s390x/async_pf: Check for apf extension and enable pfault

S390 can also use async page faults, to enhance guest scheduling.
In case of live migration we want to disable the feature and let
all pending request finish.

Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
Signed-off-by: Jens Freimann <jfrei@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

1 files changed, 48 insertions, 0 deletions

diff --git a/target-s390x/kvm.c b/target-s390x/kvm.c
index f60ccdc326..9430a35b02 100644
--- a/target-s390x/kvm.c
+++ b/target-s390x/kvm.c
@@ -87,12 +87,14 @@ const KVMCapabilityInfo kvm_arch_required_capabilities[] = {
 };
 
 static int cap_sync_regs;
+static int cap_async_pf;
 
 static void *legacy_s390_alloc(size_t size);
 
 int kvm_arch_init(KVMState *s)
 {
     cap_sync_regs = kvm_check_extension(s, KVM_CAP_SYNC_REGS);
+    cap_async_pf = kvm_check_extension(s, KVM_CAP_ASYNC_PF);
     if (!kvm_check_extension(s, KVM_CAP_S390_GMAP)
         || !kvm_check_extension(s, KVM_CAP_S390_COW)) {
         phys_mem_set_alloc(legacy_s390_alloc);
@@ -178,6 +180,29 @@ int kvm_arch_put_registers(CPUState *cs, int level)
         return ret;
     }
 
+    if (cap_async_pf) {
+        reg.id = KVM_REG_S390_PFTOKEN;
+        reg.addr = (__u64)&(env->pfault_token);
+        ret = kvm_vcpu_ioctl(cs, KVM_SET_ONE_REG, &reg);
+        if (ret < 0) {
+            return ret;
+        }
+
+        reg.id = KVM_REG_S390_PFCOMPARE;
+        reg.addr = (__u64)&(env->pfault_compare);
+        ret = kvm_vcpu_ioctl(cs, KVM_SET_ONE_REG, &reg);
+        if (ret < 0) {
+            return ret;
+        }
+
+        reg.id = KVM_REG_S390_PFSELECT;
+        reg.addr = (__u64)&(env->pfault_select);
+        ret = kvm_vcpu_ioctl(cs, KVM_SET_ONE_REG, &reg);
+        if (ret < 0) {
+            return ret;
+        }
+    }
+
     if (cap_sync_regs &&
         cs->kvm_run->kvm_valid_regs & KVM_SYNC_ACRS &&
         cs->kvm_run->kvm_valid_regs & KVM_SYNC_CRS) {
@@ -282,6 +307,29 @@ int kvm_arch_get_registers(CPUState *cs)
         return r;
     }
 
+    if (cap_async_pf) {
+        reg.id = KVM_REG_S390_PFTOKEN;
+        reg.addr = (__u64)&(env->pfault_token);
+        r = kvm_vcpu_ioctl(cs, KVM_GET_ONE_REG, &reg);
+        if (r < 0) {
+            return r;
+        }
+
+        reg.id = KVM_REG_S390_PFCOMPARE;
+        reg.addr = (__u64)&(env->pfault_compare);
+        r = kvm_vcpu_ioctl(cs, KVM_GET_ONE_REG, &reg);
+        if (r < 0) {
+            return r;
+        }
+
+        reg.id = KVM_REG_S390_PFSELECT;
+        reg.addr = (__u64)&(env->pfault_select);
+        r = kvm_vcpu_ioctl(cs, KVM_GET_ONE_REG, &reg);
+        if (r < 0) {
+            return r;
+        }
+    }
+
     return 0;
 }