[RFC] xen: map foreign pages for shared rings by updating the PTEs directly

[RFC] xen: map foreign pages for shared rings by updating the PTEs directly

[David Vrabel]

This series of patches allows the vmalloc_sync_all() to be removed
from alloc_vm_area() by getting the hypervisor to update the PTEs (in
init_mm) directly rather than having the hypervisor look in the
current page tables to find the PTEs.

Once the hypervisor has updated the PTEs, the normal mechanism of
syncing the page tables after a fault works as expected.

This mechanism doesn't currently work on the ia64 port as that does
not support the GNTMAP_contains_pte flag.

David

[PATCH 1/4] xen: use generic functions instead of xen_{alloc, free}_vm_area()

[David Vrabel]

From: David Vrabel <david.vrabel@citrix.com>

Replace calls to the Xen-specific xen_alloc_vm_area() and
xen_free_vm_area() functions with the generic equivalent
(alloc_vm_area() and free_vm_area()).

On x86, these were identical already.

Signed-off-by: David Vrabel <david.vrabel@citrix.com>
---
 arch/ia64/include/asm/xen/grant_table.h |   29 --------------
 arch/ia64/xen/grant-table.c             |   62 -------------------------------
 arch/x86/include/asm/xen/grant_table.h  |    7 ---
 arch/x86/xen/grant-table.c              |    2 +-
 drivers/xen/xenbus/xenbus_client.c      |    6 +-
 include/xen/grant_table.h               |    1 -
 6 files changed, 4 insertions(+), 103 deletions(-)
 delete mode 100644 arch/ia64/include/asm/xen/grant_table.h
 delete mode 100644 arch/x86/include/asm/xen/grant_table.h

diff --git a/arch/ia64/include/asm/xen/grant_table.h b/arch/ia64/include/asm/xen/grant_table.h
deleted file mode 100644
index 2b1fae0..0000000
--- a/arch/ia64/include/asm/xen/grant_table.h
+++ /dev/null
@@ -1,29 +0,0 @@
-/******************************************************************************
- * arch/ia64/include/asm/xen/grant_table.h
- *
- * Copyright (c) 2008 Isaku Yamahata <yamahata at valinux co jp>
- *                    VA Linux Systems Japan K.K.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
- *
- */
-
-#ifndef _ASM_IA64_XEN_GRANT_TABLE_H
-#define _ASM_IA64_XEN_GRANT_TABLE_H
-
-struct vm_struct *xen_alloc_vm_area(unsigned long size);
-void xen_free_vm_area(struct vm_struct *area);
-
-#endif /* _ASM_IA64_XEN_GRANT_TABLE_H */
diff --git a/arch/ia64/xen/grant-table.c b/arch/ia64/xen/grant-table.c
index 48cca37..c182813 100644
--- a/arch/ia64/xen/grant-table.c
+++ b/arch/ia64/xen/grant-table.c
@@ -31,68 +31,6 @@
 
 #include <asm/xen/hypervisor.h>
 
-struct vm_struct *xen_alloc_vm_area(unsigned long size)
-{
-	int order;
-	unsigned long virt;
-	unsigned long nr_pages;
-	struct vm_struct *area;
-
-	order = get_order(size);
-	virt = __get_free_pages(GFP_KERNEL, order);
-	if (virt == 0)
-		goto err0;
-	nr_pages = 1 << order;
-	scrub_pages(virt, nr_pages);
-
-	area = kmalloc(sizeof(*area), GFP_KERNEL);
-	if (area == NULL)
-		goto err1;
-
-	area->flags = VM_IOREMAP;
-	area->addr = (void *)virt;
-	area->size = size;
-	area->pages = NULL;
-	area->nr_pages = nr_pages;
-	area->phys_addr = 0;	/* xenbus_map_ring_valloc uses this field!  */
-
-	return area;
-
-err1:
-	free_pages(virt, order);
-err0:
-	return NULL;
-}
-EXPORT_SYMBOL_GPL(xen_alloc_vm_area);
-
-void xen_free_vm_area(struct vm_struct *area)
-{
-	unsigned int order = get_order(area->size);
-	unsigned long i;
-	unsigned long phys_addr = __pa(area->addr);
-
-	/* This area is used for foreign page mappping.
-	 * So underlying machine page may not be assigned. */
-	for (i = 0; i < (1 << order); i++) {
-		unsigned long ret;
-		unsigned long gpfn = (phys_addr >> PAGE_SHIFT) + i;
-		struct xen_memory_reservation reservation = {
-			.nr_extents   = 1,
-			.address_bits = 0,
-			.extent_order = 0,
-			.domid        = DOMID_SELF
-		};
-		set_xen_guest_handle(reservation.extent_start, &gpfn);
-		ret = HYPERVISOR_memory_op(XENMEM_populate_physmap,
-					   &reservation);
-		BUG_ON(ret != 1);
-	}
-	free_pages((unsigned long)area->addr, order);
-	kfree(area);
-}
-EXPORT_SYMBOL_GPL(xen_free_vm_area);
-
-
 /****************************************************************************
  * grant table hack
  * cmd: GNTTABOP_xxx
diff --git a/arch/x86/include/asm/xen/grant_table.h b/arch/x86/include/asm/xen/grant_table.h
deleted file mode 100644
index fdbbb45..0000000
--- a/arch/x86/include/asm/xen/grant_table.h
+++ /dev/null
@@ -1,7 +0,0 @@
-#ifndef _ASM_X86_XEN_GRANT_TABLE_H
-#define _ASM_X86_XEN_GRANT_TABLE_H
-
-#define xen_alloc_vm_area(size)	alloc_vm_area(size)
-#define xen_free_vm_area(area)	free_vm_area(area)
-
-#endif /* _ASM_X86_XEN_GRANT_TABLE_H */
diff --git a/arch/x86/xen/grant-table.c b/arch/x86/xen/grant-table.c
index 49ba9b5..6bbfd7a 100644
--- a/arch/x86/xen/grant-table.c
+++ b/arch/x86/xen/grant-table.c
@@ -71,7 +71,7 @@ int arch_gnttab_map_shared(unsigned long *frames, unsigned long nr_gframes,
 
 	if (shared == NULL) {
 		struct vm_struct *area =
-			xen_alloc_vm_area(PAGE_SIZE * max_nr_gframes);
+			alloc_vm_area(PAGE_SIZE * max_nr_gframes);
 		BUG_ON(area == NULL);
 		shared = area->addr;
 		*__shared = shared;
diff --git a/drivers/xen/xenbus/xenbus_client.c b/drivers/xen/xenbus/xenbus_client.c
index cdacf92..229d3ad 100644
--- a/drivers/xen/xenbus/xenbus_client.c
+++ b/drivers/xen/xenbus/xenbus_client.c
@@ -443,7 +443,7 @@ int xenbus_map_ring_valloc(struct xenbus_device *dev, int gnt_ref, void **vaddr)
 
