1 files changed, 19 insertions, 4 deletions

diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
index 27b98c361823..a8752c2c2b53 100644
--- a/drivers/pci/iov.c
+++ b/drivers/pci/iov.c
@@ -31,6 +31,21 @@ static inline u8 virtfn_devfn(struct pci_dev *dev, int id)
                 dev->sriov->stride * id) & 0xff;
 }
 
+/*
+ * Per SR-IOV spec sec 3.3.10 and 3.3.11, First VF Offset and VF Stride may
+ * change when NumVFs changes.
+ *
+ * Update iov->offset and iov->stride when NumVFs is written.
+ */
+static inline void pci_iov_set_numvfs(struct pci_dev *dev, int nr_virtfn)
+{
+        struct pci_sriov *iov = dev->sriov;
+
+        pci_write_config_word(dev, iov->pos + PCI_SRIOV_NUM_VF, nr_virtfn);
+        pci_read_config_word(dev, iov->pos + PCI_SRIOV_VF_OFFSET, &iov->offset);
+        pci_read_config_word(dev, iov->pos + PCI_SRIOV_VF_STRIDE, &iov->stride);
+}
+
 static struct pci_bus *virtfn_add_bus(struct pci_bus *bus, int busnr)
 {
         struct pci_bus *child;
@@ -253,7 +268,7 @@ static int sriov_enable(struct pci_dev *dev, int nr_virtfn)
                         return rc;
         }
 
-        pci_write_config_word(dev, iov->pos + PCI_SRIOV_NUM_VF, nr_virtfn);
+        pci_iov_set_numvfs(dev, nr_virtfn);
         iov->ctrl |= PCI_SRIOV_CTRL_VFE | PCI_SRIOV_CTRL_MSE;
         pci_cfg_access_lock(dev);
         pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
@@ -282,7 +297,7 @@ failed:
         iov->ctrl &= ~(PCI_SRIOV_CTRL_VFE | PCI_SRIOV_CTRL_MSE);
         pci_cfg_access_lock(dev);
         pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
-        pci_write_config_word(dev, iov->pos + PCI_SRIOV_NUM_VF, 0);
+        pci_iov_set_numvfs(dev, 0);
         ssleep(1);
         pci_cfg_access_unlock(dev);
 
@@ -313,7 +328,7 @@ static void sriov_disable(struct pci_dev *dev)
                 sysfs_remove_link(&dev->dev.kobj, "dep_link");
 
         iov->num_VFs = 0;
-        pci_write_config_word(dev, iov->pos + PCI_SRIOV_NUM_VF, 0);
+        pci_iov_set_numvfs(dev, 0);
 }
 
 static int sriov_init(struct pci_dev *dev, int pos)
@@ -452,7 +467,7 @@ static void sriov_restore_state(struct pci_dev *dev)
                 pci_update_resource(dev, i);
 
         pci_write_config_dword(dev, iov->pos + PCI_SRIOV_SYS_PGSIZE, iov->pgsz);
-        pci_write_config_word(dev, iov->pos + PCI_SRIOV_NUM_VF, iov->num_VFs);
+        pci_iov_set_numvfs(dev, iov->num_VFs);
         pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
         if (iov->ctrl & PCI_SRIOV_CTRL_VFE)
                 msleep(100);