[RFC PATCH v1 04/15] hw/xen: Pass grant ref to gnttab unmap

[David Woodhouse <dwmw2@infradead.org>]

From: David Woodhouse <dwmw@amazon.co.uk>

Under real Xen we only need to munmap() but in the emulation code will want
to know the original ref to keep the the tracking straight.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
---
 hw/9pfs/xen-9p-backend.c            |  7 ++++---
 hw/block/dataplane/xen-block.c      |  1 +
 hw/char/xen_console.c               |  2 +-
 hw/net/xen_nic.c                    | 13 ++++++++-----
 hw/usb/xen-usb.c                    | 21 ++++++++++++++++-----
 hw/xen/xen-bus.c                    |  4 ++--
 hw/xen/xen-legacy-backend.c         |  4 ++--
 hw/xen/xen-operations.c             |  9 ++++++++-
 include/hw/xen/xen-bus.h            |  2 +-
 include/hw/xen/xen-legacy-backend.h |  6 +++---
 include/hw/xen/xen_backend_ops.h    |  7 ++++---
 11 files changed, 50 insertions(+), 26 deletions(-)

diff --git a/hw/9pfs/xen-9p-backend.c b/hw/9pfs/xen-9p-backend.c
index 864bdaf952..d8bb0e847c 100644
--- a/hw/9pfs/xen-9p-backend.c
+++ b/hw/9pfs/xen-9p-backend.c
@@ -359,12 +359,13 @@ static int xen_9pfs_free(struct XenLegacyDevice *xendev)
         if (xen_9pdev->rings[i].data != NULL) {
             xen_be_unmap_grant_refs(&xen_9pdev->xendev,
                                     xen_9pdev->rings[i].data,
+                                    xen_9pdev->rings[i].intf->ref,
                                     (1 << xen_9pdev->rings[i].ring_order));
         }
         if (xen_9pdev->rings[i].intf != NULL) {
-            xen_be_unmap_grant_refs(&xen_9pdev->xendev,
-                                    xen_9pdev->rings[i].intf,
-                                    1);
+            xen_be_unmap_grant_ref(&xen_9pdev->xendev,
+                                   xen_9pdev->rings[i].intf,
+                                   xen_9pdev->rings[i].ref);
         }
         if (xen_9pdev->rings[i].bh != NULL) {
             qemu_bh_delete(xen_9pdev->rings[i].bh);
diff --git a/hw/block/dataplane/xen-block.c b/hw/block/dataplane/xen-block.c
index 2785b9e849..e55b713002 100644
--- a/hw/block/dataplane/xen-block.c
+++ b/hw/block/dataplane/xen-block.c
@@ -705,6 +705,7 @@ void xen_block_dataplane_stop(XenBlockDataPlane *dataplane)
         Error *local_err = NULL;
 
         xen_device_unmap_grant_refs(xendev, dataplane->sring,
+                                    dataplane->ring_ref,
                                     dataplane->nr_ring_ref, &local_err);
         dataplane->sring = NULL;
 
diff --git a/hw/char/xen_console.c b/hw/char/xen_console.c
index 63153dfde4..19ad6c946a 100644
--- a/hw/char/xen_console.c
+++ b/hw/char/xen_console.c
@@ -271,7 +271,7 @@ static void con_disconnect(struct XenLegacyDevice *xendev)
         if (!xendev->dev) {
             xenforeignmemory_unmap(xen_fmem, con->sring, 1);
         } else {
-            xen_be_unmap_grant_ref(xendev, con->sring);
+            xen_be_unmap_grant_ref(xendev, con->sring, con->ring_ref);
         }
         con->sring = NULL;
     }
diff --git a/hw/net/xen_nic.c b/hw/net/xen_nic.c
index 7d92c2d022..166d03787d 100644
--- a/hw/net/xen_nic.c
+++ b/hw/net/xen_nic.c
@@ -181,7 +181,7 @@ static void net_tx_packets(struct XenNetDev *netdev)
                 qemu_send_packet(qemu_get_queue(netdev->nic),
                                  page + txreq.offset, txreq.size);
             }
-            xen_be_unmap_grant_ref(&netdev->xendev, page);
+            xen_be_unmap_grant_ref(&netdev->xendev, page, txreq.gref);
             net_tx_response(netdev, &txreq, NETIF_RSP_OKAY);
         }
         if (!netdev->tx_work) {
@@ -261,7 +261,7 @@ static ssize_t net_rx_packet(NetClientState *nc, const uint8_t *buf, size_t size
         return -1;
     }
     memcpy(page + NET_IP_ALIGN, buf, size);
-    xen_be_unmap_grant_ref(&netdev->xendev, page);
+    xen_be_unmap_grant_ref(&netdev->xendev, page, rxreq.gref);
     net_rx_response(netdev, &rxreq, NETIF_RSP_OKAY, NET_IP_ALIGN, size, 0);
 
