[PATCH v4 2/3] KVM: s390: Enable adapter_indicators_set to use mapped pages

Douglas Freimuth
2026-04-23T23:53:33Z

The S390 adapter_indicators_set function needs to be able to use mapped
pages so that worked can be processed,on a fast path when interrupts are
disabled. If adapter indicator pages are not mapped then local mapping is
done on a slow path as it is prior to this patch. For example, Secure
Execution environments will take the local mapping path as it does prior to
this patch.

Signed-off-by: Douglas Freimuth <freimuth@linux.ibm.com>
---
arch/s390/kvm/interrupt.c | 94 ++++++++++++++++++++++++++++-----------
1 file changed, 69 insertions(+), 25 deletions(-)

diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c
index 49c95c1eb9b1..c75fb3f19bb0 100644
--- a/arch/s390/kvm/interrupt.c
+++ b/arch/s390/kvm/interrupt.c
@@ -2857,41 +2857,85 @@ static unsigned long get_ind_bit(__u64 addr, unsigned long bit_nr, bool swap)
return swap ? (bit ^ (BITS_PER_LONG - 1)) : bit;
}

+static struct s390_map_info *get_map_info(struct s390_io_adapter *adapter,
+ u64 addr)
+{
+ struct s390_map_info *map;
+
+ if (!adapter)
+ return NULL;
+
+ list_for_each_entry(map, &adapter->maps, list) {
+ if (map->addr == addr)
+ return map;
+ }
+ return NULL;
+}
+
static int adapter_indicators_set(struct kvm *kvm,
struct s390_io_adapter *adapter,
struct kvm_s390_adapter_int *adapter_int)
{
unsigned long bit;
int summary_set, idx;
- struct page *ind_page, *summary_page;
+ struct s390_map_info *ind_info, *summary_info;
void *map;
+ struct page *ind_page, *summary_page;
+ unsigned long flags;

- ind_page = get_map_page(kvm, adapter_int->ind_addr);
- if (!ind_page)
- return -1;
- summary_page = get_map_page(kvm, adapter_int->summary_addr);
- if (!summary_page) {
- put_page(ind_page);
- return -1;
+ raw_spin_lock_irqsave(&adapter->maps_lock, flags);
+ ind_info = get_map_info(adapter, adapter_int->ind_addr);
+ if (!ind_info) {
+ raw_spin_unlock_irqrestore(&adapter->maps_lock, flags);
+ ind_page = get_map_page(kvm, adapter_int->ind_addr);
+ if (!ind_page)
+ return -1;
+ idx = srcu_read_lock(&kvm->srcu);
+ map = page_address(ind_page);
+ bit = get_ind_bit(adapter_int->ind_addr,
+ adapter_int->ind_offset, adapter->swap);
+ set_bit(bit, map);
+ mark_page_dirty(kvm, adapter_int->ind_gaddr >> PAGE_SHIFT);
+ set_page_dirty_lock(ind_page);
+ srcu_read_unlock(&kvm->srcu, idx);
+ } else {
+ map = page_address(ind_info->page);
+ bit = get_ind_bit(ind_info->addr, adapter_int->ind_offset, adapter->swap);
+ set_bit(bit, map);
+ raw_spin_unlock_irqrestore(&adapter->maps_lock, flags);
+ }
+ raw_spin_lock_irqsave(&adapter->maps_lock, flags);
+ summary_info = get_map_info(adapter, adapter_int->summary_addr);
+ if (!summary_info) {
+ raw_spin_unlock_irqrestore(&adapter->maps_lock, flags);
+ summary_page = get_map_page(kvm, adapter_int->summary_addr);
+ if (!summary_page) {
+ if (!ind_info) {
+ WARN_ON_ONCE(!ind_page);
+ put_page(ind_page);
+ }
+ return -1;
+ }
+ idx = srcu_read_lock(&kvm->srcu);
+ map = page_address(summary_page);
+ bit = get_ind_bit(adapter_int->summary_addr,
+ adapter_int->summary_offset, adapter->swap);
+ summary_set = test_and_set_bit(bit, map);
+ mark_page_dirty(kvm, adapter_int->summary_gaddr >> PAGE_SHIFT);
+ set_page_dirty_lock(summary_page);
+ srcu_read_unlock(&kvm->srcu, idx);
+ } else {
+ map = page_address(summary_info->page);
+ bit = get_ind_bit(summary_info->addr, adapter_int->summary_offset,
+ adapter->swap);
+ summary_set = test_and_set_bit(bit, map);
+ raw_spin_unlock_irqrestore(&adapter->maps_lock, flags);
}

- idx = srcu_read_lock(&kvm->srcu);
- map = page_address(ind_page);
- bit = get_ind_bit(adapter_int->ind_addr,
- adapter_int->ind_offset, adapter->swap);
- set_bit(bit, map);
- mark_page_dirty(kvm, adapter_int->ind_gaddr >> PAGE_SHIFT);
- set_page_dirty_lock(ind_page);
- map = page_address(summary_page);
- bit = get_ind_bit(adapter_int->summary_addr,
- adapter_int->summary_offset, adapter->swap);
- summary_set = test_and_set_bit(bit, map);
- mark_page_dirty(kvm, adapter_int->summary_gaddr >> PAGE_SHIFT);
- set_page_dirty_lock(summary_page);
- srcu_read_unlock(&kvm->srcu, idx);
-
- put_page(ind_page);
- put_page(summary_page);
+ if (!ind_info)
+ put_page(ind_page);
+ if (!summary_info)
+ put_page(summary_page);
return summary_set ? 0 : 1;
}

--
2.52.0