Apply patch from xsa155: make sure that the backend won't read parts of the
request again (possibly because of compiler optimisations), by using copies and barrier. From XSA155: The compiler can emit optimizations in the PV backend drivers which can lead to double fetch vulnerabilities. Specifically the shared memory between the frontend and backend can be fetched twice (during which time the frontend can alter the contents) possibly leading to arbitrary code execution in backend.
This commit is contained in:
bouyer
parent
2f89dbfb73
commit
13ee92e7ec
@ -1,4 +1,4 @@
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/* $NetBSD: ring.h,v 1.2 2011/12/07 15:40:15 cegger Exp $ */
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/* $NetBSD: ring.h,v 1.3 2016/01/06 15:28:40 bouyer Exp $ */
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/******************************************************************************
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* ring.h
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*
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@ -236,6 +236,20 @@ typedef struct __name##_back_ring __name##_back_ring_t
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#define RING_GET_REQUEST(_r, _idx) \
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(&((_r)->sring->ring[((_idx) & (RING_SIZE(_r) - 1))].req))
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/*
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* Get a local copy of a request.
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*
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* Use this in preference to RING_GET_REQUEST() so all processing is
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* done on a local copy that cannot be modified by the other end.
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*
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* Note that https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58145 may cause this
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* to be ineffective where _req is a struct which consists of only bitfields.
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*/
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#define RING_COPY_REQUEST(_r, _idx, _req) do { \
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/* Use volatile to force the copy into _req. */ \
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*(_req) = *(volatile typeof(_req))RING_GET_REQUEST(_r, _idx); \
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} while (0)
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#define RING_GET_RESPONSE(_r, _idx) \
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(&((_r)->sring->ring[((_idx) & (RING_SIZE(_r) - 1))].rsp))
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@ -1,4 +1,4 @@
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/* $NetBSD: pciback.c,v 1.9 2014/03/29 19:28:30 christos Exp $ */
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/* $NetBSD: pciback.c,v 1.10 2016/01/06 15:28:40 bouyer Exp $ */
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/*
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* Copyright (c) 2009 Manuel Bouyer.
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@ -26,7 +26,7 @@
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: pciback.c,v 1.9 2014/03/29 19:28:30 christos Exp $");
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__KERNEL_RCSID(0, "$NetBSD: pciback.c,v 1.10 2016/01/06 15:28:40 bouyer Exp $");
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#include "opt_xen.h"
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@ -188,6 +188,7 @@ struct pb_xenbus_instance {
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/* communication with the domU */
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unsigned int pbx_evtchn; /* our even channel */
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struct xen_pci_sharedinfo *pbx_sh_info;
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struct xen_pci_op op;
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grant_handle_t pbx_shinfo_handle; /* to unmap shared page */
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};
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@ -721,13 +722,16 @@ pciback_xenbus_evthandler(void * arg)
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{
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struct pb_xenbus_instance *pbxi = arg;
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struct pciback_pci_dev *pbd;
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struct xen_pci_op *op = &pbxi->pbx_sh_info->op;
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struct xen_pci_op *op = &pbxi->op;
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u_int bus, dev, func;
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hypervisor_clear_event(pbxi->pbx_evtchn);
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if (xen_atomic_test_bit(&pbxi->pbx_sh_info->flags,
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_XEN_PCIF_active) == 0)
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return 0;
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memcpy(op, &pbxi->pbx_sh_info->op, sizeof (struct xen_pci_op));
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__insn_barrier();
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if (op->domain != 0) {
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aprint_error("pciback: domain %d != 0", op->domain);
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op->err = XEN_PCI_ERR_dev_not_found;
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@ -794,6 +798,8 @@ pciback_xenbus_evthandler(void * arg)
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aprint_error("pciback: unknown cmd %d\n", op->cmd);
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op->err = XEN_PCI_ERR_not_implemented;
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}
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pbxi->pbx_sh_info->op.value = op->value;
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pbxi->pbx_sh_info->op.err = op->err;
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end:
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xen_atomic_clear_bit(&pbxi->pbx_sh_info->flags, _XEN_PCIF_active);
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hypervisor_notify_via_evtchn(pbxi->pbx_evtchn);
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@ -1,4 +1,4 @@
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/* $NetBSD: xbdback_xenbus.c,v 1.61 2015/11/15 14:42:03 bouyer Exp $ */
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/* $NetBSD: xbdback_xenbus.c,v 1.62 2016/01/06 15:28:40 bouyer Exp $ */
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/*
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* Copyright (c) 2006 Manuel Bouyer.
