docs: vhost-user: add Virtio status protocol feature

This patch specifies the VHOST_USER_SET_STATUS and
VHOST_USER_GET_STATUS requests, which are sent by
the master to update and query the Virtio status
in the backend.

Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
---

Changes since v1:
=================
- Only keep the spec part in this patch, the implementation will
  be part of Cindy's Vhost vDPA series it depends on. The goal is
  to be able to implement it in next DPDK release even if Qemu part
  is not merged.
- Add GET_STATUS after discussions with Michael and Jason. It can
  be used by the master to ensure FEATURES_OK bit set is
  acknowledged by the backend.

 docs/interop/vhost-user.rst | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

Patchew URL: https://patchew.org/QEMU/20200618112908.130528-1-maxime.coquelin@redhat.com/



Hi,

This series failed the asan build test. Please find the testing commands and
their output below. If you have Docker installed, you can probably reproduce it
locally.

=== TEST SCRIPT BEGIN ===
#!/bin/bash
export ARCH=x86_64
make docker-image-fedora V=1 NETWORK=1
time make docker-test-debug@fedora TARGET_LIST=x86_64-softmmu J=14 NETWORK=1
=== TEST SCRIPT END ===

  CC      qga/commands.o
  CC      qga/guest-agent-command-state.o
  CC      qga/main.o
/usr/bin/ld: /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors_vfork.S.o): warning: common of `__interception::real_vfork' overridden by definition from /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors.cpp.o)
  CC      qga/commands-posix.o
  CC      qga/channel-posix.o
  CC      qga/qapi-generated/qga-qapi-types.o
---
  AR      libvhost-user.a
  GEN     docs/interop/qemu-ga-ref.html
  GEN     docs/interop/qemu-ga-ref.txt
/usr/bin/ld: /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors_vfork.S.o): warning: common of `__interception::real_vfork' overridden by definition from /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors.cpp.o)
  GEN     docs/interop/qemu-ga-ref.7
  AS      pc-bios/optionrom/linuxboot.o
  AS      pc-bios/optionrom/kvmvapic.o
---
  SIGN    pc-bios/optionrom/pvh.bin
  LINK    qemu-ga
  LINK    qemu-keymap
/usr/bin/ld: /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors_vfork.S.o): warning: common of `__interception::real_vfork' overridden by definition from /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors.cpp.o)
  LINK    ivshmem-client
/usr/bin/ld: /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors_vfork.S.o): warning: common of `__interception::real_vfork' overridden by definition from /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors.cpp.o)
  LINK    ivshmem-server
/usr/bin/ld: /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors_vfork.S.o): warning: common of `__interception::real_vfork' overridden by definition from /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors.cpp.o)
  LINK    qemu-nbd
/usr/bin/ld: /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors_vfork.S.o): warning: common of `__interception::real_vfork' overridden by definition from /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors.cpp.o)
  LINK    qemu-storage-daemon
  LINK    qemu-img
/usr/bin/ld: /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors_vfork.S.o): warning: common of `__interception::real_vfork' overridden by definition from /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors.cpp.o)
/usr/bin/ld: /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors_vfork.S.o): warning: common of `__interception::real_vfork' overridden by definition from /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors.cpp.o)
  LINK    qemu-io
/usr/bin/ld: /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors_vfork.S.o): warning: common of `__interception::real_vfork' overridden by definition from /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors.cpp.o)
  LINK    qemu-edid
/usr/bin/ld: /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors_vfork.S.o): warning: common of `__interception::real_vfork' overridden by definition from /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors.cpp.o)
  LINK    fsdev/virtfs-proxy-helper
/usr/bin/ld: /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors_vfork.S.o): warning: common of `__interception::real_vfork' overridden by definition from /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors.cpp.o)
