diff options
| author | Richard Henderson <richard.henderson@linaro.org> | 2023-08-25 16:13:17 -0700 |
|---|---|---|
| committer | Richard Henderson <richard.henderson@linaro.org> | 2023-08-29 09:55:06 -0700 |
| commit | 0d58c660689f6da1e3feff8a997014003d928b3b (patch) | |
| tree | 081ceb163f15f146b86d9ecc64e56f85f3fd6454 /accel | |
| parent | 86e4f93d827d3c1efd00cd8a906e38a2c0f2b5bc (diff) | |
softmmu: Use async_run_on_cpu in tcg_commit
After system startup, run the update to memory_dispatch
and the tlb_flush on the cpu. This eliminates a race,
wherein a running cpu sees the memory_dispatch change
but has not yet seen the tlb_flush.
Since the update now happens on the cpu, we need not use
qatomic_rcu_read to protect the read of memory_dispatch.
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1826
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1834
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1846
Tested-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Diffstat (limited to 'accel')
| -rw-r--r-- | accel/tcg/cpu-exec-common.c | 30 |
1 files changed, 0 insertions, 30 deletions
diff --git a/accel/tcg/cpu-exec-common.c b/accel/tcg/cpu-exec-common.c index 9a5fabf625..7e35d7f4b5 100644 --- a/accel/tcg/cpu-exec-common.c +++ b/accel/tcg/cpu-exec-common.c @@ -33,36 +33,6 @@ void cpu_loop_exit_noexc(CPUState *cpu) cpu_loop_exit(cpu); } -#if defined(CONFIG_SOFTMMU) -void cpu_reloading_memory_map(void) -{ - if (qemu_in_vcpu_thread() && current_cpu->running) { - /* The guest can in theory prolong the RCU critical section as long - * as it feels like. The major problem with this is that because it - * can do multiple reconfigurations of the memory map within the - * critical section, we could potentially accumulate an unbounded - * collection of memory data structures awaiting reclamation. - * - * Because the only thing we're currently protecting with RCU is the - * memory data structures, it's sufficient to break the critical section - * in this callback, which we know will get called every time the - * memory map is rearranged. - * - * (If we add anything else in the system that uses RCU to protect - * its data structures, we will need to implement some other mechanism - * to force TCG CPUs to exit the critical section, at which point this - * part of this callback might become unnecessary.) - * - * This pair matches cpu_exec's rcu_read_lock()/rcu_read_unlock(), which - * only protects cpu->as->dispatch. Since we know our caller is about - * to reload it, it's safe to split the critical section. - */ - rcu_read_unlock(); - rcu_read_lock(); - } -} -#endif - void cpu_loop_exit(CPUState *cpu) { /* Undo the setting in cpu_tb_exec. */ |