1 files changed, 75 insertions, 31 deletions

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 5e709ebb7c40..2e93630b4add 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -217,6 +217,11 @@ void kvm_make_mclock_inprogress_request(struct kvm *kvm)
 	make_all_cpus_request(kvm, KVM_REQ_MCLOCK_INPROGRESS);
 }
 
+void kvm_make_update_eoibitmap_request(struct kvm *kvm)
+{
+	make_all_cpus_request(kvm, KVM_REQ_EOIBITMAP);
+}
+
 int kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id)
 {
 	struct page *page;
@@ -714,6 +719,24 @@ static struct kvm_memslots *install_new_memslots(struct kvm *kvm,
 }
 
 /*
+ * KVM_SET_USER_MEMORY_REGION ioctl allows the following operations:
+ * - create a new memory slot
+ * - delete an existing memory slot
+ * - modify an existing memory slot
+ *   -- move it in the guest physical memory space
+ *   -- just change its flags
+ *
+ * Since flags can be changed by some of these operations, the following
+ * differentiation is the best we can do for __kvm_set_memory_region():
+ */
+enum kvm_mr_change {
+	KVM_MR_CREATE,
+	KVM_MR_DELETE,
+	KVM_MR_MOVE,
+	KVM_MR_FLAGS_ONLY,
+};
+
+/*
  * Allocate some memory and give it an address in the guest physical address
  * space.
  *
@@ -731,6 +754,7 @@ int __kvm_set_memory_region(struct kvm *kvm,
 	struct kvm_memory_slot *slot;
 	struct kvm_memory_slot old, new;
 	struct kvm_memslots *slots = NULL, *old_memslots;
+	enum kvm_mr_change change;
 
 	r = check_memory_region_flags(mem);
 	if (r)
@@ -772,17 +796,31 @@ int __kvm_set_memory_region(struct kvm *kvm,
 	new.npages = npages;
 	new.flags = mem->flags;
 
-	/*
-	 * Disallow changing a memory slot's size or changing anything about
-	 * zero sized slots that doesn't involve making them non-zero.
-	 */
 	r = -EINVAL;
-	if (npages && old.npages && npages != old.npages)
-		goto out;
-	if (!npages && !old.npages)
+	if (npages) {
+		if (!old.npages)
+			change = KVM_MR_CREATE;
+		else { /* Modify an existing slot. */
+			if ((mem->userspace_addr != old.userspace_addr) ||
+			    (npages != old.npages) ||
+			    ((new.flags ^ old.flags) & KVM_MEM_READONLY))
+				goto out;
+
+			if (base_gfn != old.base_gfn)
+				change = KVM_MR_MOVE;
+			else if (new.flags != old.flags)
+				change = KVM_MR_FLAGS_ONLY;
+			else { /* Nothing to change. */
+				r = 0;
+				goto out;
+			}
+		}
+	} else if (old.npages) {
+		change = KVM_MR_DELETE;
+	} else /* Modify a non-existent slot: disallowed. */
 		goto out;
 
-	if ((npages && !old.npages) || (base_gfn != old.base_gfn)) {
+	if ((change == KVM_MR_CREATE) || (change == KVM_MR_MOVE)) {
 		/* Check for overlaps */
 		r = -EEXIST;
 		kvm_for_each_memslot(slot, kvm->memslots) {
@@ -800,20 +838,12 @@ int __kvm_set_memory_region(struct kvm *kvm,
 		new.dirty_bitmap = NULL;
 
 	r = -ENOMEM;
-
-	/*
-	 * Allocate if a slot is being created.  If modifying a slot,
-	 * the userspace_addr cannot change.
-	 */
-	if (!old.npages) {
+	if (change == KVM_MR_CREATE) {
 		new.user_alloc = user_alloc;
 		new.userspace_addr = mem->userspace_addr;
 
 		if (kvm_arch_create_memslot(&new, npages))
 			goto out_free;
-	} else if (npages && mem->userspace_addr != old.userspace_addr) {
-		r = -EINVAL;
-		goto out_free;
 	}
 
 	/* Allocate page dirty bitmap if needed */
@@ -822,7 +852,7 @@ int __kvm_set_memory_region(struct kvm *kvm,
 			goto out_free;
 	}
 