  LINK    scsi/qemu-pr-helper
/usr/bin/ld: /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors_vfork.S.o): warning: common of `__interception::real_vfork' overridden by definition from /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors.cpp.o)
  LINK    qemu-bridge-helper
/usr/bin/ld: /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors_vfork.S.o): warning: common of `__interception::real_vfork' overridden by definition from /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors.cpp.o)
/usr/bin/ld: /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors_vfork.S.o): warning: common of `__interception::real_vfork' overridden by definition from /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors.cpp.o)
  LINK    virtiofsd
/usr/bin/ld: /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors_vfork.S.o): warning: common of `__interception::real_vfork' overridden by definition from /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors.cpp.o)
  LINK    vhost-user-input
/usr/bin/ld: /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors_vfork.S.o): warning: common of `__interception::real_vfork' overridden by definition from /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors.cpp.o)
  GEN     x86_64-softmmu/hmp-commands-info.h
  GEN     x86_64-softmmu/config-devices.h
  GEN     x86_64-softmmu/config-target.h
---
  CC      x86_64-softmmu/gdbstub-xml.o
  CC      x86_64-softmmu/trace/generated-helpers.o
  LINK    x86_64-softmmu/qemu-system-x86_64
/usr/bin/ld: /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors_vfork.S.o): warning: common of `__interception::real_vfork' overridden by definition from /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors.cpp.o)
common.rc: line 50: test: check: binary operator expected
(printf '#define QEMU_PKGVERSION ""\n'; printf '#define QEMU_FULL_VERSION "5.0.50"\n'; ) > qemu-version.h.tmp
make -C /tmp/qemu-test/src/slirp BUILD_DIR="/tmp/qemu-test/build/slirp" PKG_CONFIG="pkg-config" CC="clang" AR="ar"      LD="ld" RANLIB="ranlib" CFLAGS="-I/usr/include/pixman-1   -Werror -fsanitize=undefined -fsanitize=address  -pthread -I/usr/include/glib-2.0 -I/usr/lib64/glib-2.0/include  -fPIE -DPIE -m64 -mcx16 -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -Wstrict-prototypes -Wredundant-decls -Wall -Wundef -Wwrite-strings -Wmissing-prototypes -fno-strict-aliasing -fno-common -fwrapv -std=gnu99  -Wold-style-definition -Wtype-limits -Wformat-security -Wformat-y2k -Winit-self -Wignored-qualifiers -Wempty-body -Wnested-externs -Wendif-labels -Wexpansion-to-defined -Wno-initializer-overrides -Wno-missing-include-dirs -Wno-shift-negative-value -Wno-string-plus-int -Wno-typedef-redefinition -Wno-tautological-type-limit-compare -fstack-protector-strong   -I/usr/include/p11-kit-1   -DSTRUCT_IOVEC_DEFINED  -I/usr/include/libpng16  -I/usr/include/spice-1 -I/usr/include/spice-server -I/usr/include/cacard -I/usr/include/glib-2.0 -I/usr/lib64/glib-2.0/include -I/usr/include/nss3 -I/usr/include/nspr4 -pthread -I/usr/include/libmount -I/usr/include/blkid -I/usr/include/pixman-1   -I/tmp/qemu-test/src/tests -I/tmp/qemu-test/src/tests/qtest -g " LDFLAGS="-Wl,--warn-common -fsanitize=undefined -fsanitize=address -Wl,-z,relro -Wl,-z,now -pie -m64  -fstack-protector-strong"
---
clang -iquote /tmp/qemu-test/build/. -iquote . -iquote /tmp/qemu-test/src/tcg/i386 -isystem /tmp/qemu-test/src/linux-headers -isystem /tmp/qemu-test/build/linux-headers -iquote . -iquote /tmp/qemu-test/src -iquote /tmp/qemu-test/src/accel/tcg -iquote /tmp/qemu-test/src/include -iquote /tmp/qemu-test/src/disas/libvixl -I/tmp/qemu-test/src/tests/fp -I/tmp/qemu-test/src/tests/fp/berkeley-softfloat-3/source/include -I/tmp/qemu-test/src/tests/fp/berkeley-softfloat-3/source/8086-SSE -I/tmp/qemu-test/src/tests/fp/berkeley-testfloat-3/source -I/usr/include/pixman-1 -Werror -fsanitize=undefined -fsanitize=address -pthread -I/usr/include/glib-2.0 -I/usr/lib64/glib-2.0/include -fPIE -DPIE -m64 -mcx16 -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -Wstrict-prototypes -Wredundant-decls -Wall -Wundef -Wwrite-strings -Wmissing-prototypes -fno-strict-aliasing -fno-common -fwrapv -std=gnu99 -Wold-style-definition -Wtype-limits -Wformat-security -Wformat-y2k -Winit-self -Wignored-qualifiers -Wempty-body -Wnested-externs -Wendif-labels -Wexpansion-to-defined -Wno-initializer-overrides -Wno-missing-include-dirs -Wno-shift-negative-value -Wno-string-plus-int -Wno-typedef-redefinition -Wno-tautological-type-limit-compare -fstack-protector-strong -I/usr/include/p11-kit-1 -DSTRUCT_IOVEC_DEFINED -I/usr/include/libpng16 -I/usr/include/spice-1 -I/usr/include/spice-server -I/usr/include/cacard -I/usr/include/glib-2.0 -I/usr/lib64/glib-2.0/include -I/usr/include/nss3 -I/usr/include/nspr4 -pthread -I/usr/include/libmount -I/usr/include/blkid -I/usr/include/pixman-1 -DHW_POISON_H -DTARGET_ARM  -DSOFTFLOAT_ROUND_ODD -DINLINE_LEVEL=5 -DSOFTFLOAT_FAST_DIV32TO16 -DSOFTFLOAT_FAST_DIV64TO32 -DSOFTFLOAT_FAST_INT64  -DFLOAT16 -DFLOAT64 -DEXTFLOAT80 -DFLOAT128 -DFLOAT_ROUND_ODD -DLONG_DOUBLE_IS_EXTFLOAT80  -Wno-strict-prototypes -Wno-unknown-pragmas -Wno-uninitialized -Wno-missing-prototypes -Wno-return-type -Wno-unused-function -Wno-error -MMD -MP -MT functions_common.o -MF ./functions_common.d -g   -c -o functions_common.o /tmp/qemu-test/src/tests/fp/berkeley-testfloat-3/source/functions_common.c
clang -iquote /tmp/qemu-test/build/. -iquote . -iquote /tmp/qemu-test/src/tcg/i386 -isystem /tmp/qemu-test/src/linux-headers -isystem /tmp/qemu-test/build/linux-headers -iquote . -iquote /tmp/qemu-test/src -iquote /tmp/qemu-test/src/accel/tcg -iquote /tmp/qemu-test/src/include -iquote /tmp/qemu-test/src/disas/libvixl -I/tmp/qemu-test/src/tests/fp -I/tmp/qemu-test/src/tests/fp/berkeley-softfloat-3/source/include -I/tmp/qemu-test/src/tests/fp/berkeley-softfloat-3/source/8086-SSE -I/tmp/qemu-test/src/tests/fp/berkeley-testfloat-3/source -I/usr/include/pixman-1 -Werror -fsanitize=undefined -fsanitize=address -pthread -I/usr/include/glib-2.0 -I/usr/lib64/glib-2.0/include -fPIE -DPIE -m64 -mcx16 -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -Wstrict-prototypes -Wredundant-decls -Wall -Wundef -Wwrite-strings -Wmissing-prototypes -fno-strict-aliasing -fno-common -fwrapv -std=gnu99 -Wold-style-definition -Wtype-limits -Wformat-security -Wformat-y2k -Winit-self -Wignored-qualifiers -Wempty-body -Wnested-externs -Wendif-labels -Wexpansion-to-defined -Wno-initializer-overrides -Wno-missing-include-dirs -Wno-shift-negative-value -Wno-string-plus-int -Wno-typedef-redefinition -Wno-tautological-type-limit-compare -fstack-protector-strong -I/usr/include/p11-kit-1 -DSTRUCT_IOVEC_DEFINED -I/usr/include/libpng16 -I/usr/include/spice-1 -I/usr/include/spice-server -I/usr/include/cacard -I/usr/include/glib-2.0 -I/usr/lib64/glib-2.0/include -I/usr/include/nss3 -I/usr/include/nspr4 -pthread -I/usr/include/libmount -I/usr/include/blkid -I/usr/include/pixman-1 -DHW_POISON_H -DTARGET_ARM  -DSOFTFLOAT_ROUND_ODD -DINLINE_LEVEL=5 -DSOFTFLOAT_FAST_DIV32TO16 -DSOFTFLOAT_FAST_DIV64TO32 -DSOFTFLOAT_FAST_INT64  -DFLOAT16 -DFLOAT64 -DEXTFLOAT80 -DFLOAT128 -DFLOAT_ROUND_ODD -DLONG_DOUBLE_IS_EXTFLOAT80  -Wno-strict-prototypes -Wno-unknown-pragmas -Wno-uninitialized -Wno-missing-prototypes -Wno-return-type -Wno-unused-function -Wno-error -MMD -MP -MT functionInfos.o -MF ./functionInfos.d -g   -c -o functionInfos.o /tmp/qemu-test/src/tests/fp/berkeley-testfloat-3/source/functionInfos.c
clang -iquote /tmp/qemu-test/build/. -iquote . -iquote /tmp/qemu-test/src/tcg/i386 -isystem /tmp/qemu-test/src/linux-headers -isystem /tmp/qemu-test/build/linux-headers -iquote . -iquote /tmp/qemu-test/src -iquote /tmp/qemu-test/src/accel/tcg -iquote /tmp/qemu-test/src/include -iquote /tmp/qemu-test/src/disas/libvixl -I/tmp/qemu-test/src/tests/fp -I/tmp/qemu-test/src/tests/fp/berkeley-softfloat-3/source/include -I/tmp/qemu-test/src/tests/fp/berkeley-softfloat-3/source/8086-SSE -I/tmp/qemu-test/src/tests/fp/berkeley-testfloat-3/source -I/usr/include/pixman-1 -Werror -fsanitize=undefined -fsanitize=address -pthread -I/usr/include/glib-2.0 -I/usr/lib64/glib-2.0/include -fPIE -DPIE -m64 -mcx16 -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -Wstrict-prototypes -Wredundant-decls -Wall -Wundef -Wwrite-strings -Wmissing-prototypes -fno-strict-aliasing -fno-common -fwrapv -std=gnu99 -Wold-style-definition -Wtype-limits -Wformat-security -Wformat-y2k -Winit-self -Wignored-qualifiers -Wempty-body -Wnested-externs -Wendif-labels -Wexpansion-to-defined -Wno-initializer-overrides -Wno-missing-include-dirs -Wno-shift-negative-value -Wno-string-plus-int -Wno-typedef-redefinition -Wno-tautological-type-limit-compare -fstack-protector-strong -I/usr/include/p11-kit-1 -DSTRUCT_IOVEC_DEFINED -I/usr/include/libpng16 -I/usr/include/spice-1 -I/usr/include/spice-server -I/usr/include/cacard -I/usr/include/glib-2.0 -I/usr/lib64/glib-2.0/include -I/usr/include/nss3 -I/usr/include/nspr4 -pthread -I/usr/include/libmount -I/usr/include/blkid -I/usr/include/pixman-1 -DHW_POISON_H -DTARGET_ARM  -DSOFTFLOAT_ROUND_ODD -DINLINE_LEVEL=5 -DSOFTFLOAT_FAST_DIV32TO16 -DSOFTFLOAT_FAST_DIV64TO32 -DSOFTFLOAT_FAST_INT64  -DFLOAT16 -DFLOAT64 -DEXTFLOAT80 -DFLOAT128 -DFLOAT_ROUND_ODD -DLONG_DOUBLE_IS_EXTFLOAT80  -Wno-strict-prototypes -Wno-unknown-pragmas -Wno-uninitialized -Wno-missing-prototypes -Wno-return-type -Wno-unused-function -Wno-error -MMD -MP -MT standardFunctionInfos.o -MF ./standardFunctionInfos.d -g   -c -o standardFunctionInfos.o /tmp/qemu-test/src/tests/fp/berkeley-testfloat-3/source/standardFunctionInfos.c
/tmp/qemu-test/src/tests/qht-bench.c:287:29: error: implicit conversion from 'unsigned long' to 'double' changes value from 18446744073709551615 to 18446744073709551616 [-Werror,-Wimplicit-int-float-conversion]
        *threshold = rate * UINT64_MAX;
                          ~ ^~~~~~~~~~
/usr/include/stdint.h:130:23: note: expanded from macro 'UINT64_MAX'
---
^~~~~~~~~~~~~~~~~~~~~~
1 error generated.
clang -iquote /tmp/qemu-test/build/tests/qtest/libqos -iquote tests/qtest/libqos -iquote /tmp/qemu-test/src/tcg/i386 -isystem /tmp/qemu-test/src/linux-headers -isystem /tmp/qemu-test/build/linux-headers -iquote . -iquote /tmp/qemu-test/src -iquote /tmp/qemu-test/src/accel/tcg -iquote /tmp/qemu-test/src/include -iquote /tmp/qemu-test/src/disas/libvixl -I/usr/include/pixman-1   -Werror -fsanitize=undefined -fsanitize=address  -pthread -I/usr/include/glib-2.0 -I/usr/lib64/glib-2.0/include  -fPIE -DPIE -m64 -mcx16 -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -Wstrict-prototypes -Wredundant-decls -Wall -Wundef -Wwrite-strings -Wmissing-prototypes -fno-strict-aliasing -fno-common -fwrapv -std=gnu99  -Wold-style-definition -Wtype-limits -Wformat-security -Wformat-y2k -Winit-self -Wignored-qualifiers -Wempty-body -Wnested-externs -Wendif-labels -Wexpansion-to-defined -Wno-initializer-overrides -Wno-missing-include-dirs -Wno-shift-negative-value -Wno-string-plus-int -Wno-typedef-redefinition -Wno-tautological-type-limit-compare -fstack-protector-strong   -I/usr/include/p11-kit-1   -DSTRUCT_IOVEC_DEFINED  -I/usr/include/libpng16  -I/usr/include/spice-1 -I/usr/include/spice-server -I/usr/include/cacard -I/usr/include/glib-2.0 -I/usr/lib64/glib-2.0/include -I/usr/include/nss3 -I/usr/include/nspr4 -pthread -I/usr/include/libmount -I/usr/include/blkid -I/usr/include/pixman-1   -I/tmp/qemu-test/src/tests -I/tmp/qemu-test/src/tests/qtest -MMD -MP -MT tests/qtest/libqos/libqos-pc.o -MF tests/qtest/libqos/libqos-pc.d -g   -c -o tests/qtest/libqos/libqos-pc.o /tmp/qemu-test/src/tests/qtest/libqos/libqos-pc.c
make: *** [/tmp/qemu-test/src/rules.mak:69: tests/qht-bench.o] Error 1
make: *** Waiting for unfinished jobs....
clang -iquote /tmp/qemu-test/build/. -iquote . -iquote /tmp/qemu-test/src/tcg/i386 -isystem /tmp/qemu-test/src/linux-headers -isystem /tmp/qemu-test/build/linux-headers -iquote . -iquote /tmp/qemu-test/src -iquote /tmp/qemu-test/src/accel/tcg -iquote /tmp/qemu-test/src/include -iquote /tmp/qemu-test/src/disas/libvixl -I/tmp/qemu-test/src/tests/fp -I/tmp/qemu-test/src/tests/fp/berkeley-softfloat-3/source/include -I/tmp/qemu-test/src/tests/fp/berkeley-softfloat-3/source/8086-SSE -I/tmp/qemu-test/src/tests/fp/berkeley-testfloat-3/source -I/usr/include/pixman-1 -Werror -fsanitize=undefined -fsanitize=address -pthread -I/usr/include/glib-2.0 -I/usr/lib64/glib-2.0/include -fPIE -DPIE -m64 -mcx16 -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -Wstrict-prototypes -Wredundant-decls -Wall -Wundef -Wwrite-strings -Wmissing-prototypes -fno-strict-aliasing -fno-common -fwrapv -std=gnu99 -Wold-style-definition -Wtype-limits -Wformat-security -Wformat-y2k -Winit-self -Wignored-qualifiers -Wempty-body -Wnested-externs -Wendif-labels -Wexpansion-to-defined -Wno-initializer-overrides -Wno-missing-include-dirs -Wno-shift-negative-value -Wno-string-plus-int -Wno-typedef-redefinition -Wno-tautological-type-limit-compare -fstack-protector-strong -I/usr/include/p11-kit-1 -DSTRUCT_IOVEC_DEFINED -I/usr/include/libpng16 -I/usr/include/spice-1 -I/usr/include/spice-server -I/usr/include/cacard -I/usr/include/glib-2.0 -I/usr/lib64/glib-2.0/include -I/usr/include/nss3 -I/usr/include/nspr4 -pthread -I/usr/include/libmount -I/usr/include/blkid -I/usr/include/pixman-1 -DHW_POISON_H -DTARGET_ARM  -DSOFTFLOAT_ROUND_ODD -DINLINE_LEVEL=5 -DSOFTFLOAT_FAST_DIV32TO16 -DSOFTFLOAT_FAST_DIV64TO32 -DSOFTFLOAT_FAST_INT64  -DFLOAT16 -DFLOAT64 -DEXTFLOAT80 -DFLOAT128 -DFLOAT_ROUND_ODD -DLONG_DOUBLE_IS_EXTFLOAT80  -Wno-strict-prototypes -Wno-unknown-pragmas -Wno-uninitialized -Wno-missing-prototypes -Wno-return-type -Wno-unused-function -Wno-error -MMD -MP -MT random.o -MF ./random.d -g   -c -o random.o /tmp/qemu-test/src/tests/fp/berkeley-testfloat-3/source/random.c
clang -iquote /tmp/qemu-test/build/. -iquote . -iquote /tmp/qemu-test/src/tcg/i386 -isystem /tmp/qemu-test/src/linux-headers -isystem /tmp/qemu-test/build/linux-headers -iquote . -iquote /tmp/qemu-test/src -iquote /tmp/qemu-test/src/accel/tcg -iquote /tmp/qemu-test/src/include -iquote /tmp/qemu-test/src/disas/libvixl -I/tmp/qemu-test/src/tests/fp -I/tmp/qemu-test/src/tests/fp/berkeley-softfloat-3/source/include -I/tmp/qemu-test/src/tests/fp/berkeley-softfloat-3/source/8086-SSE -I/tmp/qemu-test/src/tests/fp/berkeley-testfloat-3/source -I/usr/include/pixman-1 -Werror -fsanitize=undefined -fsanitize=address -pthread -I/usr/include/glib-2.0 -I/usr/lib64/glib-2.0/include -fPIE -DPIE -m64 -mcx16 -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -Wstrict-prototypes -Wredundant-decls -Wall -Wundef -Wwrite-strings -Wmissing-prototypes -fno-strict-aliasing -fno-common -fwrapv -std=gnu99 -Wold-style-definition -Wtype-limits -Wformat-security -Wformat-y2k -Winit-self -Wignored-qualifiers -Wempty-body -Wnested-externs -Wendif-labels -Wexpansion-to-defined -Wno-initializer-overrides -Wno-missing-include-dirs -Wno-shift-negative-value -Wno-string-plus-int -Wno-typedef-redefinition -Wno-tautological-type-limit-compare -fstack-protector-strong -I/usr/include/p11-kit-1 -DSTRUCT_IOVEC_DEFINED -I/usr/include/libpng16 -I/usr/include/spice-1 -I/usr/include/spice-server -I/usr/include/cacard -I/usr/include/glib-2.0 -I/usr/lib64/glib-2.0/include -I/usr/include/nss3 -I/usr/include/nspr4 -pthread -I/usr/include/libmount -I/usr/include/blkid -I/usr/include/pixman-1 -DHW_POISON_H -DTARGET_ARM  -DSOFTFLOAT_ROUND_ODD -DINLINE_LEVEL=5 -DSOFTFLOAT_FAST_DIV32TO16 -DSOFTFLOAT_FAST_DIV64TO32 -DSOFTFLOAT_FAST_INT64  -DFLOAT16 -DFLOAT64 -DEXTFLOAT80 -DFLOAT128 -DFLOAT_ROUND_ODD -DLONG_DOUBLE_IS_EXTFLOAT80  -Wno-strict-prototypes -Wno-unknown-pragmas -Wno-uninitialized -Wno-missing-prototypes -Wno-return-type -Wno-unused-function -Wno-error -MMD -MP -MT genCases_common.o -MF ./genCases_common.d -g   -c -o genCases_common.o /tmp/qemu-test/src/tests/fp/berkeley-testfloat-3/source/genCases_common.c
---
rm -f libtestfloat.a && ar rcs libtestfloat.a uint128_inline.o uint128.o fail.o functions_common.o functionInfos.o standardFunctionInfos.o random.o genCases_common.o genCases_ui32.o genCases_ui64.o genCases_i32.o genCases_i64.o genCases_f16.o genCases_f32.o genCases_f64.o genCases_extF80.o genCases_f128.o genCases_writeTestsTotal.o verCases_inline.o verCases_common.o verCases_writeFunctionName.o readHex.o writeHex.o writeCase_a_ui32.o writeCase_a_ui64.o writeCase_a_f16.o writeCase_ab_f16.o writeCase_abc_f16.o writeCase_a_f32.o writeCase_ab_f32.o writeCase_abc_f32.o writeCase_a_f64.o writeCase_ab_f64.o writeCase_abc_f64.o writeCase_a_extF80M.o writeCase_ab_extF80M.o writeCase_a_f128M.o writeCase_ab_f128M.o writeCase_abc_f128M.o writeCase_z_bool.o writeCase_z_ui32.o writeCase_z_ui64.o writeCase_z_f16.o writeCase_z_f32.o writeCase_z_f64.o writeCase_z_extF80M.o writeCase_z_f128M.o testLoops_common.o test_a_ui32_z_f16.o test_a_ui32_z_f32.o test_a_ui32_z_f64.o test_a_ui32_z_extF80.o test_a_ui32_z_f128.o test_a_ui64_z_f16.o test_a_ui64_z_f32.o test_a_ui64_z_f64.o test_a_ui64_z_extF80.o test_a_ui64_z_f128.o test_a_i32_z_f16.o test_a_i32_z_f32.o test_a_i32_z_f64.o