KVM: MMU: remove global page optimization logic

Complexity to fix it not worthwhile the gains, as discussed
in http://article.gmane.org/gmane.comp.emulators.kvm.devel/28649.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 6 insertions, 44 deletions

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index b582adde6830..b39ec626040e 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1075,18 +1075,10 @@ static struct kvm_mmu_page *kvm_mmu_lookup_page(struct kvm *kvm, gfn_t gfn)
         return NULL;
 }
 
-static void kvm_unlink_unsync_global(struct kvm *kvm, struct kvm_mmu_page *sp)
-{
-        list_del(&sp->oos_link);
-        --kvm->stat.mmu_unsync_global;
-}
-
 static void kvm_unlink_unsync_page(struct kvm *kvm, struct kvm_mmu_page *sp)
 {
         WARN_ON(!sp->unsync);
         sp->unsync = 0;
-        if (sp->global)
-                kvm_unlink_unsync_global(kvm, sp);
         --kvm->stat.mmu_unsync;
 }
 
@@ -1249,7 +1241,6 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu,
         pgprintk("%s: adding gfn %lx role %x\n", __func__, gfn, role.word);
         sp->gfn = gfn;
         sp->role = role;
-        sp->global = 0;
         hlist_add_head(&sp->hash_link, bucket);
         if (!direct) {
                 if (rmap_write_protect(vcpu->kvm, gfn))
@@ -1647,11 +1638,7 @@ static int kvm_unsync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
         ++vcpu->kvm->stat.mmu_unsync;
         sp->unsync = 1;
 
-        if (sp->global) {
-                list_add(&sp->oos_link, &vcpu->kvm->arch.oos_global_pages);
-                ++vcpu->kvm->stat.mmu_unsync_global;
-        } else
-                kvm_mmu_mark_parents_unsync(vcpu, sp);
+        kvm_mmu_mark_parents_unsync(vcpu, sp);
 
         mmu_convert_notrap(sp);
         return 0;
@@ -1678,21 +1665,12 @@ static int mmu_need_write_protect(struct kvm_vcpu *vcpu, gfn_t gfn,
 static int set_spte(struct kvm_vcpu *vcpu, u64 *shadow_pte,
                     unsigned pte_access, int user_fault,
                     int write_fault, int dirty, int largepage,
-                    int global, gfn_t gfn, pfn_t pfn, bool speculative,
+                    gfn_t gfn, pfn_t pfn, bool speculative,
                     bool can_unsync)
 {
         u64 spte;
         int ret = 0;
         u64 mt_mask = shadow_mt_mask;
-        struct kvm_mmu_page *sp = page_header(__pa(shadow_pte));
-
-        if (!global && sp->global) {
-                sp->global = 0;
-                if (sp->unsync) {
-                        kvm_unlink_unsync_global(vcpu->kvm, sp);
-                        kvm_mmu_mark_parents_unsync(vcpu, sp);
-                }
-        }
 
         /*
          * We don't set the accessed bit, since we sometimes want to see
@@ -1766,8 +1744,8 @@ set_pte:
 static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *shadow_pte,
                          unsigned pt_access, unsigned pte_access,
                          int user_fault, int write_fault, int dirty,
-                         int *ptwrite, int largepage, int global,
-                         gfn_t gfn, pfn_t pfn, bool speculative)
+                         int *ptwrite, int largepage, gfn_t gfn,
+                         pfn_t pfn, bool speculative)
 {
         int was_rmapped = 0;
         int was_writeble = is_writeble_pte(*shadow_pte);
@@ -1796,7 +1774,7 @@ static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *shadow_pte,
                         was_rmapped = 1;
         }
         if (set_spte(vcpu, shadow_pte, pte_access, user_fault, write_fault,
-                      dirty, largepage, global, gfn, pfn, speculative, true)) {
+                      dirty, largepage, gfn, pfn, speculative, true)) {
                 if (write_fault)
                         *ptwrite = 1;
                 kvm_x86_ops->tlb_flush(vcpu);
@@ -1844,7 +1822,7 @@ static int __direct_map(struct kvm_vcpu *vcpu, gpa_t v, int write,
                     || (largepage && iterator.level == PT_DIRECTORY_LEVEL)) {
                         mmu_set_spte(vcpu, iterator.sptep, ACC_ALL, ACC_ALL,
                                      0, write, 1, &pt_write,
-                                     largepage, 0, gfn, pfn, false);
+                                     largepage, gfn, pfn, false);
                         ++vcpu->stat.pf_fixed;
                         break;
                 }
@@ -2015,15 +1993,6 @@ static void mmu_sync_roots(struct kvm_vcpu *vcpu)
         }
 }
 
-static void mmu_sync_global(struct kvm_vcpu *vcpu)
-{
-        struct kvm *kvm = vcpu->kvm;
-        struct kvm_mmu_page *sp, *n;
-
-        list_for_each_entry_safe(sp, n, &kvm->arch.oos_global_pages, oos_link)
-                kvm_sync_page(vcpu, sp);
-}
-
 void kvm_mmu_sync_roots(struct kvm_vcpu *vcpu)
 {
         spin_lock(&vcpu->kvm->mmu_lock);
@@ -2031,13 +2000,6 @@ void kvm_mmu_sync_roots(struct kvm_vcpu *vcpu)
         spin_unlock(&vcpu->kvm->mmu_lock);
 }
 
-void kvm_mmu_sync_global(struct kvm_vcpu *vcpu)
-{
-        spin_lock(&vcpu->kvm->mmu_lock);
-        mmu_sync_global(vcpu);
-        spin_unlock(&vcpu->kvm->mmu_lock);
-}
-
 static gpa_t nonpaging_gva_to_gpa(struct kvm_vcpu *vcpu, gva_t vaddr)
 {
         return vaddr;