 	*vaddr = NULL;
 
-	area = xen_alloc_vm_area(PAGE_SIZE);
+	area = alloc_vm_area(PAGE_SIZE);
 	if (!area)
 		return -ENOMEM;
 
@@ -453,7 +453,7 @@ int xenbus_map_ring_valloc(struct xenbus_device *dev, int gnt_ref, void **vaddr)
 		BUG();
 
 	if (op.status != GNTST_okay) {
-		xen_free_vm_area(area);
+		free_vm_area(area);
 		xenbus_dev_fatal(dev, op.status,
 				 "mapping in shared page %d from domain %d",
 				 gnt_ref, dev->otherend_id);
@@ -552,7 +552,7 @@ int xenbus_unmap_ring_vfree(struct xenbus_device *dev, void *vaddr)
 		BUG();
 
 	if (op.status == GNTST_okay)
-		xen_free_vm_area(area);
+		free_vm_area(area);
 	else
 		xenbus_dev_error(dev, op.status,
 				 "unmapping page at handle %d error %d",
diff --git a/include/xen/grant_table.h b/include/xen/grant_table.h
index b1fab6b..8a8bb76 100644
--- a/include/xen/grant_table.h
+++ b/include/xen/grant_table.h
@@ -43,7 +43,6 @@
 #include <xen/interface/grant_table.h>
 
 #include <asm/xen/hypervisor.h>
-#include <asm/xen/grant_table.h>
 
 #include <xen/features.h>
 
-- 
1.7.2.5

[PATCH 2/4] block: xen-blkback: use API provided by xenbus module to map rings

[David Vrabel]

From: David Vrabel <david.vrabel@citrix.com>

The xenbus module provides xenbus_map_ring_valloc() and
xenbus_map_ring_vfree().  Use these to map the ring pages granted by
the frontend.

Signed-off-by: David Vrabel <david.vrabel@citrix.com>
---
 drivers/block/xen-blkback/common.h |    5 +--
 drivers/block/xen-blkback/xenbus.c |   54 ++++-------------------------------
 2 files changed, 8 insertions(+), 51 deletions(-)

diff --git a/drivers/block/xen-blkback/common.h b/drivers/block/xen-blkback/common.h
index 9e40b28..07dd177 100644
--- a/drivers/block/xen-blkback/common.h
+++ b/drivers/block/xen-blkback/common.h
@@ -139,7 +139,7 @@ struct xen_blkif {
 	/* Comms information. */
 	enum blkif_protocol	blk_protocol;
 	union blkif_back_rings	blk_rings;
-	struct vm_struct	*blk_ring_area;
+	void			*blk_ring;
 	/* The VBD attached to this interface. */
 	struct xen_vbd		vbd;
 	/* Back pointer to the backend_info. */
@@ -163,9 +163,6 @@ struct xen_blkif {
 	int			st_wr_sect;
 
 	wait_queue_head_t	waiting_to_free;
-
-	grant_handle_t		shmem_handle;
-	grant_ref_t		shmem_ref;
 };
 
 
diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c
index 3f129b4..73703d5 100644
--- a/drivers/block/xen-blkback/xenbus.c
+++ b/drivers/block/xen-blkback/xenbus.c
@@ -120,38 +120,6 @@ static struct xen_blkif *xen_blkif_alloc(domid_t domid)
 	return blkif;
 }
 
-static int map_frontend_page(struct xen_blkif *blkif, unsigned long shared_page)
-{
-	struct gnttab_map_grant_ref op;
-
-	gnttab_set_map_op(&op, (unsigned long)blkif->blk_ring_area->addr,
-			  GNTMAP_host_map, shared_page, blkif->domid);
-
-	if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
-		BUG();
-
-	if (op.status) {
-		DPRINTK("Grant table operation failure !\n");
-		return op.status;
-	}
-
-	blkif->shmem_ref = shared_page;
-	blkif->shmem_handle = op.handle;
-
-	return 0;
-}
-
-static void unmap_frontend_page(struct xen_blkif *blkif)
-{
-	struct gnttab_unmap_grant_ref op;
-
-	gnttab_set_unmap_op(&op, (unsigned long)blkif->blk_ring_area->addr,
-			    GNTMAP_host_map, blkif->shmem_handle);
-
-	if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1))
-		BUG();
-}
-
 static int xen_blkif_map(struct xen_blkif *blkif, unsigned long shared_page,
 			 unsigned int evtchn)
 {
@@ -161,35 +129,29 @@ static int xen_blkif_map(struct xen_blkif *blkif, unsigned long shared_page,
 	if (blkif->irq)
 		return 0;
 
-	blkif->blk_ring_area = alloc_vm_area(PAGE_SIZE);
-	if (!blkif->blk_ring_area)
-		return -ENOMEM;
-
-	err = map_frontend_page(blkif, shared_page);
-	if (err) {
-		free_vm_area(blkif->blk_ring_area);
+	err = xenbus_map_ring_valloc(blkif->be->dev, shared_page, &blkif->blk_ring);
+	if (err < 0)
 		return err;
-	}
 
 	switch (blkif->blk_protocol) {
 	case BLKIF_PROTOCOL_NATIVE:
 	{
 		struct blkif_sring *sring;
-		sring = (struct blkif_sring *)blkif->blk_ring_area->addr;
+		sring = (struct blkif_sring *)blkif->blk_ring;
 		BACK_RING_INIT(&blkif->blk_rings.native, sring, PAGE_SIZE);
 		break;
 	}
 	case BLKIF_PROTOCOL_X86_32:
 	{
 		struct blkif_x86_32_sring *sring_x86_32;
-		sring_x86_32 = (struct blkif_x86_32_sring *)blkif->blk_ring_area->addr;
+		sring_x86_32 = (struct blkif_x86_32_sring *)blkif->blk_ring;
 		BACK_RING_INIT(&blkif->blk_rings.x86_32, sring_x86_32, PAGE_SIZE);
 		break;
 	}
 	case BLKIF_PROTOCOL_X86_64:
 	{
 		struct blkif_x86_64_sring *sring_x86_64;
-		sring_x86_64 = (struct blkif_x86_64_sring *)blkif->blk_ring_area->addr;
+		sring_x86_64 = (struct blkif_x86_64_sring *)blkif->blk_ring;
 		BACK_RING_INIT(&blkif->blk_rings.x86_64, sring_x86_64, PAGE_SIZE);
 		break;
 	}
@@ -201,8 +163,7 @@ static int xen_blkif_map(struct xen_blkif *blkif, unsigned long shared_page,
 						    xen_blkif_be_int, 0,
 						    "blkif-backend", blkif);
 	if (err < 0) {
-		unmap_frontend_page(blkif);
-		free_vm_area(blkif->blk_ring_area);
+		xenbus_unmap_ring_vfree(blkif->be->dev, blkif->blk_ring);
 		blkif->blk_rings.common.sring = NULL;
 		return err;
 	}
@@ -228,8 +189,7 @@ static void xen_blkif_disconnect(struct xen_blkif *blkif)
 	}
 
