Merge tag 'v6.1-rc6' into x86/core, to resolve conflicts

Resolve conflicts between these commits in arch/x86/kernel/asm-offsets.c:

 # upstream:
 debc5a1ec0d1 ("KVM: x86: use a separate asm-offsets.c file")

 # retbleed work in x86/core:
 5d8213864ade ("x86/retbleed: Add SKL return thunk")

... and these commits in include/linux/bpf.h:

  # upstram:
  18acb7fac22f ("bpf: Revert ("Fix dispatcher patchable function entry to 5 bytes nop")")

  # x86/core commits:
  931ab63664f0 ("x86/ibt: Implement FineIBT")
  bea75b33895f ("x86/Kconfig: Introduce function padding")

The latter two modify BPF_DISPATCHER_ATTRIBUTES(), which was removed upstream.

 Conflicts:
	arch/x86/kernel/asm-offsets.c
	include/linux/bpf.h

Signed-off-by: Ingo Molnar <mingo@kernel.org>

2 files changed, 66 insertions, 23 deletions

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index e30f1b4ecfa5..25d7872b29c1 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -4585,6 +4585,9 @@ static int kvm_vm_ioctl_enable_cap_generic(struct kvm *kvm,
 	}
 	case KVM_CAP_DIRTY_LOG_RING:
 	case KVM_CAP_DIRTY_LOG_RING_ACQ_REL:
+		if (!kvm_vm_ioctl_check_extension_generic(kvm, cap->cap))
+			return -EINVAL;
+
 		return kvm_vm_ioctl_enable_dirty_log_ring(kvm, cap->args[0]);
 	default:
 		return kvm_vm_ioctl_enable_cap(kvm, cap);
@@ -4839,6 +4842,12 @@ struct compat_kvm_clear_dirty_log {
 	};
 };
 
+long __weak kvm_arch_vm_compat_ioctl(struct file *filp, unsigned int ioctl,
+				     unsigned long arg)
+{
+	return -ENOTTY;
+}
+
 static long kvm_vm_compat_ioctl(struct file *filp,
 			   unsigned int ioctl, unsigned long arg)
 {
@@ -4847,6 +4856,11 @@ static long kvm_vm_compat_ioctl(struct file *filp,
 
 	if (kvm->mm != current->mm || kvm->vm_dead)
 		return -EIO;
+
+	r = kvm_arch_vm_compat_ioctl(filp, ioctl, arg);
+	if (r != -ENOTTY)
+		return r;
+
 	switch (ioctl) {
 #ifdef CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT
 	case KVM_CLEAR_DIRTY_LOG: {
@@ -5398,6 +5412,7 @@ static int kvm_debugfs_open(struct inode *inode, struct file *file,
 			   int (*get)(void *, u64 *), int (*set)(void *, u64),
 			   const char *fmt)
 {
+	int ret;
 	struct kvm_stat_data *stat_data = (struct kvm_stat_data *)
 					  inode->i_private;
 
@@ -5409,15 +5424,13 @@ static int kvm_debugfs_open(struct inode *inode, struct file *file,
 	if (!kvm_get_kvm_safe(stat_data->kvm))
 		return -ENOENT;
 
-	if (simple_attr_open(inode, file, get,
-		    kvm_stats_debugfs_mode(stat_data->desc) & 0222
-		    ? set : NULL,
-		    fmt)) {
+	ret = simple_attr_open(inode, file, get,
+			       kvm_stats_debugfs_mode(stat_data->desc) & 0222
+			       ? set : NULL, fmt);
+	if (ret)
 		kvm_put_kvm(stat_data->kvm);
-		return -ENOMEM;
-	}
 
-	return 0;
+	return ret;
 }
 
 static int kvm_debugfs_release(struct inode *inode, struct file *file)
diff --git a/virt/kvm/pfncache.c b/virt/kvm/pfncache.c
index 68ff41d39545..346e47f15572 100644
--- a/virt/kvm/pfncache.c
+++ b/virt/kvm/pfncache.c
@@ -81,6 +81,9 @@ bool kvm_gfn_to_pfn_cache_check(struct kvm *kvm, struct gfn_to_pfn_cache *gpc,
 {
 	struct kvm_memslots *slots = kvm_memslots(kvm);
 
+	if (!gpc->active)
+		return false;
+
 	if ((gpa & ~PAGE_MASK) + len > PAGE_SIZE)
 		return false;
 
@@ -240,10 +243,11 @@ int kvm_gfn_to_pfn_cache_refresh(struct kvm *kvm, struct gfn_to_pfn_cache *gpc,
 {
 	struct kvm_memslots *slots = kvm_memslots(kvm);
 	unsigned long page_offset = gpa & ~PAGE_MASK;
-	kvm_pfn_t old_pfn, new_pfn;
+	bool unmap_old = false;
 	unsigned long old_uhva;
+	kvm_pfn_t old_pfn;
 	void *old_khva;
-	int ret = 0;
+	int ret;
 
