-before-access watchpoint then that
is hardly possible to ignore it after throwing a TCG exception.
A special callback is introduced to check for architectural watchpoint
match before raising a TCG exception.
Backports commit 568496c0c0f1863a4bc18539962cd8d81baa4e30 from qemu
Clean up includes so that osdep.h is included first and headers
which it implies are not included manually.
This commit was created with scripts/clean-includes.
Backports commit 9bbc853bd4fc6e4cbdbfc8d52eab0730d3ba94ba from qemu
CPUState::crash_occurred field inside CPUState marks
that guest crash occurred. This value is added into
cpu common migration subsection.
Backports commit bac05aa9a77af1ca7972c8dc07560f4daa7c2dfc from qemu