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@ -26,7 +26,7 @@
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: xbdback_xenbus.c,v 1.61 2015/11/15 14:42:03 bouyer Exp $");
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__KERNEL_RCSID(0, "$NetBSD: xbdback_xenbus.c,v 1.62 2016/01/06 15:28:40 bouyer Exp $");
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#include <sys/atomic.h>
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#include <sys/buf.h>
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@ -1022,6 +1022,7 @@ xbdback_co_main_loop(struct xbdback_instance *xbdi, void *obj)
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req->sector_number = req64->sector_number;
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break;
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}
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__insn_barrier();
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XENPRINTF(("xbdback op %d req_cons 0x%x req_prod 0x%x "
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"resp_prod 0x%x id %" PRIu64 "\n", req->operation,
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xbdi->xbdi_ring.ring_n.req_cons,
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@ -1,4 +1,4 @@
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/* $NetBSD: xennetback_xenbus.c,v 1.53 2015/11/19 17:01:40 christos Exp $ */
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/* $NetBSD: xennetback_xenbus.c,v 1.54 2016/01/06 15:28:40 bouyer Exp $ */
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/*
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* Copyright (c) 2006 Manuel Bouyer.
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@ -26,7 +26,7 @@
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: xennetback_xenbus.c,v 1.53 2015/11/19 17:01:40 christos Exp $");
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__KERNEL_RCSID(0, "$NetBSD: xennetback_xenbus.c,v 1.54 2016/01/06 15:28:40 bouyer Exp $");
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#include "opt_xen.h"
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@ -733,7 +733,7 @@ xennetback_evthandler(void *arg)
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{
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struct xnetback_instance *xneti = arg;
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struct ifnet *ifp = &xneti->xni_if;
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netif_tx_request_t *txreq;
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netif_tx_request_t txreq;
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struct xni_pkt *pkt;
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vaddr_t pkt_va;
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struct mbuf *m;
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@ -751,15 +751,15 @@ xennetback_evthandler(void *arg)
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receive_pending);
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if (receive_pending == 0)
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break;
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txreq = RING_GET_REQUEST(&xneti->xni_txring, req_cons);
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RING_COPY_REQUEST(&xneti->xni_txring, req_cons, &txreq);
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xen_rmb();
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XENPRINTF(("%s pkt size %d\n", xneti->xni_if.if_xname,
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txreq->size));
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txreq.size));
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req_cons++;
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if (__predict_false((ifp->if_flags & (IFF_UP | IFF_RUNNING)) !=
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(IFF_UP | IFF_RUNNING))) {
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/* interface not up, drop */
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xennetback_tx_response(xneti, txreq->id,
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xennetback_tx_response(xneti, txreq.id,
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NETIF_RSP_DROPPED);
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continue;
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}
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@ -767,12 +767,12 @@ xennetback_evthandler(void *arg)
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/*
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* Do some sanity checks, and map the packet's page.
