xen: Switch to libxengnttab interface for compat shims.

In Xen 4.7 we are refactoring parts libxenctrl into a number of
separate libraries which will provide backward and forward API and ABI
compatiblity.

One such library will be libxengnttab which provides access to grant
tables.

In preparation for this switch the compatibility layer in xen_common.h
(which support building with older versions of Xen) to use what will
be the new library API. This means that the gnttab shim will disappear
for versions of Xen which include libxengnttab.

To simplify things for the <= 4.0.0 support we wrap the int fd in a
malloc(sizeof int) such that the handle is always a pointer. This
leads to less typedef headaches and the need for
XC_HANDLER_INITIAL_VALUE etc for these interfaces.

Note that this patch does not add any support for actually using
libxengnttab, it just adjusts the existing shims.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>

4 files changed, 36 insertions, 34 deletions

diff --git a/hw/block/xen_disk.c b/hw/block/xen_disk.c
index 571f651008..7bd5bdefd3 100644
--- a/hw/block/xen_disk.c
+++ b/hw/block/xen_disk.c
@@ -161,11 +161,11 @@ static gint int_cmp(gconstpointer a, gconstpointer b, gpointer user_data)
 static void destroy_grant(gpointer pgnt)
 {
     PersistentGrant *grant = pgnt;
-    XenGnttab gnt = grant->blkdev->xendev.gnttabdev;
+    xengnttab_handle *gnt = grant->blkdev->xendev.gnttabdev;
 
-    if (xc_gnttab_munmap(gnt, grant->page, 1) != 0) {
+    if (xengnttab_unmap(gnt, grant->page, 1) != 0) {
         xen_be_printf(&grant->blkdev->xendev, 0,
-                      "xc_gnttab_munmap failed: %s\n",
+                      "xengnttab_unmap failed: %s\n",
                       strerror(errno));
     }
     grant->blkdev->persistent_gnt_count--;
@@ -178,11 +178,11 @@ static void remove_persistent_region(gpointer data, gpointer dev)
 {
     PersistentRegion *region = data;
     struct XenBlkDev *blkdev = dev;
-    XenGnttab gnt = blkdev->xendev.gnttabdev;
+    xengnttab_handle *gnt = blkdev->xendev.gnttabdev;
 
-    if (xc_gnttab_munmap(gnt, region->addr, region->num) != 0) {
+    if (xengnttab_unmap(gnt, region->addr, region->num) != 0) {
         xen_be_printf(&blkdev->xendev, 0,
-                      "xc_gnttab_munmap region %p failed: %s\n",
+                      "xengnttab_unmap region %p failed: %s\n",
                       region->addr, strerror(errno));
     }
     xen_be_printf(&blkdev->xendev, 3,
@@ -317,7 +317,7 @@ err:
 
 static void ioreq_unmap(struct ioreq *ioreq)
 {
-    XenGnttab gnt = ioreq->blkdev->xendev.gnttabdev;
+    xengnttab_handle *gnt = ioreq->blkdev->xendev.gnttabdev;
     int i;
 
     if (ioreq->num_unmap == 0 || ioreq->mapped == 0) {
@@ -327,8 +327,9 @@ static void ioreq_unmap(struct ioreq *ioreq)
         if (!ioreq->pages) {
             return;
         }
-        if (xc_gnttab_munmap(gnt, ioreq->pages, ioreq->num_unmap) != 0) {
-            xen_be_printf(&ioreq->blkdev->xendev, 0, "xc_gnttab_munmap failed: %s\n",
+        if (xengnttab_unmap(gnt, ioreq->pages, ioreq->num_unmap) != 0) {
+            xen_be_printf(&ioreq->blkdev->xendev, 0,
+                          "xengnttab_unmap failed: %s\n",
                           strerror(errno));
         }
         ioreq->blkdev->cnt_map -= ioreq->num_unmap;
@@ -338,8 +339,9 @@ static void ioreq_unmap(struct ioreq *ioreq)
             if (!ioreq->page[i]) {
                 continue;
             }
-            if (xc_gnttab_munmap(gnt, ioreq->page[i], 1) != 0) {
-                xen_be_printf(&ioreq->blkdev->xendev, 0, "xc_gnttab_munmap failed: %s\n",
+            if (xengnttab_unmap(gnt, ioreq->page[i], 1) != 0) {
+                xen_be_printf(&ioreq->blkdev->xendev, 0,
+                              "xengnttab_unmap failed: %s\n",
                               strerror(errno));
             }
             ioreq->blkdev->cnt_map--;
@@ -351,7 +353,7 @@ static void ioreq_unmap(struct ioreq *ioreq)
 
 static int ioreq_map(struct ioreq *ioreq)
 {
-    XenGnttab gnt = ioreq->blkdev->xendev.gnttabdev;
+    xengnttab_handle *gnt = ioreq->blkdev->xendev.gnttabdev;
     uint32_t domids[BLKIF_MAX_SEGMENTS_PER_REQUEST];
     uint32_t refs[BLKIF_MAX_SEGMENTS_PER_REQUEST];
     void *page[BLKIF_MAX_SEGMENTS_PER_REQUEST];
@@ -402,7 +404,7 @@ static int ioreq_map(struct ioreq *ioreq)
     }
 
