PCI: Expose SR-IOV offset, stride, and VF device ID via sysfs

Expose the SR-IOV device offset, stride, and VF device ID via sysfs to make
it easier for userspace applications to consume them.

Signed-off-by: Filippo Sironi <sironi@amazon.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

drivers/pci/pci-sysfs.c

@@ -648,6 +648,33 @@ exit:
 	return count;
 }
 
+static ssize_t sriov_offset_show(struct device *dev,
+				 struct device_attribute *attr,
+				 char *buf)
+{
+	struct pci_dev *pdev = to_pci_dev(dev);
+
+	return sprintf(buf, "%u\n", pdev->sriov->offset);
+}
+
+static ssize_t sriov_stride_show(struct device *dev,
+				 struct device_attribute *attr,
+				 char *buf)
+{
+	struct pci_dev *pdev = to_pci_dev(dev);
+
+	return sprintf(buf, "%u\n", pdev->sriov->stride);
+}
+
+static ssize_t sriov_vf_device_show(struct device *dev,
+				    struct device_attribute *attr,
+				    char *buf)
+{
+	struct pci_dev *pdev = to_pci_dev(dev);
+
+	return sprintf(buf, "%x\n", pdev->sriov->vf_device);
+}
+
 static ssize_t sriov_drivers_autoprobe_show(struct device *dev,
 					    struct device_attribute *attr,
 					    char *buf)
@@ -676,6 +703,9 @@ static struct device_attribute sriov_totalvfs_attr = __ATTR_RO(sriov_totalvfs);
 static struct device_attribute sriov_numvfs_attr =
 		__ATTR(sriov_numvfs, (S_IRUGO|S_IWUSR|S_IWGRP),
 		       sriov_numvfs_show, sriov_numvfs_store);
+static struct device_attribute sriov_offset_attr = __ATTR_RO(sriov_offset);
+static struct device_attribute sriov_stride_attr = __ATTR_RO(sriov_stride);
+static struct device_attribute sriov_vf_device_attr = __ATTR_RO(sriov_vf_device);
 static struct device_attribute sriov_drivers_autoprobe_attr =
 		__ATTR(sriov_drivers_autoprobe, (S_IRUGO|S_IWUSR|S_IWGRP),
 		       sriov_drivers_autoprobe_show, sriov_drivers_autoprobe_store);
@@ -1748,6 +1778,9 @@ static const struct attribute_group pci_dev_hp_attr_group = {
 static struct attribute *sriov_dev_attrs[] = {
 	&sriov_totalvfs_attr.attr,
 	&sriov_numvfs_attr.attr,
+	&sriov_offset_attr.attr,
+	&sriov_stride_attr.attr,
+	&sriov_vf_device_attr.attr,
 	&sriov_drivers_autoprobe_attr.attr,
 	NULL,
 };