For Arm, we need 3 cases: (1) the alignment required when accessing
Normal memory, (2) the alignment required when accessing Device memory,
and (3) the atomicity of the access.
When we added TLB_CHECK_ALIGNED, we assumed that cases 2 and 3 were
identical, and thus used memop_atomicity_bits for TLB_CHECK_ALIGNED.
This is incorrect for multiple reasons, including that the atomicity
of the access is adjusted depending on whether or not we are executing
within a serial context.
For Arm, what is true is that there is an underlying alignment
requirement of the access, and for that access Normal memory
will support unalignement.
Introduce MO_ALIGN_TLB_ONLY to indicate that the alignment
specified in MO_AMASK only applies when the TLB entry has
TLB_CHECK_ALIGNED set; otherwise no alignment required.
Introduce memop_tlb_alignment_bits with an additional bool
argument that specifies whether TLB_CHECK_ALIGNED is set.
All other usage of memop_alignment_bits assumes it is not.
Remove memop_atomicity_bits as unused; it didn't properly
support MO_ATOM_SUBWORD anyway.
Update target/arm finalize_memop_atom to set MO_ALIGN_TLB_ONLY
when strict alignment isn't otherwise required.
Suggested-by: Peter Maydell <peter.maydell@linaro.org>
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/3171
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
For strict alignment targets we registered cpu_pointer_wrap_notreached,
but generic code used it before recognizing the alignment exception.
Hoist the first page lookup, so that the alignment exception happens first.
Cc: qemu-stable@nongnu.org
Buglink: https://bugs.debian.org/1112285
Fixes: a4027ed7d4 ("target: Use cpu_pointer_wrap_notreached for strict align targets")
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Expand the interface of page_set_flags to separate the
set of flags to be set and the set of flags to be cleared.
This allows us to replace PAGE_RESET with the PAGE_VALID
bit within clear_flags.
Replace PAGE_TARGET_STICKY with TARGET_PAGE_NOTSTICKY;
aarch64-linux-user is the only user.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
If we only have one vcpu, or within cpu_exec_step_atomic,
we needn't jump all the way back out to the cpu loop to
empty the code gen buffer.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Rename the function and remove the path which
performs the flush immediately.
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
We need not call tb_flush once per cpu, only once per vmload.
By moving the call from cpu_common_post_load to a tcg-specific
vm_change_state_handler, we do even better than that: we only
flush when called from HMP triggered loadvm, when we had old
state to flush.
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Expose a routine to be called when no cpus are running.
Simplify the do_tb_flush run_on_cpu callback, because
that is explicitly called with start_exclusive; there
is no need for the mmap_lock as well.
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
When we remove dest from orig's links, we lose the link
that we rely on later to reset links. This can lead to
failure to release from spinlock with self-modifying code.
Cc: qemu-stable@nongnu.org
Reported-by: 李威威 <liweiwei@kubuds.cn>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Anton Johansson <anjo@rev.ng>
Tested-by: Anton Johansson <anjo@rev.ng>
Whenever user-mode emulation needs to go all the way out of the cpu
exec loop, it uses cpu_exit(), which already sets cpu->exit_request.
Therefore, there is no need for tcg_kick_vcpu_thread() to set
cpu->exit_request again outside system emulation.
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
There is no reason for some accelerators to use qemu_process_cpu_events_common
(which is separated from qemu_process_cpu_events() specifically for round
robin TCG). They can also check for events directly on the first pass through
the loop, instead of setting cpu->exit_request to true.
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Make the code common to all accelerators: after seeing cpu->exit_request
set to true, accelerator code needs to reach qemu_process_cpu_events_common().
So for the common cases where they use qemu_process_cpu_events(), go ahead and
clear it in there. Note that the cheap qatomic_set() is enough because
at this point the thread has taken the BQL; qatomic_set_mb() is not needed.
In particular, this is the ordering of the communication between
I/O and vCPU threads is always the same.
In the I/O thread:
(a) store other memory locations that will be checked if cpu->exit_request
or cpu->interrupt_request is 1 (for example cpu->stop or cpu->work_list
for cpu->exit_request)
(b) cpu_exit(): store-release cpu->exit_request, or
(b) cpu_interrupt(): store-release cpu->interrupt_request
>>> at this point, cpu->halt_cond is broadcast and the BQL released
(c) do the accelerator-specific kick (e.g. write icount_decr for TCG,
pthread_kill for KVM, etc.)
In the vCPU thread instead the opposite order is respected:
(c) the accelerator's execution loop exits thanks to the kick
(b) then the inner execution loop checks cpu->interrupt_request
and cpu->exit_request. If needed cpu->interrupt_request is
converted into cpu->exit_request when work is needed outside
the execution loop.
(a) then the other memory locations are checked. Some may need to
be read under the BQL, but the vCPU thread may also take other
locks (e.g. for queued work items) or none at all.
qatomic_set_mb() would only be needed if the halt sleep was done
outside the BQL (though in that case, cpu->exit_request probably
would be replaced by a QemuEvent or something like that).
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Add a user-mode emulation version of the function. More will be
added later, for now it is just process_queued_cpu_work.
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
izzy2lost
Matt Borgerson
Philippe Mathieu-DaudéandRichard Henderson
Paolo Bonzini