aboutsummaryrefslogtreecommitdiffstats
path: root/virt
diff options
context:
space:
mode:
authorMarcelo Tosatti <marcelo@kvack.org>2008-02-23 11:44:30 -0300
committerAvi Kivity <avi@qumranet.com>2008-04-27 11:53:25 +0300
commit05da45583de9b383dc81dd695fe248431d6c9f2b (patch)
treea76d699e60aca4f775d5f67254214654235e2e17 /virt
parent2e53d63acba75795aa226febd140f67c58c6a353 (diff)
downloadmrst-s0i3-test-05da45583de9b383dc81dd695fe248431d6c9f2b.tar.gz
mrst-s0i3-test-05da45583de9b383dc81dd695fe248431d6c9f2b.tar.xz
mrst-s0i3-test-05da45583de9b383dc81dd695fe248431d6c9f2b.zip
KVM: MMU: large page support
Create large pages mappings if the guest PTE's are marked as such and the underlying memory is hugetlbfs backed. If the largepage contains write-protected pages, a large pte is not used. Gives a consistent 2% improvement for data copies on ram mounted filesystem, without NPT/EPT. Anthony measures a 4% improvement on 4-way kernbench, with NPT. Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
Diffstat (limited to 'virt')
-rw-r--r--virt/kvm/kvm_main.c25
1 files changed, 24 insertions, 1 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index c41eb57ce29..31db9b4d301 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -212,9 +212,13 @@ static void kvm_free_physmem_slot(struct kvm_memory_slot *free,
if (!dont || free->dirty_bitmap != dont->dirty_bitmap)
vfree(free->dirty_bitmap);
+ if (!dont || free->lpage_info != dont->lpage_info)
+ vfree(free->lpage_info);
+
free->npages = 0;
free->dirty_bitmap = NULL;
free->rmap = NULL;
+ free->lpage_info = NULL;
}
void kvm_free_physmem(struct kvm *kvm)
@@ -324,6 +328,25 @@ int __kvm_set_memory_region(struct kvm *kvm,
new.user_alloc = user_alloc;
new.userspace_addr = mem->userspace_addr;
}
+ if (npages && !new.lpage_info) {
+ int largepages = npages / KVM_PAGES_PER_HPAGE;
+ if (npages % KVM_PAGES_PER_HPAGE)
+ largepages++;
+ if (base_gfn % KVM_PAGES_PER_HPAGE)
+ largepages++;
+
+ new.lpage_info = vmalloc(largepages * sizeof(*new.lpage_info));
+
+ if (!new.lpage_info)
+ goto out_free;
+
+ memset(new.lpage_info, 0, largepages * sizeof(*new.lpage_info));
+
+ if (base_gfn % KVM_PAGES_PER_HPAGE)
+ new.lpage_info[0].write_count = 1;
+ if ((base_gfn+npages) % KVM_PAGES_PER_HPAGE)
+ new.lpage_info[largepages-1].write_count = 1;
+ }
/* Allocate page dirty bitmap if needed */
if ((new.flags & KVM_MEM_LOG_DIRTY_PAGES) && !new.dirty_bitmap) {
@@ -467,7 +490,7 @@ int kvm_is_visible_gfn(struct kvm *kvm, gfn_t gfn)
}
EXPORT_SYMBOL_GPL(kvm_is_visible_gfn);
-static unsigned long gfn_to_hva(struct kvm *kvm, gfn_t gfn)
+unsigned long gfn_to_hva(struct kvm *kvm, gfn_t gfn)
{
struct kvm_memory_slot *slot;