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KVM: s390: pv: fix index value of replaced ASCE 

[ Upstream commit c2fceb59bb ]

The index field of the struct page corresponding to a guest ASCE should
be 0. When replacing the ASCE in s390_replace_asce(), the index of the
new ASCE should also be set to 0.

Having the wrong index might lead to the wrong addresses being passed
around when notifying pte invalidations, and eventually to validity
intercepts (VM crash) if the prefix gets unmapped and the notifier gets
called with the wrong address.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Fixes: faa2f72cb3 ("KVM: s390: pv: leak the topmost page table when destroy fails")
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Message-ID: <20230705111937.33472-3-imbrenda@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Claudio Imbrenda 2023-07-05 13:19:37 +02:00 committed by Greg Kroah-Hartman
parent fee1e6a735
commit 49a2686add
1 changed files with 1 additions and 0 deletions
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arch/s390/mm/gmap.c
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@ -2791,6 +2791,7 @@ int s390_replace_asce(struct gmap *gmap)
page = alloc_pages(GFP_KERNEL_ACCOUNT, CRST_ALLOC_ORDER);
if (!page)
return -ENOMEM;
page->index = 0;
table = page_to_virt(page);
memcpy(table, gmap->table, 1UL << (CRST_ALLOC_ORDER + PAGE_SHIFT));