[Qemu-devel] [PATCH V8 4/8] pci.c: Add pci_check_bar_overlap

[Anthony PERARD <anthony.perard@citrix.com>]

From: Yuji Shimada <shimada-yxb@necst.nec.co.jp>

This function helps Xen PCI Passthrough device to check for overlap.

Signed-off-by: Yuji Shimada <shimada-yxb@necst.nec.co.jp>
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
---
 hw/pci.c |   50 ++++++++++++++++++++++++++++++++++++++++++++++++++
 hw/pci.h |    5 +++++
 2 files changed, 55 insertions(+), 0 deletions(-)

diff --git a/hw/pci.c b/hw/pci.c
index 38e1de5..f950b4e 100644
--- a/hw/pci.c
+++ b/hw/pci.c
@@ -1992,6 +1992,56 @@ MemoryRegion *pci_address_space_io(PCIDevice *dev)
     return dev->bus->address_space_io;
 }
 
+/* This function checks if an io_region overlap an io_region from another
+ * device.  The io_region to check is provide with (addr, size and type)
+ * A callback can be provide and will be called for every region that is
+ * overlapped.
+ * The return value indicate if the region is overlappsed */
+bool pci_check_bar_overlap(PCIDevice *device,
+                           pcibus_t addr, pcibus_t size, uint8_t type,
+                           void (*c)(void *o, const PCIDevice *d, int index),
+                           void *opaque)
+{
+    PCIBus *bus = device->bus;
+    int i, j;
+    bool rc = false;
+
+    for (i = 0; i < ARRAY_SIZE(bus->devices); i++) {
+        PCIDevice *d = bus->devices[i];
+        if (!d) {
+            continue;
+        }
+
+        if (d->devfn == device->devfn) {
+            continue;
+        }
+
+        /* xxx: This ignores bridges. */
+        for (j = 0; j < PCI_NUM_REGIONS; j++) {
+            PCIIORegion *r = &d->io_regions[j];
+
+            if (!r->size) {
+                continue;
+            }
+            if ((type & PCI_BASE_ADDRESS_SPACE_IO)
+                != (r->type & PCI_BASE_ADDRESS_SPACE_IO)) {
+                continue;
+            }
+
+            if (ranges_overlap(addr, size, r->addr, r->size)) {
+                if (c) {
+                    c(opaque, d, j);
+                    rc = true;
+                } else {
+                    return true;
+                }
+            }
+        }
+    }
+
+    return rc;
+}
+
 static void pci_device_class_init(ObjectClass *klass, void *data)
 {
     DeviceClass *k = DEVICE_CLASS(klass);
diff --git a/hw/pci.h b/hw/pci.h
index 4f19fdb..cbd04e1 100644
--- a/hw/pci.h
+++ b/hw/pci.h
@@ -628,4 +628,9 @@ extern const VMStateDescription vmstate_pci_device;
     .offset     = vmstate_offset_pointer(_state, _field, PCIDevice), \
 }
 
+bool pci_check_bar_overlap(PCIDevice *dev,
+                           pcibus_t addr, pcibus_t size, uint8_t type,
+                           void (*c)(void *o, const PCIDevice *d, int index),
+                           void *opaque);
+
 #endif
-- 
Anthony PERARD