[Qemu-devel] [PATCH v2] qxl: add QXL_IO_FLUSH_{SURFACES, RELEASE} for guest S3&S4 support

[Alon Levy <alevy@redhat.com>]

Add two new IOs.
 QXL_IO_FLUSH_SURFACES - equivalent to update area for all surfaces, used
  to reduce vmexits from NumSurfaces to 1 on guest S3, S4 and resolution change (windows
  driver implementation is such that this is done on each of those occasions).
 QXL_IO_FLUSH_RELEASE - used to ensure anything on last_release is put on the release ring
  for the client to free.

Cc: Yonit Halperin <yhalperi@redhat.com>
---
 hw/qxl.c |   24 ++++++++++++++++++++++++
 1 files changed, 24 insertions(+), 0 deletions(-)

diff --git a/hw/qxl.c b/hw/qxl.c
index 969a984..fab0208 100644
--- a/hw/qxl.c
+++ b/hw/qxl.c
@@ -1167,6 +1167,30 @@ static void ioport_write(void *opaque, uint32_t addr, uint32_t val)
     case QXL_IO_DESTROY_ALL_SURFACES:
         qemu_spice_destroy_surfaces(&d->ssd);
         break;
+    case QXL_IO_FLUSH_SURFACES:
+        dprint(d, 1, "QXL_IO_FLUSH_SURFACES (%d) entry (%s, s#=%d, res#=%d)\n",
+            val, qxl_mode_to_string(d->mode), d->guest_surfaces.count,
+            d->num_free_res);
+        qemu_spice_stop(&d->ssd);
+        qemu_spice_start(&d->ssd);
+        dprint(d, 1, "QXL_IO_FLUSH_SURFACES exit (%s, s#=%d, res#=%d,%p)\n",
+            qxl_mode_to_string(d->mode), d->guest_surfaces.count,
+            d->num_free_res, d->last_release);
+        break;
+    case QXL_IO_FLUSH_RELEASE: {
+        QXLReleaseRing *ring = &d->ram->release_ring;
+        if (ring->prod - ring->cons + 1 == ring->num_items) {
+            // TODO - "return" a value to the guest and let it loop?
+            fprintf(stderr,
+                "ERROR: no flush, full release ring [p%d,%dc]\n",
+                ring->prod, ring->cons);
+        }
+        qxl_push_free_res(d, 1 /* flush */);
+        dprint(d, 1, "QXL_IO_FLUSH_RELEASE exit (%s, s#=%d, res#=%d,%p)\n",
+            qxl_mode_to_string(d->mode), d->guest_surfaces.count,
+            d->num_free_res, d->last_release);
+        break;
+    }
     case QXL_IO_MEMSLOT_ADD_ASYNC:
         PANIC_ON(val >= NUM_MEMSLOTS);
         PANIC_ON(d->guest_slots[val].active);
-- 
1.7.5.4