test_a_i32_z_extF80.o test_a_i32_z_f128.o test_a_i64_z_f16.o test_a_i64_z_f32.o test_a_i64_z_f64.o test_a_i64_z_extF80.o test_a_i64_z_f128.o test_a_f16_z_ui32_rx.o test_a_f16_z_ui64_rx.o test_a_f16_z_i32_rx.o test_a_f16_z_i64_rx.o test_a_f16_z_ui32_x.o test_a_f16_z_ui64_x.o test_a_f16_z_i32_x.o test_a_f16_z_i64_x.o test_a_f16_z_f32.o test_a_f16_z_f64.o test_a_f16_z_extF80.o test_a_f16_z_f128.o test_az_f16.o test_az_f16_rx.o test_abz_f16.o test_abcz_f16.o test_ab_f16_z_bool.o test_a_f32_z_ui32_rx.o test_a_f32_z_ui64_rx.o test_a_f32_z_i32_rx.o test_a_f32_z_i64_rx.o test_a_f32_z_ui32_x.o test_a_f32_z_ui64_x.o test_a_f32_z_i32_x.o test_a_f32_z_i64_x.o test_a_f32_z_f16.o test_a_f32_z_f64.o test_a_f32_z_extF80.o test_a_f32_z_f128.o test_az_f32.o test_az_f32_rx.o test_abz_f32.o test_abcz_f32.o test_ab_f32_z_bool.o test_a_f64_z_ui32_rx.o test_a_f64_z_ui64_rx.o test_a_f64_z_i32_rx.o test_a_f64_z_i64_rx.o test_a_f64_z_ui32_x.o test_a_f64_z_ui64_x.o test_a_f64_z_i32_x.o test_a_f64_z_i64_x.o test_a_f64_z_f16.o test_a_f64_z_f32.o test_a_f64_z_extF80.o test_a_f64_z_f128.o test_az_f64.o test_az_f64_rx.o test_abz_f64.o test_abcz_f64.o test_ab_f64_z_bool.o test_a_extF80_z_ui32_rx.o test_a_extF80_z_ui64_rx.o test_a_extF80_z_i32_rx.o test_a_extF80_z_i64_rx.o test_a_extF80_z_ui32_x.o test_a_extF80_z_ui64_x.o test_a_extF80_z_i32_x.o test_a_extF80_z_i64_x.o test_a_extF80_z_f16.o test_a_extF80_z_f32.o test_a_extF80_z_f64.o test_a_extF80_z_f128.o test_az_extF80.o test_az_extF80_rx.o test_abz_extF80.o test_ab_extF80_z_bool.o test_a_f128_z_ui32_rx.o test_a_f128_z_ui64_rx.o test_a_f128_z_i32_rx.o test_a_f128_z_i64_rx.o test_a_f128_z_ui32_x.o test_a_f128_z_ui64_x.o test_a_f128_z_i32_x.o test_a_f128_z_i64_x.o test_a_f128_z_f16.o test_a_f128_z_f32.o test_a_f128_z_f64.o test_a_f128_z_extF80.o test_az_f128.o test_az_f128_rx.o test_abz_f128.o test_abcz_f128.o test_ab_f128_z_bool.o
rm -f libsoftfloat.a && ar rcs libsoftfloat.a s_eq128.o s_le128.o s_lt128.o s_shortShiftLeft128.o s_shortShiftRight128.o s_shortShiftRightJam64.o s_shortShiftRightJam64Extra.o s_shortShiftRightJam128.o s_shortShiftRightJam128Extra.o s_shiftRightJam32.o s_shiftRightJam64.o s_shiftRightJam64Extra.o s_shiftRightJam128.o s_shiftRightJam128Extra.o s_shiftRightJam256M.o s_countLeadingZeros8.o s_countLeadingZeros16.o s_countLeadingZeros32.o s_countLeadingZeros64.o s_add128.o s_add256M.o s_sub128.o s_sub256M.o s_mul64ByShifted32To128.o s_mul64To128.o s_mul128By32.o s_mul128To256M.o s_approxRecip_1Ks.o s_approxRecip32_1.o s_approxRecipSqrt_1Ks.o s_approxRecipSqrt32_1.o s_roundToUI32.o s_roundToUI64.o s_roundToI32.o s_roundToI64.o s_normSubnormalF16Sig.o s_roundPackToF16.o s_normRoundPackToF16.o s_addMagsF16.o s_subMagsF16.o s_mulAddF16.o s_normSubnormalF32Sig.o s_roundPackToF32.o s_normRoundPackToF32.o s_addMagsF32.o s_subMagsF32.o s_mulAddF32.o s_normSubnormalF64Sig.o s_roundPackToF64.o s_normRoundPackToF64.o s_addMagsF64.o s_subMagsF64.o s_mulAddF64.o s_normSubnormalExtF80Sig.o s_roundPackToExtF80.o s_normRoundPackToExtF80.o s_addMagsExtF80.o s_subMagsExtF80.o s_normSubnormalF128Sig.o s_roundPackToF128.o s_normRoundPackToF128.o s_addMagsF128.o s_subMagsF128.o s_mulAddF128.o softfloat_state.o ui32_to_f16.o ui32_to_f32.o ui32_to_f64.o ui32_to_extF80.o ui32_to_extF80M.o ui32_to_f128.o ui32_to_f128M.o ui64_to_f16.o ui64_to_f32.o ui64_to_f64.o ui64_to_extF80.o ui64_to_extF80M.o ui64_to_f128.o ui64_to_f128M.o i32_to_f16.o i32_to_f32.o i32_to_f64.o i32_to_extF80.o i32_to_extF80M.o i32_to_f128.o i32_to_f128M.o i64_to_f16.o i64_to_f32.o i64_to_f64.o i64_to_extF80.o i64_to_extF80M.o i64_to_f128.o i64_to_f128M.o f16_to_ui32.o f16_to_ui64.o f16_to_i32.o f16_to_i64.o f16_to_ui32_r_minMag.o f16_to_ui64_r_minMag.o f16_to_i32_r_minMag.o f16_to_i64_r_minMag.o f16_to_f32.o f16_to_f64.o f16_to_extF80.o f16_to_extF80M.o f16_to_f128.o f16_to_f128M.o f16_roundToInt.o f16_add.o f16_sub.o f16_mul.o f16_mulAdd.o f16_div.o f16_rem.o f16_sqrt.o f16_eq.o f16_le.o f16_lt.o f16_eq_signaling.o f16_le_quiet.o f16_lt_quiet.o f16_isSignalingNaN.o f32_to_ui32.o f32_to_ui64.o f32_to_i32.o f32_to_i64.o f32_to_ui32_r_minMag.o f32_to_ui64_r_minMag.o f32_to_i32_r_minMag.o f32_to_i64_r_minMag.o f32_to_f16.o f32_to_f64.o f32_to_extF80.o f32_to_extF80M.o f32_to_f128.o f32_to_f128M.o f32_roundToInt.o f32_add.o f32_sub.o f32_mul.o