     if (batch_maps && new_maps) {
-        ioreq->pages = xc_gnttab_map_grant_refs
+        ioreq->pages = xengnttab_map_grant_refs
             (gnt, new_maps, domids, refs, ioreq->prot);
         if (ioreq->pages == NULL) {
             xen_be_printf(&ioreq->blkdev->xendev, 0,
@@ -418,7 +420,7 @@ static int ioreq_map(struct ioreq *ioreq)
         ioreq->blkdev->cnt_map += new_maps;
     } else if (new_maps)  {
         for (i = 0; i < new_maps; i++) {
-            ioreq->page[i] = xc_gnttab_map_grant_ref
+            ioreq->page[i] = xengnttab_map_grant_ref
                 (gnt, domids[i], refs[i], ioreq->prot);
             if (ioreq->page[i] == NULL) {
                 xen_be_printf(&ioreq->blkdev->xendev, 0,
@@ -768,9 +770,9 @@ static void blk_alloc(struct XenDevice *xendev)
     if (xen_mode != XEN_EMULATE) {
         batch_maps = 1;
     }
-    if (xc_gnttab_set_max_grants(xendev->gnttabdev,
+    if (xengnttab_set_max_grants(xendev->gnttabdev,
             MAX_GRANTS(max_requests, BLKIF_MAX_SEGMENTS_PER_REQUEST)) < 0) {
-        xen_be_printf(xendev, 0, "xc_gnttab_set_max_grants failed: %s\n",
+        xen_be_printf(xendev, 0, "xengnttab_set_max_grants failed: %s\n",
                       strerror(errno));
     }
 }
@@ -980,7 +982,7 @@ static int blk_connect(struct XenDevice *xendev)
         }
     }
 
-    blkdev->sring = xc_gnttab_map_grant_ref(blkdev->xendev.gnttabdev,
+    blkdev->sring = xengnttab_map_grant_ref(blkdev->xendev.gnttabdev,
                                             blkdev->xendev.dom,
                                             blkdev->ring_ref,
                                             PROT_READ | PROT_WRITE);
@@ -1045,7 +1047,7 @@ static void blk_disconnect(struct XenDevice *xendev)
     xen_be_unbind_evtchn(&blkdev->xendev);
 
     if (blkdev->sring) {
-        xc_gnttab_munmap(blkdev->xendev.gnttabdev, blkdev->sring, 1);
+        xengnttab_unmap(blkdev->xendev.gnttabdev, blkdev->sring, 1);
         blkdev->cnt_map--;
         blkdev->sring = NULL;
     }
diff --git a/hw/char/xen_console.c b/hw/char/xen_console.c
index 63ade331f7..ac1b324432 100644
--- a/hw/char/xen_console.c
+++ b/hw/char/xen_console.c
@@ -233,7 +233,7 @@ static int con_initialise(struct XenDevice *xendev)
                                           PROT_READ|PROT_WRITE,
                                           con->ring_ref);
     } else {
-        con->sring = xc_gnttab_map_grant_ref(xendev->gnttabdev, con->xendev.dom,
+        con->sring = xengnttab_map_grant_ref(xendev->gnttabdev, con->xendev.dom,
                                              con->ring_ref,
                                              PROT_READ|PROT_WRITE);
     }
@@ -275,7 +275,7 @@ static void con_disconnect(struct XenDevice *xendev)
         if (!xendev->dev) {
             munmap(con->sring, XC_PAGE_SIZE);
         } else {
-            xc_gnttab_munmap(xendev->gnttabdev, con->sring, 1);
+            xengnttab_unmap(xendev->gnttabdev, con->sring, 1);
         }
         con->sring = NULL;
     }
diff --git a/hw/net/xen_nic.c b/hw/net/xen_nic.c
index 0da16b44f4..3ffb07d411 100644
--- a/hw/net/xen_nic.c
+++ b/hw/net/xen_nic.c
@@ -168,7 +168,7 @@ static void net_tx_packets(struct XenNetDev *netdev)
                           (txreq.flags & NETTXF_more_data)      ? " more_data"      : "",
                           (txreq.flags & NETTXF_extra_info)     ? " extra_info"     : "");
 
-            page = xc_gnttab_map_grant_ref(netdev->xendev.gnttabdev,
+            page = xengnttab_map_grant_ref(netdev->xendev.gnttabdev,
                                            netdev->xendev.dom,
                                            txreq.gref, PROT_READ);
             if (page == NULL) {
@@ -190,7 +190,7 @@ static void net_tx_packets(struct XenNetDev *netdev)
                 qemu_send_packet(qemu_get_queue(netdev->nic),
                                  page + txreq.offset, txreq.size);
             }
-            xc_gnttab_munmap(netdev->xendev.gnttabdev, page, 1);
+            xengnttab_unmap(netdev->xendev.gnttabdev, page, 1);
             net_tx_response(netdev, &txreq, NETIF_RSP_OKAY);
         }
         if (!netdev->tx_work) {
@@ -260,7 +260,7 @@ static ssize_t net_rx_packet(NetClientState *nc, const uint8_t *buf, size_t size
     memcpy(&rxreq, RING_GET_REQUEST(&netdev->rx_ring, rc), sizeof(rxreq));
     netdev->rx_ring.req_cons = ++rc;
 