 	if (blkif->blk_rings.common.sring) {
-		unmap_frontend_page(blkif);
-		free_vm_area(blkif->blk_ring_area);
+		xenbus_unmap_ring_vfree(blkif->be->dev, blkif->blk_ring);
 		blkif->blk_rings.common.sring = NULL;
 	}
 }
-- 
1.7.2.5

[PATCH 3/4] net: xen-netback: use API provided by xenbus module to map rings

[David Vrabel]

From: David Vrabel <david.vrabel@citrix.com>

The xenbus module provides xenbus_map_ring_valloc() and
xenbus_map_ring_vfree().  Use these to map the Tx and Rx ring pages
granted by the frontend.

Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Cc: Ian Campbell <ian.campbell@citrix.com>
---
 drivers/net/xen-netback/common.h  |   11 ++---
 drivers/net/xen-netback/netback.c |   80 ++++++++-----------------------------
 2 files changed, 22 insertions(+), 69 deletions(-)

diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h
index 161f207..94b79c3 100644
--- a/drivers/net/xen-netback/common.h
+++ b/drivers/net/xen-netback/common.h
@@ -58,10 +58,6 @@ struct xenvif {
 	u8               fe_dev_addr[6];
 
 	/* Physical parameters of the comms window. */
-	grant_handle_t   tx_shmem_handle;
-	grant_ref_t      tx_shmem_ref;
-	grant_handle_t   rx_shmem_handle;
-	grant_ref_t      rx_shmem_ref;
 	unsigned int     irq;
 
 	/* List of frontends to notify after a batch of frames sent. */
@@ -70,8 +66,6 @@ struct xenvif {
 	/* The shared rings and indexes. */
 	struct xen_netif_tx_back_ring tx;
 	struct xen_netif_rx_back_ring rx;
-	struct vm_struct *tx_comms_area;
-	struct vm_struct *rx_comms_area;
 
 	/* Frontend feature information. */
 	u8 can_sg:1;
@@ -106,6 +100,11 @@ struct xenvif {
 	wait_queue_head_t waiting_to_free;
 };
 
+static inline struct xenbus_device *xenvif_to_xenbus_device(struct xenvif *vif)
+{
+	return to_xenbus_device(vif->dev->dev.parent);
+}
+
 #define XEN_NETIF_TX_RING_SIZE __CONST_RING_SIZE(xen_netif_tx, PAGE_SIZE)
 #define XEN_NETIF_RX_RING_SIZE __CONST_RING_SIZE(xen_netif_rx, PAGE_SIZE)
 
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index fd00f25..3af2924 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -1577,88 +1577,42 @@ static int xen_netbk_kthread(void *data)
 
 void xen_netbk_unmap_frontend_rings(struct xenvif *vif)
 {
-	struct gnttab_unmap_grant_ref op;
-
-	if (vif->tx.sring) {
-		gnttab_set_unmap_op(&op, (unsigned long)vif->tx_comms_area->addr,
-				    GNTMAP_host_map, vif->tx_shmem_handle);
-
-		if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1))
-			BUG();
-	}
-
-	if (vif->rx.sring) {
-		gnttab_set_unmap_op(&op, (unsigned long)vif->rx_comms_area->addr,
-				    GNTMAP_host_map, vif->rx_shmem_handle);
-
-		if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1))
-			BUG();
-	}
-	if (vif->rx_comms_area)
-		free_vm_area(vif->rx_comms_area);
-	if (vif->tx_comms_area)
-		free_vm_area(vif->tx_comms_area);
+	if (vif->tx.sring)
+		xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(vif),
+					vif->tx.sring);
+	if (vif->rx.sring)
+		xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(vif),
+					vif->rx.sring);
 }
 
 int xen_netbk_map_frontend_rings(struct xenvif *vif,
 				 grant_ref_t tx_ring_ref,
 				 grant_ref_t rx_ring_ref)
 {
-	struct gnttab_map_grant_ref op;
+	void *addr;
 	struct xen_netif_tx_sring *txs;
 	struct xen_netif_rx_sring *rxs;
 
 	int err = -ENOMEM;
 
-	vif->tx_comms_area = alloc_vm_area(PAGE_SIZE);
-	if (vif->tx_comms_area == NULL)
+	err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(vif),
+				     tx_ring_ref, &addr);
+	if (err)
 		goto err;
 
-	vif->rx_comms_area = alloc_vm_area(PAGE_SIZE);
-	if (vif->rx_comms_area == NULL)
-		goto err;
-
-	gnttab_set_map_op(&op, (unsigned long)vif->tx_comms_area->addr,
-			  GNTMAP_host_map, tx_ring_ref, vif->domid);
-
-	if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
-		BUG();
-
-	if (op.status) {
-		netdev_warn(vif->dev,
-			    "failed to map tx ring. err=%d status=%d\n",
-			    err, op.status);
-		err = op.status;
-		goto err;
-	}
-
-	vif->tx_shmem_ref    = tx_ring_ref;
-	vif->tx_shmem_handle = op.handle;
-
-	txs = (struct xen_netif_tx_sring *)vif->tx_comms_area->addr;
+	txs = (struct xen_netif_tx_sring *)addr;
 	BACK_RING_INIT(&vif->tx, txs, PAGE_SIZE);
 
-	gnttab_set_map_op(&op, (unsigned long)vif->rx_comms_area->addr,
-			  GNTMAP_host_map, rx_ring_ref, vif->domid);
-
-	if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
-		BUG();
-
-	if (op.status) {
-		netdev_warn(vif->dev,
-			    "failed to map rx ring. err=%d status=%d\n",
-			    err, op.status);
-		err = op.status;
+	err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(vif),
+				     rx_ring_ref, &addr);
+	if (err)
 		goto err;
-	}
-
-	vif->rx_shmem_ref     = rx_ring_ref;
-	vif->rx_shmem_handle  = op.handle;
-	vif->rx_req_cons_peek = 0;
 
-	rxs = (struct xen_netif_rx_sring *)vif->rx_comms_area->addr;
+	rxs = (struct xen_netif_rx_sring *)addr;
 	BACK_RING_INIT(&vif->rx, rxs, PAGE_SIZE);
 
+	vif->rx_req_cons_peek = 0;
+
 	return 0;
 
 err:
-- 
1.7.2.5

[PATCH 4/4] xen: map foreign pages for shared rings by updating the PTEs directly

[David Vrabel]

From: David Vrabel <david.vrabel@citrix.com>

When mapping a foreign page with xenbus_map_ring_valloc() with the
GNTTABOP_map_grant_ref hypercall, set the GNTMAP_contains_pte flag and
pass a pointer to the PTE (in init_mm).

