On Mon, Nov 15, 2021 at 6:45 PM Vladislav Yaroshchuk <yaroshchuk2...@gmail.com> wrote: > > > > пн, 15 нояб. 2021 г. в 07:53, Jason Wang <jasow...@redhat.com>: >> >> On Fri, Nov 12, 2021 at 5:14 PM Vladislav Yaroshchuk >> <yaroshchuk2...@gmail.com> wrote: >> > >> > macOS provides networking API for VMs called 'vmnet.framework': >> > https://developer.apple.com/documentation/vmnet >> > >> > We can provide its support as the new QEMU network backends which >> > represent three different vmnet.framework interface usage modes: >> > >> > * `vmnet-shared`: >> > allows the guest to communicate with other guests in shared mode and >> > also with external network (Internet) via NAT. Has (macOS-provided) >> > DHCP server; subnet mask and IP range can be configured; >> > >> > * `vmnet-host`: >> > allows the guest to communicate with other guests in host mode. >> > By default has enabled DHCP as `vmnet-shared`, but providing >> > network unique id (uuid) can make `vmnet-host` interfaces isolated >> > from each other and also disables DHCP. >> > >> > * `vmnet-bridged`: >> > bridges the guest with a physical network interface. >> > >> > This backends cannot work on macOS Catalina 10.15 cause we use >> > vmnet.framework API provided only with macOS 11 and newer. Seems >> > that it is not a problem, because QEMU guarantees to work on two most >> > recent versions of macOS which now are Big Sur (11) and Monterey (12). >> > >> > Also, we have one inconvenient restriction: vmnet.framework interfaces >> > can create only privileged user: >> > `$ sudo qemu-system-x86_64 -nic vmnet-shared` >> > >> > Attempt of `vmnet-*` netdev creation being unprivileged user fails with >> > vmnet's 'general failure'. >> > >> > This happens because vmnet.framework requires `com.apple.vm.networking` >> > entitlement which is: "restricted to developers of virtualization software. >> > To request this entitlement, contact your Apple representative." as Apple >> > documentation says: >> > https://developer.apple.com/documentation/bundleresources/entitlements/com_apple_vm_networking >> >> Do you know how multipass work? Looks like it uses vmnet without privileges. >> > > I've just checked this, and they still need root privileges. They have a > `multipassd` daemon which is launched as root by launchd by default. > > ``` > bash-5.1$ ps axo ruser,ruid,comm | grep multipass > root 0 /Library/Application > Support/com.canonical.multipass/bin/multipassd > root 0 /Library/Application > Support/com.canonical.multipass/bin/hyperkit > ``` > > That's the reason why it's required to 'enter a password' while multipass > installation: > it creates launchd plist (kinda launch rule) and places it to > /Library/LaunchDaemons/, > which can be done only with root privileges. > > ``` > bash-5.1$ ll /Library/LaunchDaemons | grep multipass > -rw-r--r-- 1 root wheel 1.1K 15 Nov 12:47 com.canonical.multipassd.plist > ``` > > And after this launchd launches this multipassd daemon as root every boot. > > So an unprivileged user can launch a multipass VM instance, but actually the > `hyperkit` process which interacts with vmnet is gonna be launched by > multipassd > running as root.
I wonder how it passes the vmnet object to qemu? Nothing obvious from the qemu command line that multipass launched: -nic vmnet-macos,mode=shared,model=virtio-net-pci,mac=52:54:00:52:e8:e4 (But I haven't had time to check their qemu codes). > > tl;dr sadly, we can't interact with vmnet.framework without having our binary > correctly > signed and being an unprivileged user. Root privileges or special signature > with > entitlement is required. This is something similar to what happens in other OS. E.g for the tap backend, it can't be created without privileges. So qemu allows to: 1) the TAP to be created by privileged program like libvirt, and its fd could be passed to qemu via SCM_RIGHTS 2) run a set-uid helper to create and config TAP This is something we need to consider now or in the future probably. Thanks > > >> Thanks >> > > Thank you for your review, I will check it this week and reply as soon as > possible. > >> >> > >> > One more note: we still have quite useful but not supported >> > 'vmnet.framework' features as creating port forwarding rules, IPv6 >> > NAT prefix specifying and so on. >> > >> > Nevertheless, new backends work fine and tested within `qemu-system-x86-64` >> > on macOS Bir Sur 11.5.2 host with such nic models: >> > * e1000-82545em >> > * virtio-net-pci >> > * vmxnet3 >> > >> > The guests were: >> > * macOS 10.15.7 >> > * Ubuntu Bionic (server cloudimg) >> > >> > >> > This series partially reuses patches by Phillip Tennen: >> > https://patchew.org/QEMU/20210218134947.1860-1-phillip.en...@gmail.com/ >> > So I included his signed-off line into one of the commit messages and >> > also here. >> > >> > v1 -> v2: >> > Since v1 minor typos were fixed, patches rebased onto latest master, >> > redundant changes removed (small commits squashed) >> > >> > v2 -> v3: >> > - QAPI style fixes >> > - Typos fixes in comments >> > - `#include`'s updated to be in sync with recent master >> > v3 -> v4: >> > - Support vmnet interfaces isolation feature >> > - Support vmnet-host network uuid setting feature >> > - Refactored sources a bit >> > v4 -> v5: >> > - Missed 6.2 boat, now 7.0 candidate >> > - Fix qapi netdev descriptions and styles >> > (@subnetmask -> @subnet-mask) >> > - Support vmnet-shared IPv6 prefix setting feature >> > >> > Signed-off-by: Phillip Tennen <phil...@axleos.com> >> > Signed-off-by: Vladislav Yaroshchuk <yaroshchuk2...@gmail.com> >> > >> > Vladislav Yaroshchuk (6): >> > net/vmnet: add vmnet dependency and customizable option >> > net/vmnet: add vmnet backends to qapi/net >> > net/vmnet: implement shared mode (vmnet-shared) >> > net/vmnet: implement host mode (vmnet-host) >> > net/vmnet: implement bridged mode (vmnet-bridged) >> > net/vmnet: update qemu-options.hx >> > >> > meson.build | 4 + >> > meson_options.txt | 2 + >> > net/clients.h | 11 ++ >> > net/meson.build | 7 + >> > net/net.c | 10 ++ >> > net/vmnet-bridged.m | 111 ++++++++++++ >> > net/vmnet-common.m | 325 ++++++++++++++++++++++++++++++++++ >> > net/vmnet-host.c | 111 ++++++++++++ >> > net/vmnet-shared.c | 92 ++++++++++ >> > net/vmnet_int.h | 48 +++++ >> > qapi/net.json | 127 ++++++++++++- >> > qemu-options.hx | 25 +++ >> > scripts/meson-buildoptions.sh | 3 + >> > 13 files changed, 874 insertions(+), 2 deletions(-) >> > create mode 100644 net/vmnet-bridged.m >> > create mode 100644 net/vmnet-common.m >> > create mode 100644 net/vmnet-host.c >> > create mode 100644 net/vmnet-shared.c >> > create mode 100644 net/vmnet_int.h >> > >> > -- >> > 2.23.0 >> > >> > > > -- > Best Regards, > > Vladislav Yaroshchuk
