vfio: Add vfio_file_is_group()

This replaces uses of vfio_file_iommu_group() which were only detecting if the file is a VFIO file with no interest in the actual group. The only remaning user of vfio_file_iommu_group() is in KVM for the SPAPR stuff. It passes the iommu_group into the arch code through kvm for some reason. Tested-by: Matthew Rosato <[email protected]> Tested-by: Christian Borntraeger <[email protected]> Tested-by: Eric Farman <[email protected]> Signed-off-by: Jason Gunthorpe <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Alex Williamson <[email protected]>
wafgo · Oct 7, 2022 · 4b22ef0 · 4b22ef0
1 parent c82e81a
commit 4b22ef0
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Showing 4 changed files with 35 additions and 4 deletions.
diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
@@ -1313,7 +1313,7 @@ static int vfio_pci_ioctl_pci_hot_reset(struct vfio_pci_core_device *vdev,
 		}
 
 		/* Ensure the FD is a vfio group FD.*/
-		if (!vfio_file_iommu_group(file)) {
+		if (!vfio_file_is_group(file)) {
 			fput(file);
 			ret = -EINVAL;
 			break;

diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c
@@ -1553,17 +1553,31 @@ static const struct file_operations vfio_device_fops = {
  * @file: VFIO group file
  *
  * The returned iommu_group is valid as long as a ref is held on the file.
+ * This function is deprecated, only the SPAPR path in kvm should call it.
  */
 struct iommu_group *vfio_file_iommu_group(struct file *file)
 {
 	struct vfio_group *group = file->private_data;
 
-	if (file->f_op != &vfio_group_fops)
+	if (!IS_ENABLED(CONFIG_SPAPR_TCE_IOMMU))
+		return NULL;
+
+	if (!vfio_file_is_group(file))
 		return NULL;
 	return group->iommu_group;
 }
 EXPORT_SYMBOL_GPL(vfio_file_iommu_group);
 
+/**
+ * vfio_file_is_group - True if the file is usable with VFIO aPIS
+ * @file: VFIO group file
+ */
+bool vfio_file_is_group(struct file *file)
+{
+	return file->f_op == &vfio_group_fops;
+}
+EXPORT_SYMBOL_GPL(vfio_file_is_group);
+
 /**
  * vfio_file_enforced_coherent - True if the DMA associated with the VFIO file
  *        is always CPU cache coherent

diff --git a/include/linux/vfio.h b/include/linux/vfio.h
@@ -199,6 +199,7 @@ int vfio_mig_get_next_state(struct vfio_device *device,
  * External user API
  */
 struct iommu_group *vfio_file_iommu_group(struct file *file);
+bool vfio_file_is_group(struct file *file);
 bool vfio_file_enforced_coherent(struct file *file);
 void vfio_file_set_kvm(struct file *file, struct kvm *kvm);
 bool vfio_file_has_dev(struct file *file, struct vfio_device *device);

diff --git a/virt/kvm/vfio.c b/virt/kvm/vfio.c
@@ -61,6 +61,23 @@ static bool kvm_vfio_file_enforced_coherent(struct file *file)
 	return ret;
 }
 
+static bool kvm_vfio_file_is_group(struct file *file)
+{
+	bool (*fn)(struct file *file);
+	bool ret;
+
+	fn = symbol_get(vfio_file_is_group);
+	if (!fn)
+		return false;
+
+	ret = fn(file);
+
+	symbol_put(vfio_file_is_group);
+
+	return ret;
+}
+
+#ifdef CONFIG_SPAPR_TCE_IOMMU
 static struct iommu_group *kvm_vfio_file_iommu_group(struct file *file)
 {
 	struct iommu_group *(*fn)(struct file *file);
@@ -77,7 +94,6 @@ static struct iommu_group *kvm_vfio_file_iommu_group(struct file *file)
 	return ret;
 }
 
-#ifdef CONFIG_SPAPR_TCE_IOMMU
 static void kvm_spapr_tce_release_vfio_group(struct kvm *kvm,
 					     struct kvm_vfio_group *kvg)
 {
@@ -136,7 +152,7 @@ static int kvm_vfio_group_add(struct kvm_device *dev, unsigned int fd)
 		return -EBADF;
 
 	/* Ensure the FD is a vfio group FD.*/
-	if (!kvm_vfio_file_iommu_group(filp)) {
+	if (!kvm_vfio_file_is_group(filp)) {
 		ret = -EINVAL;
 		goto err_fput;
 	}