Hi Paolo
Does the compile of this series of patches require support for a
special kernel environment? I hit a compile issue after applied you
patches:
[1440/2928] Compiling C object libsystem.a.p/hw_virtio_vhost.c.o
FAILED: libsystem.a.p/hw_virtio_vhost.c.o
cc -m64 -Ilibsystem.a.p -I. -I.. -Isubprojects/dtc/libfdt
-I../subprojects/dtc/libfdt -Isubprojects/libvduse
-I../subprojects/libvduse -Iui -Iqapi -Itrace -Iui/shader
-I/usr/include/pixman-1 -I/usr/include/glib-2.0
-I/usr/lib64/glib-2.0/include -I/usr/include/libmount
-I/usr/include/blkid -I/usr/include/sysprof-6
-I/usr/include/gio-unix-2.0 -I/usr/include/slirp
-fdiagnostics-color=auto -Wall -Winvalid-pch -Werror -std=gnu11 -O0 -g
-fstack-protector-strong -Wempty-body -Wendif-labels
-Wexpansion-to-defined -Wformat-security -Wformat-y2k
-Wignored-qualifiers -Wimplicit-fallthrough=2 -Winit-self
-Wmissing-format-attribute -Wmissing-prototypes -Wnested-externs
-Wold-style-declaration -Wold-style-definition -Wredundant-decls
-Wshadow=local -Wstrict-prototypes -Wtype-limits -Wundef -Wvla
-Wwrite-strings -Wno-missing-include-dirs -Wno-psabi
-Wno-shift-negative-value -isystem
/mnt/tests/distribution/command/qemu/linux-headers -isystem
linux-headers -iquote . -iquote /mnt/tests/distribution/command/qemu
-iquote /mnt/tests/distribution/command/qemu/include -iquote
/mnt/tests/distribution/command/qemu/host/include/x86_64 -iquote
/mnt/tests/distribution/command/qemu/host/include/generic -iquote
/mnt/tests/distribution/command/qemu/tcg/i386 -pthread -mcx16 -msse2
-D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE
-fno-strict-aliasing -fno-common -fwrapv -ftrivial-auto-var-init=zero
-fzero-call-used-regs=used-gpr -fPIE -DWITH_GZFILEOP -DCONFIG_SOFTMMU
-DCOMPILING_SYSTEM_VS_USER -MD -MQ libsystem.a.p/hw_virtio_vhost.c.o
-MF libsystem.a.p/hw_virtio_vhost.c.o.d -o
libsystem.a.p/hw_virtio_vhost.c.o -c ../hw/virtio/vhost.c
../hw/virtio/vhost.c: In function ‘vhost_dev_set_features’:
../hw/virtio/vhost.c:38:9: error: ‘r’ may be used uninitialized
[-Werror=maybe-uninitialized]
38 | error_report(fmt ": %s (%d)", ## __VA_ARGS__, \
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
39 | strerror(-retval), -retval); \
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~
../hw/virtio/vhost.c:1006:9: note: in expansion of macro ‘VHOST_OPS_DEBUG’
1006 | VHOST_OPS_DEBUG(r, "extended features without device support");
| ^~~~~~~~~~~~~~~
../hw/virtio/vhost.c:989:9: note: ‘r’ was declared here
989 | int r;
| ^
cc1: all warnings being treated as errors
ninja: build stopped: subcommand failed.
