KVM: s390: ucontrol: export SIE control block to user

This patch exports the s390 SIE hardware control block to userspace
via the mapping of the vcpu file descriptor. In order to do so,
a new arch callback named kvm_arch_vcpu_fault  is introduced for all
architectures. It allows to map architecture specific pages.

Signed-off-by: Carsten Otte <cotte@de.ibm.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 13 insertions, 0 deletions

diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index af05328aca25..d6bc65aeb950 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -763,6 +763,19 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
         return r;
 }
 
+int kvm_arch_vcpu_fault(struct kvm_vcpu *vcpu, struct vm_fault *vmf)
+{
+#ifdef CONFIG_KVM_S390_UCONTROL
+        if ((vmf->pgoff == KVM_S390_SIE_PAGE_OFFSET)
+                 && (kvm_is_ucontrol(vcpu->kvm))) {
+                vmf->page = virt_to_page(vcpu->arch.sie_block);
+                get_page(vmf->page);
+                return 0;
+        }
+#endif
+        return VM_FAULT_SIGBUS;
+}
+
 /* Section: memory related */
 int kvm_arch_prepare_memory_region(struct kvm *kvm,
                                    struct kvm_memory_slot *memslot,