Am 19.09.18 um 10:48 schrieb Janosch Frank:
> Now that we have VSIE support for VMs with huge memory backing, let's
> make both features usable at the same time.
>
> Signed-off-by: Janosch Frank <frankja@xxxxxxxxxxxxx>
> ---
> Documentation/virtual/kvm/api.txt | 7 +++----
> arch/s390/kvm/kvm-s390.c | 14 ++------------
> arch/s390/mm/gmap.c | 1 -
> 3 files changed, 5 insertions(+), 17 deletions(-)
>
> diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
> index 8d8a372c8340..9ec6d23f41d5 100644
> --- a/Documentation/virtual/kvm/api.txt
> +++ b/Documentation/virtual/kvm/api.txt
> @@ -4509,15 +4509,14 @@ Do not enable KVM_FEATURE_PV_UNHALT if you disable HLT exits.
>
> Architectures: s390
> Parameters: none
> -Returns: 0 on success, -EINVAL if hpage module parameter was not set
> - or cmma is enabled, or the VM has the KVM_VM_S390_UCONTROL
> +Returns: 0 on success, -EINVAL if cmma is enabled, or the VM has the KVM_VM_S390_UCONTROL
> flag set
>
> With this capability the KVM support for memory backing with 1m pages
> through hugetlbfs can be enabled for a VM. After the capability is
> enabled, cmma can't be enabled anymore and pfmfi and the storage key
> -interpretation are disabled. If cmma has already been enabled or the
> -hpage module parameter is not set to 1, -EINVAL is returned.
> +interpretation are disabled. If cmma has already been enabled, -EINVAL
> +is returned.
>
> While it is generally possible to create a huge page backed VM without
> this capability, the VM will not be able to run.
> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
> index ac5da6b0b862..59f53b7c72d6 100644
> --- a/arch/s390/kvm/kvm-s390.c
> +++ b/arch/s390/kvm/kvm-s390.c
> @@ -172,11 +172,6 @@ static int nested;
> module_param(nested, int, S_IRUGO);
> MODULE_PARM_DESC(nested, "Nested virtualization support");
>
> -/* allow 1m huge page guest backing, if !nested */
> -static int hpage;
> -module_param(hpage, int, 0444);
> -MODULE_PARM_DESC(hpage, "1m huge page backing support");
> -
Do we want to keep the parameter for now?
This would allow admins to disable it system-wide as long as it is in
its early stage? (just like nested). We can allow co-existence, though.
> /*
> * For now we handle at most 16 double words as this is what the s390 base
> * kernel handles and stores in the prefix page. If we ever need to go beyond
> @@ -481,7 +476,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
> break;
> case KVM_CAP_S390_HPAGE_1M:
> r = 0;
> - if (hpage && !kvm_is_ucontrol(kvm))
> + if (!kvm_is_ucontrol(kvm))
> r = 1;
> break;
> case KVM_CAP_S390_MEM_OP:
> @@ -691,7 +686,7 @@ static int kvm_vm_ioctl_enable_cap(struct kvm *kvm, struct kvm_enable_cap *cap)
> mutex_lock(&kvm->lock);
> if (kvm->created_vcpus)
> r = -EBUSY;
> - else if (!hpage || kvm->arch.use_cmma || kvm_is_ucontrol(kvm))
> + else if (kvm->arch.use_cmma || kvm_is_ucontrol(kvm))
> r = -EINVAL;
> else {
> r = 0;
> @@ -4196,11 +4191,6 @@ static int __init kvm_s390_init(void)
> return -ENODEV;
> }
>
> - if (nested && hpage) {
> - pr_info("nested (vSIE) and hpage (huge page backing) can currently not be activated concurrently");
> - return -EINVAL;
> - }
> -
> for (i = 0; i < 16; i++)
> kvm_s390_fac_base[i] |=
> S390_lowcore.stfle_fac_list[i] & nonhyp_mask(i);
> diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c
> index 8d5ce51637eb..928cb5818a21 100644
> --- a/arch/s390/mm/gmap.c
> +++ b/arch/s390/mm/gmap.c
> @@ -1830,7 +1830,6 @@ struct gmap *gmap_shadow(struct gmap *parent, unsigned long asce,
> unsigned long limit;
> int rc;
>
> - BUG_ON(parent->mm->context.allow_gmap_hpage_1m);
> BUG_ON(gmap_is_shadow(parent));
> spin_lock(&parent->shadow_lock);
> sg = gmap_find_shadow(parent, asce, edat_level);
>
--
Thanks,
David / dhildenb
