Message-ID: <1384838233-24847-9-git-send-email-Bharat.Bhushan@freescale.com>
Date:	Tue, 19 Nov 2013 10:47:12 +0530
From:	Bharat Bhushan <r65777@...escale.com>
To:	<alex.williamson@...hat.com>, <joro@...tes.org>,
	<bhelgaas@...gle.com>, <agraf@...e.de>, <scottwood@...escale.com>,
	<stuart.yoder@...escale.com>, <iommu@...ts.linux-foundation.org>,
	<linux-pci@...r.kernel.org>, <linuxppc-dev@...ts.ozlabs.org>,
	<linux-kernel@...r.kernel.org>
CC:	Bharat Bhushan <Bharat.Bhushan@...escale.com>,
	Bharat Bhushan <bharat.bhushan@...escale.com>
Subject: [PATCH 8/9 v2] vfio: moving some functions in common file

Some function defined in vfio_iommu_type1.c are generic (not specific
or type1 iommu) and we want to use these for FSL IOMMU (PAMU) and
going forward in iommu-none driver.
So I have created a new file naming vfio_iommu_common.c and moved some
of generic functions into this file.

I Agree (with Alex Williamson and myself :-)) that some more functions
can be moved to this new common file (with some changes in type1/fsl_pamu
and others). But in this patch i avoided doing these changes and
just moved functions which are straight forward and allow me to
get fsl-powerpc vfio framework in place.

Signed-off-by: Bharat Bhushan <bharat.bhushan@...escale.com>
---
v1->v2
 - removed un-necessary header file inclusion
 - mark static function which are internal to *common.c

 drivers/vfio/Makefile            |    4 +-
 drivers/vfio/vfio_iommu_common.c |  227 ++++++++++++++++++++++++++++++++++++++
 drivers/vfio/vfio_iommu_common.h |   27 +++++
 drivers/vfio/vfio_iommu_type1.c  |  206 +----------------------------------
 4 files changed, 257 insertions(+), 207 deletions(-)
 create mode 100644 drivers/vfio/vfio_iommu_common.c
 create mode 100644 drivers/vfio/vfio_iommu_common.h

