[PATCH/RFC 20/21] KVM: s390: Provide guest TOD Clock Get/Set Controls

Christian Borntraeger
2015-01-15T13:43:33Z

From: "Jason J. Herne" <jjherne@linux.vnet.ibm.com>

Provide controls for setting/getting the guest TOD clock based on the VM
attribute interface.

Provide TOD and TOD_HIGH vm attributes on s390 for managing guest Time Of
Day clock value.

TOD_HIGH is presently always set to 0. In the future it will contain a high
order expansion of the tod clock value after it overflows the 64-bits of
the TOD.

Signed-off-by: Jason J. Herne <jjherne@linux.vnet.ibm.com>
Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
---
arch/s390/include/asm/kvm_host.h | 1 +
arch/s390/include/uapi/asm/kvm.h | 5 ++
arch/s390/kvm/kvm-s390.c | 128 +++++++++++++++++++++++++++++++++++++++
3 files changed, 134 insertions(+)

diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index a2dcd0e..8e22aa0 100644
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -528,6 +528,7 @@ struct kvm_arch{
struct mutex ipte_mutex;
spinlock_t start_stop_lock;
struct kvm_s390_crypto crypto;
+ u64 epoch;
};

#define KVM_HVA_ERR_BAD (-1UL)
diff --git a/arch/s390/include/uapi/asm/kvm.h b/arch/s390/include/uapi/asm/kvm.h
index ac3000d..6c2efec 100644
--- a/arch/s390/include/uapi/asm/kvm.h
+++ b/arch/s390/include/uapi/asm/kvm.h
@@ -57,12 +57,17 @@ struct kvm_s390_io_adapter_req {

/* kvm attr_group on vm fd */
#define KVM_S390_VM_MEM_CTRL 0
+#define KVM_S390_VM_TOD 1

/* kvm attributes for mem_ctrl */
#define KVM_S390_VM_MEM_ENABLE_CMMA 0
#define KVM_S390_VM_MEM_CLR_CMMA 1
#define KVM_S390_VM_MEM_LIMIT_SIZE 2

+/* kvm attributes for KVM_S390_VM_TOD */
+#define KVM_S390_VM_TOD_LOW 0
+#define KVM_S390_VM_TOD_HIGH 1
+
/* for KVM_GET_REGS and KVM_SET_REGS */
struct kvm_regs {
/* general purpose regs for s390 */
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 3677b8c..9cf899e 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -342,6 +342,113 @@ static int kvm_s390_set_mem_control(struct kvm *kvm, struct kvm_device_attr *att
return ret;
}