     return size;
@@ -343,7 +343,8 @@ static int net_connect(struct XenLegacyDevice *xendev)
                                        netdev->rx_ring_ref,
                                        PROT_READ | PROT_WRITE);
     if (!netdev->rxs) {
-        xen_be_unmap_grant_ref(&netdev->xendev, netdev->txs);
+        xen_be_unmap_grant_ref(&netdev->xendev, netdev->txs,
+                               netdev->tx_ring_ref);
         netdev->txs = NULL;
         return -1;
     }
@@ -368,11 +369,13 @@ static void net_disconnect(struct XenLegacyDevice *xendev)
     xen_pv_unbind_evtchn(&netdev->xendev);
 
     if (netdev->txs) {
-        xen_be_unmap_grant_ref(&netdev->xendev, netdev->txs);
+        xen_be_unmap_grant_ref(&netdev->xendev, netdev->txs,
+                               netdev->tx_ring_ref);
         netdev->txs = NULL;
     }
     if (netdev->rxs) {
-        xen_be_unmap_grant_ref(&netdev->xendev, netdev->rxs);
+        xen_be_unmap_grant_ref(&netdev->xendev, netdev->rxs,
+                               netdev->rx_ring_ref);
         netdev->rxs = NULL;
     }
 }
diff --git a/hw/usb/xen-usb.c b/hw/usb/xen-usb.c
index 0f7369e7ed..a770a64cb4 100644
--- a/hw/usb/xen-usb.c
+++ b/hw/usb/xen-usb.c
@@ -101,6 +101,8 @@ struct usbback_hotplug {
 struct usbback_info {
     struct XenLegacyDevice         xendev;  /* must be first */
     USBBus                   bus;
+    uint32_t                 urb_ring_ref;
+    uint32_t                 conn_ring_ref;
     void                     *urb_sring;
     void                     *conn_sring;
     struct usbif_urb_back_ring urb_ring;
@@ -277,10 +279,11 @@ static int usbback_init_packet(struct usbback_req *usbback_req)
 static void usbback_do_response(struct usbback_req *usbback_req, int32_t status,
                                 int32_t actual_length, int32_t error_count)
 {
+    uint32_t ref[USBIF_MAX_SEGMENTS_PER_REQUEST];
     struct usbback_info *usbif;
     struct usbif_urb_response *res;
     struct XenLegacyDevice *xendev;
-    unsigned int notify;
+    unsigned int notify, i;
 
     usbif = usbback_req->usbif;
     xendev = &usbif->xendev;
@@ -293,13 +296,19 @@ static void usbback_do_response(struct usbback_req *usbback_req, int32_t status,
     }
 
     if (usbback_req->buffer) {
-        xen_be_unmap_grant_refs(xendev, usbback_req->buffer,
+        for (i = 0; i < usbback_req->nr_buffer_segs; i++) {
+            ref[i] = usbback_req->req.seg[i].gref;
+        }
+        xen_be_unmap_grant_refs(xendev, usbback_req->buffer, ref,
                                 usbback_req->nr_buffer_segs);
         usbback_req->buffer = NULL;
     }
 
     if (usbback_req->isoc_buffer) {
-        xen_be_unmap_grant_refs(xendev, usbback_req->isoc_buffer,
+        for (i = 0; i < usbback_req->nr_extra_segs; i++) {
+            ref[i] = usbback_req->req.seg[i + usbback_req->req.nr_buffer_segs].gref;
+        }
+        xen_be_unmap_grant_refs(xendev, usbback_req->isoc_buffer, ref,
                                 usbback_req->nr_extra_segs);
         usbback_req->isoc_buffer = NULL;
     }
@@ -832,11 +841,11 @@ static void usbback_disconnect(struct XenLegacyDevice *xendev)
     xen_pv_unbind_evtchn(xendev);
 