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*/
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const char *msg = xennetback_tx_check_packet(txreq,
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const char *msg = xennetback_tx_check_packet(&txreq,
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xneti->xni_ec.ec_capenable & ETHERCAP_VLAN_MTU);
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if (msg) {
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printf("%s: packet with size %d is %s\n",
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ifp->if_xname, txreq->size, msg);
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xennetback_tx_response(xneti, txreq->id,
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ifp->if_xname, txreq.size, msg);
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xennetback_tx_response(xneti, txreq.id,
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NETIF_RSP_ERROR);
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ifp->if_ierrors++;
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continue;
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@ -785,15 +785,15 @@ xennetback_evthandler(void *arg)
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if (ratecheck(&lasttime, &xni_pool_errintvl))
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printf("%s: mbuf alloc failed\n",
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ifp->if_xname);
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xennetback_tx_response(xneti, txreq->id,
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xennetback_tx_response(xneti, txreq.id,
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NETIF_RSP_DROPPED);
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ifp->if_ierrors++;
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continue;
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}
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XENPRINTF(("%s pkt offset %d size %d id %d req_cons %d\n",
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xneti->xni_if.if_xname, txreq->offset,
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txreq->size, txreq->id, MASK_NETIF_TX_IDX(req_cons)));
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xneti->xni_if.if_xname, txreq.offset,
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txreq.size, txreq.id, MASK_NETIF_TX_IDX(req_cons)));
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pkt = pool_get(&xni_pkt_pool, PR_NOWAIT);
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if (__predict_false(pkt == NULL)) {
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@ -801,16 +801,16 @@ xennetback_evthandler(void *arg)
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if (ratecheck(&lasttime, &xni_pool_errintvl))
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printf("%s: xnbpkt alloc failed\n",
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ifp->if_xname);
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xennetback_tx_response(xneti, txreq->id,
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xennetback_tx_response(xneti, txreq.id,
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NETIF_RSP_DROPPED);
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ifp->if_ierrors++;
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m_freem(m);
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continue;
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}
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err = xen_shm_map(1, xneti->xni_domid, &txreq->gref, &pkt_va,
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err = xen_shm_map(1, xneti->xni_domid, &txreq.gref, &pkt_va,
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&pkt->pkt_handle, XSHM_RO);
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if (__predict_false(err == ENOMEM)) {
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xennetback_tx_response(xneti, txreq->id,
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xennetback_tx_response(xneti, txreq.id,
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NETIF_RSP_DROPPED);
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ifp->if_ierrors++;
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pool_put(&xni_pkt_pool, pkt);
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@ -821,7 +821,7 @@ xennetback_evthandler(void *arg)
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if (__predict_false(err)) {
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printf("%s: mapping foreing page failed: %d\n",
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xneti->xni_if.if_xname, err);
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xennetback_tx_response(xneti, txreq->id,
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xennetback_tx_response(xneti, txreq.id,
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NETIF_RSP_ERROR);
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ifp->if_ierrors++;
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pool_put(&xni_pkt_pool, pkt);
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@ -831,13 +831,13 @@ xennetback_evthandler(void *arg)
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if ((ifp->if_flags & IFF_PROMISC) == 0) {
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struct ether_header *eh =
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(void*)(pkt_va + txreq->offset);
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(void*)(pkt_va + txreq.offset);
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if (ETHER_IS_MULTICAST(eh->ether_dhost) == 0 &&
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memcmp(CLLADDR(ifp->if_sadl), eh->ether_dhost,
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ETHER_ADDR_LEN) != 0) {
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xni_pkt_unmap(pkt, pkt_va);
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m_freem(m);
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xennetback_tx_response(xneti, txreq->id,
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xennetback_tx_response(xneti, txreq.id,
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NETIF_RSP_OKAY);
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continue; /* packet is not for us */
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}
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@ -856,31 +856,31 @@ so always copy for now.
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* ack it. Delaying it until the mbuf is
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* freed will stall transmit.
