s390/mm: add missing arch_set_page_dat() call to vmem_crst_alloc()

[ Upstream commit 09cda0a400519b1541591c506e54c9c48e3101bf ]

If the cmma no-dat feature is available all pages that are not used for
dynamic address translation are marked as "no-dat" with the ESSA
instruction. This information is visible to the hypervisor, so that the
hypervisor can optimize purging of guest TLB entries. This also means that
pages which are used for dynamic address translation must not be marked as
"no-dat", since the hypervisor may then incorrectly not purge guest TLB
entries.

Region and segment tables allocated via vmem_crst_alloc() are incorrectly
marked as "no-dat", as soon as slab_is_available() returns true.

Such tables are allocated e.g. when kernel page tables are split, memory is
hotplugged, or a DCSS segment is loaded.

Fix this by adding the missing arch_set_page_dat() call.

Cc: <stable@vger.kernel.org>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/arch/s390/mm/vmem.c b/arch/s390/mm/vmem.c
index 9a0ce5315f36de23c1e76b8da7d4a3a6151ca63b..3cbb461820666146ff7dfeb1d7bb08a47e9f17b5 100644 (file)
--- a/arch/s390/mm/vmem.c
+++ b/arch/s390/mm/vmem.c
@@ -11,6 +11,7 @@
 #include <linux/list.h>
 #include <linux/hugetlb.h>
 #include <linux/slab.h>
+#include <asm/page-states.h>
 #include <asm/cacheflush.h>
 #include <asm/nospec-branch.h>
 #include <asm/pgalloc.h>
@@ -44,8 +45,11 @@ void *vmem_crst_alloc(unsigned long val)
        unsigned long *table;
 
        table = vmem_alloc_pages(CRST_ALLOC_ORDER);
-       if (table)
-               crst_table_init(table, val);
+       if (!table)
+               return NULL;
+       crst_table_init(table, val);
+       if (slab_is_available())
+               arch_set_page_dat(virt_to_page(table), CRST_ALLOC_ORDER);
        return table;
 }