[RFC PATCH 2/5] vfio/quirks: Add generic support for ioveventfds

[Alex Williamson <alex.williamson@xxxxxxxxxx>]

We might wish to handle some quirks via ioeventfds, add a list of
ioeventfds to the quirk.

Signed-off-by: Alex Williamson <alex.williamson@xxxxxxxxxx>
---
 hw/vfio/pci-quirks.c |   17 +++++++++++++++++
 hw/vfio/pci.h        |   11 +++++++++++
 2 files changed, 28 insertions(+)

diff --git a/hw/vfio/pci-quirks.c b/hw/vfio/pci-quirks.c
index 10af23217292..e4cf4ea2dd9c 100644
--- a/hw/vfio/pci-quirks.c
+++ b/hw/vfio/pci-quirks.c
@@ -12,6 +12,7 @@
 
 #include "qemu/osdep.h"
 #include "qemu/error-report.h"
+#include "qemu/main-loop.h"
 #include "qemu/range.h"
 #include "qapi/error.h"
 #include "qapi/visitor.h"
@@ -278,12 +279,24 @@ static const MemoryRegionOps vfio_ati_3c3_quirk = {
 static VFIOQuirk *vfio_quirk_alloc(int nr_mem)
 {
     VFIOQuirk *quirk = g_malloc0(sizeof(*quirk));
+    QLIST_INIT(&quirk->ioeventfds);
     quirk->mem = g_new0(MemoryRegion, nr_mem);
     quirk->nr_mem = nr_mem;
 
     return quirk;
 }
 
+static void vfio_ioeventfd_exit(VFIOIOEventFD *ioeventfd)
+{
+    QLIST_REMOVE(ioeventfd, next);
+    memory_region_del_eventfd(ioeventfd->mr, ioeventfd->addr, ioeventfd->size,
+                              ioeventfd->match_data, ioeventfd->data,
+                              &ioeventfd->e);
+    qemu_set_fd_handler(event_notifier_get_fd(&ioeventfd->e), NULL, NULL, NULL);
+    event_notifier_cleanup(&ioeventfd->e);
+    g_free(ioeventfd);
+}
+
 static void vfio_vga_probe_ati_3c3_quirk(VFIOPCIDevice *vdev)
 {
     VFIOQuirk *quirk;
@@ -1668,6 +1681,10 @@ void vfio_bar_quirk_exit(VFIOPCIDevice *vdev, int nr)
     int i;
 
     QLIST_FOREACH(quirk, &bar->quirks, next) {
+        while (!QLIST_EMPTY(&quirk->ioeventfds)) {
+            vfio_ioeventfd_exit(QLIST_FIRST(&quirk->ioeventfds));
+        }
+
         for (i = 0; i < quirk->nr_mem; i++) {
             memory_region_del_subregion(bar->region.mem, &quirk->mem[i]);
         }
diff --git a/hw/vfio/pci.h b/hw/vfio/pci.h
index f4aa13e021fa..146065c2f715 100644
--- a/hw/vfio/pci.h
+++ b/hw/vfio/pci.h
@@ -24,9 +24,20 @@
 
 struct VFIOPCIDevice;
 
+typedef struct VFIOIOEventFD {
+    QLIST_ENTRY(VFIOIOEventFD) next;
+    MemoryRegion *mr;
+    hwaddr addr;
+    unsigned size;
+    bool match_data;
+    uint64_t data;
+    EventNotifier e;
+} VFIOIOEventFD;
+
 typedef struct VFIOQuirk {
     QLIST_ENTRY(VFIOQuirk) next;
     void *data;
+    QLIST_HEAD(, VFIOIOEventFD) ioeventfds;
     int nr_mem;
     MemoryRegion *mem;
 } VFIOQuirk;