xen: mapcache: Fix finding matching entry

If we have request without lock and hit unlocked or invalid
entry during the search, we remap it immediately,
even if we have matching entry in next entries in bucket.
This leads to duplication of mappings of the same size,
and to possibility of selecting the wrong element
during invalidation and underflow it's entry->lock counter

Signed-off-by: Aleksandr Partanen <alex.pentagrid@gmail.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@amd.com>
Signed-off-by: Edgar E. Iglesias <edgar.iglesias@amd.com>
This commit is contained in:
Aleksandr Partanen 2025-04-10 17:46:04 +03:00 committed by Edgar E. Iglesias
parent a9e0c9c0f1
commit a4b20f737c

View file

@ -376,12 +376,12 @@ tryagain:
entry = &mc->entry[address_index % mc->nr_buckets];
while (entry && (lock || entry->lock) && entry->vaddr_base &&
(entry->paddr_index != address_index || entry->size != cache_size ||
while (entry && (!entry->vaddr_base ||
entry->paddr_index != address_index || entry->size != cache_size ||
!test_bits(address_offset >> XC_PAGE_SHIFT,
test_bit_size >> XC_PAGE_SHIFT,
entry->valid_mapping))) {
if (!free_entry && !entry->lock) {
if (!free_entry && (!entry->lock || !entry->vaddr_base)) {
free_entry = entry;
free_pentry = pentry;
}