After the page is mapped, the usual fault mechanism can be used to
update additional MMs.  This allows the vmalloc_sync_all() to be
removed from alloc_vm_area().

Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
---
 arch/x86/xen/grant-table.c         |    2 +-
 drivers/xen/xenbus/xenbus_client.c |   11 ++++++++---
 include/linux/vmalloc.h            |    2 +-
 mm/vmalloc.c                       |   27 +++++++++++++--------------
 4 files changed, 23 insertions(+), 19 deletions(-)

diff --git a/arch/x86/xen/grant-table.c b/arch/x86/xen/grant-table.c
index 6bbfd7a..5a40d24 100644
--- a/arch/x86/xen/grant-table.c
+++ b/arch/x86/xen/grant-table.c
@@ -71,7 +71,7 @@ int arch_gnttab_map_shared(unsigned long *frames, unsigned long nr_gframes,
 
 	if (shared == NULL) {
 		struct vm_struct *area =
-			alloc_vm_area(PAGE_SIZE * max_nr_gframes);
+			alloc_vm_area(PAGE_SIZE * max_nr_gframes, NULL);
 		BUG_ON(area == NULL);
 		shared = area->addr;
 		*__shared = shared;
diff --git a/drivers/xen/xenbus/xenbus_client.c b/drivers/xen/xenbus/xenbus_client.c
index 229d3ad..52bc57f 100644
--- a/drivers/xen/xenbus/xenbus_client.c
+++ b/drivers/xen/xenbus/xenbus_client.c
@@ -34,6 +34,7 @@
 #include <linux/types.h>
 #include <linux/vmalloc.h>
 #include <asm/xen/hypervisor.h>
+#include <asm/xen/page.h>
 #include <xen/interface/xen.h>
 #include <xen/interface/event_channel.h>
 #include <xen/events.h>
@@ -435,19 +436,20 @@ EXPORT_SYMBOL_GPL(xenbus_free_evtchn);
 int xenbus_map_ring_valloc(struct xenbus_device *dev, int gnt_ref, void **vaddr)
 {
 	struct gnttab_map_grant_ref op = {
-		.flags = GNTMAP_host_map,
+		.flags = GNTMAP_host_map | GNTMAP_contains_pte,
 		.ref   = gnt_ref,
 		.dom   = dev->otherend_id,
 	};
 	struct vm_struct *area;
+	pte_t *pte;
 
 	*vaddr = NULL;
 
-	area = alloc_vm_area(PAGE_SIZE);
+	area = alloc_vm_area(PAGE_SIZE, &pte);
 	if (!area)
 		return -ENOMEM;
 
-	op.host_addr = (unsigned long)area->addr;
+	op.host_addr = arbitrary_virt_to_machine(pte).maddr;
 
 	if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
 		BUG();
@@ -526,6 +528,7 @@ int xenbus_unmap_ring_vfree(struct xenbus_device *dev, void *vaddr)
 	struct gnttab_unmap_grant_ref op = {
 		.host_addr = (unsigned long)vaddr,
 	};
+	unsigned int level;
 
 	/* It'd be nice if linux/vmalloc.h provided a find_vm_area(void *addr)
 	 * method so that we don't have to muck with vmalloc internals here.
@@ -547,6 +550,8 @@ int xenbus_unmap_ring_vfree(struct xenbus_device *dev, void *vaddr)
 	}
 
 	op.handle = (grant_handle_t)area->phys_addr;
+	op.host_addr = arbitrary_virt_to_machine(
+		lookup_address((unsigned long)vaddr, &level)).maddr;
 
 	if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1))
 		BUG();
diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h
index 9332e52..1a77252 100644
--- a/include/linux/vmalloc.h
+++ b/include/linux/vmalloc.h
@@ -118,7 +118,7 @@ unmap_kernel_range(unsigned long addr, unsigned long size)
 #endif
 
 /* Allocate/destroy a 'vmalloc' VM area. */
-extern struct vm_struct *alloc_vm_area(size_t size);
+extern struct vm_struct *alloc_vm_area(size_t size, pte_t **ptes);
 extern void free_vm_area(struct vm_struct *area);
 
 /* for /dev/kmem */
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 5016f19..b5deec6 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -2105,23 +2105,30 @@ void  __attribute__((weak)) vmalloc_sync_all(void)
 
 static int f(pte_t *pte, pgtable_t table, unsigned long addr, void *data)
 {
-	/* apply_to_page_range() does all the hard work. */
+	pte_t ***p = data;
+
+	if (p) {
+		*(*p) = pte;
+		(*p)++;
+	}
 	return 0;
 }
 
 /**
  *	alloc_vm_area - allocate a range of kernel address space
  *	@size:		size of the area
+ *	@ptes:		returns the PTEs for the address space
  *
  *	Returns:	NULL on failure, vm_struct on success
  *
  *	This function reserves a range of kernel address space, and
  *	allocates pagetables to map that range.  No actual mappings
- *	are created.  If the kernel address space is not shared
- *	between processes, it syncs the pagetable across all
- *	processes.
+ *	are created.
+ *
+ *	If @ptes is non-NULL, pointers to the PTEs (in init_mm)
+ *	allocated for the VM area are returned.
  */
-struct vm_struct *alloc_vm_area(size_t size)
+struct vm_struct *alloc_vm_area(size_t size, pte_t **ptes)
 {
 	struct vm_struct *area;
 
@@ -2135,19 +2142,11 @@ struct vm_struct *alloc_vm_area(size_t size)
 	 * of kernel virtual address space and mapped into init_mm.
 	 */
 	if (apply_to_page_range(&init_mm, (unsigned long)area->addr,
-				area->size, f, NULL)) {
+				size, f, ptes ? &ptes : NULL)) {
 		free_vm_area(area);
 		return NULL;
 	}
 
