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authorMarcelo Tosatti <marcelo@kvack.org>2008-02-23 09:44:30 -0500
committerAvi Kivity <avi@qumranet.com>2008-04-27 04:53:25 -0400
commit05da45583de9b383dc81dd695fe248431d6c9f2b (patch)
treea76d699e60aca4f775d5f67254214654235e2e17 /virt/kvm
parent2e53d63acba75795aa226febd140f67c58c6a353 (diff)
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/kvm')
-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 c41eb57ce29b..31db9b4d3016 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,
212 if (!dont || free->dirty_bitmap != dont->dirty_bitmap) 212 if (!dont || free->dirty_bitmap != dont->dirty_bitmap)
213 vfree(free->dirty_bitmap); 213 vfree(free->dirty_bitmap);
214 214
215 if (!dont || free->lpage_info != dont->lpage_info)
216 vfree(free->lpage_info);
217
215 free->npages = 0; 218 free->npages = 0;
216 free->dirty_bitmap = NULL; 219 free->dirty_bitmap = NULL;
217 free->rmap = NULL; 220 free->rmap = NULL;
221 free->lpage_info = NULL;
218} 222}
219 223
220void kvm_free_physmem(struct kvm *kvm) 224void kvm_free_physmem(struct kvm *kvm)
@@ -324,6 +328,25 @@ int __kvm_set_memory_region(struct kvm *kvm,
324 new.user_alloc = user_alloc; 328 new.user_alloc = user_alloc;
325 new.userspace_addr = mem->userspace_addr; 329 new.userspace_addr = mem->userspace_addr;
326 } 330 }
331 if (npages && !new.lpage_info) {
332 int largepages = npages / KVM_PAGES_PER_HPAGE;
333 if (npages % KVM_PAGES_PER_HPAGE)
334 largepages++;
335 if (base_gfn % KVM_PAGES_PER_HPAGE)
336 largepages++;
337
338 new.lpage_info = vmalloc(largepages * sizeof(*new.lpage_info));
339
340 if (!new.lpage_info)
341 goto out_free;
342
343 memset(new.lpage_info, 0, largepages * sizeof(*new.lpage_info));
344
345 if (base_gfn % KVM_PAGES_PER_HPAGE)
346 new.lpage_info[0].write_count = 1;
347 if ((base_gfn+npages) % KVM_PAGES_PER_HPAGE)
348 new.lpage_info[largepages-1].write_count = 1;
349 }
327 350
328 /* Allocate page dirty bitmap if needed */ 351 /* Allocate page dirty bitmap if needed */
329 if ((new.flags & KVM_MEM_LOG_DIRTY_PAGES) && !new.dirty_bitmap) { 352 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)
467} 490}
468EXPORT_SYMBOL_GPL(kvm_is_visible_gfn); 491EXPORT_SYMBOL_GPL(kvm_is_visible_gfn);
469 492
470static unsigned long gfn_to_hva(struct kvm *kvm, gfn_t gfn) 493unsigned long gfn_to_hva(struct kvm *kvm, gfn_t gfn)
471{ 494{
472 struct kvm_memory_slot *slot; 495 struct kvm_memory_slot *slot;
473 496