clang's C11 atomic_fetch_*() functions only take a C11 atomic type
pointer argument. QEMU uses direct types (int, etc) and this causes a
compiler error when a QEMU code calls these functions in a source file
that also included <stdatomic.h> via a system header file:
$ CC=clang CXX=clang++ ./configure ... && make
../util/async.c:79:17: error: address argument to atomic operation must be a pointer to _Atomic type ('unsigned int *' invalid)
Avoid using atomic_*() names in QEMU's atomic.h since that namespace is
used by <stdatomic.h>. Prefix QEMU's APIs with 'q' so that atomic.h
and <stdatomic.h> can co-exist. I checked /usr/include on my machine and
searched GitHub for existing "qatomic_" users but there seem to be none.
This patch was generated using:
$ git grep -h -o '\<atomic\(64\)\?_[a-z0-9_]\+' include/qemu/atomic.h | \
sort -u >/tmp/changed_identifiers
$ for identifier in $(</tmp/changed_identifiers); do
sed -i "s%\<$identifier\>%q$identifier%g" \
$(git grep -I -l "\<$identifier\>")
done
I manually fixed line-wrap issues and misaligned rST tables.
Backports d73415a315471ac0b127ed3fad45c8ec5d711de1
commit 568496c0c0f1 ("cpu: Add callback to check architectural") and
commit 3826121d9298 ("target-arm: Implement checking of fired")
introduced an ARM-specific hack for cpu_check_watchpoint.
Make debug_check_watchpoint optional, and move it to tcg_ops.
Backports c73bdb35a91fb6b17c2c93b1ba381fc88a406f8d
commit 40612000599e ("arm: Correctly handle watchpoints for BE32 CPUs")
introduced this ARM-specific, TCG-specific hack to adjust the address,
before checking it with cpu_check_watchpoint.
Make adjust_watchpoint_address optional and move it to tcg_ops.
Backports 9ea9087bb4a86893e4ac6ff643837937dc9e5849
The TCG-specific CPU methods will be moved to a separate struct,
to make it easier to move accel-specific code outside generic CPU
code in the future. Start by moving tcg_initialize().
The new CPUClass.tcg_opts field may eventually become a pointer,
but keep it an embedded struct for now, to make code conversion
easier.
Backports e9e51b7154404efc9af8735ab87c658a9c434cfd
It turns out that some hosts have a default malloc alignment less
than that required for vectors.
We assume that, with compiler annotation on CPUArchState, that we
can properly align the vector portion of the guest state. Fix the
alignment of the allocation by using qemu_memalloc when required.
The raising of exceptions from check_watchpoint, buried inside
of the I/O subsystem, is fundamentally broken. We do not have
the helper return address with which we can unwind guest state.
Replace PHYS_SECTION_WATCH and io_mem_watch with TLB_WATCHPOINT.
Move the call to cpu_check_watchpoint into the cputlb helpers
where we do have the helper return address.
This allows watchpoints on RAM to bypass the full i/o access path.
Backports commit 50b107c5d617eaf93301cef20221312e7a986701 from qemu
This patch moves the define of target access alignment earlier from
target/foo/cpu.h to configure.
Suggested in Richard Henderson's reply to "[PATCH 1/4] tcg: TCGMemOp is now
accelerator independent MemOp"
Backports commit 52bf9771fdfce98e98cea36a17a18915be6f6b7f from qemu
Amusingly, we had already ignored the comment to keep this value
at the end of CPUState. This restores the minimum negative offset
from TCG_AREG0 for code generation.
For the couple of uses within qom/cpu.c, without NEED_CPU_H, add
a pointer from the CPUState object to the IcountDecr object within
CPUNegativeOffsetState.
Backports commit 5e1401969b25f676fee6b1c564441759cf967a43 from qemu
This hook will replace the (user-only mode specific) handle_mmu_fault
hook, and the (system mode specific) tlb_fill function.
The handle_mmu_fault hook was written as if there was a valid
way to recover from an mmu fault, and had 3 possible return states.
In reality, the only valid action is to raise an exception,
return to the main loop, and deliver the SIGSEGV to the guest.
Note that all of the current implementations of handle_mmu_fault
for guests which support linux-user do in fact only ever return 1,
which is the signal to return to the main loop.
Using the hook for system mode requires that all targets be converted,
so for now the hook is (optionally) used only from user-only mode.
Backports commit da6bbf8513e621a8fc2fd315d77318f36547474d from qemu
We were generating code during tb_invalidate_phys_page_range,
check_watchpoint, cpu_io_recompile, and (seemingly) discarding
the TB, assuming that it would magically be picked up during
the next iteration through the cpu_exec loop.
Instead, record the desired cflags in CPUState so that we request
the proper TB so that there is no more magic.
Backports commit 9b990ee5a3cc6aa38f81266fb0c6ef37a36c45b9 from qemu
Until now, the set_pc logic was unclear, which raised questions about
whether it should be used directly, applying a value to PC or adding
additional checks, for example, set the Thumb bit in Arm cpu. Let's set
the set_pc logic for “Configure the PC, as was done in the ELF file”
and implement synchronize_with_tb hook for preserving PC to cpu_tb_exec.
Backports commit 42f6ed919325413392bea247a1e6f135deb469cd from qemu
For TCG we want to distinguish which cluster a CPU is in, and
we need to do it quickly. Cache the cluster index in the CPUState
struct, by having the cluster object set cpu->cluster_index for
each CPU child when it is realized.
This means that board/SoC code must add all CPUs to the cluster
before realizing the cluster object. Regrettably QOM provides no
way to prevent adding children to a realized object and no way for
the parent to be notified when a new child is added to it, so
we don't have any way to enforce/assert this constraint; all
we can do is document it in a comment. We can at least put in a
check that the cluster contains at least one CPU, which should
catch the typical cases of "realized cluster too early" or
"forgot to parent the CPUs into it".
