From a411edf1320ed8fa3b4560902ac4e033c4a72bcf Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Tue, 2 Feb 2016 15:41:22 +0100 Subject: [PATCH] KVM: s390: vsie: add module parameter "nested" Let's be careful first and allow nested virtualization only if enabled by the system administrator. In addition, user space still has to explicitly enable it via SCLP features for it to work. Acked-by: Christian Borntraeger Signed-off-by: David Hildenbrand Signed-off-by: Christian Borntraeger --- arch/s390/kvm/kvm-s390.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 31cf22f7d846..03eeeb0ded24 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -125,6 +125,11 @@ struct kvm_stats_debugfs_item debugfs_entries[] = { { NULL } }; +/* allow nested virtualization in KVM (if enabled by user space) */ +static int nested; +module_param(nested, int, S_IRUGO); +MODULE_PARM_DESC(nested, "Nested virtualization support"); + /* upper facilities limit for kvm */ unsigned long kvm_s390_fac_list_mask[16] = { 0xffe6000000000000UL, @@ -264,7 +269,7 @@ static void kvm_s390_cpu_feat_init(void) * 64bit SCAO (SCA passthrough) and IDTE (for gmap_shadow unshadowing). */ if (!sclp.has_sief2 || !MACHINE_HAS_ESOP || !sclp.has_64bscao || - !test_facility(3)) + !test_facility(3) || !nested) return; allow_cpu_feat(KVM_S390_VM_CPU_FEAT_SIEF2); if (sclp.has_64bscao) -- 2.30.2