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*/
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m->m_len = min(MHLEN, txreq->size);
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m->m_len = min(MHLEN, txreq.size);
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m->m_pkthdr.len = 0;
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m_copyback(m, 0, txreq->size,
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(void *)(pkt_va + txreq->offset));
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m_copyback(m, 0, txreq.size,
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(void *)(pkt_va + txreq.offset));
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xni_pkt_unmap(pkt, pkt_va);
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if (m->m_pkthdr.len < txreq->size) {
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if (m->m_pkthdr.len < txreq.size) {
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ifp->if_ierrors++;
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m_freem(m);
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xennetback_tx_response(xneti, txreq->id,
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xennetback_tx_response(xneti, txreq.id,
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NETIF_RSP_DROPPED);
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continue;
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}
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xennetback_tx_response(xneti, txreq->id,
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xennetback_tx_response(xneti, txreq.id,
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NETIF_RSP_OKAY);
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} else {
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pkt->pkt_id = txreq->id;
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pkt->pkt_id = txreq.id;
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pkt->pkt_xneti = xneti;
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MEXTADD(m, pkt_va + txreq->offset,
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txreq->size, M_DEVBUF, xennetback_tx_free, pkt);
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m->m_pkthdr.len = m->m_len = txreq->size;
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MEXTADD(m, pkt_va + txreq.offset,
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txreq.size, M_DEVBUF, xennetback_tx_free, pkt);
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m->m_pkthdr.len = m->m_len = txreq.size;
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m->m_flags |= M_EXT_ROMAP;
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}
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if ((txreq->flags & NETTXF_csum_blank) != 0) {
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if ((txreq.flags & NETTXF_csum_blank) != 0) {
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xennet_checksum_fill(&m);
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if (m == NULL) {
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ifp->if_ierrors++;
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@ -964,6 +964,7 @@ xennetback_ifsoftstart_transfer(void *arg)
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mmu_update_t *mmup;
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multicall_entry_t *mclp;
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netif_rx_response_t *rxresp;
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netif_rx_request_t rxreq;
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RING_IDX req_prod, resp_prod;
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int do_event = 0;
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gnttab_transfer_t *gop;
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@ -1039,10 +1040,10 @@ xennetback_ifsoftstart_transfer(void *arg)
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nppitems++;
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}
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/* start filling ring */
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gop->ref = RING_GET_REQUEST(&xneti->xni_rxring,
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xneti->xni_rxring.req_cons)->gref;
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id = RING_GET_REQUEST(&xneti->xni_rxring,
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xneti->xni_rxring.req_cons)->id;
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RING_COPY_REQUEST(&xneti->xni_rxring,
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xneti->xni_rxring.req_cons, &rxreq);
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gop->ref = rxreq.gref;
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id = rxreq.id;
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xen_rmb();
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xneti->xni_rxring.req_cons++;
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rxresp = RING_GET_RESPONSE(&xneti->xni_rxring,
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@ -1209,6 +1210,7 @@ xennetback_ifsoftstart_copy(void *arg)
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paddr_t xmit_ma;
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int i, j;
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netif_rx_response_t *rxresp;
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netif_rx_request_t rxreq;
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RING_IDX req_prod, resp_prod;
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int do_event = 0;
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gnttab_copy_t *gop;
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@ -1320,16 +1322,16 @@ xennetback_ifsoftstart_copy(void *arg)
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gop->source.domid = DOMID_SELF;
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gop->source.u.gmfn = xmit_ma >> PAGE_SHIFT;
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gop->dest.u.ref = RING_GET_REQUEST(&xneti->xni_rxring,
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xneti->xni_rxring.req_cons)->gref;
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RING_COPY_REQUEST(&xneti->xni_rxring,
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xneti->xni_rxring.req_cons, &rxreq);
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gop->dest.u.ref = rxreq.gref;
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gop->dest.offset = 0;
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gop->dest.domid = xneti->xni_domid;
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gop->len = m->m_pkthdr.len;
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gop++;
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id = RING_GET_REQUEST(&xneti->xni_rxring,
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xneti->xni_rxring.req_cons)->id;
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id = rxreq.id;
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xen_rmb();
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xneti->xni_rxring.req_cons++;
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rxresp = RING_GET_RESPONSE(&xneti->xni_rxring,
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Loading…
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Block a user