KVM: PPC: Add HPT preallocator
We're currently allocating 16MB of linear memory on demand when creating
a guest. That does work some times, but finding 16MB of linear memory
available in the system at runtime is definitely not a given.
So let's add another command line option similar to the RMA preallocator,
that we can use to keep a pool of page tables around. Now, when a guest
gets created it has a pretty low chance of receiving an OOM.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c
index 783cd35..ddc485a 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_hv.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c
@@ -44,10 +44,20 @@
unsigned long hpt;
unsigned long lpid;
struct revmap_entry *rev;
+ struct kvmppc_linear_info *li;
/* Allocate guest's hashed page table */
- hpt = __get_free_pages(GFP_KERNEL|__GFP_ZERO|__GFP_REPEAT|__GFP_NOWARN,
- HPT_ORDER - PAGE_SHIFT);
+ li = kvm_alloc_hpt();
+ if (li) {
+ /* using preallocated memory */
+ hpt = (ulong)li->base_virt;
+ kvm->arch.hpt_li = li;
+ } else {
+ /* using dynamic memory */
+ hpt = __get_free_pages(GFP_KERNEL|__GFP_ZERO|__GFP_REPEAT|
+ __GFP_NOWARN, HPT_ORDER - PAGE_SHIFT);
+ }
+
if (!hpt) {
pr_err("kvm_alloc_hpt: Couldn't alloc HPT\n");
return -ENOMEM;
@@ -88,7 +98,10 @@
{
clear_bit(kvm->arch.lpid, lpid_inuse);
vfree(kvm->arch.revmap);
- free_pages(kvm->arch.hpt_virt, HPT_ORDER - PAGE_SHIFT);
+ if (kvm->arch.hpt_li)
+ kvm_release_hpt(kvm->arch.hpt_li);
+ else
+ free_pages(kvm->arch.hpt_virt, HPT_ORDER - PAGE_SHIFT);
}
/* Bits in first HPTE dword for pagesize 4k, 64k or 16M */