irq: inform device of IRQ mask & unmask via callback (#694)

Client masks or unmasks a device IRQ using the
VFIO_USER_DEVICE_SET_IRQS message. Inform the device of such changes to
the IRQ state.

Signed-off-by: Jagannathan Raman <jag.raman@oracle.com>
Reviewed-by: John Levon <john.levon@nutanix.com>

2 files changed, 38 insertions, 0 deletions

diff --git a/test/py/libvfio_user.py b/test/py/libvfio_user.py
index 4bdb761..76d9315 100644
--- a/test/py/libvfio_user.py
+++ b/test/py/libvfio_user.py
@@ -624,6 +624,11 @@ lib.vfu_create_ioeventfd.argtypes = (c.c_void_p, c.c_uint32, c.c_int,
 
 lib.vfu_device_quiesced.argtypes = (c.c_void_p, c.c_int)
 
+vfu_dev_irq_state_cb_t = c.CFUNCTYPE(None, c.c_void_p, c.c_uint32,
+                                     c.c_bool, use_errno=True)
+lib.vfu_setup_irq_state_callback.argtypes = (c.c_void_p, c.c_int,
+                                             vfu_dev_irq_state_cb_t)
+
 
 def to_byte(val):
     """Cast an int to a byte value."""
@@ -1030,6 +1035,20 @@ def vfu_setup_device_nr_irqs(ctx, irqtype, count):
     return lib.vfu_setup_device_nr_irqs(ctx, irqtype, count)
 
 
+def irq_state(ctx, vector, mask):
+    pass
+
+
+@vfu_dev_irq_state_cb_t
+def __irq_state(ctx, vector, mask):
+    irq_state(ctx, vector, mask)
+
+
+def vfu_setup_irq_state_callback(ctx, irqtype, cb=__irq_state):
+    assert ctx is not None
+    return lib.vfu_setup_irq_state_callback(ctx, irqtype, cb)
+
+
 def vfu_pci_init(ctx, pci_type=VFU_PCI_TYPE_EXPRESS,
                  hdr_type=PCI_HEADER_TYPE_NORMAL):
     assert ctx is not None
diff --git a/test/py/test_device_set_irqs.py b/test/py/test_device_set_irqs.py
index 382804a..7525b30 100644
--- a/test/py/test_device_set_irqs.py
+++ b/test/py/test_device_set_irqs.py
@@ -27,6 +27,8 @@
 #  DAMAGE.
 #
 
+from unittest.mock import patch
+
 from libvfio_user import *
 import errno
 import os
@@ -53,6 +55,9 @@ def test_device_set_irqs_setup():
     ret = vfu_setup_device_nr_irqs(ctx, VFU_DEV_MSIX_IRQ, 2048)
     assert ret == 0
 
+    vfu_setup_irq_state_callback(ctx, VFU_DEV_MSIX_IRQ)
+    assert ret == 0
+
     ret = vfu_realize_ctx(ctx)
     assert ret == 0
 
@@ -308,6 +313,20 @@ def test_device_set_irqs_enable_trigger_bool():
     assert struct.unpack("Q", os.read(fd2, 8))[0] == 9
 
 
+@patch('libvfio_user.irq_state')
+def test_irq_state(mock_irq_state):
+    assert mock_irq_state.call_count == 0
+
+    payload = vfio_irq_set(argsz=argsz, flags=VFIO_IRQ_SET_DATA_NONE |
+                           VFIO_IRQ_SET_ACTION_MASK,
+                           index=VFU_DEV_MSIX_IRQ,
+                           start=0, count=1)
+
+    msg(ctx, sock, VFIO_USER_DEVICE_SET_IRQS, payload)
+
+    assert mock_irq_state.call_count == 1
+
+
 def test_device_set_irqs_cleanup():
     vfu_destroy_ctx(ctx)