KVM: Avoid wasting pages for small lpage_info arrays

lpage_info is created for each large level even when the memory slot is
not for RAM.  This means that when we add one slot for a PCI device, we
end up allocating at least KVM_NR_PAGE_SIZES - 1 pages by vmalloc().

To make things worse, there is an increasing number of devices which
would result in more pages being wasted this way.

This patch mitigates this problem by using kvm_kvzalloc().

Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index be6d54929fa..f12a52408cd 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6304,7 +6304,7 @@ void kvm_arch_free_memslot(struct kvm_memory_slot *free,
 
         for (i = 0; i < KVM_NR_PAGE_SIZES - 1; ++i) {
                 if (!dont || free->arch.lpage_info[i] != dont->arch.lpage_info[i]) {
-                        vfree(free->arch.lpage_info[i]);
+                        kvm_kvfree(free->arch.lpage_info[i]);
                         free->arch.lpage_info[i] = NULL;
                 }
         }
@@ -6323,7 +6323,7 @@ int kvm_arch_create_memslot(struct kvm_memory_slot *slot, unsigned long npages)
                                       slot->base_gfn, level) + 1;
 
                 slot->arch.lpage_info[i] =
-                        vzalloc(lpages * sizeof(*slot->arch.lpage_info[i]));
+                        kvm_kvzalloc(lpages * sizeof(*slot->arch.lpage_info[i]));
                 if (!slot->arch.lpage_info[i])
                         goto out_free;