diff --git a/drivers/vfio/Makefile b/drivers/vfio/Makefile
index 72bfabc..c5792ec 100644
--- a/drivers/vfio/Makefile
+++ b/drivers/vfio/Makefile
@@ -1,4 +1,4 @@
 obj-$(CONFIG_VFIO) += vfio.o
-obj-$(CONFIG_VFIO_IOMMU_TYPE1) += vfio_iommu_type1.o
-obj-$(CONFIG_VFIO_IOMMU_SPAPR_TCE) += vfio_iommu_spapr_tce.o
+obj-$(CONFIG_VFIO_IOMMU_TYPE1) += vfio_iommu_common.o vfio_iommu_type1.o
+obj-$(CONFIG_VFIO_IOMMU_SPAPR_TCE) += vfio_iommu_common.o vfio_iommu_spapr_tce.o
 obj-$(CONFIG_VFIO_PCI) += pci/
diff --git a/drivers/vfio/vfio_iommu_common.c b/drivers/vfio/vfio_iommu_common.c
new file mode 100644
index 0000000..08eea71
--- /dev/null
+++ b/drivers/vfio/vfio_iommu_common.c
@@ -0,0 +1,227 @@
+/*
+ * VFIO: Common code for vfio IOMMU support
+ *
+ * Copyright (C) 2012 Red Hat, Inc.  All rights reserved.
+ *     Author: Alex Williamson <alex.williamson@...hat.com>
+ *     Author: Bharat Bhushan <bharat.bhushan@...escale.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * Derived from original vfio:
+ * Copyright 2010 Cisco Systems, Inc.  All rights reserved.
+ * Author: Tom Lyon, pugs@...co.com
+ */
+
+#include <linux/compat.h>
+#include <linux/iommu.h>
+#include <linux/module.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/workqueue.h>
+
+static bool disable_hugepages;
+module_param_named(disable_hugepages,
+		   disable_hugepages, bool, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(disable_hugepages,
+		 "Disable VFIO IOMMU support for IOMMU hugepages.");
+
+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)
+{
+	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);
+}
+
+void vfio_lock_acct(long npage)
+{
+	struct vwork *vwork;
+	struct mm_struct *mm;
+
+	if (!current->mm || !npage)
+		return; /* process exited or nothing to do */
+
+	if (down_write_trylock(&current->mm->mmap_sem)) {
+		current->mm->locked_vm += npage;
+		up_write(&current->mm->mmap_sem);
+		return;
+	}
+
+	/*
+	 * 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 (!vwork)
+		return;
+	mm = get_task_mm(current);
+	if (!mm) {
+		kfree(vwork);
+		return;
+	}
+	INIT_WORK(&vwork->work, vfio_lock_acct_bg);
+	vwork->mm = mm;
+	vwork->npage = npage;
+	schedule_work(&vwork->work);
+}
+
+/*
+ * Some mappings aren't backed by a struct page, for example an mmap'd
+ * MMIO range for our own or another device.  These use a different
+ * pfn conversion and shouldn't be tracked as locked pages.
+ */
+static bool is_invalid_reserved_pfn(unsigned long pfn)
+{
+	if (pfn_valid(pfn)) {
+		bool reserved;
+		struct page *tail = pfn_to_page(pfn);
+		struct page *head = compound_trans_head(tail);
+		reserved = !!(PageReserved(head));
+		if (head != tail) {
+			/*
+			 * "head" is not a dangling pointer
+			 * (compound_trans_head takes care of that)
+			 * but the hugepage may have been split
+			 * from under us (and we may not hold a
+			 * reference count on the head page so it can
+			 * be reused before we run PageReferenced), so
+			 * we've to check PageTail before returning
+			 * what we just read.
+			 */
+			smp_rmb();
+			if (PageTail(tail))
+				return reserved;
+		}
+		return PageReserved(tail);
+	}
+
+	return true;
+}
+
+static int put_pfn(unsigned long pfn, int prot)
+{
+	if (!is_invalid_reserved_pfn(pfn)) {
+		struct page *page = pfn_to_page(pfn);
+		if (prot & IOMMU_WRITE)
+			SetPageDirty(page);
