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From: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
To: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>,
	Gleb Natapov <gleb@redhat.com>,
	LKML <linux-kernel@vger.kernel.org>, KVM <kvm@vger.kernel.org>
Subject: [PATCH v3 1/5] KVM: MMU: introduce mmu_spte_establish
Date: Tue, 05 Feb 2013 16:53:19 +0800	[thread overview]
Message-ID: <5110C87F.7020601@linux.vnet.ibm.com> (raw)
In-Reply-To: <5110C853.4080705@linux.vnet.ibm.com>

There is little different between walking parent pte and walking ramp:
all spte in rmap must be present but this is not true on parent pte list,
in kvm_mmu_alloc_page, we always link the parent list before set the spte
to present

This patch introduce mmu_spte_establish which set the spte before linking
it to parent list to eliminates the different then it is possible to unify
the code of walking pte list

Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
---
 arch/x86/kvm/mmu.c         |   81 ++++++++++++++++++++++---------------------
 arch/x86/kvm/paging_tmpl.h |   16 ++++-----
 2 files changed, 48 insertions(+), 49 deletions(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 8041454..68d4d5f 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1482,9 +1482,6 @@ static unsigned kvm_page_table_hashfn(gfn_t gfn)
 static void mmu_page_add_parent_pte(struct kvm_vcpu *vcpu,
 				    struct kvm_mmu_page *sp, u64 *parent_pte)
 {
-	if (!parent_pte)
-		return;
-
 	pte_list_add(vcpu, parent_pte, &sp->parent_ptes);
 }

@@ -1502,7 +1499,7 @@ static void drop_parent_pte(struct kvm_mmu_page *sp,
 }

 static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu,
-					       u64 *parent_pte, int direct)
+					       int direct)
 {
 	struct kvm_mmu_page *sp;
 	sp = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_header_cache);
@@ -1512,7 +1509,6 @@ static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu,
 	set_page_private(virt_to_page(sp->spt), (unsigned long)sp);
 	list_add(&sp->link, &vcpu->kvm->arch.active_mmu_pages);
 	sp->parent_ptes = 0;
-	mmu_page_add_parent_pte(vcpu, sp, parent_pte);
 	kvm_mod_used_mmu_pages(vcpu->kvm, +1);
 	return sp;
 }
@@ -1845,8 +1841,7 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu,
 					     gva_t gaddr,
 					     unsigned level,
 					     int direct,
-					     unsigned access,
-					     u64 *parent_pte)
+					     unsigned access)
 {
 	union kvm_mmu_page_role role;
 	unsigned quadrant;
@@ -1876,19 +1871,15 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu,
 		if (sp->unsync && kvm_sync_page_transient(vcpu, sp))
 			break;

-		mmu_page_add_parent_pte(vcpu, sp, parent_pte);
-		if (sp->unsync_children) {
+		if (sp->unsync_children)
 			kvm_make_request(KVM_REQ_MMU_SYNC, vcpu);
-			kvm_mmu_mark_parents_unsync(sp);
-		} else if (sp->unsync)
-			kvm_mmu_mark_parents_unsync(sp);

 		__clear_sp_write_flooding_count(sp);
 		trace_kvm_mmu_get_page(sp, false);
 		return sp;
 	}
 	++vcpu->kvm->stat.mmu_cache_miss;
-	sp = kvm_mmu_alloc_page(vcpu, parent_pte, direct);
+	sp = kvm_mmu_alloc_page(vcpu, direct);
 	if (!sp)
 		return sp;
 	sp->gfn = gfn;
@@ -1908,6 +1899,35 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu,
 	return sp;
 }

