require quiesce for VFIO_USER_DIRTY_PAGES (#671)
If we require a quiesce for these calls, we can be sure that it will not race
with any usage of vfu_*_sg() calls, as a first step towards concurrency.
This is not ideal for VFIO_IOMMU_DIRTY_PAGES_FLAG_GET_BITMAP, which can
potentially be called multiple times during pre-copy phase, but that's something
we can fix later.
Signed-off-by: John Levon <john.levon@nutanix.com>
Reviewed-by: Thanos Makatos <thanos.makatos@nutanix.com>
diff --git a/lib/libvfio-user.c b/lib/libvfio-user.c
index a666316..924d109 100644
--- a/lib/libvfio-user.c
+++ b/lib/libvfio-user.c
@@ -1310,6 +1310,9 @@
case VFIO_USER_DEVICE_RESET:
return true;
+ case VFIO_USER_DIRTY_PAGES:
+ return true;
+
case VFIO_USER_REGION_WRITE:
if (msg->in.iov.iov_len < sizeof(*reg)) {
/*
diff --git a/test/py/test_dirty_pages.py b/test/py/test_dirty_pages.py
index 4169ae5..8af325a 100644
--- a/test/py/test_dirty_pages.py
+++ b/test/py/test_dirty_pages.py
@@ -28,11 +28,13 @@
#
from libvfio_user import *
+import ctypes as c
import errno
import mmap
import tempfile
ctx = None
+quiesce_errno = 0
@vfu_dma_register_cb_t
@@ -45,6 +47,14 @@
return 0
+@vfu_device_quiesce_cb_t
+def quiesce_cb(ctx):
+ if quiesce_errno:
+ c.set_errno(errno.EBUSY)
+ return -1
+ return 0
+
+
def test_dirty_pages_setup():
global ctx, sock
@@ -54,6 +64,8 @@
ret = vfu_pci_init(ctx)
assert ret == 0
+ vfu_setup_device_quiesce_cb(ctx, quiesce_cb=quiesce_cb)
+
ret = vfu_setup_device_dma(ctx, dma_register, dma_unregister)
assert ret == 0
@@ -271,7 +283,13 @@
assert br.bitmap.size == 8
-def get_dirty_page_bitmap():
+def get_dirty_page_bitmap_result(resp):
+ _, resp = vfio_user_dirty_pages.pop_from_buffer(resp)
+ _, resp = vfio_user_bitmap_range.pop_from_buffer(resp)
+ return struct.unpack("Q", resp)[0]
+
+
+def send_dirty_page_bitmap(busy=False):
argsz = len(vfio_user_dirty_pages()) + len(vfio_user_bitmap_range()) + 8
dirty_pages = vfio_user_dirty_pages(argsz=argsz,
@@ -281,11 +299,12 @@
payload = bytes(dirty_pages) + bytes(br)
- result = msg(ctx, sock, VFIO_USER_DIRTY_PAGES, payload)
+ return msg(ctx, sock, VFIO_USER_DIRTY_PAGES, payload, busy=busy)
- dirty_pages, result = vfio_user_dirty_pages.pop_from_buffer(result)
- br, result = vfio_user_bitmap_range.pop_from_buffer(result)
- return struct.unpack("Q", result)[0]
+
+def get_dirty_page_bitmap():
+ result = send_dirty_page_bitmap()
+ return get_dirty_page_bitmap_result(result)
sg3 = None
@@ -345,7 +364,7 @@
vfu_unmap_sg(ctx, sg3, iovec3)
assert get_dirty_page_bitmap() == 0b11110000
- # bitmap should be clear after it was unmapped before previous reqeust for
+ # bitmap should be clear after it was unmapped before previous request for
# dirty pages
assert get_dirty_page_bitmap() == 0b00000000
@@ -354,6 +373,68 @@
stop_logging()
+def test_dirty_pages_start_with_quiesce():
+ global quiesce_errno
+
+ quiesce_errno = errno.EBUSY
+
+ payload = vfio_user_dirty_pages(argsz=len(vfio_user_dirty_pages()),
+ flags=VFIO_IOMMU_DIRTY_PAGES_FLAG_START)
+
+ msg(ctx, sock, VFIO_USER_DIRTY_PAGES, payload, rsp=False, busy=True)
+
+ ret = vfu_device_quiesced(ctx, 0)
+ assert ret == 0
+
+ # now should be able to get the reply
+ get_reply(sock, expect=0)
+
+ quiesce_errno = 0
+
+
+def test_dirty_pages_bitmap_with_quiesce():
+ global quiesce_errno
+
+ quiesce_errno = errno.EBUSY
+
+ ret, sg1 = vfu_addr_to_sg(ctx, dma_addr=0x10000, length=0x1000)
+ assert ret == 1
+ iovec1 = iovec_t()
+ ret = vfu_map_sg(ctx, sg1, iovec1)
+ assert ret == 0
+
+ send_dirty_page_bitmap(busy=True)
+
+ ret = vfu_device_quiesced(ctx, 0)
+ assert ret == 0
+
+ # now should be able to get the reply
+ result = get_reply(sock, expect=0)
+ bitmap = get_dirty_page_bitmap_result(result)
+ assert bitmap == 0b00000001
+
+ quiesce_errno = 0
+
+
+def test_dirty_pages_stop_with_quiesce():
+ global quiesce_errno
+
+ quiesce_errno = errno.EBUSY
+
+ payload = vfio_user_dirty_pages(argsz=len(vfio_user_dirty_pages()),
+ flags=VFIO_IOMMU_DIRTY_PAGES_FLAG_STOP)
+
+ msg(ctx, sock, VFIO_USER_DIRTY_PAGES, payload, rsp=False, busy=True)
+
+ ret = vfu_device_quiesced(ctx, 0)
+ assert ret == 0
+
+ # now should be able to get the reply
+ get_reply(sock, expect=0)
+
+ quiesce_errno = 0
+
+
def test_dirty_pages_cleanup():
disconnect_client(ctx, sock)
vfu_destroy_ctx(ctx)
