tree d38925cf660917176685f29d17ee98949a79a9f3
parent 612f242359dd28a3fe48628f766f03dabf03f3ab
author Tiago Mück <tiago.muck@arm.com> 1652811648 -0500
committer Tiago Muck <tiago.muck@arm.com> 1654097027 +0000

mem-ruby: fix Evict request for CHI excl. caches

Assume core C1 with private L1/L2 and a shared exclusive L3.
C1 has a line in SC state, while the state in the L3 is
RUSC (L3 has exclusive accesses and upstream requester has line in SC).

When C1 evicts the line (Evict request), the L3 has to issue a
WriteEvictFull to the home node, however the L3 doesn't have a copy
of the line.

This fix handling Evict requests when the line state is RUSC. When
the last sharer issues an Evict request, the responder may issue
SnpOnce the obtain a copy the line if needed.

JIRA: https://gem5.atlassian.net/browse/GEM5-1195

Change-Id: Ic8f4e10b38d95cd6d84f8d65b87b0c94fcf52eea
Signed-off-by: Tiago Mück <tiago.muck@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/59991
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>