-    page = xc_gnttab_map_grant_ref(netdev->xendev.gnttabdev,
+    page = xengnttab_map_grant_ref(netdev->xendev.gnttabdev,
                                    netdev->xendev.dom,
                                    rxreq.gref, PROT_WRITE);
     if (page == NULL) {
@@ -270,7 +270,7 @@ static ssize_t net_rx_packet(NetClientState *nc, const uint8_t *buf, size_t size
         return -1;
     }
     memcpy(page + NET_IP_ALIGN, buf, size);
-    xc_gnttab_munmap(netdev->xendev.gnttabdev, page, 1);
+    xengnttab_unmap(netdev->xendev.gnttabdev, page, 1);
     net_rx_response(netdev, &rxreq, NETIF_RSP_OKAY, NET_IP_ALIGN, size, 0);
 
     return size;
@@ -342,19 +342,19 @@ static int net_connect(struct XenDevice *xendev)
         return -1;
     }
 
-    netdev->txs = xc_gnttab_map_grant_ref(netdev->xendev.gnttabdev,
+    netdev->txs = xengnttab_map_grant_ref(netdev->xendev.gnttabdev,
                                           netdev->xendev.dom,
                                           netdev->tx_ring_ref,
                                           PROT_READ | PROT_WRITE);
     if (!netdev->txs) {
         return -1;
     }
-    netdev->rxs = xc_gnttab_map_grant_ref(netdev->xendev.gnttabdev,
+    netdev->rxs = xengnttab_map_grant_ref(netdev->xendev.gnttabdev,
                                           netdev->xendev.dom,
                                           netdev->rx_ring_ref,
                                           PROT_READ | PROT_WRITE);
     if (!netdev->rxs) {
-        xc_gnttab_munmap(netdev->xendev.gnttabdev, netdev->txs, 1);
+        xengnttab_unmap(netdev->xendev.gnttabdev, netdev->txs, 1);
         netdev->txs = NULL;
         return -1;
     }
@@ -379,11 +379,11 @@ static void net_disconnect(struct XenDevice *xendev)
     xen_be_unbind_evtchn(&netdev->xendev);
 
     if (netdev->txs) {
-        xc_gnttab_munmap(netdev->xendev.gnttabdev, netdev->txs, 1);
+        xengnttab_unmap(netdev->xendev.gnttabdev, netdev->txs, 1);
         netdev->txs = NULL;
     }
     if (netdev->rxs) {
-        xc_gnttab_munmap(netdev->xendev.gnttabdev, netdev->rxs, 1);
+        xengnttab_unmap(netdev->xendev.gnttabdev, netdev->rxs, 1);
         netdev->rxs = NULL;
     }
 }
diff --git a/hw/xen/xen_backend.c b/hw/xen/xen_backend.c
index ae2a1f01bd..966e34f3cb 100644
--- a/hw/xen/xen_backend.c
+++ b/hw/xen/xen_backend.c
@@ -252,15 +252,15 @@ static struct XenDevice *xen_be_get_xendev(const char *type, int dom, int dev,
     fcntl(xenevtchn_fd(xendev->evtchndev), F_SETFD, FD_CLOEXEC);
 
     if (ops->flags & DEVOPS_FLAG_NEED_GNTDEV) {
-        xendev->gnttabdev = xen_xc_gnttab_open(NULL, 0);
-        if (xendev->gnttabdev == XC_HANDLER_INITIAL_VALUE) {
+        xendev->gnttabdev = xengnttab_open(NULL, 0);
+        if (xendev->gnttabdev == NULL) {
             xen_be_printf(NULL, 0, "can't open gnttab device\n");
             xenevtchn_close(xendev->evtchndev);
             g_free(xendev);
             return NULL;
         }
     } else {
-        xendev->gnttabdev = XC_HANDLER_INITIAL_VALUE;
+        xendev->gnttabdev = NULL;
     }
 
     QTAILQ_INSERT_TAIL(&xendevs, xendev, next);
@@ -309,8 +309,8 @@ static struct XenDevice *xen_be_del_xendev(int dom, int dev)
         if (xendev->evtchndev != NULL) {
             xenevtchn_close(xendev->evtchndev);
         }
-        if (xendev->gnttabdev != XC_HANDLER_INITIAL_VALUE) {
-            xc_gnttab_close(xendev->gnttabdev);
+        if (xendev->gnttabdev != NULL) {
+            xengnttab_close(xendev->gnttabdev);
         }
 
         QTAILQ_REMOVE(&xendevs, xendev, next);