From 380ac2bcce466f3b8f93eb749c7e85bfcf476cd6 Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Fri, 3 Sep 2021 17:55:09 +0200 Subject: [PATCH] s390x/mmu_helper: avoid setting the storage key if nothing changed Avoid setting the key if nothing changed. Signed-off-by: David Hildenbrand Reviewed-by: Thomas Huth Message-Id: <20210903155514.44772-9-david@redhat.com> Signed-off-by: Thomas Huth --- target/s390x/mmu_helper.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/target/s390x/mmu_helper.c b/target/s390x/mmu_helper.c index de6df928d2..e2b372efd9 100644 --- a/target/s390x/mmu_helper.c +++ b/target/s390x/mmu_helper.c @@ -301,7 +301,7 @@ static void mmu_handle_skey(target_ulong addr, int rw, int *flags) { static S390SKeysClass *skeyclass; static S390SKeysState *ss; - uint8_t key; + uint8_t key, old_key; int rc; /* @@ -337,6 +337,7 @@ static void mmu_handle_skey(target_ulong addr, int rw, int *flags) trace_get_skeys_nonzero(rc); return; } + old_key = key; switch (rw) { case MMU_DATA_LOAD: @@ -360,9 +361,11 @@ static void mmu_handle_skey(target_ulong addr, int rw, int *flags) /* Any store/fetch sets the reference bit */ key |= SK_R; - rc = skeyclass->set_skeys(ss, addr / TARGET_PAGE_SIZE, 1, &key); - if (rc) { - trace_set_skeys_nonzero(rc); + if (key != old_key) { + rc = skeyclass->set_skeys(ss, addr / TARGET_PAGE_SIZE, 1, &key); + if (rc) { + trace_set_skeys_nonzero(rc); + } } }