-	/*
-	 * If the allocated address space is passed to a hypercall
-	 * before being used then we cannot rely on a page fault to
-	 * trigger an update of the page tables.  So sync all the page
-	 * tables here.
-	 */
-	vmalloc_sync_all();
-
 	return area;
 }
 EXPORT_SYMBOL_GPL(alloc_vm_area);
-- 
1.7.2.5

Re: [PATCH 3/4] net: xen-netback: use API provided by xenbus module to map rings

[Ian Campbell]

On Fri, 2011-09-23 at 18:55 +0100, David Vrabel wrote:
> From: David Vrabel <david.vrabel@citrix.com>
> 
> The xenbus module provides xenbus_map_ring_valloc() and
> xenbus_map_ring_vfree().  Use these to map the Tx and Rx ring pages
> granted by the frontend.
> 
> Signed-off-by: David Vrabel <david.vrabel@citrix.com>

Acked-by: Ian Campbell <ian.campbell@citrix.com>

Re: [PATCH 3/4] net: xen-netback: use API provided by xenbus module to map rings

[Konrad Rzeszutek Wilk]

On Thu, Oct 20, 2011 at 11:45:18AM +0100, David Vrabel wrote:
> The xenbus module provides xenbus_map_ring_valloc() and
> xenbus_map_ring_vfree().  Use these to map the Tx and Rx ring pages
> granted by the frontend.
> 
> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
> Acked-by: Ian Campbell <ian.campbell@citrix.com>


Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

> Dave, this is a standalone patch and can be applied independently of
> the rest of the series.

.. or Dave, if you would like I can carry these patches.

> 
>  drivers/net/xen-netback/common.h  |   11 ++---
>  drivers/net/xen-netback/netback.c |   80 ++++++++-----------------------------
>  2 files changed, 22 insertions(+), 69 deletions(-)
> 
> diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h
> index 161f207..94b79c3 100644
> --- a/drivers/net/xen-netback/common.h
> +++ b/drivers/net/xen-netback/common.h
> @@ -58,10 +58,6 @@ struct xenvif {
>  	u8               fe_dev_addr[6];
>  
>  	/* Physical parameters of the comms window. */
> -	grant_handle_t   tx_shmem_handle;
> -	grant_ref_t      tx_shmem_ref;
> -	grant_handle_t   rx_shmem_handle;
> -	grant_ref_t      rx_shmem_ref;
>  	unsigned int     irq;
>  
>  	/* List of frontends to notify after a batch of frames sent. */
> @@ -70,8 +66,6 @@ struct xenvif {
>  	/* The shared rings and indexes. */
>  	struct xen_netif_tx_back_ring tx;
>  	struct xen_netif_rx_back_ring rx;
> -	struct vm_struct *tx_comms_area;
> -	struct vm_struct *rx_comms_area;
>  
>  	/* Frontend feature information. */
>  	u8 can_sg:1;
> @@ -106,6 +100,11 @@ struct xenvif {
>  	wait_queue_head_t waiting_to_free;
>  };
>  
> +static inline struct xenbus_device *xenvif_to_xenbus_device(struct xenvif *vif)
> +{
> +	return to_xenbus_device(vif->dev->dev.parent);
> +}
> +
>  #define XEN_NETIF_TX_RING_SIZE __CONST_RING_SIZE(xen_netif_tx, PAGE_SIZE)
>  #define XEN_NETIF_RX_RING_SIZE __CONST_RING_SIZE(xen_netif_rx, PAGE_SIZE)
>  
> diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
> index fd00f25..3af2924 100644
> --- a/drivers/net/xen-netback/netback.c
> +++ b/drivers/net/xen-netback/netback.c
> @@ -1577,88 +1577,42 @@ static int xen_netbk_kthread(void *data)
>  
>  void xen_netbk_unmap_frontend_rings(struct xenvif *vif)
>  {
> -	struct gnttab_unmap_grant_ref op;
> -
> -	if (vif->tx.sring) {
> -		gnttab_set_unmap_op(&op, (unsigned long)vif->tx_comms_area->addr,
> -				    GNTMAP_host_map, vif->tx_shmem_handle);
> -
> -		if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1))
> -			BUG();
> -	}
> -
> -	if (vif->rx.sring) {
> -		gnttab_set_unmap_op(&op, (unsigned long)vif->rx_comms_area->addr,
> -				    GNTMAP_host_map, vif->rx_shmem_handle);
> -
> -		if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1))
> -			BUG();
> -	}
> -	if (vif->rx_comms_area)
> -		free_vm_area(vif->rx_comms_area);
> -	if (vif->tx_comms_area)
> -		free_vm_area(vif->tx_comms_area);
> +	if (vif->tx.sring)
> +		xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(vif),
> +					vif->tx.sring);
> +	if (vif->rx.sring)
> +		xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(vif),
> +					vif->rx.sring);
>  }
>  
>  int xen_netbk_map_frontend_rings(struct xenvif *vif,
>  				 grant_ref_t tx_ring_ref,
>  				 grant_ref_t rx_ring_ref)
>  {
> -	struct gnttab_map_grant_ref op;
> +	void *addr;
>  	struct xen_netif_tx_sring *txs;
>  	struct xen_netif_rx_sring *rxs;
>  
>  	int err = -ENOMEM;
>  
> -	vif->tx_comms_area = alloc_vm_area(PAGE_SIZE);
> -	if (vif->tx_comms_area == NULL)
> +	err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(vif),
> +				     tx_ring_ref, &addr);
> +	if (err)
>  		goto err;
>  
> -	vif->rx_comms_area = alloc_vm_area(PAGE_SIZE);
> -	if (vif->rx_comms_area == NULL)
> -		goto err;
> -
> -	gnttab_set_map_op(&op, (unsigned long)vif->tx_comms_area->addr,
> -			  GNTMAP_host_map, tx_ring_ref, vif->domid);
> -
> -	if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
> -		BUG();
> -
> -	if (op.status) {
> -		netdev_warn(vif->dev,
> -			    "failed to map tx ring. err=%d status=%d\n",
> -			    err, op.status);
> -		err = op.status;
> -		goto err;
> -	}
> -
> -	vif->tx_shmem_ref    = tx_ring_ref;
> -	vif->tx_shmem_handle = op.handle;
> -
> -	txs = (struct xen_netif_tx_sring *)vif->tx_comms_area->addr;
> +	txs = (struct xen_netif_tx_sring *)addr;
>  	BACK_RING_INIT(&vif->tx, txs, PAGE_SIZE);
>  
> -	gnttab_set_map_op(&op, (unsigned long)vif->rx_comms_area->addr,
> -			  GNTMAP_host_map, rx_ring_ref, vif->domid);
> -
> -	if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
> -		BUG();
> -
> -	if (op.status) {
> -		netdev_warn(vif->dev,
> -			    "failed to map rx ring. err=%d status=%d\n",
> -			    err, op.status);
> -		err = op.status;
> +	err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(vif),
> +				     rx_ring_ref, &addr);
> +	if (err)
>  		goto err;
> -	}
> -
> -	vif->rx_shmem_ref     = rx_ring_ref;
> -	vif->rx_shmem_handle  = op.handle;
> -	vif->rx_req_cons_peek = 0;
>  
> -	rxs = (struct xen_netif_rx_sring *)vif->rx_comms_area->addr;
> +	rxs = (struct xen_netif_rx_sring *)addr;
>  	BACK_RING_INIT(&vif->rx, rxs, PAGE_SIZE);
>  
> +	vif->rx_req_cons_peek = 0;
> +
>  	return 0;
>  
>  err:
> -- 
> 1.7.2.5
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at  http://www.tux.org/lkml/

