[PATCH 2/33] KVM: MMU: Teach the page table walker to track guest page table gfns

Avi Kivity
2007-01-04T15:51:09Z

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>

Index: linux-2.6/drivers/kvm/paging_tmpl.h
===================================================================
--- linux-2.6.orig/drivers/kvm/paging_tmpl.h
+++ linux-2.6/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 gu
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)(
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),