Hi Fabiano,
On Tue, Apr 1, 2025 at 9:32 PM Fabiano Rosas <faro...@suse.de> wrote:
>
> Jack Wang <jinpu.w...@ionos.com> writes:
>
> > I hit following error which testing migration in pure RoCE env:
> > "-incoming rdma:[::]:8089: RDMA ERROR: You only have RoCE / iWARP devices
> > in your
> > systems and your management software has specified '[::]', but IPv6 over
> > RoCE /
> > iWARP is not supported in Linux.#012'."
> >
> > In our setup, we use rdma bind on ipv6 on target host, while connect from
> > source
> > with ipv4, remove the qemu_rdma_broken_ipv6_kernel, migration just work
> > fine.
> >
> > Checking the git history, the function was added since introducing of
> > rdma migration, which is more than 10 years ago. linux-rdma has
> > improved support on RoCE/iWARP for ipv6 over past years. There are a few
> > fixes
> > back in 2016 seems related to the issue, eg:
> > aeb76df46d11 ("IB/core: Set routable RoCE gid type for ipv4/ipv6 networks")
> >
> > other fixes back in 2018, eg:
> > 052eac6eeb56 RDMA/cma: Update RoCE multicast routines to use net namespace
> > 8d20a1f0ecd5 RDMA/cma: Fix rdma_cm raw IB path setting for RoCE
> > 9327c7afdce3 RDMA/cma: Provide a function to set RoCE path record L2
> > parameters
> > 5c181bda77f4 RDMA/cma: Set default GID type as RoCE when resolving RoCE
> > route
> > 3c7f67d1880d IB/cma: Fix default RoCE type setting
> > be1d325a3358 IB/core: Set RoCEv2 MGID according to spec
> > 63a5f483af0e IB/cma: Set default gid type to RoCEv2
> >
> > So remove the outdated function and it's usage.
> >
> > Cc: Peter Xu <pet...@redhat.com>
> > Cc: Li Zhijian <lizhij...@fujitsu.com>
> > Cc: Yu Zhang <yu.zh...@ionos.com>
> > Cc: qemu-devel@nongnu.org
> > Cc: linux-r...@vger.kernel.org
> > Cc: mich...@flatgalaxy.com
> > Signed-off-by: Jack Wang <jinpu.w...@ionos.com>
> > Tested-by: Li zhijian <lizhij...@fujitsu.com>
> > Reviewed-by: Michael Galaxy <mrgal...@nvidia.com>
> > ---
> > v1: drop RFC, fix build error (zhijian), collect Reviewed-by and Tested-by
> >
> > migration/rdma.c | 159 -----------------------------------------------
> > 1 file changed, 159 deletions(-)
> >
> > diff --git a/migration/rdma.c b/migration/rdma.c
> > index 76fb0349238a..e228520b8e01 100644
> > --- a/migration/rdma.c
> > +++ b/migration/rdma.c
> > @@ -767,149 +767,6 @@ static void qemu_rdma_dump_gid(const char *who,
> > struct rdma_cm_id *id)
> > trace_qemu_rdma_dump_gid(who, sgid, dgid);
> > }
> >
> > -/*
> > - * As of now, IPv6 over RoCE / iWARP is not supported by linux.
> > - * We will try the next addrinfo struct, and fail if there are
> > - * no other valid addresses to bind against.
> > - *
> > - * If user is listening on '[::]', then we will not have a opened a device
> > - * yet and have no way of verifying if the device is RoCE or not.
> > - *
> > - * In this case, the source VM will throw an error for ALL types of
> > - * connections (both IPv4 and IPv6) if the destination machine does not
> > have
> > - * a regular infiniband network available for use.
> > - *
> > - * The only way to guarantee that an error is thrown for broken kernels is
> > - * for the management software to choose a *specific* interface at bind
> > time
> > - * and validate what time of hardware it is.
> > - *
> > - * Unfortunately, this puts the user in a fix:
> > - *
> > - * If the source VM connects with an IPv4 address without knowing that the
> > - * destination has bound to '[::]' the migration will unconditionally fail
> > - * unless the management software is explicitly listening on the IPv4
> > - * address while using a RoCE-based device.
> > - *
> > - * If the source VM connects with an IPv6 address, then we're OK because
> > we can
> > - * throw an error on the source (and similarly on the destination).
> > - *
> > - * But in mixed environments, this will be broken for a while until it is
> > fixed
> > - * inside linux.
> > - *
> > - * We do provide a *tiny* bit of help in this function: We can list all of
> > the
> > - * devices in the system and check to see if all the devices are RoCE or
> > - * Infiniband.
> > - *
> > - * If we detect that we have a *pure* RoCE environment, then we can safely
> > - * thrown an error even if the management software has specified '[::]' as
> > the
> > - * bind address.
> > - *
> > - * However, if there is are multiple hetergeneous devices, then we cannot
> > make
> > - * this assumption and the user just has to be sure they know what they are
> > - * doing.
> > - *
> > - * Patches are being reviewed on linux-rdma.
> > - */
> > -static int qemu_rdma_broken_ipv6_kernel(struct ibv_context *verbs, Error
> > **errp)
> > -{
> > - /* This bug only exists in linux, to our knowledge. */
> > -#ifdef CONFIG_LINUX
> > - struct ibv_port_attr port_attr;
> > -
> > - /*
> > - * Verbs are only NULL if management has bound to '[::]'.
> > - *
> > - * Let's iterate through all the devices and see if there any pure IB
> > - * devices (non-ethernet).