Re: [PATCH 3/4] net: xen-netback: use API provided by xenbus module to map rings

[Konrad Rzeszutek Wilk]

On Thu, Oct 20, 2011 at 11:45:18AM +0100, David Vrabel wrote:
> The xenbus module provides xenbus_map_ring_valloc() and
> xenbus_map_ring_vfree().  Use these to map the Tx and Rx ring pages
> granted by the frontend.
> 
> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
> Acked-by: Ian Campbell <ian.campbell@citrix.com>


Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

> Dave, this is a standalone patch and can be applied independently of
> the rest of the series.

.. or Dave, if you would like I can carry these patches.

> 
>  drivers/net/xen-netback/common.h  |   11 ++---
>  drivers/net/xen-netback/netback.c |   80 ++++++++-----------------------------
>  2 files changed, 22 insertions(+), 69 deletions(-)
> 
> diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h
> index 161f207..94b79c3 100644
> --- a/drivers/net/xen-netback/common.h
> +++ b/drivers/net/xen-netback/common.h
> @@ -58,10 +58,6 @@ struct xenvif {
>  	u8               fe_dev_addr[6];
>  
>  	/* Physical parameters of the comms window. */
> -	grant_handle_t   tx_shmem_handle;
> -	grant_ref_t      tx_shmem_ref;
> -	grant_handle_t   rx_shmem_handle;
> -	grant_ref_t      rx_shmem_ref;
>  	unsigned int     irq;
>  
>  	/* List of frontends to notify after a batch of frames sent. */
> @@ -70,8 +66,6 @@ struct xenvif {
>  	/* The shared rings and indexes. */
>  	struct xen_netif_tx_back_ring tx;
>  	struct xen_netif_rx_back_ring rx;
> -	struct vm_struct *tx_comms_area;
> -	struct vm_struct *rx_comms_area;
>  
>  	/* Frontend feature information. */
>  	u8 can_sg:1;
> @@ -106,6 +100,11 @@ struct xenvif {
>  	wait_queue_head_t waiting_to_free;
>  };
>  
> +static inline struct xenbus_device *xenvif_to_xenbus_device(struct xenvif *vif)
> +{
> +	return to_xenbus_device(vif->dev->dev.parent);
> +}
> +
>  #define XEN_NETIF_TX_RING_SIZE __CONST_RING_SIZE(xen_netif_tx, PAGE_SIZE)
>  #define XEN_NETIF_RX_RING_SIZE __CONST_RING_SIZE(xen_netif_rx, PAGE_SIZE)
>  
> diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
> index fd00f25..3af2924 100644
> --- a/drivers/net/xen-netback/netback.c
> +++ b/drivers/net/xen-netback/netback.c
> @@ -1577,88 +1577,42 @@ static int xen_netbk_kthread(void *data)
>  
>  void xen_netbk_unmap_frontend_rings(struct xenvif *vif)
>  {
> -	struct gnttab_unmap_grant_ref op;
> -
> -	if (vif->tx.sring) {
> -		gnttab_set_unmap_op(&op, (unsigned long)vif->tx_comms_area->addr,
> -				    GNTMAP_host_map, vif->tx_shmem_handle);
> -
> -		if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1))
> -			BUG();
> -	}
> -
> -	if (vif->rx.sring) {
> -		gnttab_set_unmap_op(&op, (unsigned long)vif->rx_comms_area->addr,
> -				    GNTMAP_host_map, vif->rx_shmem_handle);
> -
> -		if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1))
> -			BUG();
> -	}
> -	if (vif->rx_comms_area)
> -		free_vm_area(vif->rx_comms_area);
> -	if (vif->tx_comms_area)
> -		free_vm_area(vif->tx_comms_area);
> +	if (vif->tx.sring)
> +		xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(vif),
> +					vif->tx.sring);
> +	if (vif->rx.sring)
> +		xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(vif),
> +					vif->rx.sring);
>  }
>  
>  int xen_netbk_map_frontend_rings(struct xenvif *vif,
>  				 grant_ref_t tx_ring_ref,
>  				 grant_ref_t rx_ring_ref)
>  {
> -	struct gnttab_map_grant_ref op;
> +	void *addr;
>  	struct xen_netif_tx_sring *txs;
>  	struct xen_netif_rx_sring *rxs;
>  
>  	int err = -ENOMEM;
>  
> -	vif->tx_comms_area = alloc_vm_area(PAGE_SIZE);
> -	if (vif->tx_comms_area == NULL)
> +	err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(vif),
> +				     tx_ring_ref, &addr);
> +	if (err)
>  		goto err;
>  
> -	vif->rx_comms_area = alloc_vm_area(PAGE_SIZE);
> -	if (vif->rx_comms_area == NULL)
> -		goto err;
> -
> -	gnttab_set_map_op(&op, (unsigned long)vif->tx_comms_area->addr,
> -			  GNTMAP_host_map, tx_ring_ref, vif->domid);
> -
> -	if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
> -		BUG();
> -
> -	if (op.status) {
> -		netdev_warn(vif->dev,
> -			    "failed to map tx ring. err=%d status=%d\n",
> -			    err, op.status);
> -		err = op.status;
> -		goto err;
> -	}
> -
> -	vif->tx_shmem_ref    = tx_ring_ref;
> -	vif->tx_shmem_handle = op.handle;
> -
> -	txs = (struct xen_netif_tx_sring *)vif->tx_comms_area->addr;
> +	txs = (struct xen_netif_tx_sring *)addr;
>  	BACK_RING_INIT(&vif->tx, txs, PAGE_SIZE);
>  
> -	gnttab_set_map_op(&op, (unsigned long)vif->rx_comms_area->addr,
> -			  GNTMAP_host_map, rx_ring_ref, vif->domid);
> -
> -	if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
> -		BUG();
> -
> -	if (op.status) {
> -		netdev_warn(vif->dev,
> -			    "failed to map rx ring. err=%d status=%d\n",
> -			    err, op.status);
> -		err = op.status;
> +	err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(vif),
> +				     rx_ring_ref, &addr);
> +	if (err)
>  		goto err;
> -	}
> -
> -	vif->rx_shmem_ref     = rx_ring_ref;
> -	vif->rx_shmem_handle  = op.handle;
> -	vif->rx_req_cons_peek = 0;
>  
> -	rxs = (struct xen_netif_rx_sring *)vif->rx_comms_area->addr;
> +	rxs = (struct xen_netif_rx_sring *)addr;
>  	BACK_RING_INIT(&vif->rx, rxs, PAGE_SIZE);
>  
> +	vif->rx_req_cons_peek = 0;
> +
>  	return 0;
>  
>  err:
> -- 
> 1.7.2.5
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at  http://www.tux.org/lkml/

