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[src/trunk]: src/sys/arch/xen/xen convert to bus_dma(9), no explicit xpmap_*(...



details:   https://anonhg.NetBSD.org/src/rev/34e2a02203ce
branches:  trunk
changeset: 1009059:34e2a02203ce
user:      jdolecek <jdolecek%NetBSD.org@localhost>
date:      Sat Apr 11 11:48:20 2020 +0000

description:
convert to bus_dma(9), no explicit xpmap_*() calls any more

as part of this move some global arrays into struct xnetback_instance,
and fix race for xnetif_lookup()

diffstat:

 sys/arch/xen/xen/xennetback_xenbus.c |  262 +++++++++++++++++-----------------
 1 files changed, 132 insertions(+), 130 deletions(-)

diffs (truncated from 507 to 300 lines):

diff -r 9dcbb5bafb13 -r 34e2a02203ce sys/arch/xen/xen/xennetback_xenbus.c
--- a/sys/arch/xen/xen/xennetback_xenbus.c      Sat Apr 11 11:01:12 2020 +0000
+++ b/sys/arch/xen/xen/xennetback_xenbus.c      Sat Apr 11 11:48:20 2020 +0000
@@ -1,4 +1,4 @@
-/*      $NetBSD: xennetback_xenbus.c,v 1.95 2020/04/09 10:57:02 jdolecek Exp $      */
+/*      $NetBSD: xennetback_xenbus.c,v 1.96 2020/04/11 11:48:20 jdolecek Exp $      */
 
 /*
  * Copyright (c) 2006 Manuel Bouyer.
@@ -25,7 +25,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: xennetback_xenbus.c,v 1.95 2020/04/09 10:57:02 jdolecek Exp $");
+__KERNEL_RCSID(0, "$NetBSD: xennetback_xenbus.c,v 1.96 2020/04/11 11:48:20 jdolecek Exp $");
 
 #include "opt_xen.h"
 
@@ -70,13 +70,14 @@
 #define XENPRINTF(x)
 #endif
 
-extern pt_entry_t xpmap_pg_nx;
-
 #define NET_TX_RING_SIZE __RING_SIZE((netif_tx_sring_t *)0, PAGE_SIZE)
 #define NET_RX_RING_SIZE __RING_SIZE((netif_rx_sring_t *)0, PAGE_SIZE)
 
-/* linux wants at last 16 bytes free in front of the packet */
-#define LINUX_REQUESTED_OFFSET 16
+/*
+ * Number of packets to transmit in one hypercall (= number of pages to
+ * transmit at once).
+ */
+#define NB_XMIT_PAGES_BATCH 64
 
 /* ratecheck(9) for pool allocation failures */
 static const struct timeval xni_pool_errintvl = { 30, 0 };  /* 30s, each */
@@ -88,6 +89,13 @@
        DISCONNECTED
 } xnetback_state_t;
 
+struct xnetback_xstate {
+       bus_dmamap_t xs_dmamap;
+       struct mbuf *xs_m;
+       int xs_id;
+       int xs_flags;
+};
+
 /* we keep the xnetback instances in a linked list */
 struct xnetback_instance {
        SLIST_ENTRY(xnetback_instance) next;
@@ -110,6 +118,10 @@
        grant_handle_t xni_rx_ring_handle;
        vaddr_t xni_tx_ring_va; /* to unmap the ring */
        vaddr_t xni_rx_ring_va;
+
+       /* arrays used in xennetback_ifstart(), used for both Rx and Tx */
+       gnttab_copy_t           xni_gop_copy[NB_XMIT_PAGES_BATCH];
+       struct xnetback_xstate  xni_xstate[NB_XMIT_PAGES_BATCH];
 };
 #define xni_if    xni_ec.ec_if
 #define xni_bpf   xni_if.if_bpf
@@ -128,7 +140,6 @@
 
 static inline void xennetback_tx_response(struct xnetback_instance *,
     int, int);
-static void xennetback_mbuf_addr(struct mbuf *, paddr_t *, int *);
 
 static SLIST_HEAD(, xnetback_instance) xnetback_instances;
 static kmutex_t xnetback_lock;
@@ -141,22 +152,6 @@
        .xbakd_type = "vif"
 };
 