+		put_page(page);
+		return 1;
+	}
+	return 0;
+}
+
+static int vaddr_get_pfn(unsigned long vaddr, int prot, unsigned long *pfn)
+{
+	struct page *page[1];
+	struct vm_area_struct *vma;
+	int ret = -EFAULT;
+
+	if (get_user_pages_fast(vaddr, 1, !!(prot & IOMMU_WRITE), page) == 1) {
+		*pfn = page_to_pfn(page[0]);
+		return 0;
+	}
+
+	down_read(&current->mm->mmap_sem);
+
+	vma = find_vma_intersection(current->mm, vaddr, vaddr + 1);
+
+	if (vma && vma->vm_flags & VM_PFNMAP) {
+		*pfn = ((vaddr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
+		if (is_invalid_reserved_pfn(*pfn))
+			ret = 0;
+	}
+
+	up_read(&current->mm->mmap_sem);
+
+	return ret;
+}
+
+/*
+ * Attempt to pin pages.  We really don't want to track all the pfns and
+ * the iommu can only map chunks of consecutive pfns anyway, so get the
+ * first page and all consecutive pages with the same locking.
+ */
+long vfio_pin_pages(unsigned long vaddr, long npage,
+			   int prot, unsigned long *pfn_base)
+{
+	unsigned long limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
+	bool lock_cap = capable(CAP_IPC_LOCK);
+	long ret, i;
+
+	if (!current->mm)
+		return -ENODEV;
+
+	ret = vaddr_get_pfn(vaddr, prot, pfn_base);
+	if (ret)
+		return ret;
+
+	if (is_invalid_reserved_pfn(*pfn_base))
+		return 1;
+
+	if (!lock_cap && current->mm->locked_vm + 1 > limit) {
+		put_pfn(*pfn_base, prot);
+		pr_warn("%s: RLIMIT_MEMLOCK (%ld) exceeded\n", __func__,
+			limit << PAGE_SHIFT);
+		return -ENOMEM;
+	}
+
+	if (unlikely(disable_hugepages)) {
+		vfio_lock_acct(1);
+		return 1;
+	}
+
+	/* Lock all the consecutive pages from pfn_base */
+	for (i = 1, vaddr += PAGE_SIZE; i < npage; i++, vaddr += PAGE_SIZE) {
+		unsigned long pfn = 0;
+
+		ret = vaddr_get_pfn(vaddr, prot, &pfn);
+		if (ret)
+			break;
+
+		if (pfn != *pfn_base + i || is_invalid_reserved_pfn(pfn)) {
+			put_pfn(pfn, prot);
+			break;
+		}
+
+		if (!lock_cap && current->mm->locked_vm + i + 1 > limit) {
+			put_pfn(pfn, prot);
+			pr_warn("%s: RLIMIT_MEMLOCK (%ld) exceeded\n",
+				__func__, limit << PAGE_SHIFT);
+			break;
+		}
+	}
+
+	vfio_lock_acct(i);
+
+	return i;
+}
+
+long vfio_unpin_pages(unsigned long pfn, long npage,
+			     int prot, bool do_accounting)
+{
+	unsigned long unlocked = 0;
+	long i;
+
+	for (i = 0; i < npage; i++)
+		unlocked += put_pfn(pfn++, prot);
+
+	if (do_accounting)
+		vfio_lock_acct(-unlocked);
+
+	return unlocked;
+}
diff --git a/drivers/vfio/vfio_iommu_common.h b/drivers/vfio/vfio_iommu_common.h
new file mode 100644
index 0000000..2566ce6
--- /dev/null
+++ b/drivers/vfio/vfio_iommu_common.h
@@ -0,0 +1,27 @@
+/*
+ * Copyright (C) 2012 Red Hat, Inc.  All rights reserved.
+ * Copyright (C) 2013 Freescale Semiconductor, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
+ */
+
+#ifndef _VFIO_IOMMU_COMMON_H
+#define _VFIO_IOMMU_COMMON_H
+
+void vfio_lock_acct(long npage);
+long vfio_pin_pages(unsigned long vaddr, long npage, int prot,
+		    unsigned long *pfn_base);
+long vfio_unpin_pages(unsigned long pfn, long npage,
+		      int prot, bool do_accounting);
+#endif
diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index a9807de..e9a58fa 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -37,6 +37,7 @@
 #include <linux/uaccess.h>
 #include <linux/vfio.h>
 #include <linux/workqueue.h>
+#include "vfio_iommu_common.h"
 
