vfio: unmap and free BAR data in instance_finalize

In the case of VFIO, the unrealize callback is too early to munmap the
BARs.  The munmap must be delayed until memory accesses are complete.
To do this, split vfio_unmap_bars in two.  The removal step, now called
vfio_unregister_bars, remains in vfio_exitfn.  The reclamation step
is vfio_unmap_bars and is moved to the instance_finalize callback.

Similarly, quirk MemoryRegions have to be removed during
vfio_unregister_bars, but freeing the data structure must be delayed
to vfio_unmap_bars.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

1 files changed, 57 insertions, 8 deletions

diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index 0271c801b6..fa6a5e9268 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -1996,12 +1996,23 @@ static void vfio_vga_quirk_setup(VFIOPCIDevice *vdev)
 
 static void vfio_vga_quirk_teardown(VFIOPCIDevice *vdev)
 {
+    VFIOQuirk *quirk;
+    int i;
+
+    for (i = 0; i < ARRAY_SIZE(vdev->vga.region); i++) {
+        QLIST_FOREACH(quirk, &vdev->vga.region[i].quirks, next) {
+            memory_region_del_subregion(&vdev->vga.region[i].mem, &quirk->mem);
+        }
+    }
+}
+
+static void vfio_vga_quirk_free(VFIOPCIDevice *vdev)
+{
     int i;
 
     for (i = 0; i < ARRAY_SIZE(vdev->vga.region); i++) {
         while (!QLIST_EMPTY(&vdev->vga.region[i].quirks)) {
             VFIOQuirk *quirk = QLIST_FIRST(&vdev->vga.region[i].quirks);
-            memory_region_del_subregion(&vdev->vga.region[i].mem, &quirk->mem);
             object_unparent(OBJECT(&quirk->mem));
             QLIST_REMOVE(quirk, next);
             g_free(quirk);
@@ -2022,10 +2033,19 @@ static void vfio_bar_quirk_setup(VFIOPCIDevice *vdev, int nr)
 static void vfio_bar_quirk_teardown(VFIOPCIDevice *vdev, int nr)
 {
     VFIOBAR *bar = &vdev->bars[nr];
+    VFIOQuirk *quirk;
+
+    QLIST_FOREACH(quirk, &bar->quirks, next) {
+        memory_region_del_subregion(&bar->region.mem, &quirk->mem);
+    }
+}
+
+static void vfio_bar_quirk_free(VFIOPCIDevice *vdev, int nr)
+{
+    VFIOBAR *bar = &vdev->bars[nr];
 
     while (!QLIST_EMPTY(&bar->quirks)) {
         VFIOQuirk *quirk = QLIST_FIRST(&bar->quirks);
-        memory_region_del_subregion(&bar->region.mem, &quirk->mem);
         object_unparent(OBJECT(&quirk->mem));
         QLIST_REMOVE(quirk, next);
         g_free(quirk);
@@ -2281,7 +2301,7 @@ static void vfio_mmap_set_enabled(VFIOPCIDevice *vdev, bool enabled)
     }
 }
 
-static void vfio_unmap_bar(VFIOPCIDevice *vdev, int nr)
+static void vfio_unregister_bar(VFIOPCIDevice *vdev, int nr)
 {
     VFIOBAR *bar = &vdev->bars[nr];
 
@@ -2292,10 +2312,25 @@ static void vfio_unmap_bar(VFIOPCIDevice *vdev, int nr)
     vfio_bar_quirk_teardown(vdev, nr);
 
     memory_region_del_subregion(&bar->region.mem, &bar->region.mmap_mem);
-    munmap(bar->region.mmap, memory_region_size(&bar->region.mmap_mem));
 
     if (vdev->msix && vdev->msix->table_bar == nr) {
         memory_region_del_subregion(&bar->region.mem, &vdev->msix->mmap_mem);
+    }
+}
+
+static void vfio_unmap_bar(VFIOPCIDevice *vdev, int nr)
+{
+    VFIOBAR *bar = &vdev->bars[nr];
+
+    if (!bar->region.size) {
+        return;
+    }
+
+    vfio_bar_quirk_free(vdev, nr);
+
+    munmap(bar->region.mmap, memory_region_size(&bar->region.mmap_mem));
+
+    if (vdev->msix && vdev->msix->table_bar == nr) {
         munmap(vdev->msix->mmap, memory_region_size(&vdev->msix->mmap_mem));
     }
 }
@@ -2403,12 +2438,12 @@ static void vfio_map_bars(VFIOPCIDevice *vdev)
     }
 }
 
-static void vfio_unmap_bars(VFIOPCIDevice *vdev)
+static void vfio_unregister_bars(VFIOPCIDevice *vdev)
 {
     int i;
 
     for (i = 0; i < PCI_ROM_SLOT; i++) {
-        vfio_unmap_bar(vdev, i);
+        vfio_unregister_bar(vdev, i);
     }
 
     if (vdev->has_vga) {
@@ -2417,6 +2452,19 @@ static void vfio_unmap_bars(VFIOPCIDevice *vdev)
     }
 }
 
+static void vfio_unmap_bars(VFIOPCIDevice *vdev)
+{
+    int i;
+
+    for (i = 0; i < PCI_ROM_SLOT; i++) {
+        vfio_unmap_bar(vdev, i);
+    }
+
+    if (vdev->has_vga) {
+        vfio_vga_quirk_free(vdev);
+    }
+}
+
 /*
  * General setup
  */
@@ -3328,7 +3376,7 @@ static int vfio_initfn(PCIDevice *pdev)
 out_teardown:
     pci_device_set_intx_routing_notifier(&vdev->pdev, NULL);
     vfio_teardown_msi(vdev);
-    vfio_unmap_bars(vdev);
+    vfio_unregister_bars(vdev);
     return ret;
 }
 
@@ -3338,6 +3386,7 @@ static void vfio_instance_finalize(Object *obj)
     VFIOPCIDevice *vdev = DO_UPCAST(VFIOPCIDevice, pdev, pci_dev);
     VFIOGroup *group = vdev->vbasedev.group;
 
+    vfio_unmap_bars(vdev);
     g_free(vdev->emulated_config_bits);
     g_free(vdev->rom);
     vfio_put_device(vdev);
@@ -3355,7 +3404,7 @@ static void vfio_exitfn(PCIDevice *pdev)
         timer_free(vdev->intx.mmap_timer);
     }
     vfio_teardown_msi(vdev);
-    vfio_unmap_bars(vdev);
+    vfio_unregister_bars(vdev);
 }
 
 static void vfio_pci_reset(DeviceState *dev)