> > - *
> > - * If not, then we can safely proceed with the migration.
> > - * Otherwise, there are no guarantees until the bug is fixed in linux.
> > - */
> > - if (!verbs) {
> > - int num_devices;
> > - struct ibv_device **dev_list = ibv_get_device_list(&num_devices);
> > - bool roce_found = false;
> > - bool ib_found = false;
> > -
> > - for (int x = 0; x < num_devices; x++) {
> > - verbs = ibv_open_device(dev_list[x]);
> > - /*
> > - * ibv_open_device() is not documented to set errno. If
> > - * it does, it's somebody else's doc bug. If it doesn't,
> > - * the use of errno below is wrong.
> > - * TODO Find out whether ibv_open_device() sets errno.
> > - */
> > - if (!verbs) {
> > - if (errno == EPERM) {
> > - continue;
> > - } else {
> > - error_setg_errno(errp, errno,
> > - "could not open RDMA device context");
> > - return -1;
> > - }
> > - }
> > -
> > - if (ibv_query_port(verbs, 1, &port_attr)) {
> > - ibv_close_device(verbs);
> > - error_setg(errp,
> > - "RDMA ERROR: Could not query initial IB port");
> > - return -1;
> > - }
> > -
> > - if (port_attr.link_layer == IBV_LINK_LAYER_INFINIBAND) {
> > - ib_found = true;
> > - } else if (port_attr.link_layer == IBV_LINK_LAYER_ETHERNET) {
> > - roce_found = true;
> > - }
> > -
> > - ibv_close_device(verbs);
> > -
> > - }
> > -
> > - if (roce_found) {
> > - if (ib_found) {
> > - warn_report("migrations may fail:"
> > - " IPv6 over RoCE / iWARP in linux"
> > - " is broken. But since you appear to have a"
> > - " mixed RoCE / IB environment, be sure to only"
> > - " migrate over the IB fabric until the kernel "
> > - " fixes the bug.");
> > - } else {
> > - error_setg(errp, "RDMA ERROR: "
> > - "You only have RoCE / iWARP devices in your
> > systems"
> > - " and your management software has specified
> > '[::]'"
> > - ", but IPv6 over RoCE / iWARP is not supported
> > in Linux.");
> > - return -1;
> > - }
> > - }
> > -
> > - return 0;
> > - }
> > -
> > - /*
> > - * If we have a verbs context, that means that some other than '[::]'
> > was
> > - * used by the management software for binding. In which case we can
> > - * actually warn the user about a potentially broken kernel.
> > - */
> > -
> > - /* IB ports start with 1, not 0 */
> > - if (ibv_query_port(verbs, 1, &port_attr)) {
> > - error_setg(errp, "RDMA ERROR: Could not query initial IB port");
> > - return -1;
> > - }
> > -
> > - if (port_attr.link_layer == IBV_LINK_LAYER_ETHERNET) {
> > - error_setg(errp, "RDMA ERROR: "
> > - "Linux kernel's RoCE / iWARP does not support IPv6 "
> > - "(but patches on linux-rdma in progress)");
> > - return -1;
> > - }
> > -
> > -#endif
> > -
> > - return 0;
> > -}
> > -
> > /*
> > * Figure out which RDMA device corresponds to the requested IP hostname
> > * Also create the initial connection manager identifiers for opening
> > @@ -955,7 +812,6 @@ static int qemu_rdma_resolve_host(RDMAContext *rdma,
> > Error **errp)
> >
> > /* Try all addresses, saving the first error in @err */
> > for (struct rdma_addrinfo *e = res; e != NULL; e = e->ai_next) {
> > - Error **local_errp = err ? NULL : &err;
> >
> > inet_ntop(e->ai_family,
> > &((struct sockaddr_in *) e->ai_dst_addr)->sin_addr, ip, sizeof
> > ip);
> > @@ -964,13 +820,6 @@ static int qemu_rdma_resolve_host(RDMAContext *rdma,
> > Error **errp)
> > ret = rdma_resolve_addr(rdma->cm_id, NULL, e->ai_dst_addr,
> > RDMA_RESOLVE_TIMEOUT_MS);
> > if (ret >= 0) {
> > - if (e->ai_family == AF_INET6) {
> > - ret = qemu_rdma_broken_ipv6_kernel(rdma->cm_id->verbs,
> > - local_errp);
> > - if (ret < 0) {
> > - continue;
> > - }
> > - }
> > error_free(err);
>
> err is now unused and should be removed entirely. The comment before the
> loop needs touching up as well.
Good catch, will fix both in v2.
>
> > goto route;
> > }
> > @@ -2663,7 +2512,6 @@ static int qemu_rdma_dest_init(RDMAContext *rdma,
> > Error **errp)
> >
> > /* Try all addresses, saving the first error in @err */
> > for (e = res; e != NULL; e = e->ai_next) {
> > - Error **local_errp = err ? NULL : &err;
> >
> > inet_ntop(e->ai_family,
> > &((struct sockaddr_in *) e->ai_dst_addr)->sin_addr, ip, sizeof
> > ip);
> > @@ -2672,13 +2520,6 @@ static int qemu_rdma_dest_init(RDMAContext *rdma,
> > Error **errp)
> > if (ret < 0) {
> > continue;
> > }
> > - if (e->ai_family == AF_INET6) {
> > - ret = qemu_rdma_broken_ipv6_kernel(listen_id->verbs,
> > - local_errp);
> > - if (ret < 0) {
> > - continue;
> > - }
> > - }
> > error_free(err);
>
> Same here.
>
> > break;
> > }