+static int kvm_s390_set_tod_high(struct kvm *kvm, struct kvm_device_attr *attr)
+{
+ u8 gtod_high;
+
+ if (copy_from_user(&gtod_high, (void __user *)attr->addr,
+ sizeof(gtod_high)))
+ return -EFAULT;
+
+ if (gtod_high != 0)
+ return -EINVAL;
+
+ return 0;
+}
+
+static int kvm_s390_set_tod_low(struct kvm *kvm, struct kvm_device_attr *attr)
+{
+ struct kvm_vcpu *cur_vcpu;
+ unsigned int vcpu_idx;
+ u64 host_tod, gtod;
+ int r;
+
+ if (copy_from_user(&gtod, (void __user *)attr->addr, sizeof(gtod)))
+ return -EFAULT;
+
+ r = store_tod_clock(&host_tod);
+ if (r)
+ return r;
+
+ mutex_lock(&kvm->lock);
+ kvm->arch.epoch = gtod - host_tod;
+ kvm_for_each_vcpu(vcpu_idx, cur_vcpu, kvm) {
+ cur_vcpu->arch.sie_block->epoch = kvm->arch.epoch;
+ exit_sie(cur_vcpu);
+ }
+ mutex_unlock(&kvm->lock);
+ return 0;
+}
+
+static int kvm_s390_set_tod(struct kvm *kvm, struct kvm_device_attr *attr)
+{
+ int ret;
+
+ if (attr->flags)
+ return -EINVAL;
+
+ switch (attr->attr) {
+ case KVM_S390_VM_TOD_HIGH:
+ ret = kvm_s390_set_tod_high(kvm, attr);
+ break;
+ case KVM_S390_VM_TOD_LOW:
+ ret = kvm_s390_set_tod_low(kvm, attr);
+ break;
+ default:
+ ret = -ENXIO;
+ break;
+ }
+ return ret;
+}
+
+static int kvm_s390_get_tod_high(struct kvm *kvm, struct kvm_device_attr *attr)
+{
+ u8 gtod_high = 0;
+
+ if (copy_to_user((void __user *)attr->addr, &gtod_high,
+ sizeof(gtod_high)))
+ return -EFAULT;
+
+ return 0;
+}
+
+static int kvm_s390_get_tod_low(struct kvm *kvm, struct kvm_device_attr *attr)
+{
+ u64 host_tod, gtod;
+ int r;
+
+ r = store_tod_clock(&host_tod);
+ if (r)
+ return r;
+
+ gtod = host_tod + kvm->arch.epoch;
+ if (copy_to_user((void __user *)attr->addr, &gtod, sizeof(gtod)))
+ return -EFAULT;
+
+ return 0;
+}
+
+static int kvm_s390_get_tod(struct kvm *kvm, struct kvm_device_attr *attr)
+{
+ int ret;
+
+ if (attr->flags)
+ return -EINVAL;
+
+ switch (attr->attr) {
+ case KVM_S390_VM_TOD_HIGH:
+ ret = kvm_s390_get_tod_high(kvm, attr);
+ break;
+ case KVM_S390_VM_TOD_LOW:
+ ret = kvm_s390_get_tod_low(kvm, attr);
+ break;
+ default:
+ ret = -ENXIO;
+ break;
+ }
+ return ret;
+}
+
static int kvm_s390_vm_set_attr(struct kvm *kvm, struct kvm_device_attr *attr)
{
int ret;
@@ -350,6 +457,9 @@ static int kvm_s390_vm_set_attr(struct kvm *kvm, struct kvm_device_attr *attr)
case KVM_S390_VM_MEM_CTRL:
ret = kvm_s390_set_mem_control(kvm, attr);
break;
+ case KVM_S390_VM_TOD:
+ ret = kvm_s390_set_tod(kvm, attr);
+ break;
default:
ret = -ENXIO;
break;
@@ -366,6 +476,9 @@ static int kvm_s390_vm_get_attr(struct kvm *kvm, struct kvm_device_attr *attr)
case KVM_S390_VM_MEM_CTRL:
ret = kvm_s390_get_mem_control(kvm, attr);
break;
+ case KVM_S390_VM_TOD:
+ ret = kvm_s390_get_tod(kvm, attr);
+ break;
default:
ret = -ENXIO;
break;
@@ -391,6 +504,17 @@ static int kvm_s390_vm_has_attr(struct kvm *kvm, struct kvm_device_attr *attr)
break;
}
break;
+ case KVM_S390_VM_TOD:
+ switch (attr->attr) {
+ case KVM_S390_VM_TOD_LOW:
+ case KVM_S390_VM_TOD_HIGH:
+ ret = 0;
+ break;
+ default:
+ ret = -ENXIO;
+ break;
+ }
+ break;
default:
ret = -ENXIO;
break;
@@ -541,6 +665,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)

kvm->arch.css_support = 0;
kvm->arch.use_irqchip = 0;
+ kvm->arch.epoch = 0;

spin_lock_init(&kvm->arch.start_stop_lock);

@@ -686,6 +811,9 @@ static void kvm_s390_vcpu_initial_reset(struct kvm_vcpu *vcpu)

void kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu)
{
+ mutex_lock(&vcpu->kvm->lock);
+ vcpu->arch.sie_block->epoch = vcpu->kvm->arch.epoch;
+ mutex_unlock(&vcpu->kvm->lock);
if (!kvm_is_ucontrol(vcpu->kvm))
vcpu->arch.gmap = vcpu->kvm->arch.gmap;
}
--
1.9.3