f32_mulAdd.o f32_div.o f32_rem.o f32_sqrt.o f32_eq.o f32_le.o f32_lt.o f32_eq_signaling.o f32_le_quiet.o f32_lt_quiet.o f32_isSignalingNaN.o f64_to_ui32.o f64_to_ui64.o f64_to_i32.o f64_to_i64.o f64_to_ui32_r_minMag.o f64_to_ui64_r_minMag.o f64_to_i32_r_minMag.o f64_to_i64_r_minMag.o f64_to_f16.o f64_to_f32.o f64_to_extF80.o f64_to_extF80M.o f64_to_f128.o f64_to_f128M.o f64_roundToInt.o f64_add.o f64_sub.o f64_mul.o f64_mulAdd.o f64_div.o f64_rem.o f64_sqrt.o f64_eq.o f64_le.o f64_lt.o f64_eq_signaling.o f64_le_quiet.o f64_lt_quiet.o f64_isSignalingNaN.o extF80_to_ui32.o extF80_to_ui64.o extF80_to_i32.o extF80_to_i64.o extF80_to_ui32_r_minMag.o extF80_to_ui64_r_minMag.o extF80_to_i32_r_minMag.o extF80_to_i64_r_minMag.o extF80_to_f16.o extF80_to_f32.o extF80_to_f64.o extF80_to_f128.o extF80_roundToInt.o extF80_add.o extF80_sub.o extF80_mul.o extF80_div.o extF80_rem.o extF80_sqrt.o extF80_eq.o extF80_le.o extF80_lt.o extF80_eq_signaling.o extF80_le_quiet.o extF80_lt_quiet.o extF80_isSignalingNaN.o extF80M_to_ui32.o extF80M_to_ui64.o extF80M_to_i32.o extF80M_to_i64.o extF80M_to_ui32_r_minMag.o extF80M_to_ui64_r_minMag.o extF80M_to_i32_r_minMag.o extF80M_to_i64_r_minMag.o extF80M_to_f16.o extF80M_to_f32.o extF80M_to_f64.o extF80M_to_f128M.o extF80M_roundToInt.o extF80M_add.o extF80M_sub.o extF80M_mul.o extF80M_div.o extF80M_rem.o extF80M_sqrt.o extF80M_eq.o extF80M_le.o extF80M_lt.o extF80M_eq_signaling.o extF80M_le_quiet.o extF80M_lt_quiet.o f128_to_ui32.o f128_to_ui64.o f128_to_i32.o f128_to_i64.o f128_to_ui32_r_minMag.o f128_to_ui64_r_minMag.o f128_to_i32_r_minMag.o f128_to_i64_r_minMag.o f128_to_f16.o f128_to_f32.o f128_to_extF80.o f128_to_f64.o f128_roundToInt.o f128_add.o f128_sub.o f128_mul.o f128_mulAdd.o f128_div.o f128_rem.o f128_sqrt.o f128_eq.o f128_le.o f128_lt.o f128_eq_signaling.o f128_le_quiet.o f128_lt_quiet.o f128_isSignalingNaN.o f128M_to_ui32.o f128M_to_ui64.o f128M_to_i32.o f128M_to_i64.o f128M_to_ui32_r_minMag.o f128M_to_ui64_r_minMag.o f128M_to_i32_r_minMag.o f128M_to_i64_r_minMag.o f128M_to_f16.o f128M_to_f32.o f128M_to_extF80M.o f128M_to_f64.o f128M_roundToInt.o f128M_add.o f128M_sub.o f128M_mul.o f128M_mulAdd.o f128M_div.o f128M_rem.o f128M_sqrt.o f128M_eq.o f128M_le.o f128M_lt.o f128M_eq_signaling.o f128M_le_quiet.o f128M_lt_quiet.o softfloat_raiseFlags.o s_f16UIToCommonNaN.o s_commonNaNToF16UI.o s_propagateNaNF16UI.o s_f32UIToCommonNaN.o s_commonNaNToF32UI.o s_propagateNaNF32UI.o s_f64UIToCommonNaN.o s_commonNaNToF64UI.o s_propagateNaNF64UI.o extF80M_isSignalingNaN.o s_extF80UIToCommonNaN.o s_commonNaNToExtF80UI.o s_propagateNaNExtF80UI.o f128M_isSignalingNaN.o s_f128UIToCommonNaN.o s_commonNaNToF128UI.o s_propagateNaNF128UI.o
clang++ -g  -Wl,--warn-common -fsanitize=undefined -fsanitize=address -Wl,-z,relro -Wl,-z,now -pie -m64  -fstack-protector-strong -o fp-test fp-test.o slowfloat.o softfloat.o  libtestfloat.a libsoftfloat.a /tmp/qemu-test/build/libqemuutil.a   -lm -lz  -lgthread-2.0 -pthread -lglib-2.0  -lnettle  -lgnutls  -lzstd   -lrt
/usr/bin/ld: /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors_vfork.S.o): warning: common of `__interception::real_vfork' overridden by definition from /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors.cpp.o)
make[1]: Leaving directory '/tmp/qemu-test/build/tests/fp'
Traceback (most recent call last):
  File "./tests/docker/docker.py", line 669, in <module>
---
    raise CalledProcessError(retcode, cmd)
subprocess.CalledProcessError: Command '['sudo', '-n', 'docker', 'run', '--label', 'com.qemu.instance.uuid=c5af4bb5040b4c4988fc1757727e0a25', '-u', '1001', '--security-opt', 'seccomp=unconfined', '--rm', '-e', 'TARGET_LIST=x86_64-softmmu', '-e', 'EXTRA_CONFIGURE_OPTS=', '-e', 'V=', '-e', 'J=14', '-e', 'DEBUG=', '-e', 'SHOW_ENV=', '-e', 'CCACHE_DIR=/var/tmp/ccache', '-v', '/home/patchew/.cache/qemu-docker-ccache:/var/tmp/ccache:z', '-v', '/var/tmp/patchew-tester-tmp-cj1ldcnx/src/docker-src.2020-06-18-07.50.05.24944:/var/tmp/qemu:z,ro', 'qemu:fedora', '/var/tmp/qemu/run', 'test-debug']' returned non-zero exit status 2.
filter=--filter=label=com.qemu.instance.uuid=c5af4bb5040b4c4988fc1757727e0a25
make[1]: *** [docker-run] Error 1
make[1]: Leaving directory `/var/tmp/patchew-tester-tmp-cj1ldcnx/src'
make: *** [docker-run-test-debug@fedora] Error 2

