KVM: s390: allow sync of fp registers via vregs

If we have MACHINE_HAS_VX, the floating point registers are stored
in the vector register format, event if the guest isn't enabled for vector
registers. So we can allow KVM_SYNC_VRS as soon as MACHINE_HAS_VX is
available.

This can in return be used by user space to support floating point
registers via struct kvm_run when the machine has vector registers.

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

diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 4af21c771f9b3925bf860d0dc86cebcc803cf965..8fcdf9836321a33e211eb78ef41cf93814cca811 100644 (file)
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -1414,7 +1414,10 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
                                    KVM_SYNC_PFAULT;
        if (test_kvm_facility(vcpu->kvm, 64))
                vcpu->run->kvm_valid_regs |= KVM_SYNC_RICCB;
-       if (test_kvm_facility(vcpu->kvm, 129))
+       /* fprs can be synchronized via vrs, even if the guest has no vx. With
+        * MACHINE_HAS_VX, (load|store)_fpu_regs() will work with vrs format.
+        */
+       if (MACHINE_HAS_VX)
                vcpu->run->kvm_valid_regs |= KVM_SYNC_VRS;
 
        if (kvm_is_ucontrol(vcpu->kvm))