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Commit c2d0ee46 authored by Marcelo Tosatti's avatar Marcelo Tosatti Committed by Avi Kivity
Browse files

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: default avatarMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent 2f8b9ee1

arch/x86/include/asm/kvm_host.h

+0 −4
Original line number Diff line number Diff line
@@ -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 kvm_vcpu *vcpu); 
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
Original line number Diff line number Diff line
@@ -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))
@@ -1647,10 +1638,6 @@ 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);



	mmu_convert_notrap(sp);
@@ -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 @@ static int set_spte(struct kvm_vcpu *vcpu, u64 *shadow_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;

arch/x86/kvm/paging_tmpl.h

+2 −4
Original line number Diff line number Diff line
@@ -268,8 +268,7 @@ static void FNAME(update_pte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *page, 
	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 *vcpu, gva_t addr, 
				     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_vcpu *vcpu, struct kvm_mmu_page *sp) 
		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
Original line number Diff line number Diff line
@@ -108,7 +108,6 @@ struct kvm_stats_debugfs_item debugfs_entries[] = { 
	{ "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 }
@@ -322,7 +321,6 @@ void kvm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0) 
	kvm_x86_ops->set_cr0(vcpu, cr0);

	vcpu->arch.cr0 = cr0;



	kvm_mmu_sync_global(vcpu);

	kvm_mmu_reset_context(vcpu);

	return;

}
@@ -371,7 +369,6 @@ void kvm_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4) 
	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);
@@ -4364,7 +4361,6 @@ 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 */