Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
KVM: s390: Enable 1M pages for gmap
While userspace is allowed to have pages of any size, the new gmap
would always use 4k pages to back the guest.
Enable 1M pages for gmap.
This allows 1M pages to be used to back a guest when userspace is using
1M pages for the corresponding addresses (e.g. THP or hugetlbfs).
Remove the limitation that disallowed having nested guests and
hugepages at the same time.
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
+5
-6
+1
-1
arch/s390/kvm/gmap.c
+1
-1
arch/s390/kvm/gmap.c
+1
-5
arch/s390/kvm/kvm-s390.c
+1
-5
arch/s390/kvm/kvm-s390.c
···
851
851
r = -EINVAL;
852
852
else {
853
853
r = 0;
854
+
set_bit(GMAP_FLAG_ALLOW_HPAGE_1M, &kvm->arch.gmap->flags);
854
855
/*
855
856
* We might have to create fake 4k page
856
857
* tables. To avoid that the hardware works on
···
5728
5727
if (!sclp.has_sief2) {
5729
5728
pr_info("SIE is not available\n");
5730
5729
return -ENODEV;
5731
-
}
5732
-
5733
-
if (nested && hpage) {
5734
-
pr_info("A KVM host that supports nesting cannot back its KVM guests with huge pages\n");
5735
-
return -EINVAL;
5736
5730
}
5737
5731
5738
5732
for (i = 0; i < 16; i++)
+3
arch/s390/kvm/pv.c
+3
arch/s390/kvm/pv.c
···
721
721
uvcb.flags.ap_allow_instr = kvm->arch.model.uv_feat_guest.ap;
722
722
uvcb.flags.ap_instr_intr = kvm->arch.model.uv_feat_guest.ap_intr;
723
723
724
+
clear_bit(GMAP_FLAG_ALLOW_HPAGE_1M, &kvm->arch.gmap->flags);
725
+
gmap_split_huge_pages(kvm->arch.gmap);
726
+
724
727
cc = uv_call_sched(0, (u64)&uvcb);
725
728
*rc = uvcb.header.rc;
726
729
*rrc = uvcb.header.rrc;