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KVM: s390: Enable adapter_indicators_set to use mapped pages

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The s390 adapter_indicators_set function can now be optimized to use
long-term mapped pages when available so that work 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.

Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
Signed-off-by: Douglas Freimuth <freimuth@linux.ibm.com>
Acked-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Message-ID: <20260604192755.203143-3-freimuth@linux.ibm.com>
This commit is contained in:
Douglas Freimuth 2026-06-04 21:27:54 +02:00 committed by Claudio Imbrenda
parent c9a5688380
commit 1e95e3bc6b
1 changed files with 63 additions and 24 deletions
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87
arch/s390/kvm/interrupt.c
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@ -2892,41 +2892,80 @@ 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 = pin_map_page(kvm, adapter_int->ind_addr, 0);
if (!ind_page)
return -1;
summary_page = pin_map_page(kvm, adapter_int->summary_addr, 0);
if (!summary_page) {
ind_page = NULL;
spin_lock_irqsave(&adapter->maps_lock, flags);
ind_info = get_map_info(adapter, adapter_int->ind_addr);
if (!ind_info) {
spin_unlock_irqrestore(&adapter->maps_lock, flags);
ind_page = pin_map_page(kvm, adapter_int->ind_addr, 0);
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);
unpin_user_page(ind_page);
return -1;
} else {
map = page_address(ind_info->page);
bit = get_ind_bit(ind_info->addr, adapter_int->ind_offset, adapter->swap);
set_bit(bit, map);
spin_unlock_irqrestore(&adapter->maps_lock, flags);
}
spin_lock_irqsave(&adapter->maps_lock, flags);
summary_info = get_map_info(adapter, adapter_int->summary_addr);
if (!summary_info) {
spin_unlock_irqrestore(&adapter->maps_lock, flags);
summary_page = pin_map_page(kvm, adapter_int->summary_addr, 0);
if (WARN_ON_ONCE(!summary_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);
unpin_user_page(summary_page);
} 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);
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);
unpin_user_page(ind_page);
unpin_user_page(summary_page);
return summary_set ? 0 : 1;
}