From b904bd5437ead0dfc2c4c0977f3d29d63299c601 Mon Sep 17 00:00:00 2001 From: Andreas Sandberg Date: Fri, 15 Feb 2013 17:40:09 -0500 Subject: sim: Add a system-global option to bypass caches Virtualized CPUs and the fastmem mode of the atomic CPU require direct access to physical memory. We currently require caches to be disabled when using them to prevent chaos. This is not ideal when switching between hardware virutalized CPUs and other CPU models as it would require a configuration change on each switch. This changeset introduces a new version of the atomic memory mode, 'atomic_noncaching', where memory accesses are inserted into the memory system as atomic accesses, but bypass caches. To make memory mode tests cleaner, the following methods are added to the System class: * isAtomicMode() -- True if the memory mode is 'atomic' or 'direct'. * isTimingMode() -- True if the memory mode is 'timing'. * bypassCaches() -- True if caches should be bypassed. The old getMemoryMode() and setMemoryMode() methods should never be used from the C++ world anymore. --- src/python/m5/simulate.py | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'src/python/m5') diff --git a/src/python/m5/simulate.py b/src/python/m5/simulate.py index 3583e8264..682104c26 100644 --- a/src/python/m5/simulate.py +++ b/src/python/m5/simulate.py @@ -63,6 +63,7 @@ MaxTick = 2**63 - 1 _memory_modes = { "atomic" : objects.params.atomic, "timing" : objects.params.timing, + "atomic_noncaching" : objects.params.atomic_noncaching, } # The final hook to generate .ini files. Called from the user script @@ -288,6 +289,13 @@ def switchCpus(system, cpuList, do_drain=True): # Change the memory mode if required. We check if this is needed # to avoid printing a warning if no switch was performed. if system.getMemoryMode() != memory_mode: + # Flush the memory system if we are switching to a memory mode + # that disables caches. This typically happens when switching to a + # hardware virtualized CPU. + if memory_mode == objects.params.atomic_noncaching: + memWriteback(system) + memInvalidate(system) + _changeMemoryMode(system, memory_mode) for old_cpu, new_cpu in cpuList: -- cgit v1.2.3