[PATCH v1 2/3] Enable adapter_indicators_set to use mapped pages

[Douglas Freimuth]

Patch 2: This patch enables adapter_indicators_set to use mapped pages.
If adapter indicator pages are not mapped then local mapping is done 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@xxxxxxxxxxxxx>
---
 arch/s390/kvm/interrupt.c | 89 +++++++++++++++++++++++++++------------
 1 file changed, 62 insertions(+), 27 deletions(-)

diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c
index cafc03e20f8f..350106f84763 100644
--- a/arch/s390/kvm/interrupt.c
+++ b/arch/s390/kvm/interrupt.c
@@ -2836,41 +2836,74 @@ 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->guest_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)
+				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;
 
-	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;
+	ind_info = get_map_info(adapter, adapter_int->ind_addr);
+	if (!ind_info) {
+		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);
 	}
 
-	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);
+		summary_page = get_map_page(kvm, adapter_int->summary_addr);
+		if (!summary_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);
+}
+
+	if (!ind_info)
+		put_page(ind_page);
+	if (!summary_info)
+		put_page(summary_page);
 	return summary_set ? 0 : 1;
 }
 
@@ -2892,7 +2925,9 @@ static int set_adapter_int(struct kvm_kernel_irq_routing_entry *e,
 	adapter = get_io_adapter(kvm, e->adapter.adapter_id);
 	if (!adapter)
 		return -1;
+	down_read(&adapter->maps_lock);
 	ret = adapter_indicators_set(kvm, adapter, &e->adapter);
+	up_read(&adapter->maps_lock);
 	if ((ret > 0) && !adapter->masked) {
 		ret = kvm_s390_inject_airq(kvm, adapter);
 		if (ret == 0)
-- 
2.52.0