On Wed, Feb 23, 2022 at 9:31 PM Yuri Benditovich <yuri.benditovich@xxxxxxxxxx> wrote: > > Hi Jason, > We agree that the same can be done also using the old way, i.e. try to > set specific offload - if failed, probably it is not supported. > We think this is a little not scalable and we suggest adding the ioctl > that will allow us to query allo the supported features in a single > call. Possibly but then you need some kind of probing. E.g we need endup with probing TUNGETSUPPORTEDOFFLOADS iotctl itself. > We think this will make QEMU code more simple also in future. We can discuss this when qemu patches were sent. > Do I understand correctly that you suggest to skip this new ioctl and > use the old way of query for this (USO) feature and all future > extensions? Yes, since it's not a must. And we can do the TUNGETSUPPORTEDOFFLOADS in a separate series. Thanks > > Thanks > > > On Wed, Feb 23, 2022 at 5:53 AM Jason Wang <jasowang@xxxxxxxxxx> wrote: > > > > On Tue, Feb 22, 2022 at 9:28 PM Andrew Melnichenko <andrew@xxxxxxxxxx> wrote: > > > > > > Hi all, > > > > > > On Wed, Feb 9, 2022 at 6:26 AM Jason Wang <jasowang@xxxxxxxxxx> wrote: > > > > > > > > > > > > 在 2022/1/25 下午4:46, Andrew Melnychenko 写道: > > > > > Added TUNGETSUPPORTEDOFFLOADS that should allow > > > > > to get bits of supported offloads. > > > > > > > > > > > > So we don't use dedicated ioctls in the past, instead, we just probing > > > > by checking the return value of TUNSETOFFLOADS. > > > > > > > > E.g qemu has the following codes: > > > > > > > > int tap_probe_has_ufo(int fd) > > > > { > > > > unsigned offload; > > > > > > > > offload = TUN_F_CSUM | TUN_F_UFO; > > > > > > > > if (ioctl(fd, TUNSETOFFLOAD, offload) < 0) > > > > return 0; > > > > > > > > return 1; > > > > } > > > > > > > > Any reason we can't keep using that? > > > > > > > > Thanks > > > > > > > > > > Well, even in this example. To check the ufo feature, we trying to set it. > > > What if we don't need to "enable" UFO and/or do not change its state? > > > > So at least Qemu doesn't have such a requirement since during the > > probe the virtual networking backend is not even started. > > > > > I think it's a good idea to have the ability to get supported offloads > > > without changing device behavior. > > > > Do you see a real user for this? > > > > Btw, we still need to probe this new ioctl anyway. > > > > Thanks > > > > > > > > > > > > > > Added 2 additional offlloads for USO(IPv4 & IPv6). > > > > > Separate offloads are required for Windows VM guests, > > > > > g.e. Windows may set USO rx only for IPv4. > > > > > > > > > > Signed-off-by: Andrew Melnychenko <andrew@xxxxxxxxxx> > > > > > --- > > > > > include/uapi/linux/if_tun.h | 3 +++ > > > > > 1 file changed, 3 insertions(+) > > > > > > > > > > diff --git a/include/uapi/linux/if_tun.h b/include/uapi/linux/if_tun.h > > > > > index 454ae31b93c7..07680fae6e18 100644 > > > > > --- a/include/uapi/linux/if_tun.h > > > > > +++ b/include/uapi/linux/if_tun.h > > > > > @@ -61,6 +61,7 @@ > > > > > #define TUNSETFILTEREBPF _IOR('T', 225, int) > > > > > #define TUNSETCARRIER _IOW('T', 226, int) > > > > > #define TUNGETDEVNETNS _IO('T', 227) > > > > > +#define TUNGETSUPPORTEDOFFLOADS _IOR('T', 228, unsigned int) > > > > > > > > > > /* TUNSETIFF ifr flags */ > > > > > #define IFF_TUN 0x0001 > > > > > @@ -88,6 +89,8 @@ > > > > > #define TUN_F_TSO6 0x04 /* I can handle TSO for IPv6 packets */ > > > > > #define TUN_F_TSO_ECN 0x08 /* I can handle TSO with ECN bits. */ > > > > > #define TUN_F_UFO 0x10 /* I can handle UFO packets */ > > > > > +#define TUN_F_USO4 0x20 /* I can handle USO for IPv4 packets */ > > > > > +#define TUN_F_USO6 0x40 /* I can handle USO for IPv6 packets */ > > > > > > > > > > /* Protocol info prepended to the packets (when IFF_NO_PI is not set) */ > > > > > #define TUN_PKT_STRIP 0x0001 > > > > > > > > > > _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization