1 files changed, 168 insertions, 81 deletions

diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index 4a814bf..613ec9a 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -25,11 +25,11 @@
 #if PTTYPE == 64
 	#define pt_element_t u64
 	#define guest_walker guest_walker64
+	#define shadow_walker shadow_walker64
 	#define FNAME(name) paging##64_##name
 	#define PT_BASE_ADDR_MASK PT64_BASE_ADDR_MASK
 	#define PT_DIR_BASE_ADDR_MASK PT64_DIR_BASE_ADDR_MASK
 	#define PT_INDEX(addr, level) PT64_INDEX(addr, level)
-	#define SHADOW_PT_INDEX(addr, level) PT64_INDEX(addr, level)
 	#define PT_LEVEL_MASK(level) PT64_LEVEL_MASK(level)
 	#define PT_LEVEL_BITS PT64_LEVEL_BITS
 	#ifdef CONFIG_X86_64
@@ -42,11 +42,11 @@
 #elif PTTYPE == 32
 	#define pt_element_t u32
 	#define guest_walker guest_walker32
+	#define shadow_walker shadow_walker32
 	#define FNAME(name) paging##32_##name
 	#define PT_BASE_ADDR_MASK PT32_BASE_ADDR_MASK
 	#define PT_DIR_BASE_ADDR_MASK PT32_DIR_BASE_ADDR_MASK
 	#define PT_INDEX(addr, level) PT32_INDEX(addr, level)
-	#define SHADOW_PT_INDEX(addr, level) PT64_INDEX(addr, level)
 	#define PT_LEVEL_MASK(level) PT32_LEVEL_MASK(level)
 	#define PT_LEVEL_BITS PT32_LEVEL_BITS
 	#define PT_MAX_FULL_LEVELS 2
@@ -73,6 +73,17 @@ struct guest_walker {
 	u32 error_code;
 };
 
+struct shadow_walker {
+	struct kvm_shadow_walk walker;
+	struct guest_walker *guest_walker;
+	int user_fault;
+	int write_fault;
+	int largepage;
+	int *ptwrite;
+	pfn_t pfn;
+	u64 *sptep;
+};
+
 static gfn_t gpte_to_gfn(pt_element_t gpte)
 {
 	return (gpte & PT_BASE_ADDR_MASK) >> PAGE_SHIFT;
@@ -91,14 +102,10 @@ static bool FNAME(cmpxchg_gpte)(struct kvm *kvm,
 	pt_element_t *table;
 	struct page *page;
 
-	down_read(&current->mm->mmap_sem);
 	page = gfn_to_page(kvm, table_gfn);
-	up_read(&current->mm->mmap_sem);
 
 	table = kmap_atomic(page, KM_USER0);
-
 	ret = CMPXCHG(&table[index], orig_pte, new_pte);
-
 	kunmap_atomic(table, KM_USER0);
 
 	kvm_release_page_dirty(page);
@@ -274,86 +281,89 @@ static void FNAME(update_pte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *page,
 /*
  * Fetch a shadow pte for a specific level in the paging hierarchy.
  */
-static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
-			 struct guest_walker *walker,
-			 int user_fault, int write_fault, int largepage,
-			 int *ptwrite, pfn_t pfn)
+static int FNAME(shadow_walk_entry)(struct kvm_shadow_walk *_sw,
+				    struct kvm_vcpu *vcpu, u64 addr,
+				    u64 *sptep, int level)
 {
-	hpa_t shadow_addr;
-	int level;
-	u64 *shadow_ent;
-	unsigned access = walker->pt_access;
-
-	if (!is_present_pte(walker->ptes[walker->level - 1]))
-		return NULL;
-
-	shadow_addr = vcpu->arch.mmu.root_hpa;
-	level = vcpu->arch.mmu.shadow_root_level;
-	if (level == PT32E_ROOT_LEVEL) {
-		shadow_addr = vcpu->arch.mmu.pae_root[(addr >> 30) & 3];
-		shadow_addr &= PT64_BASE_ADDR_MASK;
-		--level;
+	struct shadow_walker *sw =
+		container_of(_sw, struct shadow_walker, walker);
+	struct guest_walker *gw = sw->guest_walker;
+	unsigned access = gw->pt_access;
+	struct kvm_mmu_page *shadow_page;
+	u64 spte;
+	int metaphysical;
+	gfn_t table_gfn;
+	int r;
+	pt_element_t curr_pte;
+
+	if (level == PT_PAGE_TABLE_LEVEL
+	    || (sw->largepage && level == PT_DIRECTORY_LEVEL)) {
+		mmu_set_spte(vcpu, sptep, access, gw->pte_access & access,
+			     sw->user_fault, sw->write_fault,
+			     gw->ptes[gw->level-1] & PT_DIRTY_MASK,
+			     sw->ptwrite, sw->largepage, gw->gfn, sw->pfn,
+			     false);
+		sw->sptep = sptep;
+		return 1;
 	}
 