make[1]: *** [Makefile:168: run-ninja] Error 1
make[1]: Leaving directory '/mnt/tests/distribution/command/qemu/build'
make[1]: Entering directory '/mnt/tests/distribution/command/qemu/build'
[1/1493] Generating subprojects/dtc/version_gen.h with a custom command
[2/1493] Generating qemu-version.h with a custom command (wrapped by
meson to capture output)
[3/1492] Compiling C object libsystem.a.p/hw_virtio_vhost.c.o
FAILED: libsystem.a.p/hw_virtio_vhost.c.o
cc -m64 -Ilibsystem.a.p -I. -I.. -Isubprojects/dtc/libfdt
-I../subprojects/dtc/libfdt -Isubprojects/libvduse
-I../subprojects/libvduse -Iui -Iqapi -Itrace -Iui/shader
-I/usr/include/pixman-1 -I/usr/include/glib-2.0
-I/usr/lib64/glib-2.0/include -I/usr/include/libmount
-I/usr/include/blkid -I/usr/include/sysprof-6
-I/usr/include/gio-unix-2.0 -I/usr/include/slirp
-fdiagnostics-color=auto -Wall -Winvalid-pch -Werror -std=gnu11 -O0 -g
-fstack-protector-strong -Wempty-body -Wendif-labels
-Wexpansion-to-defined -Wformat-security -Wformat-y2k
-Wignored-qualifiers -Wimplicit-fallthrough=2 -Winit-self
-Wmissing-format-attribute -Wmissing-prototypes -Wnested-externs
-Wold-style-declaration -Wold-style-definition -Wredundant-decls
-Wshadow=local -Wstrict-prototypes -Wtype-limits -Wundef -Wvla
-Wwrite-strings -Wno-missing-include-dirs -Wno-psabi
-Wno-shift-negative-value -isystem
/mnt/tests/distribution/command/qemu/linux-headers -isystem
linux-headers -iquote . -iquote /mnt/tests/distribution/command/qemu
-iquote /mnt/tests/distribution/command/qemu/include -iquote
/mnt/tests/distribution/command/qemu/host/include/x86_64 -iquote
/mnt/tests/distribution/command/qemu/host/include/generic -iquote
/mnt/tests/distribution/command/qemu/tcg/i386 -pthread -mcx16 -msse2
-D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE
-fno-strict-aliasing -fno-common -fwrapv -ftrivial-auto-var-init=zero
-fzero-call-used-regs=used-gpr -fPIE -DWITH_GZFILEOP -DCONFIG_SOFTMMU
-DCOMPILING_SYSTEM_VS_USER -MD -MQ libsystem.a.p/hw_virtio_vhost.c.o
-MF libsystem.a.p/hw_virtio_vhost.c.o.d -o
libsystem.a.p/hw_virtio_vhost.c.o -c ../hw/virtio/vhost.c
../hw/virtio/vhost.c: In function ‘vhost_dev_set_features’:
../hw/virtio/vhost.c:38:9: error: ‘r’ may be used uninitialized
[-Werror=maybe-uninitialized]
38 | error_report(fmt ": %s (%d)", ## __VA_ARGS__, \
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
39 | strerror(-retval), -retval); \
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~
../hw/virtio/vhost.c:1006:9: note: in expansion of macro ‘VHOST_OPS_DEBUG’
1006 | VHOST_OPS_DEBUG(r, "extended features without device support");
| ^~~~~~~~~~~~~~~
../hw/virtio/vhost.c:989:9: note: ‘r’ was declared here
989 | int r;
| ^
cc1: all warnings being treated as errors
ninja: build stopped: subcommand failed.
make[1]: *** [Makefile:168: run-ninja] Error 1
make[1]: Leaving directory '/mnt/tests/distribution/command/qemu/build'
Thanks
Lei
On Fri, Jul 11, 2025 at 9:08 PM Paolo Abeni <pab...@redhat.com> wrote:
>
> Some virtualized deployments use UDP tunnel pervasively and are impacted
> negatively by the lack of GSO support for such kind of traffic in the
> virtual NIC driver.
>
> The virtio_net specification recently introduced support for GSO over
> UDP tunnel, and the kernel side of the implementation has been merged
> into the net-next tree; this series updates the virtio implementation to
> support such a feature.
>
> Currently the qemu virtio support limits the feature space to 64 bits,
> while the virtio specification allows for a larger number of features.
