From 969b4362432659f436925c1d4266d8d4f6fae121 Mon Sep 17 00:00:00 2001 From: Andreas Hansson Date: Tue, 18 Feb 2014 05:50:58 -0500 Subject: [PATCH] mem: Filter cache snoops based on address ranges This patch adds a filter to the cache to drop snoop requests that are not for a range covered by the cache. This fixes an issue observed when multiple caches are placed in parallel, covering different address ranges. Without this patch, all the caches will forward the snoop upwards, when only one should do so. --- src/mem/cache/cache_impl.hh | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff --git a/src/mem/cache/cache_impl.hh b/src/mem/cache/cache_impl.hh index 76fb697c2..b482d6314 100644 --- a/src/mem/cache/cache_impl.hh +++ b/src/mem/cache/cache_impl.hh @@ -1475,10 +1475,23 @@ Cache::recvTimingSnoopReq(PacketPtr pkt) // Snoops shouldn't happen when bypassing caches assert(!system->bypassCaches()); + // check if the packet is for an address range covered by this + // cache, partly to not waste time looking for it, but also to + // ensure that we only forward the snoop upwards if it is within + // our address ranges + bool in_range = false; + for (AddrRangeList::const_iterator r = addrRanges.begin(); + r != addrRanges.end(); ++r) { + if (r->contains(pkt->getAddr())) { + in_range = true; + break; + } + } + // Note that some deferred snoops don't have requests, since the // original access may have already completed if ((pkt->req && pkt->req->isUncacheable()) || - pkt->cmd == MemCmd::Writeback) { + pkt->cmd == MemCmd::Writeback || !in_range) { //Can't get a hit on an uncacheable address //Revisit this for multi level coherence return; -- 2.30.2