s390x/flic: introduce modify_ais_mode callback

In order to emulate the adapter interruption suppression (AIS)
facility properly, the guest needs to be able to modify the AIS mask.
Interrupt suppression will be handled via the flic (for kvm, via a
recently introduced kernel backend; for !kvm, in the flic code), so
let's introduce a method to change the mode via the flic interface.

We introduce the 'simm' and 'nimm' fields to QEMUS390FLICState
to store interruption modes for each ISC. Each bit in 'simm' and
'nimm' targets one ISC, and collaboratively indicate three modes:
ALL-Interruptions, SINGLE-Interruption and NO-Interruptions. This
interface can initiate most transitions between the states; transition
from SINGLE-Interruption to NO-Interruptions via adapter interrupt
injection will be introduced in a following patch. The meaningful
combinations are as follows:

    interruption mode | simm bit | nimm bit
    ------------------|----------|----------
             ALL      |    0     |     0
           SINGLE     |    1     |     0
             NO       |    1     |     1

Co-authored-by: Yi Min Zhao <zyimin@linux.vnet.ibm.com>
Signed-off-by: Yi Min Zhao <zyimin@linux.vnet.ibm.com>
Signed-off-by: Fei Li <sherrylf@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

1 files changed, 8 insertions, 1 deletions

diff --git a/include/hw/s390x/s390_flic.h b/include/hw/s390x/s390_flic.h
index d4145ad..f500184 100644
--- a/include/hw/s390x/s390_flic.h
+++ b/include/hw/s390x/s390_flic.h
@@ -44,7 +44,7 @@ typedef struct S390FLICState {
     SysBusDevice parent_obj;
     /* to limit AdapterRoutes.num_routes for compat */
     uint32_t adapter_routes_max_batch;
-
+    bool ais_supported;
 } S390FLICState;
 
 #define S390_FLIC_COMMON_CLASS(klass) \
@@ -63,6 +63,7 @@ typedef struct S390FLICStateClass {
     void (*release_adapter_routes)(S390FLICState *fs, AdapterRoutes *routes);
     int (*clear_io_irq)(S390FLICState *fs, uint16_t subchannel_id,
                         uint16_t subchannel_nr);
+    int (*modify_ais_mode)(S390FLICState *fs, uint8_t isc, uint16_t mode);
 } S390FLICStateClass;
 
 #define TYPE_KVM_S390_FLIC "s390-flic-kvm"
@@ -73,8 +74,14 @@ typedef struct S390FLICStateClass {
 #define QEMU_S390_FLIC(obj) \
     OBJECT_CHECK(QEMUS390FLICState, (obj), TYPE_QEMU_S390_FLIC)
 
+#define SIC_IRQ_MODE_ALL 0
+#define SIC_IRQ_MODE_SINGLE 1
+#define AIS_MODE_MASK(isc) (0x80 >> isc)
+
 typedef struct QEMUS390FLICState {
     S390FLICState parent_obj;
+    uint8_t simm;
+    uint8_t nimm;
 } QEMUS390FLICState;
 
 void s390_flic_init(void);