[Qemu-devel] [PATCH v1] hw/rdma: Add support for GID state changes for non-qmp frameworks

[Yuval Shaia <yuval.shaia@oracle.com>]

Any GID change in guest must be propagated to the host. This is already
done by firing QMP event to management system such as libvirt which in
turn will update the host with the relevant change.

When qemu is executed on non-qmp framework (ex from command-line) we
need to update the host instead.
Fix it by adding support to update the RoCE device's Ethernet function
IP list from qemu via netlink.

Signed-off-by: Yuval Shaia <yuval.shaia@oracle.com>
---
v0 -> v1:
	* Fix spelling mistakes pointed by Eric Blake
---
 configure              |  6 ++++
 hw/rdma/rdma_backend.c | 74 +++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 79 insertions(+), 1 deletion(-)

diff --git a/configure b/configure
index 5b183c2e39..1f707b1a62 100755
--- a/configure
+++ b/configure
@@ -3132,6 +3132,8 @@ fi
 
 cat > $TMPC <<EOF &&
 #include <sys/mman.h>
+#include <libmnl/libmnl.h>
+#include <linux/rtnetlink.h>
 
 int
 main(void)
@@ -3144,10 +3146,13 @@ main(void)
 }
 EOF
 
+pvrdma_libs="-lmnl"
+
 if test "$rdma" = "yes" ; then
     case "$pvrdma" in
     "")
         if compile_prog "" ""; then
+            libs_softmmu="$libs_softmmu $pvrdma_libs"
             pvrdma="yes"
         else
             pvrdma="no"
@@ -3156,6 +3161,7 @@ if test "$rdma" = "yes" ; then
     "yes")
         if ! compile_prog "" ""; then
             error_exit "PVRDMA is not supported since mremap is not implemented"
+                        " or libmnl-devel is not installed"
         fi
         pvrdma="yes"
         ;;
diff --git a/hw/rdma/rdma_backend.c b/hw/rdma/rdma_backend.c
index 05f6b03221..f75e916195 100644
--- a/hw/rdma/rdma_backend.c
+++ b/hw/rdma/rdma_backend.c
@@ -16,6 +16,11 @@
 #include "qemu/osdep.h"
 #include "qapi/qapi-events-rdma.h"
 
+#include "linux/if_addr.h"
+#include "libmnl/libmnl.h"
+#include "linux/rtnetlink.h"
+#include "net/if.h"
+
 #include <infiniband/verbs.h>
 
 #include "contrib/rdmacm-mux/rdmacm-mux.h"
@@ -47,6 +52,61 @@ static void dummy_comp_handler(void *ctx, struct ibv_wc *wc)
     rdma_error_report("No completion handler is registered");
 }
 
+static int netlink_route_update(const char *ifname, union ibv_gid *gid,
+                                __u16 type)
+{
+    char buf[MNL_SOCKET_BUFFER_SIZE];
+    struct nlmsghdr *nlh;
+    struct ifaddrmsg *ifm;
+    struct mnl_socket *nl;
+    int ret;
+    uint32_t ipv4;
+
+    nl = mnl_socket_open(NETLINK_ROUTE);
+    if (!nl) {
+        rdma_error_report("Fail to connect to netlink\n");
+        return -EIO;
+    }
+
+    ret = mnl_socket_bind(nl, 0, MNL_SOCKET_AUTOPID);
+    if (ret < 0) {
+        rdma_error_report("Fail to bind to netlink\n");
+        goto out;
+    }
+
+    nlh = mnl_nlmsg_put_header(buf);
+    nlh->nlmsg_type = type;
+    nlh->nlmsg_flags = NLM_F_REQUEST | NLM_F_CREATE | NLM_F_EXCL;
+    nlh->nlmsg_seq = 1;
+
+    ifm = mnl_nlmsg_put_extra_header(nlh, sizeof(*ifm));
+    ifm->ifa_index = if_nametoindex(ifname);
+    if (gid->global.subnet_prefix) {
+        ifm->ifa_family = AF_INET6;
+        ifm->ifa_prefixlen = 64;
+        ifm->ifa_flags = IFA_F_PERMANENT;
+        ifm->ifa_scope = RT_SCOPE_UNIVERSE;
+        mnl_attr_put(nlh, IFA_ADDRESS, sizeof(*gid), gid);
+    } else {
+        ifm->ifa_family = AF_INET;
+        ifm->ifa_prefixlen = 24;
+        memcpy(&ipv4, (char *)&gid->global.interface_id + 4, sizeof(ipv4));
+        mnl_attr_put(nlh, IFA_LOCAL, 4, &ipv4);
+    }
+
+    ret = mnl_socket_sendto(nl, nlh, nlh->nlmsg_len);
+    if (ret < 0) {
+        rdma_error_report("Fail to send msg to to netlink\n");
+        goto out;
+    }
+
+    ret = 0;
+
+out:
+    mnl_socket_close(nl);
+    return ret;
+}
+
 static inline void complete_work(enum ibv_wc_status status, uint32_t vendor_err,
                                  void *ctx)
 {
@@ -1123,7 +1183,13 @@ int rdma_backend_add_gid(RdmaBackendDev *backend_dev, const char *ifname,
                                             gid->global.subnet_prefix,
                                             gid->global.interface_id);
 
-    return ret;
+    /*
+     * We ignore return value since operation might have completed
+     * successfully by the QMP consumer
+     */
+    netlink_route_update(ifname, gid, RTM_NEWADDR);
+
+    return 0;
 }
 
 int rdma_backend_del_gid(RdmaBackendDev *backend_dev, const char *ifname,
@@ -1149,6 +1215,12 @@ int rdma_backend_del_gid(RdmaBackendDev *backend_dev, const char *ifname,
                                             gid->global.subnet_prefix,
                                             gid->global.interface_id);
 
+    /*
+     * We ignore return value since operation might have completed
+     * successfully by the QMP consumer
+     */
+    netlink_route_update(ifname, gid, RTM_DELADDR);
+
     return 0;
 }
 
-- 
2.20.1