s390x/kvm: cleanup partial register handling

The partial register handling (introduced with commits
420840e58b85f7f4e5493dca3f273566f261090a and
3474b679486caa8f6448bae974e131370f360c13 ) aimed to improve intercept
handling performance.

It made the code more complicated though. During development for life
migration/init/reset etc it turned out that this might cause several
hard to debug programming errors. With the introduction of ioeventfd
(and future irqfd patches) the qemu intercept handlers are no longer
hot-path. And therefore the partial register handling can be
removed to simplify the code.

Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
CC: Jason J. Herne <jjherne@us.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Alexander Graf <agraf@suse.de>

1 files changed, 53 insertions, 83 deletions

diff --git a/target-s390x/kvm.c b/target-s390x/kvm.c
index f7b772668c..f60ccdc326 100644
--- a/target-s390x/kvm.c
+++ b/target-s390x/kvm.c
@@ -152,33 +152,30 @@ int kvm_arch_put_registers(CPUState *cs, int level)
         }
     }
 
-    if (env->runtime_reg_dirty_mask == KVM_S390_RUNTIME_DIRTY_FULL) {
-        reg.id = KVM_REG_S390_CPU_TIMER;
-        reg.addr = (__u64)&(env->cputm);
-        ret = kvm_vcpu_ioctl(cs, KVM_SET_ONE_REG, &reg);
-        if (ret < 0) {
-            return ret;
-        }
+    /* Do we need to save more than that? */
+    if (level == KVM_PUT_RUNTIME_STATE) {
+        return 0;
+    }
 
-        reg.id = KVM_REG_S390_CLOCK_COMP;
-        reg.addr = (__u64)&(env->ckc);
-        ret = kvm_vcpu_ioctl(cs, KVM_SET_ONE_REG, &reg);
-        if (ret < 0) {
-            return ret;
-        }
+    reg.id = KVM_REG_S390_CPU_TIMER;
+    reg.addr = (__u64)&(env->cputm);
+    ret = kvm_vcpu_ioctl(cs, KVM_SET_ONE_REG, &reg);
+    if (ret < 0) {
+        return ret;
+    }
 
-        reg.id = KVM_REG_S390_TODPR;
-        reg.addr = (__u64)&(env->todpr);
-        ret = kvm_vcpu_ioctl(cs, KVM_SET_ONE_REG, &reg);
-        if (ret < 0) {
-            return ret;
-        }
+    reg.id = KVM_REG_S390_CLOCK_COMP;
+    reg.addr = (__u64)&(env->ckc);
+    ret = kvm_vcpu_ioctl(cs, KVM_SET_ONE_REG, &reg);
+    if (ret < 0) {
+        return ret;
     }
-    env->runtime_reg_dirty_mask = KVM_S390_RUNTIME_DIRTY_NONE;
 
-    /* Do we need to save more than that? */
-    if (level == KVM_PUT_RUNTIME_STATE) {
-        return 0;
+    reg.id = KVM_REG_S390_TODPR;
+    reg.addr = (__u64)&(env->todpr);
+    ret = kvm_vcpu_ioctl(cs, KVM_SET_ONE_REG, &reg);
+    if (ret < 0) {
+        return ret;
     }
 
     if (cap_sync_regs &&
@@ -216,50 +213,9 @@ int kvm_arch_get_registers(CPUState *cs)
     S390CPU *cpu = S390_CPU(cs);
     CPUS390XState *env = &cpu->env;
     struct kvm_one_reg reg;
-    int r;
-
-    r = kvm_s390_get_registers_partial(cs);
-    if (r < 0) {
-        return r;
-    }
-
-    reg.id = KVM_REG_S390_CPU_TIMER;
-    reg.addr = (__u64)&(env->cputm);
-    r = kvm_vcpu_ioctl(cs, KVM_GET_ONE_REG, &reg);
-    if (r < 0) {
-        return r;
-    }
-
-    reg.id = KVM_REG_S390_CLOCK_COMP;
-    reg.addr = (__u64)&(env->ckc);
-    r = kvm_vcpu_ioctl(cs, KVM_GET_ONE_REG, &reg);
-    if (r < 0) {
-        return r;
-    }
-
-    reg.id = KVM_REG_S390_TODPR;
-    reg.addr = (__u64)&(env->todpr);
-    r = kvm_vcpu_ioctl(cs, KVM_GET_ONE_REG, &reg);
-    if (r < 0) {
-        return r;
-    }
-
-    env->runtime_reg_dirty_mask = KVM_S390_RUNTIME_DIRTY_FULL;
-    return 0;
-}
-
-int kvm_s390_get_registers_partial(CPUState *cs)
-{
-    S390CPU *cpu = S390_CPU(cs);
-    CPUS390XState *env = &cpu->env;
     struct kvm_sregs sregs;
     struct kvm_regs regs;
-    int ret;
-    int i;
-
-    if (env->runtime_reg_dirty_mask) {
-        return 0;
-    }
+    int i, r;
 
