[PATCH v13 05/22] vfio iommu: Added pin and unpin callback functions to vfio_iommu_driver_ops

[Kirti Wankhede]

Added APIs for pining and unpining set of pages. These call back into
backend iommu module to actually pin and unpin pages.
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.

Renamed static functions in vfio_type1_iommu.c to resolve conflicts

Signed-off-by: Kirti Wankhede <kwankhede@xxxxxxxxxx>
Signed-off-by: Neo Jia <cjia@xxxxxxxxxx>
Change-Id: Ia7417723aaae86bec2959ad9ae6c2915ddd340e0
---
 drivers/vfio/vfio.c             | 103 ++++++++++++++++++++++++++++++++++++++++
 drivers/vfio/vfio_iommu_type1.c |  20 ++++----
 include/linux/vfio.h            |  14 +++++-
 3 files changed, 126 insertions(+), 11 deletions(-)

diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index 2e83bdf007fe..3bf8a01bf67b 100644
--- a/drivers/vfio/vfio.c
+++ b/drivers/vfio/vfio.c
@@ -1799,6 +1799,109 @@ 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 to be unpinned. Number of user/guest
+ *		  PFNs should not be greater than VFIO_PIN_PAGES_MAX_ENTRIES.
+ * @npage [in] :count of elements in array.  This count should not be greater
+ *		than PAGE_SIZE.
+ * @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 || !npage)
+		return -EINVAL;
+
+	if (npage > VFIO_PIN_PAGES_MAX_ENTRIES)
+		return -E2BIG;
+
+	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 = -ENOTTY;
+
+	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. Number of user/guest
+ *		  PFNs should not be greater than VFIO_PIN_PAGES_MAX_ENTRIES.
+ * @npage [in] :count of elements in array.  This count should not be greater
+ *		than PAGE_SIZE.
+ * Return error or number of pages unpinned.
+ */
+int vfio_unpin_pages(struct device *dev, unsigned long *user_pfn, int npage)
+{
+	struct vfio_container *container;
+	struct vfio_group *group;
+	struct vfio_iommu_driver *driver;
+	int ret;
+
+	if (!dev || !user_pfn || !npage)
+		return -EINVAL;
+
+	if (npage > VFIO_PIN_PAGES_MAX_ENTRIES)
+		return -E2BIG;
+
+	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,
+					       npage);
+	else
+		ret = -ENOTTY;
+
+	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..9f3d58d3dfaf 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..420cdc928786 100644
--- a/include/linux/vfio.h
+++ b/include/linux/vfio.h
@@ -75,7 +75,11 @@ 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, int npage);
 };
 
 extern int vfio_register_iommu_driver(const struct vfio_iommu_driver_ops *ops);
@@ -127,6 +131,14 @@ static inline long vfio_spapr_iommu_eeh_ioctl(struct iommu_group *group,
 }
 #endif /* CONFIG_EEH */
 
+#define VFIO_PIN_PAGES_MAX_ENTRIES	(PAGE_SIZE/sizeof(unsigned long))
+
+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,
+			    int npage);
+
 /*
  * IRQfd - generic
  */
-- 
2.7.0