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disable unsync global page optimization

PATCH Applied Marcelo Tosatti 2 participants 4 messages Apr 5, 2009 – Apr 9, 2009

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#1 lore raw

PATCH 1/2 KVM: MMU: disable global page optimization

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

arch/x86/kvm/mmu.c +1 -1
Index: kvm/arch/x86/kvm/mmu.c
===================================================================
@@ -1254,7 +1254,7 @@ static struct kvm_mmu_page *kvm_mmu_get_
 	pgprintk("%s: adding gfn %lx role %x\n", __func__, gfn, role.word);
 	sp->gfn = gfn;
 	sp->role = role;
-	sp->global = role.cr4_pge;
+	sp->global = 0;
 	hlist_add_head(&sp->hash_link, bucket);
 	if (!direct) {
 		if (rmap_write_protect(vcpu->kvm, gfn))
#2 lore raw

PATCH 2/2 KVM: MMU: remove global page optimization logic

In reply to Marcelo Tosatti

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

arch/x86/include/asm/kvm_host.h +0 -4
Index: kvm/arch/x86/include/asm/kvm_host.h
===================================================================
@@ -213,7 +213,6 @@ struct kvm_mmu_page {
 	int multimapped;         /* More than one parent_pte? */
 	int root_count;          /* Currently serving as active root */
 	bool unsync;
-	bool global;
 	unsigned int unsync_children;
 	union {
 		u64 *parent_pte;               /* !multimapped */
@@ -395,7 +394,6 @@ struct kvm_arch{
 	 */
 	struct list_head active_mmu_pages;
 	struct list_head assigned_dev_head;
-	struct list_head oos_global_pages;
 	struct iommu_domain *iommu_domain;
 	struct kvm_pic *vpic;
 	struct kvm_ioapic *vioapic;
@@ -425,7 +423,6 @@ struct kvm_vm_stat {
 	u32 mmu_recycled;
 	u32 mmu_cache_miss;
 	u32 mmu_unsync;
-	u32 mmu_unsync_global;
 	u32 remote_tlb_flush;
 	u32 lpages;
 };
@@ -640,7 +637,6 @@ void __kvm_mmu_free_some_pages(struct kv
 int kvm_mmu_load(struct kvm_vcpu *vcpu);
 void kvm_mmu_unload(struct kvm_vcpu *vcpu);
 void kvm_mmu_sync_roots(struct kvm_vcpu *vcpu);
-void kvm_mmu_sync_global(struct kvm_vcpu *vcpu);
 
 int kvm_emulate_hypercall(struct kvm_vcpu *vcpu);
 
arch/x86/kvm/mmu.c +6 -44

113 lines not on this page · raw message

arch/x86/kvm/paging_tmpl.h +2 -4
Index: kvm/arch/x86/kvm/paging_tmpl.h
===================================================================
@@ -268,8 +268,7 @@ static void FNAME(update_pte)(struct kvm
 	kvm_get_pfn(pfn);
 	mmu_set_spte(vcpu, spte, page->role.access, pte_access, 0, 0,
 		     gpte & PT_DIRTY_MASK, NULL, largepage,
-		     gpte & PT_GLOBAL_MASK, gpte_to_gfn(gpte),
-		     pfn, true);
+		     gpte_to_gfn(gpte), pfn, true);
 }
 
 /*
@@ -303,7 +302,6 @@ static u64 *FNAME(fetch)(struct kvm_vcpu
 				     user_fault, write_fault,
 				     gw->ptes[gw->level-1] & PT_DIRTY_MASK,
 				     ptwrite, largepage,
-				     gw->ptes[gw->level-1] & PT_GLOBAL_MASK,
 				     gw->gfn, pfn, false);
 			break;
 		}
@@ -592,7 +590,7 @@ static int FNAME(sync_page)(struct kvm_v
 		nr_present++;
 		pte_access = sp->role.access & FNAME(gpte_access)(vcpu, gpte);
 		set_spte(vcpu, &sp->spt[i], pte_access, 0, 0,
-			 is_dirty_pte(gpte), 0, gpte & PT_GLOBAL_MASK, gfn,
+			 is_dirty_pte(gpte), 0, gfn,
 			 spte_to_pfn(sp->spt[i]), true, false);
 	}
 
arch/x86/kvm/x86.c +0 -4
Index: kvm/arch/x86/kvm/x86.c
===================================================================
@@ -108,7 +108,6 @@ struct kvm_stats_debugfs_item debugfs_en
 	{ "mmu_recycled", VM_STAT(mmu_recycled) },
 	{ "mmu_cache_miss", VM_STAT(mmu_cache_miss) },
 	{ "mmu_unsync", VM_STAT(mmu_unsync) },
-	{ "mmu_unsync_global", VM_STAT(mmu_unsync_global) },
 	{ "remote_tlb_flush", VM_STAT(remote_tlb_flush) },
 	{ "largepages", VM_STAT(lpages) },
 	{ NULL }
@@ -321,7 +320,6 @@ void kvm_set_cr0(struct kvm_vcpu *vcpu, 
 	kvm_x86_ops->set_cr0(vcpu, cr0);
 	vcpu->arch.cr0 = cr0;
 
-	kvm_mmu_sync_global(vcpu);
 	kvm_mmu_reset_context(vcpu);
 	return;
 }
@@ -366,7 +364,6 @@ void kvm_set_cr4(struct kvm_vcpu *vcpu, 
 	kvm_x86_ops->set_cr4(vcpu, cr4);
 	vcpu->arch.cr4 = cr4;
 	vcpu->arch.mmu.base_role.cr4_pge = (cr4 & X86_CR4_PGE) && !tdp_enabled;
-	kvm_mmu_sync_global(vcpu);
 	kvm_mmu_reset_context(vcpu);
 }
 EXPORT_SYMBOL_GPL(kvm_set_cr4);
@@ -4329,7 +4326,6 @@ struct  kvm *kvm_arch_create_vm(void)
 		return ERR_PTR(-ENOMEM);
 
 	INIT_LIST_HEAD(&kvm->arch.active_mmu_pages);
-	INIT_LIST_HEAD(&kvm->arch.oos_global_pages);
 	INIT_LIST_HEAD(&kvm->arch.assigned_dev_head);
 
 	/* Reserve bit 0 of irq_sources_bitmap for userspace irq source */