     /* get the PSW */
     env->psw.addr = cs->kvm_run->psw_addr;
@@ -271,9 +227,9 @@ int kvm_s390_get_registers_partial(CPUState *cs)
             env->regs[i] = cs->kvm_run->s.regs.gprs[i];
         }
     } else {
-        ret = kvm_vcpu_ioctl(cs, KVM_GET_REGS, &regs);
-        if (ret < 0) {
-            return ret;
+        r = kvm_vcpu_ioctl(cs, KVM_GET_REGS, &regs);
+        if (r < 0) {
+            return r;
         }
          for (i = 0; i < 16; i++) {
             env->regs[i] = regs.gprs[i];
@@ -289,9 +245,9 @@ int kvm_s390_get_registers_partial(CPUState *cs)
             env->cregs[i] = cs->kvm_run->s.regs.crs[i];
         }
     } else {
-        ret = kvm_vcpu_ioctl(cs, KVM_GET_SREGS, &sregs);
-        if (ret < 0) {
-            return ret;
+        r = kvm_vcpu_ioctl(cs, KVM_GET_SREGS, &sregs);
+        if (r < 0) {
+            return r;
         }
          for (i = 0; i < 16; i++) {
             env->aregs[i] = sregs.acrs[i];
@@ -299,14 +255,33 @@ int kvm_s390_get_registers_partial(CPUState *cs)
         }
     }
 
-    /* Finally the prefix */
+    /* The prefix */
     if (cap_sync_regs && cs->kvm_run->kvm_valid_regs & KVM_SYNC_PREFIX) {
         env->psa = cs->kvm_run->s.regs.prefix;
-    } else {
-        /* no prefix without sync regs */
     }
 
-    env->runtime_reg_dirty_mask = KVM_S390_RUNTIME_DIRTY_PARTIAL;
+    /* One Regs */
+    reg.id = KVM_REG_S390_CPU_TIMER;
+    reg.addr = (__u64)&(env->cputm);
+    r = kvm_vcpu_ioctl(cs, KVM_GET_ONE_REG, &reg);
+    if (r < 0) {
+        return r;
+    }
+
+    reg.id = KVM_REG_S390_CLOCK_COMP;
+    reg.addr = (__u64)&(env->ckc);
+    r = kvm_vcpu_ioctl(cs, KVM_GET_ONE_REG, &reg);
+    if (r < 0) {
+        return r;
+    }
+
+    reg.id = KVM_REG_S390_TODPR;
+    reg.addr = (__u64)&(env->todpr);
+    r = kvm_vcpu_ioctl(cs, KVM_GET_ONE_REG, &reg);
+    if (r < 0) {
+        return r;
+    }
+
     return 0;
 }
 
@@ -442,15 +417,13 @@ static int kvm_handle_css_inst(S390CPU *cpu, struct kvm_run *run,
                                uint8_t ipa0, uint8_t ipa1, uint8_t ipb)
 {
     CPUS390XState *env = &cpu->env;
-    CPUState *cs = CPU(cpu);
 
     if (ipa0 != 0xb2) {
         /* Not handled for now. */
         return -1;
     }
 
-    kvm_s390_get_registers_partial(cs);
-    cs->kvm_vcpu_dirty = true;
+    cpu_synchronize_state(CPU(cpu));
 
     switch (ipa1) {
     case PRIV_XSCH:
@@ -537,11 +510,9 @@ static int handle_priv(S390CPU *cpu, struct kvm_run *run,
 
 static int handle_hypercall(S390CPU *cpu, struct kvm_run *run)
 {
-    CPUState *cs = CPU(cpu);
     CPUS390XState *env = &cpu->env;
 
-    kvm_s390_get_registers_partial(cs);
-    cs->kvm_vcpu_dirty = true;
+    cpu_synchronize_state(CPU(cpu));
     env->regs[2] = s390_virtio_hypercall(env);
 
     return 0;
@@ -767,8 +738,7 @@ static int handle_tsch(S390CPU *cpu)
     struct kvm_run *run = cs->kvm_run;
     int ret;
 
-    kvm_s390_get_registers_partial(cs);
-    cs->kvm_vcpu_dirty = true;
+    cpu_synchronize_state(cs);
 
     ret = ioinst_handle_tsch(env, env->regs[1], run->s390_tsch.ipb);
     if (ret >= 0) {