xen/pci: Allocate memory for physdev_pci_device_add's optarr

physdev_pci_device_add's optarr[] is a zero-sized array and therefore
reference to add.optarr[0] is accessing memory that does not belong to
the 'add' variable.

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>

1 files changed, 16 insertions, 11 deletions

diff --git a/drivers/xen/pci.c b/drivers/xen/pci.c
index dd9c249ea311..95ee4302ffb8 100644
--- a/drivers/xen/pci.c
+++ b/drivers/xen/pci.c
@@ -41,24 +41,29 @@ static int xen_add_device(struct device *dev)
 #endif
 
         if (pci_seg_supported) {
-                struct physdev_pci_device_add add = {
-                        .seg = pci_domain_nr(pci_dev->bus),
-                        .bus = pci_dev->bus->number,
-                        .devfn = pci_dev->devfn
+                struct {
+                        struct physdev_pci_device_add add;
+                        uint32_t pxm;
+                } add_ext = {
+                        .add.seg = pci_domain_nr(pci_dev->bus),
+                        .add.bus = pci_dev->bus->number,
+                        .add.devfn = pci_dev->devfn
                 };
+                struct physdev_pci_device_add *add = &add_ext.add;
+
 #ifdef CONFIG_ACPI
                 acpi_handle handle;
 #endif
 
 #ifdef CONFIG_PCI_IOV
                 if (pci_dev->is_virtfn) {
-                        add.flags = XEN_PCI_DEV_VIRTFN;
-                        add.physfn.bus = physfn->bus->number;
-                        add.physfn.devfn = physfn->devfn;
+                        add->flags = XEN_PCI_DEV_VIRTFN;
+                        add->physfn.bus = physfn->bus->number;
+                        add->physfn.devfn = physfn->devfn;
                 } else
 #endif
                 if (pci_ari_enabled(pci_dev->bus) && PCI_SLOT(pci_dev->devfn))
-                        add.flags = XEN_PCI_DEV_EXTFN;
+                        add->flags = XEN_PCI_DEV_EXTFN;
 
 #ifdef CONFIG_ACPI
                 handle = ACPI_HANDLE(&pci_dev->dev);
@@ -77,8 +82,8 @@ static int xen_add_device(struct device *dev)
                                 status = acpi_evaluate_integer(handle, "_PXM",
                                                                NULL, &pxm);
                                 if (ACPI_SUCCESS(status)) {
-                                        add.optarr[0] = pxm;
-                                        add.flags |= XEN_PCI_DEV_PXM;
+                                        add->optarr[0] = pxm;
+                                        add->flags |= XEN_PCI_DEV_PXM;
                                         break;
                                 }
                                 status = acpi_get_parent(handle, &handle);
@@ -86,7 +91,7 @@ static int xen_add_device(struct device *dev)
                 }
 #endif /* CONFIG_ACPI */
 
-                r = HYPERVISOR_physdev_op(PHYSDEVOP_pci_device_add, &add);
+                r = HYPERVISOR_physdev_op(PHYSDEVOP_pci_device_add, add);
                 if (r != -ENOSYS)
                         return r;
                 pci_seg_supported = false;