     if (usbif->urb_sring) {
-        xen_be_unmap_grant_ref(xendev, usbif->urb_sring);
+        xen_be_unmap_grant_ref(xendev, usbif->urb_sring, usbif->urb_ring_ref);
         usbif->urb_sring = NULL;
     }
     if (usbif->conn_sring) {
-        xen_be_unmap_grant_ref(xendev, usbif->conn_sring);
+        xen_be_unmap_grant_ref(xendev, usbif->conn_sring, usbif->conn_ring_ref);
         usbif->conn_sring = NULL;
     }
 
@@ -889,6 +898,8 @@ static int usbback_connect(struct XenLegacyDevice *xendev)
         return -1;
     }
 
+    usbif->urb_ring_ref = urb_ring_ref;
+    usbif->conn_ring_ref = conn_ring_ref;
     urb_sring = usbif->urb_sring;
     conn_sring = usbif->conn_sring;
     BACK_RING_INIT(&usbif->urb_ring, urb_sring, XC_PAGE_SIZE);
diff --git a/hw/xen/xen-bus.c b/hw/xen/xen-bus.c
index ecdce3b98b..492364f3df 100644
--- a/hw/xen/xen-bus.c
+++ b/hw/xen/xen-bus.c
@@ -966,10 +966,10 @@ void *xen_device_map_grant_refs(XenDevice *xendev, uint32_t *refs,
     return map;
 }
 
-void xen_device_unmap_grant_refs(XenDevice *xendev, void *map,
+void xen_device_unmap_grant_refs(XenDevice *xendev, void *map, uint32_t *refs,
                                  unsigned int nr_refs, Error **errp)
 {
-    if (qemu_xen_gnttab_unmap(xendev->xgth, map, nr_refs)) {
+    if (qemu_xen_gnttab_unmap(xendev->xgth, map, refs, nr_refs)) {
         error_setg_errno(errp, errno, "xengnttab_unmap failed");
     }
 }
diff --git a/hw/xen/xen-legacy-backend.c b/hw/xen/xen-legacy-backend.c
index 88d2ae3f0a..047463d89c 100644
--- a/hw/xen/xen-legacy-backend.c
+++ b/hw/xen/xen-legacy-backend.c
@@ -137,11 +137,11 @@ void *xen_be_map_grant_refs(struct XenLegacyDevice *xendev, uint32_t *refs,
 }
 
 void xen_be_unmap_grant_refs(struct XenLegacyDevice *xendev, void *ptr,
-                             unsigned int nr_refs)
+                             uint32_t *refs, unsigned int nr_refs)
 {
     assert(xendev->ops->flags & DEVOPS_FLAG_NEED_GNTDEV);
 
-    if (qemu_xen_gnttab_unmap(xendev->gnttabdev, ptr, nr_refs)) {
+    if (qemu_xen_gnttab_unmap(xendev->gnttabdev, ptr, refs, nr_refs)) {
         xen_pv_printf(xendev, 0, "xengnttab_unmap failed: %s\n",
                       strerror(errno));
     }
diff --git a/hw/xen/xen-operations.c b/hw/xen/xen-operations.c
index eb5fb0a59f..73dabac8e5 100644
--- a/hw/xen/xen-operations.c
+++ b/hw/xen/xen-operations.c
@@ -200,6 +200,13 @@ static xengnttab_handle *libxengnttab_backend_open(void)
     return xengnttab_open(NULL, 0);
 }
 