-	if (!npages || base_gfn != old.base_gfn) {
+	if ((change == KVM_MR_DELETE) || (change == KVM_MR_MOVE)) {
 		r = -ENOMEM;
 		slots = kmemdup(kvm->memslots, sizeof(struct kvm_memslots),
 				GFP_KERNEL);
@@ -863,15 +893,23 @@ int __kvm_set_memory_region(struct kvm *kvm,
 			goto out_free;
 	}
 
-	/* map new memory slot into the iommu */
-	if (npages) {
+	/*
+	 * IOMMU mapping:  New slots need to be mapped.  Old slots need to be
+	 * un-mapped and re-mapped if their base changes.  Since base change
+	 * unmapping is handled above with slot deletion, mapping alone is
+	 * needed here.  Anything else the iommu might care about for existing
+	 * slots (size changes, userspace addr changes and read-only flag
+	 * changes) is disallowed above, so any other attribute changes getting
+	 * here can be skipped.
+	 */
+	if ((change == KVM_MR_CREATE) || (change == KVM_MR_MOVE)) {
 		r = kvm_iommu_map_pages(kvm, &new);
 		if (r)
 			goto out_slots;
 	}
 
 	/* actual memory is freed via old in kvm_free_physmem_slot below */
-	if (!npages) {
+	if (change == KVM_MR_DELETE) {
 		new.dirty_bitmap = NULL;
 		memset(&new.arch, 0, sizeof(new.arch));
 	}
@@ -1669,6 +1707,7 @@ bool kvm_vcpu_yield_to(struct kvm_vcpu *target)
 {
 	struct pid *pid;
 	struct task_struct *task = NULL;
+	bool ret = false;
 
 	rcu_read_lock();
 	pid = rcu_dereference(target->pid);
@@ -1676,17 +1715,15 @@ bool kvm_vcpu_yield_to(struct kvm_vcpu *target)
 		task = get_pid_task(target->pid, PIDTYPE_PID);
 	rcu_read_unlock();
 	if (!task)
-		return false;
+		return ret;
 	if (task->flags & PF_VCPU) {
 		put_task_struct(task);
-		return false;
-	}
-	if (yield_to(task, 1)) {
-		put_task_struct(task);
-		return true;
+		return ret;
 	}
+	ret = yield_to(task, 1);
 	put_task_struct(task);
-	return false;
+
+	return ret;
 }
 EXPORT_SYMBOL_GPL(kvm_vcpu_yield_to);
 
@@ -1727,12 +1764,14 @@ bool kvm_vcpu_eligible_for_directed_yield(struct kvm_vcpu *vcpu)
 	return eligible;
 }
 #endif
+
 void kvm_vcpu_on_spin(struct kvm_vcpu *me)
 {
 	struct kvm *kvm = me->kvm;
 	struct kvm_vcpu *vcpu;
 	int last_boosted_vcpu = me->kvm->last_boosted_vcpu;
 	int yielded = 0;
+	int try = 3;
 	int pass;
 	int i;
 
@@ -1744,7 +1783,7 @@ void kvm_vcpu_on_spin(struct kvm_vcpu *me)
 	 * VCPU is holding the lock that we need and will release it.
 	 * We approximate round-robin by starting at the last boosted VCPU.
 	 */
-	for (pass = 0; pass < 2 && !yielded; pass++) {
+	for (pass = 0; pass < 2 && !yielded && try; pass++) {
 		kvm_for_each_vcpu(i, vcpu, kvm) {
 			if (!pass && i <= last_boosted_vcpu) {
 				i = last_boosted_vcpu;
@@ -1757,10 +1796,15 @@ void kvm_vcpu_on_spin(struct kvm_vcpu *me)
 				continue;
 			if (!kvm_vcpu_eligible_for_directed_yield(vcpu))
 				continue;
-			if (kvm_vcpu_yield_to(vcpu)) {
+
+			yielded = kvm_vcpu_yield_to(vcpu);
+			if (yielded > 0) {
 				kvm->last_boosted_vcpu = i;
-				yielded = 1;
 				break;
+			} else if (yielded < 0) {
+				try--;
+				if (!try)
+					break;
 			}
 		}
 	}