KVM: MMU: Remove global pte tracking

The initial, noncaching, version of the kvm mmu flushed the all nonglobal
shadow page table translations (much like a native tlb flush).  The new
implementation flushes translations only when they change, rendering global
pte tracking superfluous.

This removes the unused tracking mechanism and storage space.
Signed-off-by: Avi Kivity <avi@qumranet.com>

drivers/kvm/kvm.h

@@ -136,7 +136,6 @@ struct kvm_mmu_page {
 	unsigned long slot_bitmap; /* One bit set per slot which has memory
 				    * in this shadow page.
 				    */
-	int global;              /* Set if all ptes in this page are global */
 	int multimapped;         /* More than one parent_pte? */
 	int root_count;          /* Currently serving as active root */
 	union {

drivers/kvm/mmu.c

@@ -461,7 +461,6 @@ static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu,
 	list_add(&page->link, &vcpu->kvm->active_mmu_pages);
 	ASSERT(is_empty_shadow_page(page->page_hpa));
 	page->slot_bitmap = 0;
-	page->global = 1;
 	page->multimapped = 0;
 	page->parent_pte = parent_pte;
 	--vcpu->kvm->n_free_mmu_pages;
@@ -927,11 +926,6 @@ static void paging_new_cr3(struct kvm_vcpu *vcpu)
 	kvm_arch_ops->set_cr3(vcpu, vcpu->mmu.root_hpa);
 }
 
-static void mark_pagetable_nonglobal(void *shadow_pte)
-{
-	page_header(__pa(shadow_pte))->global = 0;
-}
-
 static inline void set_pte_common(struct kvm_vcpu *vcpu,
 			     u64 *shadow_pte,
 			     gpa_t gaddr,
@@ -949,9 +943,6 @@ static inline void set_pte_common(struct kvm_vcpu *vcpu,
 
 	*shadow_pte |= access_bits;
 
-	if (!(*shadow_pte & PT_GLOBAL_MASK))
-		mark_pagetable_nonglobal(shadow_pte);
-
 	if (is_error_hpa(paddr)) {
 		*shadow_pte |= gaddr;
 		*shadow_pte |= PT_SHADOW_IO_MARK;