[PATCH 3/4] net: xen-netback: use API provided by xenbus module to map rings

[David Vrabel]

The xenbus module provides xenbus_map_ring_valloc() and
xenbus_map_ring_vfree().  Use these to map the Tx and Rx ring pages
granted by the frontend.

Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
---
Dave, this is a standalone patch and can be applied independently of
the rest of the series.

 drivers/net/xen-netback/common.h  |   11 ++---
 drivers/net/xen-netback/netback.c |   80 ++++++++-----------------------------
 2 files changed, 22 insertions(+), 69 deletions(-)

diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h
index 161f207..94b79c3 100644
--- a/drivers/net/xen-netback/common.h
+++ b/drivers/net/xen-netback/common.h
@@ -58,10 +58,6 @@ struct xenvif {
 	u8               fe_dev_addr[6];
 
 	/* Physical parameters of the comms window. */
-	grant_handle_t   tx_shmem_handle;
-	grant_ref_t      tx_shmem_ref;
-	grant_handle_t   rx_shmem_handle;
-	grant_ref_t      rx_shmem_ref;
 	unsigned int     irq;
 
 	/* List of frontends to notify after a batch of frames sent. */
@@ -70,8 +66,6 @@ struct xenvif {
 	/* The shared rings and indexes. */
 	struct xen_netif_tx_back_ring tx;
 	struct xen_netif_rx_back_ring rx;
-	struct vm_struct *tx_comms_area;
-	struct vm_struct *rx_comms_area;
 
 	/* Frontend feature information. */
 	u8 can_sg:1;
@@ -106,6 +100,11 @@ struct xenvif {
 	wait_queue_head_t waiting_to_free;
 };
 
+static inline struct xenbus_device *xenvif_to_xenbus_device(struct xenvif *vif)
+{
+	return to_xenbus_device(vif->dev->dev.parent);
+}
+
 #define XEN_NETIF_TX_RING_SIZE __CONST_RING_SIZE(xen_netif_tx, PAGE_SIZE)
 #define XEN_NETIF_RX_RING_SIZE __CONST_RING_SIZE(xen_netif_rx, PAGE_SIZE)
 
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index fd00f25..3af2924 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -1577,88 +1577,42 @@ static int xen_netbk_kthread(void *data)
 
 void xen_netbk_unmap_frontend_rings(struct xenvif *vif)
 {
-	struct gnttab_unmap_grant_ref op;
-
-	if (vif->tx.sring) {
-		gnttab_set_unmap_op(&op, (unsigned long)vif->tx_comms_area->addr,
-				    GNTMAP_host_map, vif->tx_shmem_handle);
-
-		if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1))
-			BUG();
-	}
-
-	if (vif->rx.sring) {
-		gnttab_set_unmap_op(&op, (unsigned long)vif->rx_comms_area->addr,
-				    GNTMAP_host_map, vif->rx_shmem_handle);
-
-		if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1))
-			BUG();
-	}
-	if (vif->rx_comms_area)
-		free_vm_area(vif->rx_comms_area);
-	if (vif->tx_comms_area)
-		free_vm_area(vif->tx_comms_area);
+	if (vif->tx.sring)
+		xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(vif),
+					vif->tx.sring);
+	if (vif->rx.sring)
+		xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(vif),
+					vif->rx.sring);
 }
 
 int xen_netbk_map_frontend_rings(struct xenvif *vif,
 				 grant_ref_t tx_ring_ref,
 				 grant_ref_t rx_ring_ref)
 {
-	struct gnttab_map_grant_ref op;
+	void *addr;
 	struct xen_netif_tx_sring *txs;
 	struct xen_netif_rx_sring *rxs;
 
 	int err = -ENOMEM;
 
-	vif->tx_comms_area = alloc_vm_area(PAGE_SIZE);
-	if (vif->tx_comms_area == NULL)
+	err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(vif),
+				     tx_ring_ref, &addr);
+	if (err)
 		goto err;
 
-	vif->rx_comms_area = alloc_vm_area(PAGE_SIZE);
-	if (vif->rx_comms_area == NULL)
-		goto err;
-
-	gnttab_set_map_op(&op, (unsigned long)vif->tx_comms_area->addr,
-			  GNTMAP_host_map, tx_ring_ref, vif->domid);
-
-	if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
-		BUG();
-
-	if (op.status) {
-		netdev_warn(vif->dev,
-			    "failed to map tx ring. err=%d status=%d\n",
-			    err, op.status);
-		err = op.status;
-		goto err;
-	}
-
-	vif->tx_shmem_ref    = tx_ring_ref;
-	vif->tx_shmem_handle = op.handle;
-
-	txs = (struct xen_netif_tx_sring *)vif->tx_comms_area->addr;
+	txs = (struct xen_netif_tx_sring *)addr;
 	BACK_RING_INIT(&vif->tx, txs, PAGE_SIZE);
 
-	gnttab_set_map_op(&op, (unsigned long)vif->rx_comms_area->addr,
-			  GNTMAP_host_map, rx_ring_ref, vif->domid);
-
-	if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
-		BUG();
-
-	if (op.status) {
-		netdev_warn(vif->dev,
-			    "failed to map rx ring. err=%d status=%d\n",
-			    err, op.status);
-		err = op.status;
+	err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(vif),
+				     rx_ring_ref, &addr);
+	if (err)
 		goto err;
-	}
-
-	vif->rx_shmem_ref     = rx_ring_ref;
-	vif->rx_shmem_handle  = op.handle;
-	vif->rx_req_cons_peek = 0;
 
