s390x/kvm: synchronize guest floating point registers

Add code to kvm_arch_get_registers and kvm_arch_put_registers to
save/restore floating point registers. This missing sync was
unnoticed until migration of userspace that uses fprs.

Signed-off-by: Jason J. Herne <jjherne@us.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
[Update patch to latest upstream]
Cc: qemu-stable@nongnu.org
Reviewed-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>

(cherry picked from commit 85ad623)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>

target-s390x/kvm.c

@@ -164,6 +164,7 @@ int kvm_arch_put_registers(CPUState *cs, int level)
     CPUS390XState *env = &cpu->env;
     struct kvm_sregs sregs;
     struct kvm_regs regs;
+    struct kvm_fpu fpu;
     int r;
     int i;
 
@@ -186,6 +187,17 @@ int kvm_arch_put_registers(CPUState *cs, int level)
         }
     }
 
+    /* Floating point */
+    for (i = 0; i < 16; i++) {
+        fpu.fprs[i] = env->fregs[i].ll;
+    }
+    fpu.fpc = env->fpc;
+
+    r = kvm_vcpu_ioctl(cs, KVM_SET_FPU, &fpu);
+    if (r < 0) {
+        return r;
+    }
+
     /* Do we need to save more than that? */
     if (level == KVM_PUT_RUNTIME_STATE) {
         return 0;
@@ -251,6 +263,7 @@ int kvm_arch_get_registers(CPUState *cs)
     CPUS390XState *env = &cpu->env;
     struct kvm_sregs sregs;
     struct kvm_regs regs;
+    struct kvm_fpu fpu;
     int i, r;
 
     /* get the PSW */
@@ -291,6 +304,16 @@ int kvm_arch_get_registers(CPUState *cs)
         }
     }
 
+    /* Floating point */
+    r = kvm_vcpu_ioctl(cs, KVM_GET_FPU, &fpu);
+    if (r < 0) {
+        return r;
+    }
+    for (i = 0; i < 16; i++) {
+        env->fregs[i].ll = fpu.fprs[i];
+    }
+    env->fpc = fpu.fpc;
+
     /* The prefix */
     if (cap_sync_regs && cs->kvm_run->kvm_valid_regs & KVM_SYNC_PREFIX) {
         env->psa = cs->kvm_run->s.regs.prefix;