[RFC PATCH v1 06/38] iommufd: Add and option to request for bar mapping with IORESOURCE_EXCLUSIVE

["Aneesh Kumar K.V (Arm)" <aneesh.kumar@kernel.org>]

Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org>
---
 drivers/iommu/iommufd/device.c          | 54 +++++++++++++++++++++++++
 drivers/iommu/iommufd/iommufd_private.h |  4 ++
 drivers/iommu/iommufd/main.c            |  3 ++
 drivers/vfio/pci/vfio_pci_core.c        |  9 ++++-
 include/linux/iommufd.h                 |  1 +
 include/uapi/linux/iommufd.h            |  1 +
 6 files changed, 71 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c
index 65fbd098f9e9..3bd6972836a1 100644
--- a/drivers/iommu/iommufd/device.c
+++ b/drivers/iommu/iommufd/device.c
@@ -1660,3 +1660,57 @@ int iommufd_get_hw_info(struct iommufd_ucmd *ucmd)
 	iommufd_put_object(ucmd->ictx, &idev->obj);
 	return rc;
 }
+
+static int iommufd_device_option_exclusive_ranges(struct iommu_option *cmd,
+					  struct iommufd_device *idev)
+{
+	if (cmd->op == IOMMU_OPTION_OP_GET) {
+		cmd->val64 = idev->flags & IOMMUFD_DEVICE_EXCLUSIVE_RANGE;
+		return 0;
+	}
+
+	if (cmd->op == IOMMU_OPTION_OP_SET) {
+		if (cmd->val64 == 0) {
+			idev->flags &= ~IOMMUFD_DEVICE_EXCLUSIVE_RANGE;
+			return 0;
+		} else if (cmd->val64 & IOMMUFD_DEVICE_EXCLUSIVE_RANGE) {
+			idev->flags |= IOMMUFD_DEVICE_EXCLUSIVE_RANGE;
+			return 0;
+		}
+		return -EINVAL;
+	}
+	return -EOPNOTSUPP;
+}
+bool iommufd_device_need_exclusive_range(struct iommufd_device *idev)
+{
+	return !!(idev->flags & IOMMUFD_DEVICE_EXCLUSIVE_RANGE);
+}
+
+int iommufd_device_option(struct iommufd_ucmd *ucmd)
+{
+	struct iommu_option *cmd = ucmd->cmd;
+	struct iommufd_device *idev;
+	int rc = 0;
+
+	if (cmd->__reserved)
+		return -EOPNOTSUPP;
+
+	idev = iommufd_get_device(ucmd, cmd->object_id);
+	if (IS_ERR(idev))
+		return PTR_ERR(idev);
+
+	mutex_lock(&idev->igroup->lock);
+
+
+	switch (cmd->option_id) {
+	case IOMMU_OPTION_EXCLUSIVE_RANGES:
+		rc = iommufd_device_option_exclusive_ranges(cmd, idev);
+		break;
+	default:
+		rc = -EOPNOTSUPP;
+	}
+
+	mutex_unlock(&idev->igroup->lock);
+	iommufd_put_object(ucmd->ictx, &idev->obj);
+	return rc;
+}
diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h
index 0da2a81eedfa..fce68714c80f 100644
--- a/drivers/iommu/iommufd/iommufd_private.h
+++ b/drivers/iommu/iommufd/iommufd_private.h
@@ -346,6 +346,7 @@ int iommufd_ioas_change_process(struct iommufd_ucmd *ucmd);
 int iommufd_ioas_copy(struct iommufd_ucmd *ucmd);
 int iommufd_ioas_unmap(struct iommufd_ucmd *ucmd);
 int iommufd_ioas_option(struct iommufd_ucmd *ucmd);
+int iommufd_device_option(struct iommufd_ucmd *ucmd);
 int iommufd_option_rlimit_mode(struct iommu_option *cmd,
 			       struct iommufd_ctx *ictx);
 
@@ -489,10 +490,13 @@ struct iommufd_device {
 	/* always the physical device */
 	struct device *dev;
 	bool enforce_cache_coherency;
+	unsigned long flags;
 	struct iommufd_vdevice *vdev;
 	bool destroying;
 };
 
+#define IOMMUFD_DEVICE_EXCLUSIVE_RANGE		BIT(0)
+
 static inline struct iommufd_device *
 iommufd_get_device(struct iommufd_ucmd *ucmd, u32 id)
 {
diff --git a/drivers/iommu/iommufd/main.c b/drivers/iommu/iommufd/main.c
index 15af7ced0501..89830da8b418 100644
--- a/drivers/iommu/iommufd/main.c
+++ b/drivers/iommu/iommufd/main.c
@@ -376,6 +376,9 @@ static int iommufd_option(struct iommufd_ucmd *ucmd)
 	case IOMMU_OPTION_HUGE_PAGES:
 		rc = iommufd_ioas_option(ucmd);
 		break;
+	case IOMMU_OPTION_EXCLUSIVE_RANGES:
+		rc = iommufd_device_option(ucmd);
+		break;
 	default:
 		return -EOPNOTSUPP;
 	}
diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
index 6328c3a05bcd..bee3cf3226e9 100644
--- a/drivers/vfio/pci/vfio_pci_core.c
+++ b/drivers/vfio/pci/vfio_pci_core.c
@@ -1753,8 +1753,15 @@ int vfio_pci_core_mmap(struct vfio_device *core_vdev, struct vm_area_struct *vma
 	 * we need to request the region and the barmap tracks that.
 	 */
 	if (!vdev->barmap[index]) {
-		ret = pci_request_selected_regions(pdev,
+
+		if (core_vdev->iommufd_device &&
+		    iommufd_device_need_exclusive_range(core_vdev->iommufd_device))
+			ret = pci_request_selected_regions_exclusive(pdev,
+							1 << index, "vfio-pci");
+		else
+			ret = pci_request_selected_regions(pdev,
 						   1 << index, "vfio-pci");
+
 		if (ret)
 			return ret;
 
diff --git a/include/linux/iommufd.h b/include/linux/iommufd.h
index 6e7efe83bc5d..55ae02581f9b 100644
--- a/include/linux/iommufd.h
+++ b/include/linux/iommufd.h
@@ -70,6 +70,7 @@ void iommufd_device_detach(struct iommufd_device *idev, ioasid_t pasid);
 
 struct iommufd_ctx *iommufd_device_to_ictx(struct iommufd_device *idev);
 u32 iommufd_device_to_id(struct iommufd_device *idev);
+bool iommufd_device_need_exclusive_range(struct iommufd_device *idev);
 
 struct iommufd_access_ops {
 	u8 needs_pin_pages : 1;
diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h
index c218c89e0e2e..548d4b5afcd4 100644
--- a/include/uapi/linux/iommufd.h
+++ b/include/uapi/linux/iommufd.h
@@ -310,6 +310,7 @@ struct iommu_ioas_unmap {
 enum iommufd_option {
 	IOMMU_OPTION_RLIMIT_MODE = 0,
 	IOMMU_OPTION_HUGE_PAGES = 1,
+	IOMMU_OPTION_EXCLUSIVE_RANGES = 2,
 };
 
 /**
-- 
2.43.0