Merge tag 'vfio-v4.12-rc1' of git://github.com/awilliam/linux-vfio

Pull VFIO updates from Alex Williamson:

 - Updates for SPAPR IOMMU backend including compatibility test and
   memory allocation check (Alexey Kardashevskiy)

 - Updates for type1 IOMMU backend to remove asynchronous locked page
   accounting and remove redundancy (Alex Williamson)

* tag 'vfio-v4.12-rc1' of git://github.com/awilliam/linux-vfio:
  vfio/type1: Reduce repetitive calls in vfio_pin_pages_remote()
  vfio/type1: Prune vfio_pin_page_external()
  vfio/type1: Remove locked page accounting workqueue
  vfio/spapr_tce: Check kzalloc() return when preregistering memory
  vfio/powerpc/spapr_tce: Enforce IOMMU type compatibility check

2 files changed, 77 insertions, 86 deletions

diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c
index cf3de91fbfe7..78dca1aa6410 100644
--- a/drivers/vfio/vfio_iommu_spapr_tce.c
+++ b/drivers/vfio/vfio_iommu_spapr_tce.c
@@ -198,6 +198,11 @@ static long tce_iommu_register_pages(struct tce_container *container,
 		return ret;
 
 	tcemem = kzalloc(sizeof(*tcemem), GFP_KERNEL);
+	if (!tcemem) {
+		mm_iommu_put(container->mm, mem);
+		return -ENOMEM;
+	}
+
 	tcemem->mem = mem;
 	list_add(&tcemem->next, &container->prereg_list);
 
@@ -1335,8 +1340,16 @@ static int tce_iommu_attach_group(void *iommu_data,
 
 	if (!table_group->ops || !table_group->ops->take_ownership ||
 			!table_group->ops->release_ownership) {
+		if (container->v2) {
+			ret = -EPERM;
+			goto unlock_exit;
+		}
 		ret = tce_iommu_take_ownership(container, table_group);
 	} else {
+		if (!container->v2) {
+			ret = -EPERM;
+			goto unlock_exit;
+		}
 		ret = tce_iommu_take_ownership_ddw(container, table_group);
 		if (!tce_groups_attached(container) && !container->tables[0])
 			container->def_window_pending = true;
diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 32d2633092a3..8549cb111627 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -246,69 +246,46 @@ static int vfio_iova_put_vfio_pfn(struct vfio_dma *dma, struct vfio_pfn *vpfn)
 	return ret;
 }
 
-struct vwork {
-	struct mm_struct	*mm;
-	long			npage;
-	struct work_struct	work;
-};
-
-/* delayed decrement/increment for locked_vm */
-static void vfio_lock_acct_bg(struct work_struct *work)
+static int vfio_lock_acct(struct task_struct *task, long npage, bool *lock_cap)
 {
-	struct vwork *vwork = container_of(work, struct vwork, work);
-	struct mm_struct *mm;
-
-	mm = vwork->mm;
-	down_write(&mm->mmap_sem);
-	mm->locked_vm += vwork->npage;
-	up_write(&mm->mmap_sem);
-	mmput(mm);
-	kfree(vwork);
-}
-
-static void vfio_lock_acct(struct task_struct *task, long npage)
-{
-	struct vwork *vwork;
 	struct mm_struct *mm;
 	bool is_current;
+	int ret;
 
 	if (!npage)
-		return;
+		return 0;
 
 	is_current = (task->mm == current->mm);
 
 	mm = is_current ? task->mm : get_task_mm(task);
 	if (!mm)
-		return; /* process exited */
+		return -ESRCH; /* process exited */
 
-	if (down_write_trylock(&mm->mmap_sem)) {
-		mm->locked_vm += npage;
-		up_write(&mm->mmap_sem);
-		if (!is_current)
-			mmput(mm);
-		return;
-	}
+	ret = down_write_killable(&mm->mmap_sem);
+	if (!ret) {
+		if (npage > 0) {
+			if (lock_cap ? !*lock_cap :
+			    !has_capability(task, CAP_IPC_LOCK)) {
+				unsigned long limit;
+
+				limit = task_rlimit(task,
+						RLIMIT_MEMLOCK) >> PAGE_SHIFT;
+
+				if (mm->locked_vm + npage > limit)
+					ret = -ENOMEM;
+			}
+		}
+
+		if (!ret)
+			mm->locked_vm += npage;
 