The restriction on how many clusters can exist in the system
is imposed by TCG code which will be added in a subsequent commit,
but the check to enforce it in cluster.c fits better in this one.
Backports relevant parts of commit 7ea7b9ad532e59c3efbcabff0e3484f4df06104c 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
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
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
Move vcpu's associated numa_node field out of generic CPUState
into inherited classes that actually care about cpu<->numa mapping,
i.e: ARMCPU, PowerPCCPU, X86CPU.
Backports relevant parts of commit 15f8b14228b856850df3fa5ba999ad96521f2208 from qemu
Unify half a dozen copies of very similar code (the only difference being
whether comparisons were case-sensitive) and use it also in Tricore,
which did not do any sorting of CPU model names.
Backports commit 47c66009ab793241e8210b3018c77a9ce9506aa8 from qemu
Now all TYPE_MACHINE subclasses use MACHINE_TYPE_NAME to generate the
class name. So instead of requiring each subclass to set
MachineClass::name manually, we can now set it automatically at the
TYPE_MACHINE class_base_init() function.
Backports commit 98cec76a7076c4a38e16f1a9de170a7942b3be54 from qemu
Move qapi-schema.json to qapi/, so it's next to its modules, and all
files get generated to qapi/, not just the ones generated for modules.
Consistently name the generated files qapi-MODULE.EXT:
qmp-commands.[ch] become qapi-commands.[ch], qapi-event.[ch] become
qapi-events.[ch], and qmp-introspect.[ch] become qapi-introspect.[ch].
This gets rid of the temporary hacks in scripts/qapi/commands.py,
scripts/qapi/events.py, and scripts/qapi/common.py.
Backports commit eb815e248f50cde9ab86eddd57eca5019b71ca78 from qemu
In my "build everything" tree, a change to the types in
qapi-schema.json triggers a recompile of about 4800 out of 5100
objects.
The previous commit split up qmp-commands.h, qmp-event.h, qmp-visit.h,
qapi-types.h. Each of these headers still includes all its shards.
Reduce compile time by including just the shards we actually need.
To illustrate the benefits: adding a type to qapi/migration.json now
recompiles some 2300 instead of 4800 objects. The next commit will
improve it further.
Backports commit 9af2398977a78d37bf184d6ff6bd04c72bfbf006 from qemu
The MC68040 MMU provides the size of the access that
triggers the page fault.
This size is set in the Special Status Word which
is written in the stack frame of the access fault
exception.
So we need the size in m68k_cpu_unassigned_access() and
m68k_cpu_handle_mmu_fault().
To be able to do that, this patch modifies the prototype of
handle_mmu_fault handler, tlb_fill() and probe_write().
do_unassigned_access() already includes a size parameter.
This patch also updates handle_mmu_fault handlers and
tlb_fill() of all targets (only parameter, no code change).
Backports commit 98670d47cd8d63a529ff230fd39ddaa186156f8c from qemu
DEFINE_TYPES() will help to simplify following routine patterns:
static void foo_register_types(void)
{
type_register_static(&foo1_type_info);
type_register_static(&foo2_type_info);
...
}
type_init(foo_register_types)
or
static void foo_register_types(void)
{
int i;
for (i = 0; i < ARRAY_SIZE(type_infos); i++) {
type_register_static(&type_infos[i]);
}
}
type_init(foo_register_types)
with a single line
DEFINE_TYPES(type_infos)
where types have static definition which could be consolidated in
a single array of TypeInfo structures.
It saves us ~6-10LOC per use case and would help to replace
imperative foo_register_types() there with declarative style of
type registration.
Backports commit 38b5d79b2e8cf6085324066d84e8bb3b3bbe8548 from qemu
it will help to remove code duplication of registration
static types in places that have open coded loop to
perform batch type registering.
Backports commit aa04c9d20704fa5b9ab239d5111adbcce5f49808 from qemu
We have object_get_objects_root() to keep user created objects, however
no place for objects that will be used internally. Create such a
container for internal objects.
Backports commit 7c47c4ead75d0b733ee8f2f51fd1de0644cc1308 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
Currently we have a rather half-baked setup for allowing CPUs to
generate exceptions on accesses to invalid memory: the CPU has a
cpu_unassigned_access() hook which the memory system calls in
unassigned_mem_write() and unassigned_mem_read() if the current_cpu
pointer is non-NULL. This was originally designed before we
implemented the MemTxResult type that allows memory operations to
report a success or failure code, which is why the hook is called
right at the bottom of the memory system. The major problem with
this is that it means that the hook can be called even when the
access was not actually done by the CPU: for instance if the CPU
writes to a DMA engine register which causes the DMA engine to begin
a transaction which has been set up by the guest to operate on
invalid memory then this will casue the CPU to take an exception
incorrectly. Another minor problem is that currently if a device
returns a transaction error then this won't turn into a CPU exception
at all.
The right way to do this is to have allow the CPU to respond
to memory system transaction failures at the point where the
CPU specific code calls into the memory system.
Define a new QOM CPU method and utility function
cpu_transaction_failed() which is called in these cases.
The functionality here overlaps with the existing
cpu_unassigned_access() because individual target CPUs will
need some work to convert them to the new system. When this
transition is complete we can remove the old cpu_unassigned_access()
code.
Backports commit 0dff0939f6fc6a7abd966d4295f06a06d7a01df9 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
link's check callback is supposed to verify/permit setting it,
however currently nothing restricts it from misusing it
and modifying target object from within.
Make sure that readonly semantics are checked by compiler
to prevent callback's misuse.
Backports commit 8f5d58ef2c92d7b82d9a6eeefd7c8854a183ba4a 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
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