-	rxs = (struct xen_netif_rx_sring *)vif->rx_comms_area->addr;
+	rxs = (struct xen_netif_rx_sring *)addr;
 	BACK_RING_INIT(&vif->rx, rxs, PAGE_SIZE);
 
+	vif->rx_req_cons_peek = 0;
+
 	return 0;
 
 err:
-- 
1.7.2.5

[PATCH 3/4] net: xen-netback: use API provided by xenbus module to map rings

[David Vrabel]

From: David Vrabel <david.vrabel@citrix.com>

The xenbus module provides xenbus_map_ring_valloc() and
xenbus_map_ring_vfree().  Use these to map the Tx and Rx ring pages
granted by the frontend.

Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
---
 drivers/net/xen-netback/common.h  |   11 ++---
 drivers/net/xen-netback/netback.c |   80 ++++++++-----------------------------
 2 files changed, 22 insertions(+), 69 deletions(-)

diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h
index 161f207..94b79c3 100644
--- a/drivers/net/xen-netback/common.h
+++ b/drivers/net/xen-netback/common.h
@@ -58,10 +58,6 @@ struct xenvif {
 	u8               fe_dev_addr[6];
 
 	/* Physical parameters of the comms window. */
-	grant_handle_t   tx_shmem_handle;
-	grant_ref_t      tx_shmem_ref;
-	grant_handle_t   rx_shmem_handle;
-	grant_ref_t      rx_shmem_ref;
 	unsigned int     irq;
 
 	/* List of frontends to notify after a batch of frames sent. */
@@ -70,8 +66,6 @@ struct xenvif {
 	/* The shared rings and indexes. */
 	struct xen_netif_tx_back_ring tx;
 	struct xen_netif_rx_back_ring rx;
-	struct vm_struct *tx_comms_area;
-	struct vm_struct *rx_comms_area;
 
 	/* Frontend feature information. */
 	u8 can_sg:1;
@@ -106,6 +100,11 @@ struct xenvif {
 	wait_queue_head_t waiting_to_free;
 };
 
+static inline struct xenbus_device *xenvif_to_xenbus_device(struct xenvif *vif)
+{
+	return to_xenbus_device(vif->dev->dev.parent);
+}
+
 #define XEN_NETIF_TX_RING_SIZE __CONST_RING_SIZE(xen_netif_tx, PAGE_SIZE)
 #define XEN_NETIF_RX_RING_SIZE __CONST_RING_SIZE(xen_netif_rx, PAGE_SIZE)
 
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index fd00f25..3af2924 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -1577,88 +1577,42 @@ static int xen_netbk_kthread(void *data)
 
 void xen_netbk_unmap_frontend_rings(struct xenvif *vif)
 {
-	struct gnttab_unmap_grant_ref op;
-
-	if (vif->tx.sring) {
-		gnttab_set_unmap_op(&op, (unsigned long)vif->tx_comms_area->addr,
-				    GNTMAP_host_map, vif->tx_shmem_handle);
-
-		if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1))
-			BUG();
-	}
-
-	if (vif->rx.sring) {
-		gnttab_set_unmap_op(&op, (unsigned long)vif->rx_comms_area->addr,
-				    GNTMAP_host_map, vif->rx_shmem_handle);
-
-		if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1))
-			BUG();
-	}
-	if (vif->rx_comms_area)
-		free_vm_area(vif->rx_comms_area);
-	if (vif->tx_comms_area)
-		free_vm_area(vif->tx_comms_area);
+	if (vif->tx.sring)
+		xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(vif),
+					vif->tx.sring);
+	if (vif->rx.sring)
+		xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(vif),
+					vif->rx.sring);
 }
 
 int xen_netbk_map_frontend_rings(struct xenvif *vif,
 				 grant_ref_t tx_ring_ref,
 				 grant_ref_t rx_ring_ref)
 {
-	struct gnttab_map_grant_ref op;
+	void *addr;
 	struct xen_netif_tx_sring *txs;
 	struct xen_netif_rx_sring *rxs;
 
 	int err = -ENOMEM;
 
-	vif->tx_comms_area = alloc_vm_area(PAGE_SIZE);
-	if (vif->tx_comms_area == NULL)
+	err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(vif),
+				     tx_ring_ref, &addr);
+	if (err)
 		goto err;
 
-	vif->rx_comms_area = alloc_vm_area(PAGE_SIZE);
-	if (vif->rx_comms_area == NULL)
-		goto err;
-
-	gnttab_set_map_op(&op, (unsigned long)vif->tx_comms_area->addr,
-			  GNTMAP_host_map, tx_ring_ref, vif->domid);
-
-	if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
-		BUG();
-
-	if (op.status) {
-		netdev_warn(vif->dev,
-			    "failed to map tx ring. err=%d status=%d\n",
-			    err, op.status);
-		err = op.status;
-		goto err;
-	}
-
-	vif->tx_shmem_ref    = tx_ring_ref;
-	vif->tx_shmem_handle = op.handle;
-
-	txs = (struct xen_netif_tx_sring *)vif->tx_comms_area->addr;
+	txs = (struct xen_netif_tx_sring *)addr;
 	BACK_RING_INIT(&vif->tx, txs, PAGE_SIZE);
 
-	gnttab_set_map_op(&op, (unsigned long)vif->rx_comms_area->addr,
-			  GNTMAP_host_map, rx_ring_ref, vif->domid);
-
-	if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
-		BUG();
-
-	if (op.status) {
-		netdev_warn(vif->dev,
-			    "failed to map rx ring. err=%d status=%d\n",
-			    err, op.status);
-		err = op.status;
+	err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(vif),
+				     rx_ring_ref, &addr);
+	if (err)
 		goto err;
-	}
-
-	vif->rx_shmem_ref     = rx_ring_ref;
-	vif->rx_shmem_handle  = op.handle;
-	vif->rx_req_cons_peek = 0;
 
-	rxs = (struct xen_netif_rx_sring *)vif->rx_comms_area->addr;
+	rxs = (struct xen_netif_rx_sring *)addr;
 	BACK_RING_INIT(&vif->rx, rxs, PAGE_SIZE);
 
+	vif->rx_req_cons_peek = 0;
+
 	return 0;
 
 err:
-- 
1.7.2.5