-	for (; ; level--) {
-		u32 index = SHADOW_PT_INDEX(addr, level);
-		struct kvm_mmu_page *shadow_page;
-		u64 shadow_pte;
-		int metaphysical;
-		gfn_t table_gfn;
-
-		shadow_ent = ((u64 *)__va(shadow_addr)) + index;
-		if (level == PT_PAGE_TABLE_LEVEL)
-			break;
-
-		if (largepage && level == PT_DIRECTORY_LEVEL)
-			break;
+	if (is_shadow_present_pte(*sptep) && !is_large_pte(*sptep))
+		return 0;
 
-		if (is_shadow_present_pte(*shadow_ent)
-		    && !is_large_pte(*shadow_ent)) {
-			shadow_addr = *shadow_ent & PT64_BASE_ADDR_MASK;
-			continue;
-		}
+	if (is_large_pte(*sptep)) {
+		set_shadow_pte(sptep, shadow_trap_nonpresent_pte);
+		kvm_flush_remote_tlbs(vcpu->kvm);
+		rmap_remove(vcpu->kvm, sptep);
+	}
 
-		if (is_large_pte(*shadow_ent))
-			rmap_remove(vcpu->kvm, shadow_ent);
-
-		if (level - 1 == PT_PAGE_TABLE_LEVEL
-		    && walker->level == PT_DIRECTORY_LEVEL) {
-			metaphysical = 1;
-			if (!is_dirty_pte(walker->ptes[level - 1]))
-				access &= ~ACC_WRITE_MASK;
-			table_gfn = gpte_to_gfn(walker->ptes[level - 1]);
-		} else {
-			metaphysical = 0;
-			table_gfn = walker->table_gfn[level - 2];
-		}
-		shadow_page = kvm_mmu_get_page(vcpu, table_gfn, addr, level-1,
-					       metaphysical, access,
-					       shadow_ent);
-		if (!metaphysical) {
-			int r;
-			pt_element_t curr_pte;
-			r = kvm_read_guest_atomic(vcpu->kvm,
-						  walker->pte_gpa[level - 2],
-						  &curr_pte, sizeof(curr_pte));
-			if (r || curr_pte != walker->ptes[level - 2]) {
-				kvm_release_pfn_clean(pfn);
-				return NULL;
-			}
+	if (level == PT_DIRECTORY_LEVEL && gw->level == PT_DIRECTORY_LEVEL) {
+		metaphysical = 1;
+		if (!is_dirty_pte(gw->ptes[level - 1]))
+			access &= ~ACC_WRITE_MASK;
+		table_gfn = gpte_to_gfn(gw->ptes[level - 1]);
+	} else {
+		metaphysical = 0;
+		table_gfn = gw->table_gfn[level - 2];
+	}
+	shadow_page = kvm_mmu_get_page(vcpu, table_gfn, (gva_t)addr, level-1,
+				       metaphysical, access, sptep);
+	if (!metaphysical) {
+		r = kvm_read_guest_atomic(vcpu->kvm, gw->pte_gpa[level - 2],
+					  &curr_pte, sizeof(curr_pte));
+		if (r || curr_pte != gw->ptes[level - 2]) {
+			kvm_release_pfn_clean(sw->pfn);
+			sw->sptep = NULL;
+			return 1;
 		}
-		shadow_addr = __pa(shadow_page->spt);
-		shadow_pte = shadow_addr | PT_PRESENT_MASK | PT_ACCESSED_MASK
-			| PT_WRITABLE_MASK | PT_USER_MASK;
-		set_shadow_pte(shadow_ent, shadow_pte);
 	}
 
-	mmu_set_spte(vcpu, shadow_ent, access, walker->pte_access & access,
-		     user_fault, write_fault,
-		     walker->ptes[walker->level-1] & PT_DIRTY_MASK,
-		     ptwrite, largepage, walker->gfn, pfn, false);
+	spte = __pa(shadow_page->spt) | PT_PRESENT_MASK | PT_ACCESSED_MASK
+		| PT_WRITABLE_MASK | PT_USER_MASK;
+	*sptep = spte;
+	return 0;
+}
+
+static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
+			 struct guest_walker *guest_walker,
+			 int user_fault, int write_fault, int largepage,
+			 int *ptwrite, pfn_t pfn)
+{
+	struct shadow_walker walker = {
+		.walker = { .entry = FNAME(shadow_walk_entry), },
+		.guest_walker = guest_walker,
+		.user_fault = user_fault,
+		.write_fault = write_fault,
+		.largepage = largepage,
+		.ptwrite = ptwrite,
+		.pfn = pfn,
+	};
+
+	if (!is_present_pte(guest_walker->ptes[guest_walker->level - 1]))
+		return NULL;
+
+	walk_shadow(&walker.walker, vcpu, addr);
 