+static void link_shadow_page(u64 *sptep, struct kvm_mmu_page *sp)
+{
+	u64 spte;
+
+	spte = __pa(sp->spt) | PT_PRESENT_MASK | PT_WRITABLE_MASK |
+	       shadow_user_mask | shadow_x_mask | shadow_accessed_mask;
+
+	mmu_spte_set(sptep, spte);
+}
+
+static struct kvm_mmu_page *
+mmu_spte_establish(struct kvm_vcpu *vcpu, u64 *spte, gfn_t gfn, gva_t gaddr,
+		   unsigned level, int direct, unsigned access)
+{
+	struct kvm_mmu_page *sp;
+
+	WARN_ON(is_shadow_present_pte(*spte));
+
+	sp = kvm_mmu_get_page(vcpu, gfn, gaddr, level, direct, access);
+
+	link_shadow_page(spte, sp);
+	mmu_page_add_parent_pte(vcpu, sp, spte);
+
+	if (sp->unsync_children || sp->unsync)
+		kvm_mmu_mark_parents_unsync(sp);
+
+	return sp;
+}
+
 static void shadow_walk_init(struct kvm_shadow_walk_iterator *iterator,
 			     struct kvm_vcpu *vcpu, u64 addr)
 {
@@ -1957,16 +1977,6 @@ static void shadow_walk_next(struct kvm_shadow_walk_iterator *iterator)
 	return __shadow_walk_next(iterator, *iterator->sptep);
 }

-static void link_shadow_page(u64 *sptep, struct kvm_mmu_page *sp)
-{
-	u64 spte;
-
-	spte = __pa(sp->spt) | PT_PRESENT_MASK | PT_WRITABLE_MASK |
-	       shadow_user_mask | shadow_x_mask | shadow_accessed_mask;
-
-	mmu_spte_set(sptep, spte);
-}
-
 static void validate_direct_spte(struct kvm_vcpu *vcpu, u64 *sptep,
 				   unsigned direct_access)
 {
@@ -2023,11 +2033,6 @@ static void kvm_mmu_page_unlink_children(struct kvm *kvm,
 		mmu_page_zap_pte(kvm, sp, sp->spt + i);
 }

-static void kvm_mmu_put_page(struct kvm_mmu_page *sp, u64 *parent_pte)
-{
-	mmu_page_remove_parent_pte(sp, parent_pte);
-}
-
 static void kvm_mmu_unlink_parents(struct kvm *kvm, struct kvm_mmu_page *sp)
 {
 	u64 *sptep;
@@ -2582,9 +2587,7 @@ static int __direct_map(struct kvm_vcpu *vcpu, gpa_t v, int write,
 			bool prefault)
 {
 	struct kvm_shadow_walk_iterator iterator;
-	struct kvm_mmu_page *sp;
 	int emulate = 0;
-	gfn_t pseudo_gfn;

 	for_each_shadow_entry(vcpu, (u64)gfn << PAGE_SHIFT, iterator) {
 		if (iterator.level == level) {
@@ -2602,12 +2605,11 @@ static int __direct_map(struct kvm_vcpu *vcpu, gpa_t v, int write,
 			u64 base_addr = iterator.addr;

 			base_addr &= PT64_LVL_ADDR_MASK(iterator.level);
-			pseudo_gfn = base_addr >> PAGE_SHIFT;
-			sp = kvm_mmu_get_page(vcpu, pseudo_gfn, iterator.addr,
-					      iterator.level - 1,
-					      1, ACC_ALL, iterator.sptep);
+			mmu_spte_establish(vcpu, iterator.sptep,
+					   gpa_to_gfn(base_addr),
+					   iterator.addr, iterator.level - 1,
+					   1, ACC_ALL);

