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authorPaolo Bonzini <pbonzini@redhat.com>2015-06-24 14:16:26 +0200
committerPaolo Bonzini <pbonzini@redhat.com>2015-08-14 23:40:32 +0200
commit414b15c909c88e4cf5f10e80d033b3aa90bcc9e1 (patch)
tree04d817361a25bc06a6243d5cfcf693017fe4bc5c /include/qom/cpu.h
parentb4a4b8d0e0767c85946fd8fc404643bf5766351a (diff)
exec: drop cpu_can_do_io, just read cpu->can_do_io
After commit 626cf8f (icount: set can_do_io outside TB execution, 2014-12-08), can_do_io is set to 1 if not executing code. It is no longer necessary to make this assumption in cpu_can_do_io. It is also possible to remove the use_icount test, simply by never setting cpu->can_do_io to 0 unless use_icount is true. With these changes cpu_can_do_io boils down to a read of cpu->can_do_io. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'include/qom/cpu.h')
-rw-r--r--include/qom/cpu.h4
1 files changed, 3 insertions, 1 deletions
diff --git a/include/qom/cpu.h b/include/qom/cpu.h
index 20aabc9cb3..39712ab7cb 100644
--- a/include/qom/cpu.h
+++ b/include/qom/cpu.h
@@ -231,7 +231,9 @@ struct kvm_run;
* @icount_decr: Number of cycles left, with interrupt flag in high bit.
* This allows a single read-compare-cbranch-write sequence to test
* for both decrementer underflow and exceptions.
- * @can_do_io: Nonzero if memory-mapped IO is safe.
+ * @can_do_io: Nonzero if memory-mapped IO is safe. Deterministic execution
+ * requires that IO only be performed on the last instruction of a TB
+ * so that interrupts take effect immediately.
* @env_ptr: Pointer to subclass-specific CPUArchState field.
* @current_tb: Currently executing TB.
* @gdb_regs: Additional GDB registers.