[libvirt] [PATCH v2 05/23] qemu: add socket datagram capability

[Michal Privoznik]

On 8/8/19 4:54 PM, marcandre.lureau at redhat.com wrote:
> From: Marc-André Lureau <marcandre.lureau at redhat.com>
> 
> Datagram socket is available since qemu 4.0, commit
> fdec16e3c2a614e2861f3086b05d444b5d8c3406 ("net/socket: learn to talk
> with a unix dgram socket").
> 
> Required for slirp-helper communication.
> 
> Signed-off-by: Marc-André Lureau <marcandre.lureau at redhat.com>
> ---
>   src/qemu/qemu_capabilities.c                      | 6 ++++++
>   src/qemu/qemu_capabilities.h                      | 1 +
>   tests/qemucapabilitiesdata/caps_4.0.0.aarch64.xml | 1 +
>   tests/qemucapabilitiesdata/caps_4.0.0.ppc64.xml   | 1 +
>   tests/qemucapabilitiesdata/caps_4.0.0.riscv32.xml | 1 +
>   tests/qemucapabilitiesdata/caps_4.0.0.riscv64.xml | 1 +
>   tests/qemucapabilitiesdata/caps_4.0.0.s390x.xml   | 1 +
>   tests/qemucapabilitiesdata/caps_4.0.0.x86_64.xml  | 1 +
>   tests/qemucapabilitiesdata/caps_4.1.0.x86_64.xml  | 1 +
>   9 files changed, 14 insertions(+)
> 
> diff --git a/src/qemu/qemu_capabilities.c b/src/qemu/qemu_capabilities.c
> index 405bc3f288..4cb135cd93 100644
> --- a/src/qemu/qemu_capabilities.c
> +++ b/src/qemu/qemu_capabilities.c
> @@ -536,6 +536,7 @@ VIR_ENUM_IMPL(virQEMUCaps,
>   
>                 /* 335 */
>                 "bochs-display",
> +              "net-socket-dgram",
>       );
>   
>   
> @@ -4389,6 +4390,11 @@ virQEMUCapsInitQMPVersionCaps(virQEMUCapsPtr qemuCaps)
>           ARCH_IS_PPC64(qemuCaps->arch)) {
>           virQEMUCapsSet(qemuCaps, QEMU_CAPS_MACHINE_PSERIES_MAX_CPU_COMPAT);
>       }
> +
> +    /* -net socket,fd= with dgram socket (for ex, with slirp helper) */
> +    if (qemuCaps->version >= 3001092) {
> +        virQEMUCapsSet(qemuCaps, QEMU_CAPS_NET_SOCKET_DGRAM);
> +    }

For some weird reasons we don't allow curly braces around a single line 
body. Also, I know this is available since 3.1.92 because that's how 
qemu advertises its versions towards the end of release cycle, but I'd 
rather see 4.0.0 encoded - that's what is going to match version from a 
package anyway.

Or even better, isn't there a way for libvirt to detect this using some 
monitor sorcery?

Michal