 	/*
 	 * If must fit within a single page. The 'len' argument is
@@ -261,6 +265,11 @@ int kvm_gfn_to_pfn_cache_refresh(struct kvm *kvm, struct gfn_to_pfn_cache *gpc,
 
 	write_lock_irq(&gpc->lock);
 
+	if (!gpc->active) {
+		ret = -EINVAL;
+		goto out_unlock;
+	}
+
 	old_pfn = gpc->pfn;
 	old_khva = gpc->khva - offset_in_page(gpc->khva);
 	old_uhva = gpc->uhva;
@@ -291,6 +300,7 @@ int kvm_gfn_to_pfn_cache_refresh(struct kvm *kvm, struct gfn_to_pfn_cache *gpc,
 		/* If the HVA→PFN mapping was already valid, don't unmap it. */
 		old_pfn = KVM_PFN_ERR_FAULT;
 		old_khva = NULL;
+		ret = 0;
 	}
 
  out:
@@ -305,14 +315,15 @@ int kvm_gfn_to_pfn_cache_refresh(struct kvm *kvm, struct gfn_to_pfn_cache *gpc,
 		gpc->khva = NULL;
 	}
 
-	/* Snapshot the new pfn before dropping the lock! */
-	new_pfn = gpc->pfn;
+	/* Detect a pfn change before dropping the lock! */
+	unmap_old = (old_pfn != gpc->pfn);
 
+out_unlock:
 	write_unlock_irq(&gpc->lock);
 
 	mutex_unlock(&gpc->refresh_lock);
 
-	if (old_pfn != new_pfn)
+	if (unmap_old)
 		gpc_unmap_khva(kvm, old_pfn, old_khva);
 
 	return ret;
@@ -346,42 +357,61 @@ void kvm_gfn_to_pfn_cache_unmap(struct kvm *kvm, struct gfn_to_pfn_cache *gpc)
 }
 EXPORT_SYMBOL_GPL(kvm_gfn_to_pfn_cache_unmap);
 
+void kvm_gpc_init(struct gfn_to_pfn_cache *gpc)
+{
+	rwlock_init(&gpc->lock);
+	mutex_init(&gpc->refresh_lock);
+}
+EXPORT_SYMBOL_GPL(kvm_gpc_init);
 
-int kvm_gfn_to_pfn_cache_init(struct kvm *kvm, struct gfn_to_pfn_cache *gpc,
-			      struct kvm_vcpu *vcpu, enum pfn_cache_usage usage,
-			      gpa_t gpa, unsigned long len)
+int kvm_gpc_activate(struct kvm *kvm, struct gfn_to_pfn_cache *gpc,
+		     struct kvm_vcpu *vcpu, enum pfn_cache_usage usage,
+		     gpa_t gpa, unsigned long len)
 {
 	WARN_ON_ONCE(!usage || (usage & KVM_GUEST_AND_HOST_USE_PFN) != usage);
 
 	if (!gpc->active) {
-		rwlock_init(&gpc->lock);
-		mutex_init(&gpc->refresh_lock);
-
 		gpc->khva = NULL;
 		gpc->pfn = KVM_PFN_ERR_FAULT;
 		gpc->uhva = KVM_HVA_ERR_BAD;
 		gpc->vcpu = vcpu;
 		gpc->usage = usage;
 		gpc->valid = false;
-		gpc->active = true;
 
 		spin_lock(&kvm->gpc_lock);
 		list_add(&gpc->list, &kvm->gpc_list);
 		spin_unlock(&kvm->gpc_lock);
+
+		/*
+		 * Activate the cache after adding it to the list, a concurrent
+		 * refresh must not establish a mapping until the cache is
+		 * reachable by mmu_notifier events.
+		 */
+		write_lock_irq(&gpc->lock);
+		gpc->active = true;
+		write_unlock_irq(&gpc->lock);
 	}
 	return kvm_gfn_to_pfn_cache_refresh(kvm, gpc, gpa, len);
 }
-EXPORT_SYMBOL_GPL(kvm_gfn_to_pfn_cache_init);
+EXPORT_SYMBOL_GPL(kvm_gpc_activate);
 
-void kvm_gfn_to_pfn_cache_destroy(struct kvm *kvm, struct gfn_to_pfn_cache *gpc)
+void kvm_gpc_deactivate(struct kvm *kvm, struct gfn_to_pfn_cache *gpc)
 {
 	if (gpc->active) {
+		/*
+		 * Deactivate the cache before removing it from the list, KVM
+		 * must stall mmu_notifier events until all users go away, i.e.
+		 * until gpc->lock is dropped and refresh is guaranteed to fail.
+		 */
+		write_lock_irq(&gpc->lock);
+		gpc->active = false;
+		write_unlock_irq(&gpc->lock);
+
 		spin_lock(&kvm->gpc_lock);
 		list_del(&gpc->list);
 		spin_unlock(&kvm->gpc_lock);
 
 		kvm_gfn_to_pfn_cache_unmap(kvm, gpc);
-		gpc->active = false;
 	}
 }
-EXPORT_SYMBOL_GPL(kvm_gfn_to_pfn_cache_destroy);
+EXPORT_SYMBOL_GPL(kvm_gpc_deactivate);