Currently there are only two places that require we reset this
value before exiting to the main loop, but that will change.
Reviewed-by: Warner Losh <imp@bsdimp.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Currently the change in cpu_tb_exec is masked by the debug exception
being raised by the translators. But this allows us to remove that code.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Commit 372579427a ("tcg: enable thread-per-vCPU") added the following
comment describing EXCP_HALTED in qemu_tcg_cpu_thread_fn():
case EXCP_HALTED:
/* during start-up the vCPU is reset and the thread is
* kicked several times. If we don't ensure we go back
* to sleep in the halted state we won't cleanly
* start-up when the vCPU is enabled.
*
* cpu->halted should ensure we sleep in wait_io_event
*/
g_assert(cpu->halted);
break;
qemu_wait_io_event() is sysemu-specific, so we can restrict the
cpu_handle_halt() call in cpu_exec() to system emulation.
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20210912172731.789788-2-f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
All targets call TCGCPUOps::cpu_exec_interrupt() from sysemu code.
Move its declaration to restrict it to system emulation.
Extend the code guarded.
Restrict the static inlined need_replay_interrupt() method to
avoid a "defined but not used" warning.
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20210911165434.531552-24-f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
do_interrupt() is sysemu specific. However due to some X86
specific hack, it is also used in user-mode emulation, which
is why it couldn't be restricted to CONFIG_SOFTMMU (see the
comment around added in commit 7827168471: "cpu: tcg_ops:
move to tcg-cpu-ops.h, keep a pointer in CPUClass").
Keep the hack but rename the handler as fake_user_interrupt()
and restrict do_interrupt() to sysemu.
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Warner Losh <imp@bsdimp.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20210911165434.531552-6-f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
From clang-13:
accel/tcg/cpu-exec.c:783:15: error: variable 'cc' set but not used \
[-Werror,-Wunused-but-set-variable]
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
In cpu_loop_exec_tb(), we decide whether to look for a TB with
exactly insns_left instructions in it using the condition
(!cpu->icount_extra && insns_left > 0 && insns_left < tb->icount)
The check for icount_extra == 0 is unnecessary, because we just set
insns_left = MIN(0xffff, cpu->icount_budget);
icount_extra = icount_budget - insns_left;
and so icount_extra can only be non-zero if icount_budget > 0xffff
and insns_left == 0xffff. But in that case insns_left >= tb->icount
because 0xffff is much larger than TCG_MAX_INSNS, so the condition
will be false anyway.
Remove the unnecessary check, and instead assert:
* that we are only going to execute a partial TB here if the
icount budget has run out (ie icount_extra == 0)
* that the number of insns we're going to execute does fit into
the CF_COUNT_MASK
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20210725174405.24568-3-peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
In cpu_loop_exec_tb() we were bounding the number of insns we might
try to execute in a TB using CF_COUNT_MASK. This is incorrect,
because we can validly put up to 0xffff into icount_decr.u16.low. In
particular, since commit 78ff82bb1b reduced CF_COUNT_MASK to
511 this meant that we would incorrectly only try to execute 511
instructions in a 512-instruction TB, which could result in QEMU
hanging when in icount mode.
Use the actual maximum value, which is 0xffff. (This brings this code
in to line with the similar logic in icount_prepare_for_run() in
tcg-accel-ops-icount.c.)
Fixes: 78ff82bb1b
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/499
Message-Id: <20210725174405.24568-2-peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
We are going to want two things:
(1) check for breakpoints will want to break out of the loop here,
(2) cflags can only be calculated with pc in hand.
Tested-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Split out CPU_LOG_EXEC and CPU_LOG_TB_CPU logging from
cpu_tb_exec to a new function. Perform only one pc
range check after a combined mask check.
Use the new function in lookup_tb_ptr. This enables
CPU_LOG_TB_CPU between indirectly chained tbs.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Now that we've moved helper_lookup_tb_ptr, the only user
of tb-lookup.h is cpu-exec.c; merge the contents in.
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This will allow additional code sharing.
No functional change.
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Only the TCG accelerator uses the TranslationBlock API.
Move the tb-context.h / tb-hash.h / tb-lookup.h from the
global namespace to the TCG one (in accel/tcg).
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20210524170453.3791436-3-f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Only 2 headers require "exec/tb-context.h". Instead of having
all files including "exec/exec-all.h" also including it, directly
include it where it is required:
- accel/tcg/cpu-exec.c
- accel/tcg/translate-all.c
For plugins/plugin.h, we were implicitly relying on
exec/exec-all.h -> exec/tb-context.h -> qemu/qht.h
which is now included directly.
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20210524170453.3791436-2-f4bug@amsat.org>
[rth: Fix plugins/plugin.h compilation]
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
The primary motivation is to remove a dozen insns along
the fast-path in tb_lookup. As a byproduct, this allows
us to completely remove parallel_cpus.
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
We don't really deal in cf_mask most of the time. The one time it's
relevant is when we want to remove an invalidated TB from the QHT
lookup. Everywhere else we should be looking up things without
CF_INVALID set.