-			link_shadow_page(iterator.sptep, sp);
 		}
 	}
 	return emulate;
@@ -2926,7 +2928,7 @@ static int mmu_alloc_direct_roots(struct kvm_vcpu *vcpu)
 		spin_lock(&vcpu->kvm->mmu_lock);
 		kvm_mmu_free_some_pages(vcpu);
 		sp = kvm_mmu_get_page(vcpu, 0, 0, PT64_ROOT_LEVEL,
-				      1, ACC_ALL, NULL);
+				      1, ACC_ALL);
 		++sp->root_count;
 		spin_unlock(&vcpu->kvm->mmu_lock);
 		vcpu->arch.mmu.root_hpa = __pa(sp->spt);
@@ -2939,8 +2941,7 @@ static int mmu_alloc_direct_roots(struct kvm_vcpu *vcpu)
 			kvm_mmu_free_some_pages(vcpu);
 			sp = kvm_mmu_get_page(vcpu, i << (30 - PAGE_SHIFT),
 					      i << 30,
-					      PT32_ROOT_LEVEL, 1, ACC_ALL,
-					      NULL);
+					      PT32_ROOT_LEVEL, 1, ACC_ALL);
 			root = __pa(sp->spt);
 			++sp->root_count;
 			spin_unlock(&vcpu->kvm->mmu_lock);
@@ -2977,7 +2978,7 @@ static int mmu_alloc_shadow_roots(struct kvm_vcpu *vcpu)
 		spin_lock(&vcpu->kvm->mmu_lock);
 		kvm_mmu_free_some_pages(vcpu);
 		sp = kvm_mmu_get_page(vcpu, root_gfn, 0, PT64_ROOT_LEVEL,
-				      0, ACC_ALL, NULL);
+				      0, ACC_ALL);
 		root = __pa(sp->spt);
 		++sp->root_count;
 		spin_unlock(&vcpu->kvm->mmu_lock);
@@ -3012,7 +3013,7 @@ static int mmu_alloc_shadow_roots(struct kvm_vcpu *vcpu)
 		kvm_mmu_free_some_pages(vcpu);
 		sp = kvm_mmu_get_page(vcpu, root_gfn, i << 30,
 				      PT32_ROOT_LEVEL, 0,
-				      ACC_ALL, NULL);
+				      ACC_ALL);
 		root = __pa(sp->spt);
 		++sp->root_count;
 		spin_unlock(&vcpu->kvm->mmu_lock);
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index 105dd5b..3605ff7 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -434,8 +434,9 @@ static int FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
 		sp = NULL;
 		if (!is_shadow_present_pte(*it.sptep)) {
 			table_gfn = gw->table_gfn[it.level - 2];
-			sp = kvm_mmu_get_page(vcpu, table_gfn, addr, it.level-1,
-					      false, access, it.sptep);
+			sp = mmu_spte_establish(vcpu, it.sptep, table_gfn,
+						addr, it.level-1, false,
+						access);
 		}

 		/*
@@ -444,9 +445,6 @@ static int FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
 		 */
 		if (FNAME(gpte_changed)(vcpu, gw, it.level - 1))
 			goto out_gpte_changed;
-
-		if (sp)
-			link_shadow_page(it.sptep, sp);
 	}

 	for (;
@@ -464,9 +462,8 @@ static int FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,

 		direct_gfn = gw->gfn & ~(KVM_PAGES_PER_HPAGE(it.level) - 1);

-		sp = kvm_mmu_get_page(vcpu, direct_gfn, addr, it.level-1,
-				      true, direct_access, it.sptep);
-		link_shadow_page(it.sptep, sp);
+		mmu_spte_establish(vcpu, it.sptep, direct_gfn, addr,
+				   it.level-1, true, direct_access);
 	}

 	clear_sp_write_flooding_count(it.sptep);
@@ -478,7 +475,8 @@ static int FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,

 out_gpte_changed:
 	if (sp)
-		kvm_mmu_put_page(sp, it.sptep);
+		drop_parent_pte(sp, it.sptep);
+
 	kvm_release_pfn_clean(pfn);
 	return 0;
 }
-- 
1.7.7.6


  reply	other threads:[~2013-02-05  8:53 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-02-05  8:52 [PATCH v3 0/5] KVM: MMU: unify and cleanup the code of walking pte list Xiao Guangrong
2013-02-05  8:53 ` Xiao Guangrong [this message]
2013-02-08 21:35   ` [PATCH v3 1/5] KVM: MMU: introduce mmu_spte_establish Marcelo Tosatti
2013-02-05  8:53 ` [PATCH v3 2/5] KVM: MMU: clarify the logic in kvm_set_pte_rmapp Xiao Guangrong
2013-02-05  8:54 ` [PATCH v3 3/5] KVM: MMU: unify the code of walking pte list Xiao Guangrong
2013-02-05  8:54 ` [PATCH v3 4/5] KVM: MMU: fix spte assertion Xiao Guangrong
2013-02-05  8:55 ` [PATCH v3 5/5] KVM: MMU: fast drop all spte on the pte_list Xiao Guangrong
2013-02-08 21:48   ` Marcelo Tosatti
2013-02-05 13:04 ` [PATCH v3 0/5] KVM: MMU: unify and cleanup the code of walking pte list Gleb Natapov

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