-/*
- * Number of packets to transmit in one hypercall (= number of pages to
- * transmit at once).
- */
-#define NB_XMIT_PAGES_BATCH 64
-
-/* arrays used in xennetback_ifstart(), too large to allocate on stack */
-/* XXXSMP */
-static gnttab_copy_t     xstart_gop_copy[NB_XMIT_PAGES_BATCH];
-static struct mbuf *mbufs_sent[NB_XMIT_PAGES_BATCH];
-static struct _req_info {
-       int id;
-       int flags;
-} xstart_req[NB_XMIT_PAGES_BATCH];
-
-
 void
 xvifattach(int n)
 {
@@ -193,14 +188,21 @@
                return err;
        }
 
-       if (xnetif_lookup(domid, handle)) {
-               return EEXIST;
-       }
        xneti = kmem_zalloc(sizeof(*xneti), KM_SLEEP);
        xneti->xni_domid = domid;
        xneti->xni_handle = handle;
        xneti->xni_status = DISCONNECTED;
 
+       /* Need to keep the lock for lookup and the list update */
+       mutex_enter(&xnetback_lock);
+       if (xnetif_lookup(domid, handle)) {
+               mutex_exit(&xnetback_lock);
+               kmem_free(xneti, sizeof(*xneti));
+               return EEXIST;
+       }
+       SLIST_INSERT_HEAD(&xnetback_instances, xneti, next);
+       mutex_exit(&xnetback_lock);
+
        xbusd->xbusd_u.b.b_cookie = xneti;
        xbusd->xbusd_u.b.b_detach = xennetback_xenbus_destroy;
        xneti->xni_xbusd = xbusd;
@@ -230,6 +232,20 @@
 
        /* we can't use the same MAC addr as our guest */
        xneti->xni_enaddr[3]++;
+
+       /* Initialize DMA map, used only for loading PA */
+       for (i = 0; i < __arraycount(xneti->xni_xstate); i++) {
+               if (bus_dmamap_create(xneti->xni_xbusd->xbusd_dmat, PAGE_SIZE,
+                   1, PAGE_SIZE, PAGE_SIZE, BUS_DMA_WAITOK | BUS_DMA_ALLOCNOW,
+                   &xneti->xni_xstate[i].xs_dmamap)
+                   != 0) {
+                       aprint_error_ifnet(ifp,
+                           "failed to allocate dma map\n");
+                       err = ENOMEM;
+                       goto fail;
+               }
+       }
+
        /* create pseudo-interface */
        aprint_verbose_ifnet(ifp, "Ethernet address %s\n",
            ether_sprintf(xneti->xni_enaddr));
@@ -258,10 +274,6 @@
        if_deferred_start_init(ifp, NULL);
        ether_ifattach(&xneti->xni_if, xneti->xni_enaddr);
 
-       mutex_enter(&xnetback_lock);
-       SLIST_INSERT_HEAD(&xnetback_instances, xneti, next);
-       mutex_exit(&xnetback_lock);
-
        xbusd->xbusd_otherend_changed = xennetback_frontend_changed;
 
        do {
@@ -579,14 +591,14 @@
        struct xnetback_instance *xneti;
        bool found = false;
 
-       mutex_enter(&xnetback_lock);
+       KASSERT(mutex_owned(&xnetback_lock));
+
        SLIST_FOREACH(xneti, &xnetback_instances, next) {
                if (xneti->xni_domid == dom && xneti->xni_handle == handle) {
                        found = true;
                        break;
                }
        }
-       mutex_exit(&xnetback_lock);
 
        return found;
 }
@@ -639,50 +651,50 @@
 {
        int i = 0;
        gnttab_copy_t *gop;
-       struct mbuf *m;
-       struct _req_info *req;
+       struct xnetback_xstate *xst;
 
        /*
         * Copy the data and ack it. Delaying it until the mbuf is
         * freed will stall transmit.
         */
-       if (HYPERVISOR_grant_table_op(GNTTABOP_copy, xstart_gop_copy, queued)
-           != 0) {
-               printf("%s: GNTTABOP_copy failed", ifp->if_xname);
+       if (HYPERVISOR_grant_table_op(GNTTABOP_copy, xneti->xni_gop_copy,
+           queued) != 0) {
+               printf("%s: GNTTABOP_copy Tx failed", ifp->if_xname);
                goto abort;
        }
 
        for (; i < queued; i++) {
-               gop = &xstart_gop_copy[i];
-               m = mbufs_sent[i];
-               req = &xstart_req[i];
+               gop = &xneti->xni_gop_copy[i];
+               xst = &xneti->xni_xstate[i];
 
                if (gop->status != GNTST_okay) {
-                       printf("%s GNTTABOP_copy[%d] %d\n",
+                       printf("%s GNTTABOP_copy[%d] Tx %d\n",
                            ifp->if_xname, i, gop->status);
                        goto abort;
                }
 
