KVM: s390: split SIE state guest prefix field

This patch splits the SIE state guest prefix at offset 4
into a prefix bit field. Additionally it provides the
access functions:

 - kvm_s390_get_prefix()
 - kvm_s390_set_prefix()

to access the prefix per vcpu.

Signed-off-by: Michael Mueller <mimu@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>

1 files changed, 7 insertions, 1 deletions

diff --git a/arch/s390/kvm/kvm-s390.h b/arch/s390/kvm/kvm-s390.h
index 87edfc919db9..a8655ed31616 100644
--- a/arch/s390/kvm/kvm-s390.h
+++ b/arch/s390/kvm/kvm-s390.h
@@ -61,9 +61,15 @@ static inline int kvm_is_ucontrol(struct kvm *kvm)
 #endif
 }
 
+#define GUEST_PREFIX_SHIFT 13
+static inline u32 kvm_s390_get_prefix(struct kvm_vcpu *vcpu)
+{
+        return vcpu->arch.sie_block->prefix << GUEST_PREFIX_SHIFT;
+}
+
 static inline void kvm_s390_set_prefix(struct kvm_vcpu *vcpu, u32 prefix)
 {
-        vcpu->arch.sie_block->prefix = prefix & 0x7fffe000u;
+        vcpu->arch.sie_block->prefix = prefix >> GUEST_PREFIX_SHIFT;
         vcpu->arch.sie_block->ihcpu  = 0xffff;
         kvm_make_request(KVM_REQ_MMU_RELOAD, vcpu);
 }