-	return shadow_ent;
+	return walker.sptep;
 }
 
 /*
@@ -407,7 +417,6 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr,
 		return 0;
 	}
 
-	down_read(&current->mm->mmap_sem);
 	if (walker.level == PT_DIRECTORY_LEVEL) {
 		gfn_t large_gfn;
 		large_gfn = walker.gfn & ~(KVM_PAGES_PER_HPAGE-1);
@@ -417,9 +426,8 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr,
 		}
 	}
 	mmu_seq = vcpu->kvm->mmu_notifier_seq;
-	/* implicit mb(), we'll read before PT lock is unlocked */
+	smp_rmb();
 	pfn = gfn_to_pfn(vcpu->kvm, walker.gfn);
-	up_read(&current->mm->mmap_sem);
 
 	/* mmio */
 	if (is_error_pfn(pfn)) {
@@ -453,6 +461,31 @@ out_unlock:
 	return 0;
 }
 
+static int FNAME(shadow_invlpg_entry)(struct kvm_shadow_walk *_sw,
+				      struct kvm_vcpu *vcpu, u64 addr,
+				      u64 *sptep, int level)
+{
+
+	if (level == PT_PAGE_TABLE_LEVEL) {
+		if (is_shadow_present_pte(*sptep))
+			rmap_remove(vcpu->kvm, sptep);
+		set_shadow_pte(sptep, shadow_trap_nonpresent_pte);
+		return 1;
+	}
+	if (!is_shadow_present_pte(*sptep))
+		return 1;
+	return 0;
+}
+
+static void FNAME(invlpg)(struct kvm_vcpu *vcpu, gva_t gva)
+{
+	struct shadow_walker walker = {
+		.walker = { .entry = FNAME(shadow_invlpg_entry), },
+	};
+
+	walk_shadow(&walker.walker, vcpu, gva);
+}
+
 static gpa_t FNAME(gva_to_gpa)(struct kvm_vcpu *vcpu, gva_t vaddr)
 {
 	struct guest_walker walker;
@@ -499,12 +532,66 @@ static void FNAME(prefetch_page)(struct kvm_vcpu *vcpu,
 	}
 }
 
+/*
+ * Using the cached information from sp->gfns is safe because:
+ * - The spte has a reference to the struct page, so the pfn for a given gfn
+ *   can't change unless all sptes pointing to it are nuked first.
+ * - Alias changes zap the entire shadow cache.
+ */
+static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
+{
+	int i, offset, nr_present;
+
+	offset = nr_present = 0;
+
+	if (PTTYPE == 32)
+		offset = sp->role.quadrant << PT64_LEVEL_BITS;
+
+	for (i = 0; i < PT64_ENT_PER_PAGE; i++) {
+		unsigned pte_access;
+		pt_element_t gpte;
+		gpa_t pte_gpa;
+		gfn_t gfn = sp->gfns[i];
+
+		if (!is_shadow_present_pte(sp->spt[i]))
+			continue;
+
+		pte_gpa = gfn_to_gpa(sp->gfn);
+		pte_gpa += (i+offset) * sizeof(pt_element_t);
+
+		if (kvm_read_guest_atomic(vcpu->kvm, pte_gpa, &gpte,
+					  sizeof(pt_element_t)))
+			return -EINVAL;
+
+		if (gpte_to_gfn(gpte) != gfn || !is_present_pte(gpte) ||
+		    !(gpte & PT_ACCESSED_MASK)) {
+			u64 nonpresent;
+
+			rmap_remove(vcpu->kvm, &sp->spt[i]);
+			if (is_present_pte(gpte))
+				nonpresent = shadow_trap_nonpresent_pte;
+			else
+				nonpresent = shadow_notrap_nonpresent_pte;
+			set_shadow_pte(&sp->spt[i], nonpresent);
+			continue;
+		}
+
+		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, gfn,
+			 spte_to_pfn(sp->spt[i]), true, false);
+	}
+
+	return !nr_present;
+}
+
 #undef pt_element_t
 #undef guest_walker
+#undef shadow_walker
 #undef FNAME
 #undef PT_BASE_ADDR_MASK
 #undef PT_INDEX
-#undef SHADOW_PT_INDEX
 #undef PT_LEVEL_MASK
 #undef PT_DIR_BASE_ADDR_MASK
 #undef PT_LEVEL_BITS