-               xennetback_tx_response(xneti, req->id, NETIF_RSP_OKAY);
+               xennetback_tx_response(xneti, xst->xs_id, NETIF_RSP_OKAY);
 
-               if (req->flags & NETTXF_csum_blank)
-                       xennet_checksum_fill(ifp, m);
-               else if (req->flags & NETTXF_data_validated)
-                       m->m_pkthdr.csum_flags = XN_M_CSUM_SUPPORTED;
-               m_set_rcvif(m, ifp);
+               if (xst->xs_flags & NETTXF_csum_blank)
+                       xennet_checksum_fill(ifp, xst->xs_m);
+               else if (xst->xs_flags & NETTXF_data_validated)
+                       xst->xs_m->m_pkthdr.csum_flags = XN_M_CSUM_SUPPORTED;
+               m_set_rcvif(xst->xs_m, ifp);
 
-               if_percpuq_enqueue(ifp->if_percpuq, m);
+               if_percpuq_enqueue(ifp->if_percpuq, xst->xs_m);
+
+               bus_dmamap_unload(xneti->xni_xbusd->xbusd_dmat,
+                    xst->xs_dmamap);
        }
 
        return;
 
 abort:
        for (; i < queued; i++) {
-               m = mbufs_sent[i];
-               req = &xstart_req[i];
+               xst = &xneti->xni_xstate[i];
 
-               m_freem(m);
-               xennetback_tx_response(xneti, req->id, NETIF_RSP_ERROR);
+               m_freem(xst->xs_m);
+               xennetback_tx_response(xneti, xst->xs_id, NETIF_RSP_ERROR);
                if_statinc(ifp, if_ierrors);
        }
 }
@@ -697,8 +709,9 @@
        int receive_pending;
        RING_IDX req_cons;
        gnttab_copy_t *gop;
-       paddr_t pa;
-       int offset, queued = 0;
+       paddr_t ma;
+       int queued = 0;
+       struct xnetback_xstate *xst;
 
        XENPRINTF(("xennetback_evthandler "));
        req_cons = xneti->xni_txring.req_cons;
@@ -729,7 +742,7 @@
                 */
                const char *msg = xennetback_tx_check_packet(&txreq,
                    xneti->xni_ec.ec_capenable & ETHERCAP_VLAN_MTU);
-               if (msg) {
+               if (__predict_false(msg != NULL)) {
                        printf("%s: packet with size %d is %s\n",
                            ifp->if_xname, txreq.size, msg);
                        xennetback_tx_response(xneti, txreq.id,
@@ -760,15 +773,30 @@
                                continue;
                        }
                }
+               m->m_len = m->m_pkthdr.len = txreq.size;
 
                XENPRINTF(("%s pkt offset %d size %d id %d req_cons %d\n",
                    xneti->xni_if.if_xname, txreq.offset,
                    txreq.size, txreq.id, MASK_NETIF_TX_IDX(req_cons)));
 
-               xennetback_mbuf_addr(m, &pa, &offset);
+               xst = &xneti->xni_xstate[queued];
+               xst->xs_m = m;
+               xst->xs_id = txreq.id;
+               xst->xs_flags = txreq.flags;
+
+               if (bus_dmamap_load_mbuf(xneti->xni_xbusd->xbusd_dmat,
+                   xst->xs_dmamap, m, BUS_DMA_NOWAIT) != 0) {
+                       printf("%s: mbuf load failed\n", ifp->if_xname);
+                       m_freem(m);
+                       xennetback_tx_response(xneti, txreq.id,
+                           NETIF_RSP_DROPPED);
+                       if_statinc(ifp, if_ierrors);
+                       continue;
+               }
+               ma = xst->xs_dmamap->dm_segs[0].ds_addr;
 
                /* Queue for the copy */
-               gop = &xstart_gop_copy[queued];
+               gop = &xneti->xni_gop_copy[queued];
                memset(gop, 0, sizeof(*gop));
                gop->flags = GNTCOPY_source_gref;
                gop->len = txreq.size;
@@ -777,15 +805,11 @@
                gop->source.offset = txreq.offset;
                gop->source.domid = xneti->xni_domid;
 
-               gop->dest.offset = offset;
+               gop->dest.offset = ma & PAGE_MASK;
                gop->dest.domid = DOMID_SELF;
-               gop->dest.u.gmfn = xpmap_ptom(pa) >> PAGE_SHIFT;



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