real    4m15.830s
user    0m8.563s


The full log is available at
http://patchew.org/logs/20200618112908.130528-1-maxime.coquelin@redhat.com/testing.asan/?type=message.
---
Email generated automatically by Patchew [https://patchew.org/].
Please send your feedback to patchew-devel@redhat.com

On 2020/6/18 下午7:29, Maxime Coquelin wrote:
> This patch specifies the VHOST_USER_SET_STATUS and
> VHOST_USER_GET_STATUS requests, which are sent by
> the master to update and query the Virtio status
> in the backend.
>
> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
> ---
>
> Changes since v1:
> =================
> - Only keep the spec part in this patch, the implementation will
>    be part of Cindy's Vhost vDPA series it depends on. The goal is
>    to be able to implement it in next DPDK release even if Qemu part
>    is not merged.
> - Add GET_STATUS after discussions with Michael and Jason. It can
>    be used by the master to ensure FEATURES_OK bit set is
>    acknowledged by the backend.
>
>   docs/interop/vhost-user.rst | 24 ++++++++++++++++++++++++
>   1 file changed, 24 insertions(+)
>
> diff --git a/docs/interop/vhost-user.rst b/docs/interop/vhost-user.rst
> index 688b7c6900..866d7c2fb7 100644
> --- a/docs/interop/vhost-user.rst
> +++ b/docs/interop/vhost-user.rst
> @@ -816,6 +816,7 @@ Protocol features
>     #define VHOST_USER_PROTOCOL_F_RESET_DEVICE         13
>     #define VHOST_USER_PROTOCOL_F_INBAND_NOTIFICATIONS 14
>     #define VHOST_USER_PROTOCOL_F_CONFIGURE_MEM_SLOTS  15
> +  define VHOST_USER_PROTOCOL_F_STATUS                16


Miss a '#"?

Other looks good.

Thanks


>   
>   Master message types
>   --------------------
> @@ -1307,6 +1308,29 @@ Master message types
>     ``VHOST_USER_ADD_MEM_REG`` message, this message is used to set and
>     update the memory tables of the slave device.
>   
> +``VHOST_USER_SET_STATUS``
> +  :id: 39
> +  :equivalent ioctl: VHOST_VDPA_SET_STATUS
> +  :slave payload: N/A
> +  :master payload: ``u64``
> +
> +  When the ``VHOST_USER_PROTOCOL_F_STATUS`` protocol feature has been
> +  successfully negotiated, this message is submitted by the master to
> +  notify the backend with updated device status as defined in the Virtio
> +  specification.
> +
> +``VHOST_USER_GET_STATUS``
> +  :id: 40
> +  :equivalent ioctl: VHOST_VDPA_GET_STATUS
> +  :slave payload: ``u64``
> +  :master payload: N/A
> +
> +  When the ``VHOST_USER_PROTOCOL_F_STATUS`` protocol feature has been
> +  successfully negotiated, this message is submitted by the master to
> +  query the backend for its device status as defined in the Virtio
> +  specification.
> +
> +
>   Slave message types
>   -------------------
>

On 6/18/20 2:50 PM, Jason Wang wrote:
> 
> On 2020/6/18 下午7:29, Maxime Coquelin wrote:
>> This patch specifies the VHOST_USER_SET_STATUS and
>> VHOST_USER_GET_STATUS requests, which are sent by
>> the master to update and query the Virtio status
>> in the backend.
>>
>> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
>> ---
>>
>> Changes since v1:
>> =================
>> - Only keep the spec part in this patch, the implementation will
>>    be part of Cindy's Vhost vDPA series it depends on. The goal is
>>    to be able to implement it in next DPDK release even if Qemu part
>>    is not merged.
>> - Add GET_STATUS after discussions with Michael and Jason. It can
>>    be used by the master to ensure FEATURES_OK bit set is
>>    acknowledged by the backend.
>>
>>   docs/interop/vhost-user.rst | 24 ++++++++++++++++++++++++
>>   1 file changed, 24 insertions(+)
>>
>> diff --git a/docs/interop/vhost-user.rst b/docs/interop/vhost-user.rst
>> index 688b7c6900..866d7c2fb7 100644
>> --- a/docs/interop/vhost-user.rst
>> +++ b/docs/interop/vhost-user.rst
>> @@ -816,6 +816,7 @@ Protocol features
>>     #define VHOST_USER_PROTOCOL_F_RESET_DEVICE         13
>>     #define VHOST_USER_PROTOCOL_F_INBAND_NOTIFICATIONS 14
>>     #define VHOST_USER_PROTOCOL_F_CONFIGURE_MEM_SLOTS  15
>> +  define VHOST_USER_PROTOCOL_F_STATUS                16
> 
> 
> Miss a '#"?

Indeed, I will fix that.

Thanks,
Maxime

> Other looks good.
> 
> Thanks
> 
> 
>>     Master message types
>>   --------------------
>> @@ -1307,6 +1308,29 @@ Master message types
>>     ``VHOST_USER_ADD_MEM_REG`` message, this message is used to set and
>>     update the memory tables of the slave device.
>>   +``VHOST_USER_SET_STATUS``
>> +  :id: 39
>> +  :equivalent ioctl: VHOST_VDPA_SET_STATUS
>> +  :slave payload: N/A
>> +  :master payload: ``u64``
>> +
>> +  When the ``VHOST_USER_PROTOCOL_F_STATUS`` protocol feature has been
>> +  successfully negotiated, this message is submitted by the master to
>> +  notify the backend with updated device status as defined in the Virtio
>> +  specification.
>> +
>> +``VHOST_USER_GET_STATUS``
>> +  :id: 40
>> +  :equivalent ioctl: VHOST_VDPA_GET_STATUS
>> +  :slave payload: ``u64``
>> +  :master payload: N/A
>> +
>> +  When the ``VHOST_USER_PROTOCOL_F_STATUS`` protocol feature has been
>> +  successfully negotiated, this message is submitted by the master to
>> +  query the backend for its device status as defined in the Virtio
>> +  specification.
>> +
>> +
>>   Slave message types
>>   -------------------
>>