 #define DRIVER_VERSION  "0.2"
 #define DRIVER_AUTHOR   "Alex Williamson <alex.williamson@...hat.com>"
@@ -48,12 +49,6 @@ module_param_named(allow_unsafe_interrupts,
 MODULE_PARM_DESC(allow_unsafe_interrupts,
 		 "Enable VFIO IOMMU support for on platforms without interrupt remapping support.");
 
-static bool disable_hugepages;
-module_param_named(disable_hugepages,
-		   disable_hugepages, bool, S_IRUGO | S_IWUSR);
-MODULE_PARM_DESC(disable_hugepages,
-		 "Disable VFIO IOMMU support for IOMMU hugepages.");
-
 struct vfio_iommu {
 	struct iommu_domain	*domain;
 	struct mutex		lock;
@@ -123,205 +118,6 @@ static void vfio_remove_dma(struct vfio_iommu *iommu, struct vfio_dma *old)
 	rb_erase(&old->node, &iommu->dma_list);
 }
 
-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)
-{
-	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(long npage)
-{
-	struct vwork *vwork;
-	struct mm_struct *mm;
-
-	if (!current->mm || !npage)
-		return; /* process exited or nothing to do */
-
-	if (down_write_trylock(&current->mm->mmap_sem)) {
-		current->mm->locked_vm += npage;
-		up_write(&current->mm->mmap_sem);
-		return;
-	}
-
-	/*
-	 * 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 (!vwork)
-		return;
-	mm = get_task_mm(current);
-	if (!mm) {
-		kfree(vwork);
-		return;
-	}
-	INIT_WORK(&vwork->work, vfio_lock_acct_bg);
-	vwork->mm = mm;
-	vwork->npage = npage;
-	schedule_work(&vwork->work);
-}
-
-/*
- * Some mappings aren't backed by a struct page, for example an mmap'd
- * MMIO range for our own or another device.  These use a different
- * pfn conversion and shouldn't be tracked as locked pages.
- */
-static bool is_invalid_reserved_pfn(unsigned long pfn)
-{
-	if (pfn_valid(pfn)) {
-		bool reserved;
-		struct page *tail = pfn_to_page(pfn);
-		struct page *head = compound_trans_head(tail);
-		reserved = !!(PageReserved(head));
-		if (head != tail) {
-			/*
-			 * "head" is not a dangling pointer
-			 * (compound_trans_head takes care of that)
-			 * but the hugepage may have been split
-			 * from under us (and we may not hold a
-			 * reference count on the head page so it can
-			 * be reused before we run PageReferenced), so
-			 * we've to check PageTail before returning
-			 * what we just read.
-			 */
-			smp_rmb();
-			if (PageTail(tail))
-				return reserved;
-		}
-		return PageReserved(tail);
-	}
-
-	return true;
-}
-
-static int put_pfn(unsigned long pfn, int prot)
-{
-	if (!is_invalid_reserved_pfn(pfn)) {
-		struct page *page = pfn_to_page(pfn);
-		if (prot & IOMMU_WRITE)
-			SetPageDirty(page);
-		put_page(page);
-		return 1;
-	}
-	return 0;
-}
-
-static int vaddr_get_pfn(unsigned long vaddr, int prot, unsigned long *pfn)
-{
-	struct page *page[1];
-	struct vm_area_struct *vma;
-	int ret = -EFAULT;
-
-	if (get_user_pages_fast(vaddr, 1, !!(prot & IOMMU_WRITE), page) == 1) {
-		*pfn = page_to_pfn(page[0]);
-		return 0;
-	}
-
-	down_read(&current->mm->mmap_sem);
-
-	vma = find_vma_intersection(current->mm, vaddr, vaddr + 1);
-
-	if (vma && vma->vm_flags & VM_PFNMAP) {
-		*pfn = ((vaddr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
-		if (is_invalid_reserved_pfn(*pfn))
-			ret = 0;
-	}
-
-	up_read(&current->mm->mmap_sem);
-
-	return ret;
-}
-
-/*
- * Attempt to pin pages.  We really don't want to track all the pfns and
- * the iommu can only map chunks of consecutive pfns anyway, so get the
- * first page and all consecutive pages with the same locking.
- */
-static long vfio_pin_pages(unsigned long vaddr, long npage,
-			   int prot, unsigned long *pfn_base)
-{
-	unsigned long limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
-	bool lock_cap = capable(CAP_IPC_LOCK);
-	long ret, i;
-
-	if (!current->mm)
-		return -ENODEV;
-
-	ret = vaddr_get_pfn(vaddr, prot, pfn_base);
-	if (ret)
-		return ret;
-
-	if (is_invalid_reserved_pfn(*pfn_base))
-		return 1;
-
-	if (!lock_cap && current->mm->locked_vm + 1 > limit) {
-		put_pfn(*pfn_base, prot);
-		pr_warn("%s: RLIMIT_MEMLOCK (%ld) exceeded\n", __func__,
-			limit << PAGE_SHIFT);
-		return -ENOMEM;
-	}
-
-	if (unlikely(disable_hugepages)) {
-		vfio_lock_acct(1);
-		return 1;
-	}
-
-	/* Lock all the consecutive pages from pfn_base */
-	for (i = 1, vaddr += PAGE_SIZE; i < npage; i++, vaddr += PAGE_SIZE) {
-		unsigned long pfn = 0;
-
-		ret = vaddr_get_pfn(vaddr, prot, &pfn);
-		if (ret)
-			break;
-
-		if (pfn != *pfn_base + i || is_invalid_reserved_pfn(pfn)) {
-			put_pfn(pfn, prot);
-			break;
-		}
-
-		if (!lock_cap && current->mm->locked_vm + i + 1 > limit) {
-			put_pfn(pfn, prot);
-			pr_warn("%s: RLIMIT_MEMLOCK (%ld) exceeded\n",
-				__func__, limit << PAGE_SHIFT);
-			break;
-		}
-	}
-
-	vfio_lock_acct(i);
-
-	return i;
-}
-
-static long vfio_unpin_pages(unsigned long pfn, long npage,
-			     int prot, bool do_accounting)
-{
-	unsigned long unlocked = 0;
-	long i;
-
-	for (i = 0; i < npage; i++)
-		unlocked += put_pfn(pfn++, prot);
-
-	if (do_accounting)
-		vfio_lock_acct(-unlocked);
-
-	return unlocked;
-}
-
 static int vfio_unmap_unpin(struct vfio_iommu *iommu, struct vfio_dma *dma,
 			    dma_addr_t iova, size_t *size)
 {
-- 
1.7.0.4


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