[Qemu-devel] [PATCH 2/3] s390/migration: Qemu S390 special register migration

[Christian Borntraeger <borntraeger@de.ibm.com>]

From: "Jason J. herne" <jjherne@us.ibm.com>

Use the KVM ONE_REG capability to save and restore the following special S390
cpu registers: clock comparator, tod clock programmable register and the cpu
timer.  Save/loading of these registers is required to enable guest migration on
the S390 platform.

Signed-off-by: Jason J. herne <jjherne@us.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
---
 target-s390x/cpu.h     |    4 ++++
 target-s390x/machine.c |   41 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 45 insertions(+)

diff --git a/target-s390x/cpu.h b/target-s390x/cpu.h
index ba695dd..de77335 100644
--- a/target-s390x/cpu.h
+++ b/target-s390x/cpu.h
@@ -92,6 +92,10 @@ typedef struct CPUS390XState {
 
     int ext_index;
 
+    uint64_t ckc;
+    uint64_t cputm;
+    uint32_t todpr;
+
     CPU_COMMON
 
     /* reset does memset(0) up to here */
diff --git a/target-s390x/machine.c b/target-s390x/machine.c
index 02706fd..925afb5 100644
--- a/target-s390x/machine.c
+++ b/target-s390x/machine.c
@@ -18,6 +18,7 @@ static void cpu_pre_save(void *opaque)
 {
     CPUS390XState *env = opaque;
     struct kvm_fpu fpu;
+    struct kvm_one_reg reg;
     int i, r;
 
     if (!kvm_enabled()) {
@@ -30,12 +31,31 @@ static void cpu_pre_save(void *opaque)
         env->fregs[i].ll = fpu.fprs[i];
     }
     env->fpc = fpu.fpc;
+
+    /* Retreive cpu timer value from kvm */
+    reg.id = KVM_REG_S390_CPU_TIMER;
+    reg.addr = (__u64)&(env->cputm);
+    r = kvm_vcpu_ioctl(env, KVM_GET_ONE_REG, &reg);
+    assert(r == 0);
+
+    /* Retreive clock comparator value from kvm */
+    reg.id = KVM_REG_S390_CLOCK_COMP;
+    reg.addr = (__u64)&(env->ckc);
+    r = kvm_vcpu_ioctl(env, KVM_GET_ONE_REG, &reg);
+    assert(r == 0);
+
+    /* Retreive clock comparator value from kvm */
+    reg.id = KVM_REG_S390_TODPR;
+    reg.addr = (__u64)&(env->todpr);
+    r = kvm_vcpu_ioctl(env, KVM_GET_ONE_REG, &reg);
+    assert(r == 0);
 }
 
 static int cpu_post_load(void *opaque, int version_id)
 {
     CPUS390XState *env = opaque;
     struct kvm_fpu fpu;
+    struct kvm_one_reg reg;
     int i, r;
 
     if (!kvm_enabled()) {
@@ -50,6 +70,24 @@ static int cpu_post_load(void *opaque, int version_id)
     r = kvm_vcpu_ioctl(env, KVM_SET_FPU, &fpu);
     assert(r == 0);
 
+    /* Tell KVM what the new cpu timer value is */
+    reg.id = KVM_REG_S390_CPU_TIMER;
+    reg.addr = (__u64)&(env->cputm);
+    r = kvm_vcpu_ioctl(env, KVM_SET_ONE_REG, &reg);
+    assert(r == 0);
+
+    /* Tell KVM what the new clock comparator value is */
+    reg.id = KVM_REG_S390_CLOCK_COMP;
+    reg.addr = (__u64)&(env->ckc);
+    r = kvm_vcpu_ioctl(env, KVM_SET_ONE_REG, &reg);
+    assert(r == 0);
+
+    /* Tell KVM what the new todpr value is */
+    reg.id = KVM_REG_S390_TODPR;
+    reg.addr = (__u64)&(env->todpr);
+    r = kvm_vcpu_ioctl(env, KVM_SET_ONE_REG, &reg);
+    assert(r == 0);
+
     return 0;
 }
 #else
@@ -93,6 +131,9 @@ static const VMStateDescription vmstate_cpu = {
         VMSTATE_UINT64(psw.addr, CPUS390XState),
         VMSTATE_UINT64(psa, CPUS390XState),
         VMSTATE_UINT32(fpc, CPUS390XState),
+        VMSTATE_UINT32(todpr, CPUS390XState),
+        VMSTATE_UINT64(cputm, CPUS390XState),
+        VMSTATE_UINT64(ckc, CPUS390XState),
         VMSTATE_UINT32_ARRAY(aregs, CPUS390XState, 16),
         VMSTATE_UINT64_ARRAY(cregs, CPUS390XState, 16),
         VMSTATE_END_OF_LIST()
-- 
1.7.10.1