| Message ID | 20230206164602.138068-10-scgl@linux.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: s390: Extend MEM_OP ioctl by storage key checked cmpxchg | expand |
On 2/6/23 17:45, Janis Schoetterl-Glausch wrote: > Instead of having one function covering all mem_op operations, > have a function implementing absolute access and dispatch to that > function in its caller, based on the operation code. > This way additional future operations can be implemented by adding an > implementing function without changing existing operations. > > Suggested-by: Janosch Frank <frankja@linux.ibm.com> > Signed-off-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com> > Reviewed-by: Thomas Huth <thuth@redhat.com> Reviewed-by: Janosch Frank <frankja@linux.ibm.com> > --- > arch/s390/kvm/kvm-s390.c | 38 ++++++++++++++++++++++++-------------- > 1 file changed, 24 insertions(+), 14 deletions(-) > > diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c > index 0367c1a7e69a..707967a296f1 100644 > --- a/arch/s390/kvm/kvm-s390.c > +++ b/arch/s390/kvm/kvm-s390.c > @@ -2779,7 +2779,7 @@ static int mem_op_validate_common(struct kvm_s390_mem_op *mop, u64 supported_fla > return 0; > } > > -static int kvm_s390_vm_mem_op(struct kvm *kvm, struct kvm_s390_mem_op *mop) > +static int kvm_s390_vm_mem_op_abs(struct kvm *kvm, struct kvm_s390_mem_op *mop) > { > void __user *uaddr = (void __user *)mop->buf; > void *tmpbuf = NULL; > @@ -2790,17 +2790,6 @@ static int kvm_s390_vm_mem_op(struct kvm *kvm, struct kvm_s390_mem_op *mop) > if (r) > return r; > > - /* > - * This is technically a heuristic only, if the kvm->lock is not > - * taken, it is not guaranteed that the vm is/remains non-protected. > - * This is ok from a kernel perspective, wrongdoing is detected > - * on the access, -EFAULT is returned and the vm may crash the > - * next time it accesses the memory in question. > - * There is no sane usecase to do switching and a memop on two > - * different CPUs at the same time. > - */ > - if (kvm_s390_pv_get_handle(kvm)) > - return -EINVAL; > if (!(mop->flags & KVM_S390_MEMOP_F_CHECK_ONLY)) { > tmpbuf = vmalloc(mop->size); > if (!tmpbuf) > @@ -2841,8 +2830,6 @@ static int kvm_s390_vm_mem_op(struct kvm *kvm, struct kvm_s390_mem_op *mop) > } > break; > } > - default: > - r = -EINVAL; > } > > out_unlock: > @@ -2852,6 +2839,29 @@ static int kvm_s390_vm_mem_op(struct kvm *kvm, struct kvm_s390_mem_op *mop) > return r; > } > > +static int kvm_s390_vm_mem_op(struct kvm *kvm, struct kvm_s390_mem_op *mop) > +{ > + /* > + * This is technically a heuristic only, if the kvm->lock is not > + * taken, it is not guaranteed that the vm is/remains non-protected. > + * This is ok from a kernel perspective, wrongdoing is detected > + * on the access, -EFAULT is returned and the vm may crash the > + * next time it accesses the memory in question. > + * There is no sane usecase to do switching and a memop on two > + * different CPUs at the same time. > + */ > + if (kvm_s390_pv_get_handle(kvm)) > + return -EINVAL; > + > + switch (mop->op) { > + case KVM_S390_MEMOP_ABSOLUTE_READ: > + case KVM_S390_MEMOP_ABSOLUTE_WRITE: > + return kvm_s390_vm_mem_op_abs(kvm, mop); > + default: > + return -EINVAL; > + } > +} > + > long kvm_arch_vm_ioctl(struct file *filp, > unsigned int ioctl, unsigned long arg) > {
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 0367c1a7e69a..707967a296f1 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -2779,7 +2779,7 @@ static int mem_op_validate_common(struct kvm_s390_mem_op *mop, u64 supported_fla return 0; } -static int kvm_s390_vm_mem_op(struct kvm *kvm, struct kvm_s390_mem_op *mop) +static int kvm_s390_vm_mem_op_abs(struct kvm *kvm, struct kvm_s390_mem_op *mop) { void __user *uaddr = (void __user *)mop->buf; void *tmpbuf = NULL; @@ -2790,17 +2790,6 @@ static int kvm_s390_vm_mem_op(struct kvm *kvm, struct kvm_s390_mem_op *mop) if (r) return r; - /* - * This is technically a heuristic only, if the kvm->lock is not - * taken, it is not guaranteed that the vm is/remains non-protected. - * This is ok from a kernel perspective, wrongdoing is detected - * on the access, -EFAULT is returned and the vm may crash the - * next time it accesses the memory in question. - * There is no sane usecase to do switching and a memop on two - * different CPUs at the same time. - */ - if (kvm_s390_pv_get_handle(kvm)) - return -EINVAL; if (!(mop->flags & KVM_S390_MEMOP_F_CHECK_ONLY)) { tmpbuf = vmalloc(mop->size); if (!tmpbuf) @@ -2841,8 +2830,6 @@ static int kvm_s390_vm_mem_op(struct kvm *kvm, struct kvm_s390_mem_op *mop) } break; } - default: - r = -EINVAL; } out_unlock: @@ -2852,6 +2839,29 @@ static int kvm_s390_vm_mem_op(struct kvm *kvm, struct kvm_s390_mem_op *mop) return r; } +static int kvm_s390_vm_mem_op(struct kvm *kvm, struct kvm_s390_mem_op *mop) +{ + /* + * This is technically a heuristic only, if the kvm->lock is not + * taken, it is not guaranteed that the vm is/remains non-protected. + * This is ok from a kernel perspective, wrongdoing is detected + * on the access, -EFAULT is returned and the vm may crash the + * next time it accesses the memory in question. + * There is no sane usecase to do switching and a memop on two + * different CPUs at the same time. + */ + if (kvm_s390_pv_get_handle(kvm)) + return -EINVAL; + + switch (mop->op) { + case KVM_S390_MEMOP_ABSOLUTE_READ: + case KVM_S390_MEMOP_ABSOLUTE_WRITE: + return kvm_s390_vm_mem_op_abs(kvm, mop); + default: + return -EINVAL; + } +} + long kvm_arch_vm_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg) {