[PATCH v11 05/22] vfio iommu: Added pin and unpin callback functions to vfio_iommu_driver_ops

[Kirti Wankhede <kwankhede@nvidia.com>]

Added two new callback functions to struct vfio_iommu_driver_ops. Backend
IOMMU module that supports pining and unpinning pages for mdev devices
should provide these functions.
Added APIs for pining and unpining pages to VFIO module. These calls back
into backend iommu module to actually pin and unpin pages.
Renamed static functions in vfio_type1_iommu.c to resolve conflicts

Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
Signed-off-by: Neo Jia <cjia@nvidia.com>
Change-Id: Ia7417723aaae86bec2959ad9ae6c2915ddd340e0
---
 drivers/vfio/vfio.c             | 96 +++++++++++++++++++++++++++++++++++++++++
 drivers/vfio/vfio_iommu_type1.c | 20 ++++-----
 include/linux/vfio.h            | 14 +++++-
 3 files changed, 119 insertions(+), 11 deletions(-)

diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index 2e83bdf007fe..76d260e98930 100644
--- a/drivers/vfio/vfio.c
+++ b/drivers/vfio/vfio.c
@@ -1799,6 +1799,102 @@ void vfio_info_cap_shift(struct vfio_info_cap *caps, size_t offset)
 }
 EXPORT_SYMBOL_GPL(vfio_info_cap_shift);
 
+
+/*
+ * Pin a set of guest PFNs and return their associated host PFNs for local
+ * domain only.
+ * @dev [in] : device
+ * @user_pfn [in]: array of user/guest PFNs
+ * @npage [in]: count of array elements
+ * @prot [in] : protection flags
+ * @phys_pfn[out] : array of host PFNs
+ * Return error or number of pages pinned.
+ */
+int vfio_pin_pages(struct device *dev, unsigned long *user_pfn,
+		   int npage, int prot, unsigned long *phys_pfn)
+{
+	struct vfio_container *container;
+	struct vfio_group *group;
+	struct vfio_iommu_driver *driver;
+	int ret;
+
+	if (!dev || !user_pfn || !phys_pfn)
+		return -EINVAL;
+
+	group = vfio_group_get_from_dev(dev);
+	if (IS_ERR(group))
+		return PTR_ERR(group);
+
+	ret = vfio_group_add_container_user(group);
+	if (ret)
+		goto err_pin_pages;
+
+	container = group->container;
+	down_read(&container->group_lock);
+
+	driver = container->iommu_driver;
+	if (likely(driver && driver->ops->pin_pages))
+		ret = driver->ops->pin_pages(container->iommu_data, user_pfn,
+					     npage, prot, phys_pfn);
+	else
+		ret = -EINVAL;
+
+	up_read(&container->group_lock);
+	vfio_group_try_dissolve_container(group);
+
+err_pin_pages:
+	vfio_group_put(group);
+	return ret;
+
+}
+EXPORT_SYMBOL(vfio_pin_pages);
+
+/*
+ * Unpin set of host PFNs for local domain only.
+ * @dev [in] : device
+ * @user_pfn [in]: array of user/guest PFNs to be unpinned
+ * @pfn [in] : array of host PFNs to be unpinned.
+ * @npage [in] :count of elements in array, that is number of pages.
+ * Return error or number of pages unpinned.
+ */
+int vfio_unpin_pages(struct device *dev, unsigned long *user_pfn,
+		     unsigned long *pfn, int npage)
+{
+	struct vfio_container *container;
+	struct vfio_group *group;
+	struct vfio_iommu_driver *driver;
+	int ret;
+
+	if (!dev || !pfn)
+		return -EINVAL;
+
+	group = vfio_group_get_from_dev(dev);
+	if (IS_ERR(group))
+		return PTR_ERR(group);
+
+	ret = vfio_group_add_container_user(group);
+	if (ret)
+		goto err_unpin_pages;
+
+	container = group->container;
+	down_read(&container->group_lock);
+
+	driver = container->iommu_driver;
+	if (likely(driver && driver->ops->unpin_pages))
+		ret = driver->ops->unpin_pages(container->iommu_data, user_pfn,
+					       pfn, npage);
+	else
+		ret = -EINVAL;
+
+	up_read(&container->group_lock);
+	vfio_group_try_dissolve_container(group);
+
+err_unpin_pages:
+	vfio_group_put(group);
+	return ret;
+}
+EXPORT_SYMBOL(vfio_unpin_pages);
+
 /**
  * Module/class support
  */
diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 2ba19424e4a1..7fb87f008e0a 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -259,8 +259,8 @@ static int vaddr_get_pfn(unsigned long vaddr, int prot, unsigned long *pfn)
  * 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)
+static long __vfio_pin_pages_remote(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);
@@ -318,8 +318,8 @@ static long vfio_pin_pages(unsigned long vaddr, long npage,
 	return i;
 }
 