-	if (is_current) {
-		mm = get_task_mm(task);
-		if (!mm)
-			return;
+		up_write(&mm->mmap_sem);
 	}
 
-	/*
-	 * Couldn't get mmap_sem lock, so must setup to update
-	 * mm->locked_vm later. If locked_vm were atomic, we
-	 * wouldn't need this silliness
-	 */
-	vwork = kmalloc(sizeof(struct vwork), GFP_KERNEL);
-	if (WARN_ON(!vwork)) {
+	if (!is_current)
 		mmput(mm);
-		return;
-	}
-	INIT_WORK(&vwork->work, vfio_lock_acct_bg);
-	vwork->mm = mm;
-	vwork->npage = npage;
-	schedule_work(&vwork->work);
+
+	return ret;
 }
 
 /*
@@ -403,10 +380,10 @@ static int vaddr_get_pfn(struct mm_struct *mm, unsigned long vaddr,
  * first page and all consecutive pages with the same locking.
  */
 static long vfio_pin_pages_remote(struct vfio_dma *dma, unsigned long vaddr,
-				  long npage, unsigned long *pfn_base)
+				  long npage, unsigned long *pfn_base,
+				  bool lock_cap, unsigned long limit)
 {
-	unsigned long limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
-	bool lock_cap = capable(CAP_IPC_LOCK);
+	unsigned long pfn = 0;
 	long ret, pinned = 0, lock_acct = 0;
 	bool rsvd;
 	dma_addr_t iova = vaddr - dma->vaddr + dma->iova;
@@ -442,8 +419,6 @@ static long vfio_pin_pages_remote(struct vfio_dma *dma, unsigned long vaddr,
 	/* Lock all the consecutive pages from pfn_base */
 	for (vaddr += PAGE_SIZE, iova += PAGE_SIZE; pinned < npage;
 	     pinned++, vaddr += PAGE_SIZE, iova += PAGE_SIZE) {
-		unsigned long pfn = 0;
-
 		ret = vaddr_get_pfn(current->mm, vaddr, dma->prot, &pfn);
 		if (ret)
 			break;
@@ -460,14 +435,25 @@ static long vfio_pin_pages_remote(struct vfio_dma *dma, unsigned long vaddr,
 				put_pfn(pfn, dma->prot);
 				pr_warn("%s: RLIMIT_MEMLOCK (%ld) exceeded\n",
 					__func__, limit << PAGE_SHIFT);
-				break;
+				ret = -ENOMEM;
+				goto unpin_out;
 			}
 			lock_acct++;
 		}
 	}
 
 out:
-	vfio_lock_acct(current, lock_acct);
+	ret = vfio_lock_acct(current, lock_acct, &lock_cap);
+
+unpin_out:
+	if (ret) {
+		if (!rsvd) {
+			for (pfn = *pfn_base ; pinned ; pfn++, pinned--)
+				put_pfn(pfn, dma->prot);
+		}
+
+		return ret;
+	}
 
 	return pinned;
 }
@@ -488,7 +474,7 @@ static long vfio_unpin_pages_remote(struct vfio_dma *dma, dma_addr_t iova,
 	}
 
 	if (do_accounting)
-		vfio_lock_acct(dma->task, locked - unlocked);
+		vfio_lock_acct(dma->task, locked - unlocked, NULL);
 
 	return unlocked;
 }
@@ -496,37 +482,26 @@ static long vfio_unpin_pages_remote(struct vfio_dma *dma, dma_addr_t iova,
 static int vfio_pin_page_external(struct vfio_dma *dma, unsigned long vaddr,
 				  unsigned long *pfn_base, bool do_accounting)
 {
-	unsigned long limit;
-	bool lock_cap = has_capability(dma->task, CAP_IPC_LOCK);
 	struct mm_struct *mm;
 	int ret;
-	bool rsvd;
 
 	mm = get_task_mm(dma->task);
 	if (!mm)
 		return -ENODEV;
 
