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author | Thanos Makatos <thanos.makatos@nutanix.com> | 2022-07-04 12:16:08 +0100 |
---|---|---|
committer | GitHub <noreply@github.com> | 2022-07-04 12:16:08 +0100 |
commit | 36beb63be45ad1412562a98d9373a4c0bd91ab3d (patch) | |
tree | 61bb44f0befc0055292b120909251c0fc2d27b0e /test | |
parent | 1c274027bb4f9d68eee846036e8d50dcde2fd7e9 (diff) | |
download | libvfio-user-36beb63be45ad1412562a98d9373a4c0bd91ab3d.zip libvfio-user-36beb63be45ad1412562a98d9373a4c0bd91ab3d.tar.gz libvfio-user-36beb63be45ad1412562a98d9373a4c0bd91ab3d.tar.bz2 |
support for shadow ioeventfd (#698)
When an ioeventfd is written to, KVM discards the value since it has no
memory to write it to, and simply kicks the eventfd. This a problem for
devices such a NVMe controllers that need the value (e.g. doorbells on
BAR0). This patch allows the vfio-user server to pass a file descriptor
that can be mmap'ed and KVM can write the ioeventfd value to this
_shadow_ memory instead of discarding it. This shadow memory is not
exposed to the guest.
Signed-off-by: Thanos Makatos <thanos.makatos@nutanix.com>
Reviewed-by: John Levon <john.levon@nutanix.com>
Change-Id: Iad849c94076ffa5988e034c8bf7ec312d01f095f
Diffstat (limited to 'test')
-rw-r--r-- | test/py/libvfio_user.py | 15 | ||||
-rw-r--r-- | test/py/meson.build | 4 | ||||
-rw-r--r-- | test/py/test_device_get_region_io_fds.py | 1 | ||||
-rw-r--r-- | test/py/test_pci_caps.py | 4 | ||||
-rw-r--r-- | test/py/test_shadow_ioeventfd.py | 105 |
5 files changed, 121 insertions, 8 deletions
diff --git a/test/py/libvfio_user.py b/test/py/libvfio_user.py index 0ebf773..c852542 100644 --- a/test/py/libvfio_user.py +++ b/test/py/libvfio_user.py @@ -194,6 +194,7 @@ VFIO_IOMMU_DIRTY_PAGES_FLAG_GET_BITMAP = (1 << 2) VFIO_USER_IO_FD_TYPE_IOEVENTFD = 0 VFIO_USER_IO_FD_TYPE_IOREGIONFD = 1 +VFIO_USER_IO_FD_TYPE_IOEVENTFD_SHADOW = 2 # enum vfu_dev_irq_type @@ -620,7 +621,7 @@ lib.vfu_sgl_put.argtypes = (c.c_void_p, c.POINTER(dma_sg_t), lib.vfu_create_ioeventfd.argtypes = (c.c_void_p, c.c_uint32, c.c_int, c.c_size_t, c.c_uint32, c.c_uint32, - c.c_uint64) + c.c_uint64, c.c_int32) lib.vfu_device_quiesced.argtypes = (c.c_void_p, c.c_int) @@ -635,6 +636,10 @@ def to_byte(val): return val.to_bytes(1, 'little') +def to_bytes_le(n, length=1): + return n.to_bytes(length, 'little') + + def skip(fmt, buf): """Return the data remaining after skipping the given elements.""" return buf[struct.calcsize(fmt):] @@ -645,6 +650,9 @@ def parse_json(json_str): return json.loads(json_str, object_hook=lambda d: SimpleNamespace(**d)) +IOEVENT_SIZE = 8 + + def eventfd(initval=0, flags=0): libc.eventfd.argtypes = (c.c_uint, c.c_int) return libc.eventfd(initval, flags) @@ -1184,11 +1192,12 @@ def vfu_sgl_put(ctx, sg, iovec, cnt=1): return lib.vfu_sgl_put(ctx, sg, iovec, cnt) -def vfu_create_ioeventfd(ctx, region_idx, fd, offset, size, flags, datamatch): +def vfu_create_ioeventfd(ctx, region_idx, fd, offset, size, flags, datamatch, + shadow_fd=-1): assert ctx is not None return lib.vfu_create_ioeventfd(ctx, region_idx, fd, offset, size, - flags, datamatch) + flags, datamatch, shadow_fd) def vfu_device_quiesced(ctx, err): diff --git a/test/py/meson.build b/test/py/meson.build index d9c97b3..0ea9f08 100644 --- a/test/py/meson.build +++ b/test/py/meson.build @@ -49,6 +49,10 @@ python_tests = [ 'test_vfu_realize_ctx.py', ] +if get_option('shadow-ioeventfd') + python_tests += 'test_shadow_ioeventfd.py' +endif + python_files = python_tests_common + python_tests if pytest.found() and opt_sanitizers == 'none' diff --git a/test/py/test_device_get_region_io_fds.py b/test/py/test_device_get_region_io_fds.py index cb1b732..924f462 100644 --- a/test/py/test_device_get_region_io_fds.py +++ b/test/py/test_device_get_region_io_fds.py @@ -36,7 +36,6 @@ import struct ctx = None sock = None fds = [] -IOEVENT_SIZE = 8 def test_device_get_region_io_fds_setup(): diff --git a/test/py/test_pci_caps.py b/test/py/test_pci_caps.py index b83c06c..01f23a2 100644 --- a/test/py/test_pci_caps.py +++ b/test/py/test_pci_caps.py @@ -349,10 +349,6 @@ def