KVM: s390: add kvm reference to struct sie_page2

Adding the kvm reference to struct sie_page2 will allow to
determine the kvm a given gisa belongs to:

  container_of(gisa, struct sie_page2, gisa)->kvm

This functionality will be required to process a gisa in
gib alert interruption context.
Signed-off-by: Michael Mueller <mimu@linux.ibm.com>
Reviewed-by: Pierre Morel <pmorel@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Halil Pasic <pasic@linux.ibm.com>
Message-Id: <20190131085247.13826-11-mimu@linux.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

arch/s390/include/asm/kvm_host.h

@@ -801,7 +801,8 @@ struct sie_page2 {
 	__u64 fac_list[S390_ARCH_FAC_LIST_SIZE_U64];	/* 0x0000 */
 	struct kvm_s390_crypto_cb crycb;		/* 0x0800 */
 	struct kvm_s390_gisa gisa;			/* 0x0900 */
-	u8 reserved920[0x1000 - 0x920];			/* 0x0920 */
+	struct kvm *kvm;				/* 0x0920 */
+	u8 reserved928[0x1000 - 0x928];			/* 0x0928 */
 };
 
 struct kvm_s390_vsie {

arch/s390/kvm/kvm-s390.c

@@ -2210,6 +2210,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
 	if (!kvm->arch.sie_page2)
 		goto out_err;
 
+	kvm->arch.sie_page2->kvm = kvm;
 	kvm->arch.model.fac_list = kvm->arch.sie_page2->fac_list;
 
 	for (i = 0; i < kvm_s390_fac_size(); i++) {