This patch allows the user to fault in pages on a virtual cpus address space for user controlled virtual machines. Typically this is superfluous because userspace can just create a mapping and let the kernel's page fault logic take are of it. There is one exception: SIE won't start if the lowcore is not present. Normally the kernel takes care of this [handle_validity() in arch/s390/kvm/intercept.c] but since the kernel does not handle intercepts for user controlled virtual machines, userspace needs to be able to handle this condition.
Signed-off-by: Carsten Otte <[email protected]> --- --- arch/s390/kvm/kvm-s390.c | 6 ++++++ include/linux/kvm.h | 1 + 2 files changed, 7 insertions(+) --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -777,6 +777,12 @@ long kvm_arch_vcpu_ioctl(struct file *fi break; } #endif + case KVM_S390_VCPU_FAULT: { + r = gmap_fault(arg, vcpu->arch.gmap); + if (!IS_ERR_VALUE(r)) + r = 0; + break; + } default: r = -EINVAL; } --- a/include/linux/kvm.h +++ b/include/linux/kvm.h @@ -669,6 +669,7 @@ struct kvm_s390_ucas_mapping { #define KVM_S390_ENABLE_UCONTROL _IO(KVMIO, 0x49) #define KVM_S390_UCAS_MAP _IOW(KVMIO, 0x50, struct kvm_s390_ucas_mapping) #define KVM_S390_UCAS_UNMAP _IOW(KVMIO, 0x51, struct kvm_s390_ucas_mapping) +#define KVM_S390_VCPU_FAULT _IOW(KVMIO, 0x52, unsigned long) /* Device model IOC */ #define KVM_CREATE_IRQCHIP _IO(KVMIO, 0x60) -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