test_pci_cap_write_px(mock_quiesce, mock_reset): expect=errno.EINVAL) -def to_bytes_le(n, length=1): - return n.to_bytes(length, 'little') - - def test_pci_cap_write_msix(): setup_pci_dev(realize=True) sock = connect_client(ctx) diff --git a/test/py/test_shadow_ioeventfd.py b/test/py/test_shadow_ioeventfd.py new file mode 100644 index 0000000..642ad0e --- /dev/null +++ b/test/py/test_shadow_ioeventfd.py @@ -0,0 +1,105 @@ +# +# Copyright (c) 2022 Nutanix Inc. All rights reserved. +# +# Authors: Thanos Makatos <thanos.makatos@nutanix.com> +# +# Redistribution and use in source and binary forms, with or without +# modification, are permitted provided that the following conditions are met: +# * Redistributions of source code must retain the above copyright +# notice, this list of conditions and the following disclaimer. +# * Redistributions in binary form must reproduce the above copyright +# notice, this list of conditions and the following disclaimer in the +# documentation and/or other materials provided with the distribution. +# * Neither the name of Nutanix nor the names of its contributors may be +# used to endorse or promote products derived from this software without +# specific prior written permission. +# +# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" +# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +# ARE DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY +# DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES +# (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR +# SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER +# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY +# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH +# DAMAGE. +# + +from libvfio_user import * +import tempfile +import mmap +import errno + + +def test_shadow_ioeventfd(): + """Configure a shadow ioeventfd, have the client trigger it, confirm that + the server receives the notification and can see the value.""" + + # server setup + ctx = vfu_create_ctx(flags=LIBVFIO_USER_FLAG_ATTACH_NB) + assert ctx is not None + ret = vfu_setup_region(ctx, index=VFU_PCI_DEV_BAR0_REGION_IDX, size=0x1000, + flags=VFU_REGION_FLAG_RW) + assert ret == 0 + fo = tempfile.TemporaryFile(dir="/dev/shm") + fo.truncate(0x1000) + + # FIXME + # Use pip install eventfd? + # $ grep EFD_NONBLOCK -wr /usr/include/ + # /usr/include/bits/eventfd.h: EFD_NONBLOCK = 00004000 + EFD_NONBLOCK = 0o00004000 + + efd = eventfd(flags=EFD_NONBLOCK) + ret = vfu_create_ioeventfd(ctx, VFU_PCI_DEV_BAR0_REGION_IDX, efd, 0x8, + 0x16, 0, 0, shadow_fd=fo.fileno()) + assert ret == 0 + ret = vfu_realize_ctx(ctx) + assert ret == 0 + + # client queries I/O region FDs + sock = connect_client(ctx) + payload = vfio_user_region_io_fds_request( + argsz=len(vfio_user_region_io_fds_reply()) + + len(vfio_user_sub_region_ioeventfd()), flags=0, + index=VFU_PCI_DEV_BAR0_REGION_IDX, count=0) + newfds, ret = msg_fds(ctx, sock, VFIO_USER_DEVICE_GET_REGION_IO_FDS, + payload, expect=0) + reply, ret = vfio_user_region_io_fds_reply.pop_from_buffer(ret) + assert reply.count == 1 # 1 eventfd + ioevent, _ = vfio_user_sub_region_ioeventfd.pop_from_buffer(ret) + assert ioevent.offset == 0x8 + assert ioevent.size == 0x16 + assert ioevent.fd_index == 0 + assert ioevent.type == VFIO_USER_IO_FD_TYPE_IOEVENTFD_SHADOW + assert ioevent.flags == 0 + assert ioevent.datamatch == 0 + + assert len(newfds) == 2 # 2 FDs: eventfd plus shadow FD + cefd = newfds[0] + csfd = newfds[1] + cmem = mmap.mmap(csfd, 0x1000) + + # vfio-user app reads the eventfd, there should be nothing there + try: + os.read(efd, IOEVENT_SIZE) + except BlockingIOError as e: + if e.errno != errno.EAGAIN: + assert False + else: + assert False + + # Client writes to the I/O region. The write to the eventfd would be done + # by KVM and the value would be the same in both cases. + cmem.seek(0x8) + cmem.write(c.c_ulonglong(0xdeadbeef)) + os.write(cefd, c.c_ulonglong(0xcafebabe)) + + # vfio-user app reads eventfd + assert os.read(efd, IOEVENT_SIZE) == to_bytes_le(0xcafebabe, 8) + fo.seek(0x8) + assert fo.read(0x8) == to_bytes_le(0xdeadbeef, 8) + + vfu_destroy_ctx(ctx) |