From: Heiko Carstens hca@linux.ibm.com
stable inclusion from stable-v6.6.3 commit 8847617e2f0a0344ff88147a2cd89a42bd309ed8 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I8LBQP
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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commit 09cda0a400519b1541591c506e54c9c48e3101bf upstream.
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: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com --- arch/s390/mm/vmem.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/arch/s390/mm/vmem.c b/arch/s390/mm/vmem.c index 6957d2ed97bf..6d276103c6d5 100644 --- a/arch/s390/mm/vmem.c +++ b/arch/s390/mm/vmem.c @@ -12,6 +12,7 @@ #include <linux/hugetlb.h> #include <linux/slab.h> #include <linux/sort.h> +#include <asm/page-states.h> #include <asm/cacheflush.h> #include <asm/nospec-branch.h> #include <asm/pgalloc.h> @@ -45,8 +46,11 @@ 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; }