+static int libxengnttab_backend_unmap(xengnttab_handle *xgt,
+                                      void *start_address, uint32_t *refs,
+                                      uint32_t count)
+{
+    return xengnttab_unmap(xgt, start_address, count);
+}
+
 
 static struct gnttab_backend_ops libxengnttab_backend_ops = {
     .features = XEN_GNTTAB_OP_FEATURE_MAP_MULTIPLE,
@@ -208,7 +215,7 @@ static struct gnttab_backend_ops libxengnttab_backend_ops = {
     .grant_copy = libxengnttab_fallback_grant_copy,
     .set_max_grants = xengnttab_set_max_grants,
     .map_refs = xengnttab_map_domain_grant_refs,
-    .unmap = xengnttab_unmap,
+    .unmap = libxengnttab_backend_unmap,
 };
 
 void setup_xen_backend_ops(void)
diff --git a/include/hw/xen/xen-bus.h b/include/hw/xen/xen-bus.h
index 1280a2547c..c9932b7f0a 100644
--- a/include/hw/xen/xen-bus.h
+++ b/include/hw/xen/xen-bus.h
@@ -101,7 +101,7 @@ void xen_device_set_max_grant_refs(XenDevice *xendev, unsigned int nr_refs,
 void *xen_device_map_grant_refs(XenDevice *xendev, uint32_t *refs,
                                 unsigned int nr_refs, int prot,
                                 Error **errp);
-void xen_device_unmap_grant_refs(XenDevice *xendev, void *map,
+void xen_device_unmap_grant_refs(XenDevice *xendev, void *map, uint32_t *refs,
                                  unsigned int nr_refs, Error **errp);
 
 typedef struct XenDeviceGrantCopySegment {
diff --git a/include/hw/xen/xen-legacy-backend.h b/include/hw/xen/xen-legacy-backend.h
index 01c12952b7..ea84a9246f 100644
--- a/include/hw/xen/xen-legacy-backend.h
+++ b/include/hw/xen/xen-legacy-backend.h
@@ -53,7 +53,7 @@ void xen_be_set_max_grant_refs(struct XenLegacyDevice *xendev,
 void *xen_be_map_grant_refs(struct XenLegacyDevice *xendev, uint32_t *refs,
                             unsigned int nr_refs, int prot);
 void xen_be_unmap_grant_refs(struct XenLegacyDevice *xendev, void *ptr,
-                             unsigned int nr_refs);
+                             uint32_t *refs, unsigned int nr_refs);
 
 int xen_be_copy_grant_refs(struct XenLegacyDevice *xendev,
                            bool to_domain, XenGrantCopySegment segs[],
@@ -66,9 +66,9 @@ static inline void *xen_be_map_grant_ref(struct XenLegacyDevice *xendev,
 }
 
 static inline void xen_be_unmap_grant_ref(struct XenLegacyDevice *xendev,
-                                          void *ptr)
+                                          void *ptr, uint32_t ref)
 {
-    return xen_be_unmap_grant_refs(xendev, ptr, 1);
+    return xen_be_unmap_grant_refs(xendev, ptr, &ref, 1);
 }
 
 /* actual backend drivers */
diff --git a/include/hw/xen/xen_backend_ops.h b/include/hw/xen/xen_backend_ops.h
index acb7838e63..3e9392d3fa 100644
--- a/include/hw/xen/xen_backend_ops.h
+++ b/include/hw/xen/xen_backend_ops.h
@@ -144,7 +144,8 @@ struct gnttab_backend_ops {
     int (*set_max_grants)(xengnttab_handle *xgt, uint32_t nr_grants);
     void *(*map_refs)(xengnttab_handle *xgt, uint32_t count, uint32_t domid,
                       uint32_t *refs, int prot);
-    int (*unmap)(xengnttab_handle *xgt, void *start_address, uint32_t count);
+    int (*unmap)(xengnttab_handle *xgt, void *start_address, uint32_t *refs,
+                 uint32_t count);
 };
 
 extern struct gnttab_backend_ops *xen_gnttab_ops;
@@ -197,13 +198,13 @@ static inline void *qemu_xen_gnttab_map_refs(xengnttab_handle *xgt, uint32_t cou
 }
 
 static inline int qemu_xen_gnttab_unmap(xengnttab_handle *xgt,
-                                        void *start_address,
+                                        void *start_address, uint32_t *refs,
                                         uint32_t count)
 {
     if (!xen_gnttab_ops) {
         return -ENOSYS;
     }
-    return xen_gnttab_ops->unmap(xgt, start_address, count);
+    return xen_gnttab_ops->unmap(xgt, start_address, refs, count);
 }
 
 void setup_xen_backend_ops(void);
-- 
2.35.3