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20210224165811.11567-4-alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Again there is no reason to jump through the nocache hoops to execute
a single instruction block. We do have to add an additional wrinkle to
the cpu_handle_interrupt case to ensure we let through a TB where we
have specifically disabled icount for the block.
As the last user of cpu_exec_nocache we can now remove the function.
Further clean-up will follow in subsequent patches.
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20210213130325.14781-18-alex.bennee@linaro.org>
When we exit a block under icount with instructions left to execute we
might need a shorter than normal block to take us to the next
deterministic event. Instead of creating a throwaway block on demand
we use the existing compile flags mechanism to ensure we fetch (or
compile and fetch) a block with exactly the number of instructions we
need.
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20210213130325.14781-17-alex.bennee@linaro.org>
In cpu_exec() we have a longstanding workaround for compilers which
do not correctly implement the part of the sigsetjmp()/siglongjmp()
spec which requires that local variables which are not changed
between the setjmp and the longjmp retain their value.
I recently ran across the upstream clang bug report for this; add a
link to it to the comment describing the workaround, and generally
expand the comment, so that we have a reasonable chance in future of
understanding why it's there and determining when we can remove it,
assuming clang eventually fixes the bug.
Remove the /* buggy compiler */ comments on the #else and #endif:
they don't add anything to understanding and are somewhat misleading
since they're sandwiching the code path for *non*-buggy compilers.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-id: 20210129130330.30820-1-peter.maydell@linaro.org
we cannot in principle make the TCG Operations field definitions
conditional on CONFIG_TCG in code that is included by both common_ss
and specific_ss modules.
Therefore, what we can do safely to restrict the TCG fields to TCG-only
builds, is to move all tcg cpu operations into a separate header file,
which is only included by TCG, target-specific code.
This leaves just a NULL pointer in the cpu.h for the non-TCG builds.
This also tidies up the code in all targets a bit, having all TCG cpu
operations neatly contained by a dedicated data struct.
Signed-off-by: Claudio Fontana <cfontana@suse.de>
Message-Id: <20210204163931.7358-16-cfontana@suse.de>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
The cpu_exec_step_atomic() function is called with the cpu->running
clear and proceeds to run target code without setting this flag. If
this target code generates an exception then handle_cpu_signal() will
unnecessarily abort. For example if atomic code generates a memory
protection fault.
This patch at least sets and clears this running flag, and adds some
assertions to help detect other cases.
Signed-off-by: Douglas Crosher <dtc-ubuntu@scieneer.com>
Message-Id: <a272c656-f7c5-019d-1cc0-499b8f80f2fc@scieneer.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This produces a small pc-relative displacement within the
generated code to the TB structure that preceeds it.
Reviewed-by: Joelle van Dyne <j@getutm.app>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Pass both rx and rw addresses to tb_target_set_jmp_target.
Reviewed-by: Joelle van Dyne <j@getutm.app>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Add two helper functions, using a global variable to hold
the displacement. The displacement is currently always 0,
so no change in behaviour.
Begin using the functions in tcg common code only.
Reviewed-by: Joelle van Dyne <j@getutm.app>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
LLVM/Clang, supports runtime checks for forward-edge Control-Flow
Integrity (CFI).
CFI on indirect function calls (cfi-icall) ensures that, in indirect
function calls, the function called is of the right signature for the
pointer type defined at compile time.
For this check to work, the code must always respect the function
signature when using function pointer, the function must be defined
at compile time, and be compiled with link-time optimization.
This rules out, for example, shared libraries that are dynamically loaded
(given that functions are not known at compile time), and code that is
dynamically generated at run-time.
This patch:
1) Introduces the CONFIG_CFI flag to support cfi in QEMU
2) Introduces a decorator to allow the definition of "sensitive"
functions, where a non-instrumented function may be called at runtime
through a pointer. The decorator will take care of disabling cfi-icall
checks on such functions, when cfi is enabled.
3) Marks functions currently in QEMU that exhibit such behavior,
in particular:
- The function in TCG that calls pre-compiled TBs
- The function in TCI that interprets instructions
- Functions in the plugin infrastructures that jump to callbacks
- Functions in util that directly call a signal handler
Signed-off-by: Daniele Buono <dbuono@linux.vnet.ibm.com>
Acked-by: Alex Bennée <alex.bennee@linaro.org
Message-Id: <20201204230615.2392-3-dbuono@linux.vnet.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
cpu-exec tries to execute TB without caching when current
icount budget is over. But sometimes refilled budget is big
enough to try executing cached blocks.
This patch checks that instruction budget is big enough
for next block execution instead of just running cpu_exec_nocache.
It halves the number of calls of cpu_exec_nocache function
during tested OS boot scenario.
Signed-off-by: Pavel Dovgalyuk <pavel.dovgalyuk@ispras.ru>
Message-Id: <160741865825.348476.7169239332367828943.stgit@pasha-ThinkPad-X280>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
