[PATCH] KVM: MMU: Teach the page table walker to track guest page table gfns

Saving the table gfns removes the need to walk the guest and host page tables
in lockstep.

Signed-off-by: Avi Kivity <avi@qumranet.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/drivers/kvm/paging_tmpl.h b/drivers/kvm/paging_tmpl.h
index 8c48528..3a35c80 100644 (file)
--- a/drivers/kvm/paging_tmpl.h
+++ b/drivers/kvm/paging_tmpl.h
@@ -52,6 +52,7 @@
  */
 struct guest_walker {
        int level;
+       gfn_t table_gfn;
        pt_element_t *table;
        pt_element_t inherited_ar;
 };
@@ -63,8 +64,8 @@ static void FNAME(init_walker)(struct guest_walker *walker,
        struct kvm_memory_slot *slot;
 
        walker->level = vcpu->mmu.root_level;
-       slot = gfn_to_memslot(vcpu->kvm,
-                             (vcpu->cr3 & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT);
+       walker->table_gfn = (vcpu->cr3 & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT;
+       slot = gfn_to_memslot(vcpu->kvm, walker->table_gfn);
        hpa = safe_gpa_to_hpa(vcpu, vcpu->cr3 & PT64_BASE_ADDR_MASK);
        walker->table = kmap_atomic(pfn_to_page(hpa >> PAGE_SHIFT), KM_USER0);
 
@@ -133,6 +134,8 @@ static pt_element_t *FNAME(fetch_guest)(struct kvm_vcpu *vcpu,
                        return &walker->table[index];
                if (walker->level != 3 || is_long_mode(vcpu))
                        walker->inherited_ar &= walker->table[index];
+               walker->table_gfn = (walker->table[index] & PT_BASE_ADDR_MASK)
+                       >> PAGE_SHIFT;
                paddr = safe_gpa_to_hpa(vcpu, walker->table[index] & PT_BASE_ADDR_MASK);
                kunmap_atomic(walker->table, KM_USER0);
                walker->table = kmap_atomic(pfn_to_page(paddr >> PAGE_SHIFT),