-static long vfio_unpin_pages(unsigned long pfn, long npage,
-			     int prot, bool do_accounting)
+static long __vfio_unpin_pages_remote(unsigned long pfn, long npage,
+				      int prot, bool do_accounting)
 {
 	unsigned long unlocked = 0;
 	long i;
@@ -382,9 +382,9 @@ static void vfio_unmap_unpin(struct vfio_iommu *iommu, struct vfio_dma *dma)
 		if (WARN_ON(!unmapped))
 			break;
 
-		unlocked += vfio_unpin_pages(phys >> PAGE_SHIFT,
-					     unmapped >> PAGE_SHIFT,
-					     dma->prot, false);
+		unlocked += __vfio_unpin_pages_remote(phys >> PAGE_SHIFT,
+						      unmapped >> PAGE_SHIFT,
+						      dma->prot, false);
 		iova += unmapped;
 
 		cond_resched();
@@ -613,8 +613,8 @@ static int vfio_dma_do_map(struct vfio_iommu *iommu,
 
 	while (size) {
 		/* Pin a contiguous chunk of memory */
-		npage = vfio_pin_pages(vaddr + dma->size,
-				       size >> PAGE_SHIFT, prot, &pfn);
+		npage = __vfio_pin_pages_remote(vaddr + dma->size,
+						size >> PAGE_SHIFT, prot, &pfn);
 		if (npage <= 0) {
 			WARN_ON(!npage);
 			ret = (int)npage;
@@ -624,7 +624,7 @@ static int vfio_dma_do_map(struct vfio_iommu *iommu,
 		/* Map it! */
 		ret = vfio_iommu_map(iommu, iova + dma->size, pfn, npage, prot);
 		if (ret) {
-			vfio_unpin_pages(pfn, npage, prot, true);
+			__vfio_unpin_pages_remote(pfn, npage, prot, true);
 			break;
 		}
 
diff --git a/include/linux/vfio.h b/include/linux/vfio.h
index 0ecae0b1cd34..ba1b64cb7d4b 100644
--- a/include/linux/vfio.h
+++ b/include/linux/vfio.h
@@ -75,7 +75,13 @@ struct vfio_iommu_driver_ops {
 					struct iommu_group *group);
 	void		(*detach_group)(void *iommu_data,
 					struct iommu_group *group);
-
+	int		(*pin_pages)(void *iommu_data, unsigned long *user_pfn,
+				     int npage, int prot,
+				     unsigned long *phys_pfn);
+	int		(*unpin_pages)(void *iommu_data,
+				       unsigned long *user_pfn,
+				       unsigned long *pfn,
+				       int npage);
 };
 
 extern int vfio_register_iommu_driver(const struct vfio_iommu_driver_ops *ops);
@@ -127,6 +133,12 @@ static inline long vfio_spapr_iommu_eeh_ioctl(struct iommu_group *group,
 }
 #endif /* CONFIG_EEH */
 
+extern int vfio_pin_pages(struct device *dev, unsigned long *user_pfn,
+			  int npage, int prot, unsigned long *phys_pfn);
+
+extern int vfio_unpin_pages(struct device *dev, unsigned long *user_pfn,
+			    unsigned long *pfn, int npage);
+
 /*
  * IRQfd - generic
  */
-- 
2.7.0