KVM: s390: represent SIMD cap in kvm facility

The patch represents capability KVM_CAP_S390_VECTOR_REGISTERS by means
of the SIMD facility bit. This allows to a) disable the use of SIMD when
used in conjunction with a not-SIMD-aware QEMU, b) to enable SIMD when
used with a SIMD-aware version of QEMU and c) finally by means of a QEMU
version using the future cpu model ioctls.

Signed-off-by: Michael Mueller <mimu@linux.vnet.ibm.com>
Reviewed-by: Eric Farman <farman@linux.vnet.ibm.com>
Tested-by: Eric Farman <farman@linux.vnet.ibm.com>
Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

1 files changed, 11 insertions, 0 deletions

diff --git a/arch/s390/kvm/kvm-s390.h b/arch/s390/kvm/kvm-s390.h
index 5d54191e573e..c5aefef158e5 100644
--- a/arch/s390/kvm/kvm-s390.h
+++ b/arch/s390/kvm/kvm-s390.h
@@ -149,6 +149,17 @@ static inline int test_kvm_facility(struct kvm *kvm, unsigned long nr)
                 __test_facility(nr, kvm->arch.model.fac->list);
 }
 
+static inline int set_kvm_facility(u64 *fac_list, unsigned long nr)
+{
+        unsigned char *ptr;
+
+        if (nr >= MAX_FACILITY_BIT)
+                return -EINVAL;
+        ptr = (unsigned char *) fac_list + (nr >> 3);
+        *ptr |= (0x80UL >> (nr & 7));
+        return 0;
+}
+
 /* are cpu states controlled by user space */
 static inline int kvm_s390_user_cpu_state_ctrl(struct kvm *kvm)
 {