 	ret = vaddr_get_pfn(mm, vaddr, dma->prot, pfn_base);
-	if (ret)
-		goto pin_page_exit;
-
-	rsvd = is_invalid_reserved_pfn(*pfn_base);
-	limit = task_rlimit(dma->task, RLIMIT_MEMLOCK) >> PAGE_SHIFT;
-
-	if (!rsvd && !lock_cap && mm->locked_vm + 1 > limit) {
-		put_pfn(*pfn_base, dma->prot);
-		pr_warn("%s: Task %s (%d) RLIMIT_MEMLOCK (%ld) exceeded\n",
-			__func__, dma->task->comm, task_pid_nr(dma->task),
-			limit << PAGE_SHIFT);
-		ret = -ENOMEM;
-		goto pin_page_exit;
+	if (!ret && do_accounting && !is_invalid_reserved_pfn(*pfn_base)) {
+		ret = vfio_lock_acct(dma->task, 1, NULL);
+		if (ret) {
+			put_pfn(*pfn_base, dma->prot);
+			if (ret == -ENOMEM)
+				pr_warn("%s: Task %s (%d) RLIMIT_MEMLOCK "
+					"(%ld) exceeded\n", __func__,
+					dma->task->comm, task_pid_nr(dma->task),
+					task_rlimit(dma->task, RLIMIT_MEMLOCK));
+		}
 	}
 
-	if (!rsvd && do_accounting)
-		vfio_lock_acct(dma->task, 1);
-	ret = 1;
-
-pin_page_exit:
 	mmput(mm);
 	return ret;
 }
@@ -543,7 +518,7 @@ static int vfio_unpin_page_external(struct vfio_dma *dma, dma_addr_t iova,
 	unlocked = vfio_iova_put_vfio_pfn(dma, vpfn);
 
 	if (do_accounting)
-		vfio_lock_acct(dma->task, -unlocked);
+		vfio_lock_acct(dma->task, -unlocked, NULL);
 
 	return unlocked;
 }
@@ -606,10 +581,8 @@ static int vfio_iommu_type1_pin_pages(void *iommu_data,
 		remote_vaddr = dma->vaddr + iova - dma->iova;
 		ret = vfio_pin_page_external(dma, remote_vaddr, &phys_pfn[i],
 					     do_accounting);
-		if (ret <= 0) {
-			WARN_ON(!ret);
+		if (ret)
 			goto pin_unwind;
-		}
 
 		ret = vfio_add_to_pfn_list(dma, iova, phys_pfn[i]);
 		if (ret) {
@@ -740,7 +713,7 @@ static long vfio_unmap_unpin(struct vfio_iommu *iommu, struct vfio_dma *dma,
 
 	dma->iommu_mapped = false;
 	if (do_accounting) {
-		vfio_lock_acct(dma->task, -unlocked);
+		vfio_lock_acct(dma->task, -unlocked, NULL);
 		return 0;
 	}
 	return unlocked;
@@ -951,13 +924,15 @@ static int vfio_pin_map_dma(struct vfio_iommu *iommu, struct vfio_dma *dma,
 	unsigned long vaddr = dma->vaddr;
 	size_t size = map_size;
 	long npage;
-	unsigned long pfn;
+	unsigned long pfn, limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
+	bool lock_cap = capable(CAP_IPC_LOCK);
 	int ret = 0;
 
 	while (size) {
 		/* Pin a contiguous chunk of memory */
 		npage = vfio_pin_pages_remote(dma, vaddr + dma->size,
-					      size >> PAGE_SHIFT, &pfn);
+					      size >> PAGE_SHIFT, &pfn,
+					      lock_cap, limit);
 		if (npage <= 0) {
 			WARN_ON(!npage);
 			ret = (int)npage;
@@ -1067,6 +1042,8 @@ static int vfio_iommu_replay(struct vfio_iommu *iommu,
 {
 	struct vfio_domain *d;
 	struct rb_node *n;
+	unsigned long limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
+	bool lock_cap = capable(CAP_IPC_LOCK);
 	int ret;
 
 	/* Arbitrarily pick the first domain in the list for lookups */
@@ -1113,7 +1090,8 @@ static int vfio_iommu_replay(struct vfio_iommu *iommu,
 
 				npage = vfio_pin_pages_remote(dma, vaddr,
 							      n >> PAGE_SHIFT,
-							      &pfn);
+							      &pfn, lock_cap,
+							      limit);
 				if (npage <= 0) {
 					WARN_ON(!npage);
 					ret = (int)npage;
@@ -1382,7 +1360,7 @@ static void vfio_iommu_unmap_unpin_reaccount(struct vfio_iommu *iommu)
 			if (!is_invalid_reserved_pfn(vpfn->pfn))
 				locked++;
 		}
-		vfio_lock_acct(dma->task, locked - unlocked);
+		vfio_lock_acct(dma->task, locked - unlocked, NULL);
 	}
 }