KVM: s390: only one external call may be pending at a time

Only one external call may be pending at a vcpu at a time. For this
reason, we have to detect whether the SIGP externcal call interpretation
facility is available. If so, all external calls have to be injected
using this mechanism.

SIGP EXTERNAL CALL orders have to return whether another external
call is already pending. This check was missing until now.

SIGP SENSE hasn't returned yet in all conditions whether an external
call was pending.

If a SIGP EXTERNAL CALL irq is to be injected and one is already
pending, -EBUSY is returned.

Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

1 files changed, 5 insertions, 3 deletions

diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index 02e42480609d..4de479e47f71 100644
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -35,11 +35,13 @@
 #define KVM_NR_IRQCHIPS 1
 #define KVM_IRQCHIP_NUM_PINS 4096
 
-#define SIGP_CTRL_C     0x00800000
+#define SIGP_CTRL_C             0x80
+#define SIGP_CTRL_SCN_MASK      0x3f
 
 struct sca_entry {
-        atomic_t ctrl;
-        __u32   reserved;
+        __u8    reserved0;
+        __u8    sigp_ctrl;
+        __u16   reserved[3];
         __u64   sda;
         __u64   reserved2[2];
 } __attribute__((packed));