> Specifically the GSO-over-UDP-tunnel-related virtio features use bits
> 65-69; the larger part of this series (patches 3-11) actually deals with
> extending the features space.
>
> The extended features are carried by fixed size uint64_t arrays,
> bringing the current maximum features number to 128.
>
> The patches use some syntactic sugar to try to minimize the otherwise
> very large code churn. Specifically the extended features are boundled
> in an union with 'legacy' features definition, allowing no changes in
> the virtio devices not needing the extended features set.
>
> The actual offload implementation is in patches 12 and 13 and boils down
> to propagating the new offload to the tun devices and the vhost backend.
>
> Finally patch 1 is a small pre-req refactor that ideally could enter the
> tree separately; it's presented here in the same series to help
> reviewers more easily getting the full picture and patch 2 is a needed
> linux headers update.
>
> Tested with basic stream transfer with all the possible permutations of
> host kernel/qemu/guest kernel with/without GSO over UDP tunnel support,
> vs snapshots creation and restore and vs migration.
>
> Sharing again as RFC as the kernel bits have not entered the Linus tree
> yet - but they should on next merge window.
>
> Paolo Abeni (13):
> net: bundle all offloads in a single struct
> linux-headers: Update to Linux ~v6.16-rc5 net-next
> virtio: introduce extended features type
> virtio: serialize extended features state
> virtio: add support for negotiating extended features
> virtio-pci: implement support for extended features
> vhost: add support for negotiating extended features
> qmp: update virtio features map to support extended features
> vhost-backend: implement extended features support
> vhost-net: implement extended features support
> virtio-net: implement extended features support
> net: implement tunnel probing
> net: implement UDP tunnel features offloading
>
> hw/net/e1000e_core.c | 5 +-
> hw/net/igb_core.c | 5 +-
> hw/net/vhost_net-stub.c | 8 +-
> hw/net/vhost_net.c | 50 +++--
> hw/net/virtio-net.c | 215 +++++++++++++------
> hw/net/vmxnet3.c | 13 +-
> hw/virtio/vhost-backend.c | 62 +++++-
> hw/virtio/vhost.c | 73 ++++++-
> hw/virtio/virtio-bus.c | 11 +-
> hw/virtio/virtio-hmp-cmds.c | 3 +-
> hw/virtio/virtio-pci.c | 101 ++++++++-
> hw/virtio/virtio-qmp.c | 89 +++++---
> hw/virtio/virtio-qmp.h | 3 +-
> hw/virtio/virtio.c | 111 ++++++++--
> include/hw/virtio/vhost-backend.h | 6 +
> include/hw/virtio/vhost.h | 36 +++-
> include/hw/virtio/virtio-features.h | 124 +++++++++++
> include/hw/virtio/virtio-net.h | 2 +-
> include/hw/virtio/virtio-pci.h | 6 +-
> include/hw/virtio/virtio.h | 11 +-
> include/net/net.h | 20 +-
> include/net/vhost_net.h | 33 ++-
> include/standard-headers/linux/ethtool.h | 4 +-
> include/standard-headers/linux/vhost_types.h | 5 +
> include/standard-headers/linux/virtio_net.h | 33 +++
> linux-headers/asm-x86/kvm.h | 8 +-
> linux-headers/linux/kvm.h | 4 +
> linux-headers/linux/vhost.h | 7 +
> net/net.c | 17 +-
> net/netmap.c | 3 +-
> net/tap-bsd.c | 8 +-
> net/tap-linux.c | 38 +++-
> net/tap-linux.h | 9 +
> net/tap-solaris.c | 9 +-
> net/tap-stub.c | 8 +-
> net/tap.c | 19 +-
> net/tap_int.h | 5 +-
> qapi/virtio.json | 8 +-
> 38 files changed, 945 insertions(+), 227 deletions(-)
> create mode 100644 include/hw/virtio/virtio-features.h
>
> --
> 2.50.0
>
>
