KVM: s390: interface to query and configure cpu features
For now, we only have an interface to query and configure facilities
indicated via STFL(E). However, we also have features indicated via
SCLP, that have to be indicated to the guest by user space and usually
require KVM support.
This patch allows user space to query and configure available cpu features
for the guest.
Please note that disabling a feature doesn't necessarily mean that it is
completely disabled (e.g. ESOP is mostly handled by the SIE). We will try
our best to disable it.
Most features (e.g. SCLP) can't directly be forwarded, as most of them need
in addition to hardware support, support in KVM. As we later on want to
turn these features in KVM explicitly on/off (to simulate different
behavior), we have to filter all features provided by the hardware and
make them configurable.
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 44297ff..6960468 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -26,6 +26,7 @@
#include <linux/slab.h>
#include <linux/timer.h>
#include <linux/vmalloc.h>
+#include <linux/bitmap.h>
#include <asm/asm-offsets.h>
#include <asm/lowcore.h>
#include <asm/etr.h>
@@ -132,6 +133,9 @@
return ARRAY_SIZE(kvm_s390_fac_list_mask);
}
+/* available cpu features supported by kvm */
+static DECLARE_BITMAP(kvm_s390_available_cpu_feat, KVM_S390_VM_CPU_FEAT_NR_BITS);
+
static struct gmap_notifier gmap_notifier;
debug_info_t *kvm_s390_dbf;
@@ -677,6 +681,29 @@
return ret;
}
+static int kvm_s390_set_processor_feat(struct kvm *kvm,
+ struct kvm_device_attr *attr)
+{
+ struct kvm_s390_vm_cpu_feat data;
+ int ret = -EBUSY;
+
+ if (copy_from_user(&data, (void __user *)attr->addr, sizeof(data)))
+ return -EFAULT;
+ if (!bitmap_subset((unsigned long *) data.feat,
+ kvm_s390_available_cpu_feat,
+ KVM_S390_VM_CPU_FEAT_NR_BITS))
+ return -EINVAL;
+
+ mutex_lock(&kvm->lock);
+ if (!atomic_read(&kvm->online_vcpus)) {
+ bitmap_copy(kvm->arch.cpu_feat, (unsigned long *) data.feat,
+ KVM_S390_VM_CPU_FEAT_NR_BITS);
+ ret = 0;
+ }
+ mutex_unlock(&kvm->lock);
+ return ret;
+}
+
static int kvm_s390_set_cpu_model(struct kvm *kvm, struct kvm_device_attr *attr)
{
int ret = -ENXIO;
@@ -685,6 +712,9 @@
case KVM_S390_VM_CPU_PROCESSOR:
ret = kvm_s390_set_processor(kvm, attr);
break;
+ case KVM_S390_VM_CPU_PROCESSOR_FEAT:
+ ret = kvm_s390_set_processor_feat(kvm, attr);
+ break;
}
return ret;
}
@@ -733,6 +763,31 @@
return ret;
}
+static int kvm_s390_get_processor_feat(struct kvm *kvm,
+ struct kvm_device_attr *attr)
+{
+ struct kvm_s390_vm_cpu_feat data;
+
+ bitmap_copy((unsigned long *) data.feat, kvm->arch.cpu_feat,
+ KVM_S390_VM_CPU_FEAT_NR_BITS);
+ if (copy_to_user((void __user *)attr->addr, &data, sizeof(data)))
+ return -EFAULT;
+ return 0;
+}
+
+static int kvm_s390_get_machine_feat(struct kvm *kvm,
+ struct kvm_device_attr *attr)
+{
+ struct kvm_s390_vm_cpu_feat data;
+
+ bitmap_copy((unsigned long *) data.feat,
+ kvm_s390_available_cpu_feat,
+ KVM_S390_VM_CPU_FEAT_NR_BITS);
+ if (copy_to_user((void __user *)attr->addr, &data, sizeof(data)))
+ return -EFAULT;
+ return 0;
+}
+
static int kvm_s390_get_cpu_model(struct kvm *kvm, struct kvm_device_attr *attr)
{
int ret = -ENXIO;
@@ -744,6 +799,12 @@
case KVM_S390_VM_CPU_MACHINE:
ret = kvm_s390_get_machine(kvm, attr);
break;
+ case KVM_S390_VM_CPU_PROCESSOR_FEAT:
+ ret = kvm_s390_get_processor_feat(kvm, attr);
+ break;
+ case KVM_S390_VM_CPU_MACHINE_FEAT:
+ ret = kvm_s390_get_machine_feat(kvm, attr);
+ break;
}
return ret;
}
@@ -827,6 +888,8 @@
switch (attr->attr) {
case KVM_S390_VM_CPU_PROCESSOR:
case KVM_S390_VM_CPU_MACHINE:
+ case KVM_S390_VM_CPU_PROCESSOR_FEAT:
+ case KVM_S390_VM_CPU_MACHINE_FEAT:
ret = 0;
break;
default: