Paging support updates for XCP dom0

Quoted 1 line

Quoted 1 line · Andres Lagar-Cavilla

arch/x86/mm/ioremap-xen.c | 12 ++++--------

 1 files changed, 4 insertions(+), 8 deletions(-)

This change fixes the xc_map_foreign_bulk interface, which would otherwise cause SIGBUS when pages are gone because -ENOENT is not returned as expected by the IOCTL_PRIVCMD_MMAPBATCH_V2 ioctl.

Signed-off-by Jan Beulich <[email protected]>

Quoted 1 line

Quoted 1 line

Quoted 1 line

On 01.12.11 at 21:51, Andres Lagar-Cavilla <[email protected]>

Quoted 4 lines · wrote:

arch/x86/mm/ioremap-xen.c | 12 ++++--------

 1 files changed, 4 insertions(+), 8 deletions(-)

Quoted 5 lines

This change fixes the xc_map_foreign_bulk interface, which would otherwise cause SIGBUS when pages are gone because -ENOENT is not returned as expected by the IOCTL_PRIVCMD_MMAPBATCH_V2 ioctl.

Signed-off-by Jan Beulich <[email protected]>

You lost authorship here.

Jan

Quoted 11 lines

Quoted 2 lines · Andres Lagar-Cavilla

Quoted 1 line

Quoted 1 line

On 01.12.11 at 21:51, Andres Lagar-Cavilla <[email protected]>

Quoted 8 lines · wrote:

arch/x86/mm/ioremap-xen.c | 12 ++++--------

 1 files changed, 4 insertions(+), 8 deletions(-)

This change fixes the xc_map_foreign_bulk interface, which would otherwise cause SIGBUS when pages are gone because -ENOENT is not returned as expected by the IOCTL_PRIVCMD_MMAPBATCH_V2 ioctl.

Quoted 3 lines

Quoted 1 line

Signed-off-by Jan Beulich <[email protected]>

You lost authorship here.

I used this:
http://xenbits.xen.org/hg/linux-2.6.18-xen.hg/rev/0051d294bb60

Quoted 13 lines

Quoted 13 lines

Quoted 3 lines

Quoted 1 line · Andres Lagar-Cavilla

Quoted 1 line

On 01.12.11 at 21:51, Andres Lagar-Cavilla

<[email protected]>

Quoted 8 lines · wrote:

arch/x86/mm/ioremap-xen.c | 12 ++++--------

 1 files changed, 4 insertions(+), 8 deletions(-)

This change fixes the xc_map_foreign_bulk interface, which would otherwise cause SIGBUS when pages are gone because -ENOENT is not returned as expected by the IOCTL_PRIVCMD_MMAPBATCH_V2 ioctl.

Quoted 5 lines

Quoted 3 lines

Quoted 1 line

Signed-off-by Jan Beulich <[email protected]>

You lost authorship here.

I used this:
http://xenbits.xen.org/hg/linux-2.6.18-xen.hg/rev/0051d294bb60

And you dropped the "From: Olaf Hering <[email protected]>" line.

Jan

 drivers/xen/blkback/blkback.c              |   6 ++-
 drivers/xen/blkback/interface.c            |   9 +++-
 drivers/xen/core/gnttab.c                  |   4 +-
 drivers/xen/gntdev/gntdev.c                |  49 +++++++++++++++++------------
 drivers/xen/netback/interface.c            |   5 +-
 drivers/xen/netback/netback.c              |  16 ++++++---
 drivers/xen/scsiback/interface.c           |  10 +++---
 drivers/xen/scsiback/scsiback.c            |   4 +-
 drivers/xen/tpmback/interface.c            |   7 +--
 drivers/xen/tpmback/tpmback.c              |  20 ++++-------
 drivers/xen/usbback/interface.c            |  16 ++++----
 drivers/xen/usbback/usbback.c              |   4 +-
 drivers/xen/xenbus/xenbus_backend_client.c |  10 +++---
 include/xen/gnttab.h                       |  37 ++++++++++++++++++++++
 14 files changed, 126 insertions(+), 71 deletions(-)

Handle GNTST_eagain status from GNTTABOP_map_grant_ref and GNTTABOP_copy operations properly to allow usage of xenpaging without causing crashes or data corruption.

Replace all relevant HYPERVISOR_grant_table_op() calls with a retry loop. This loop is implemented as a macro to allow different GNTTABOP_* args. It will sleep up to 33 seconds and wait for the page to be paged in again.

All ->status checks were updated to use the GNTST_* namespace. All return values are converted from GNTST_* namespace to 0/-EINVAL, since all callers did not use the actual return value.

Signed-off-by Olaf Hering <[email protected]>

Acked-by Patrick Colp <[email protected]>

This is a port from xenlinux 2.6.18 to the 2.6.32 xcp tree

Signed-off-by Andres Lagar-Cavilla <[email protected]>

diff -r df9e25a0189b -r 1170bc32db41 drivers/xen/blkback/blkback.c

drivers/xen/blkback/blkback.c +4 -2

@@ -701,11 +701,13 @@ static void dispatch_rw_block_io(blkif_t
 	BUG_ON(ret);
 
 	for (i = 0; i < nseg; i++) {
-		if (unlikely(map[i].status != 0)) {
+		if (unlikely(map[i].status == GNTST_eagain))
+			gnttab_check_GNTST_eagain_do_while(GNTTABOP_map_grant_ref, &map[i]);
+		if (unlikely(map[i].status != GNTST_okay)) {
 			DPRINTK("grant map of dom %u gref %u failed: status %d\n",
 				blkif->domid, req->seg[i].gref, map[i].status);
 			map[i].handle = BLKBACK_INVALID_HANDLE;
-			ret |= 1;
+			ret = 1;
 			continue;
 		}
 

diff -r df9e25a0189b -r 1170bc32db41 drivers/xen/blkback/interface.c

drivers/xen/blkback/interface.c +6 -3

@@ -95,7 +95,7 @@ static int map_frontend_pages(blkif_t *b
 	struct vm_struct *area = blkif->blk_ring_area;
 	struct gnttab_map_grant_ref op[BLKIF_MAX_RING_PAGES];
 	unsigned int i;
-	int status = 0;
+	int status = GNTST_okay;
 
 	for (i = 0; i < nr_shared_pages; i++) {
 		unsigned long addr = (unsigned long)area->addr +

@@ -110,7 +110,10 @@ static int map_frontend_pages(blkif_t *b
 		BUG();
 
 	for (i = 0; i < nr_shared_pages; i++) {
-		if ((status = op[i].status) != 0) {
+		if (op[i].status == GNTST_eagain)
+			gnttab_check_GNTST_eagain_do_while(GNTTABOP_map_grant_ref, &op[i]);
+		if (op[i].status != GNTST_okay) {
+			status = op[i].status;
 			blkif->shmem_handle[i] = INVALID_GRANT_HANDLE;
 			continue;
 		}

@@ -120,7 +123,7 @@ static int map_frontend_pages(blkif_t *b
 
 	blkif->nr_shared_pages = nr_shared_pages;
 
-	if (status != 0) {
+	if (status != GNTST_okay) {
 		DPRINTK(" Grant table operation failure !\n");
 		unmap_frontend_pages(blkif);
 	}

diff -r df9e25a0189b -r 1170bc32db41 drivers/xen/core/gnttab.c

drivers/xen/core/gnttab.c +2 -2

@@ -773,7 +773,7 @@ static int gnttab_map(unsigned int start
 		return -ENOSYS;
 	}
 
-	BUG_ON(rc || setup.status);
+	BUG_ON(rc || (setup.status != GNTST_okay));
 
 	if (shared.raw == NULL)
 		shared.raw = arch_gnttab_alloc_shared(gframes);

@@ -901,7 +901,7 @@ int gnttab_copy_grant_page(grant_ref_t r
 	err = HYPERVISOR_grant_table_op(GNTTABOP_unmap_and_replace,
 					&unmap, 1);
 	BUG_ON(err);
-	BUG_ON(unmap.status);
+	BUG_ON(unmap.status != GNTST_okay);
 
 	write_sequnlock_irq(&gnttab_dma_lock);
 

diff -r df9e25a0189b -r 1170bc32db41 drivers/xen/gntdev/gntdev.c

drivers/xen/gntdev/gntdev.c +29 -20

@@ -503,7 +503,7 @@ static int gntdev_mmap (struct file *fli
 	uint64_t ptep;
 	int ret;
 	int flags;
-	int i;
+	int i, exit_ret;
 	struct page *page;
 	gntdev_file_private_data_t *private_data = flip->private_data;
 

@@ -578,6 +578,7 @@ static int gntdev_mmap (struct file *fli
 	vma->vm_mm->context.has_foreign_mappings = 1;
 #endif
 
+	exit_ret = -ENOMEM;
 	for (i = 0; i < size; ++i) {
 
 		flags = GNTMAP_host_map;

@@ -598,14 +599,18 @@ static int gntdev_mmap (struct file *fli
 		ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, 
 						&op, 1);
 		BUG_ON(ret);
-		if (op.status) {
-			printk(KERN_ERR "Error mapping the grant reference "
-			       "into the kernel (%d). domid = %d; ref = %d\n",
-			       op.status,
-			       private_data->grants[slot_index+i]
-			       .u.valid.domid,
-			       private_data->grants[slot_index+i]
-			       .u.valid.ref);
+		if (op.status != GNTST_okay) {
+			if (op.status != GNTST_eagain)
+				printk(KERN_ERR "Error mapping the grant reference "
+					   "into the kernel (%d). domid = %d; ref = %d\n",
+					   op.status,
+					   private_data->grants[slot_index+i]
+					   .u.valid.domid,
+					   private_data->grants[slot_index+i]
+					   .u.valid.ref);
+			else
+				/* Propagate instead of trying to fix it up */
+				exit_ret = -EAGAIN;
 			goto undo_map_out;
 		}
 

@@ -674,14 +679,17 @@ static int gntdev_mmap (struct file *fli
 			ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref,
 							&op, 1);
 			BUG_ON(ret);
-			if (op.status) {
+			if (op.status != GNTST_okay) {
 				printk(KERN_ERR "Error mapping the grant "
-				       "reference into user space (%d). domid "
-				       "= %d; ref = %d\n", op.status,
-				       private_data->grants[slot_index+i].u
-				       .valid.domid,
-				       private_data->grants[slot_index+i].u
-				       .valid.ref);
+					   "reference into user space (%d). domid "
+					   "= %d; ref = %d\n", op.status,
+					   private_data->grants[slot_index+i].u
+					   .valid.domid,
+					   private_data->grants[slot_index+i].u
+					   .valid.ref);
+				/* GNTST_eagain (i.e. page paged out) sohuld never happen
+				 * once we've mapped into kernel space */
+				BUG_ON(op.status == GNTST_eagain);
 				goto undo_map_out;
 			}
 

@@ -705,9 +713,10 @@ static int gntdev_mmap (struct file *fli
 		}
 
 	}
+	exit_ret = 0;
 
 	up_write(&private_data->grants_sem);
-	return 0;
+	return exit_ret;
 
 undo_map_out:
 	/* If we have a mapping failure, the unmapping will be taken care of

@@ -725,7 +734,7 @@ undo_map_out:
 
 	up_write(&private_data->grants_sem);
 
-	return -ENOMEM;
+	return exit_ret;
 }
 
 static pte_t gntdev_clear_pte(struct vm_area_struct *vma, unsigned long addr,

@@ -777,7 +786,7 @@ static pte_t gntdev_clear_pte(struct vm_
 			ret = HYPERVISOR_grant_table_op(
 				GNTTABOP_unmap_grant_ref, &op, 1);
 			BUG_ON(ret);
-			if (op.status)
+			if (op.status != GNTST_okay)
 				printk("User unmap grant status = %d\n", 
 				       op.status);
 		} else {

@@ -794,7 +803,7 @@ static pte_t gntdev_clear_pte(struct vm_
 		ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, 
 						&op, 1);
 		BUG_ON(ret);
-		if (op.status)
+		if (op.status != GNTST_okay)
 			printk("Kernel unmap grant status = %d\n", op.status);
 
 

diff -r df9e25a0189b -r 1170bc32db41 drivers/xen/netback/interface.c

drivers/xen/netback/interface.c +2 -3

@@ -381,10 +381,9 @@ static int map_frontend_pages(struct xen
 	gnttab_set_map_op(&op, (unsigned long)comms->ring_area->addr,
 			  GNTMAP_host_map, ring_ref, domid);
 
-	if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
-		BUG();
+	gnttab_check_GNTST_eagain_do_while(GNTTABOP_map_grant_ref, &op);
 
-	if (op.status) {
+	if (op.status != GNTST_okay) {
 		DPRINTK(" Gnttab failure mapping ring_ref!\n");
 		free_vm_area(comms->ring_area);
 		return op.status;

diff -r df9e25a0189b -r 1170bc32db41 drivers/xen/netback/netback.c

drivers/xen/netback/netback.c +11 -5

@@ -419,11 +419,13 @@ static int netbk_check_gop(int nr_copy_s
 
 	for (i = 0; i < nr_copy_slots; i++) {
 		copy_op = npo->copy + npo->copy_cons++;
+		if (copy_op->status == GNTST_eagain)
+			gnttab_check_GNTST_eagain_while(GNTTABOP_copy, copy_op);
 		if (copy_op->status != GNTST_okay) {
-				DPRINTK("Bad status %d from copy to DOM%d.\n",
-					copy_op->status, domid);
-				status = NETIF_RSP_ERROR;
-			}
+			DPRINTK("Bad status %d from copy to DOM%d.\n",
+				copy_op->status, domid);
+			status = NETIF_RSP_ERROR;
+		}
 	}
 
 	return status;

@@ -1020,7 +1022,11 @@ static int netbk_tx_check_mop(struct xen
 
 	/* Check status of header. */
 	err = mop->status;
-	if (unlikely(err)) {
+	if (err == GNTST_eagain) {
+		gnttab_check_GNTST_eagain_do_while(GNTTABOP_map_grant_ref, mop);
+		err = mop->status;
+	}
+	if (unlikely(err != GNTST_okay)) {
 		pending_ring_idx_t index;
 		index = pending_index(netbk->pending_prod++);
 		txp = &pending_tx_info[pending_idx].req;

diff -r df9e25a0189b -r 1170bc32db41 drivers/xen/scsiback/interface.c

drivers/xen/scsiback/interface.c +5 -5

@@ -69,18 +69,18 @@ static int map_frontend_page( struct vsc
 				GNTMAP_host_map, ring_ref,
 				info->domid);
 
-	err = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1);
-	BUG_ON(err);
+	gnttab_check_GNTST_eagain_do_while(GNTTABOP_map_grant_ref, &op);
 
-	if (op.status) {
-		printk(KERN_ERR "scsiback: Grant table operation failure !\n");
+	if (op.status != GNTST_okay) {
+		printk(KERN_ERR "scsiback: Grant table operation failure %d!\n", 
+							(int) op.status);
 		return op.status;
 	}
 
 	info->shmem_ref    = ring_ref;
 	info->shmem_handle = op.handle;
 
-	return (GNTST_okay);
+	return 0;
 }
 
 static void unmap_frontend_page(struct vscsibk_info *info)

diff -r df9e25a0189b -r 1170bc32db41 drivers/xen/scsiback/scsiback.c

drivers/xen/scsiback/scsiback.c +3 -1

@@ -287,7 +287,9 @@ static int scsiback_gnttab_data_map(vscs
 		for_each_sg (pending_req->sgl, sg, nr_segments, i) {
 			struct page *pg;
 
-			if (unlikely(map[i].status != 0)) {
+			if (unlikely(map[i].status == GNTST_eagain))
+				gnttab_check_GNTST_eagain_while(GNTTABOP_map_grant_ref, &map[i]);
+			if (unlikely(map[i].status != GNTST_okay)) {
 				printk(KERN_ERR "scsiback: invalid buffer -- could not remap it\n");
 				map[i].handle = SCSIBACK_INVALID_HANDLE;
 				err |= 1;

diff -r df9e25a0189b -r 1170bc32db41 drivers/xen/tpmback/interface.c

drivers/xen/tpmback/interface.c +3 -4

@@ -86,11 +86,10 @@ static int map_frontend_page(tpmif_t *tp
 	gnttab_set_map_op(&op, (unsigned long)tpmif->tx_area->addr,
 			  GNTMAP_host_map, shared_page, tpmif->domid);
 
-	if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
-		BUG();
+	gnttab_check_GNTST_eagain_do_while(GNTTABOP_map_grant_ref, &op);
 
-	if (op.status) {
-		DPRINTK(" Grant table operation failure !\n");
+	if (op.status != GNTST_okay) {
+		DPRINTK(" Grant table operation failure %d!\n", (int) op.status);
 		return op.status;
 	}
 

diff -r df9e25a0189b -r 1170bc32db41 drivers/xen/tpmback/tpmback.c

drivers/xen/tpmback/tpmback.c +8 -12

@@ -256,15 +256,13 @@ int _packet_write(struct packet *pak,
 		gnttab_set_map_op(&map_op, idx_to_kaddr(tpmif, i),
 				  GNTMAP_host_map, tx->ref, tpmif->domid);
 
-		if (unlikely(HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref,
-						       &map_op, 1))) {
-			BUG();
-		}
+		gnttab_check_GNTST_eagain_do_while(GNTTABOP_map_grant_ref, &map_op);
 
 		handle = map_op.handle;
 
-		if (map_op.status) {
-			DPRINTK(" Grant table operation failure !\n");
+		if (map_op.status != GNTST_okay) {
+			DPRINTK(" Grant table operation failure %d!\n", 
+						(int) map_op.status);
 			return 0;
 		}
 

@@ -394,13 +392,11 @@ static int packet_read_shmem(struct pack
 		gnttab_set_map_op(&map_op, idx_to_kaddr(tpmif, i),
 				  GNTMAP_host_map, tx->ref, tpmif->domid);
 
-		if (unlikely(HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref,
-						       &map_op, 1))) {
-			BUG();
-		}
+		gnttab_check_GNTST_eagain_do_while(GNTTABOP_map_grant_ref, &map_op);
 
-		if (map_op.status) {
-			DPRINTK(" Grant table operation failure !\n");
+		if (map_op.status != GNTST_okay) {
+			DPRINTK(" Grant table operation failure %d!\n",
+						(int) map_op.status);
 			return -EFAULT;
 		}
 

diff -r df9e25a0189b -r 1170bc32db41 drivers/xen/usbback/interface.c

drivers/xen/usbback/interface.c +8 -8

@@ -109,11 +109,11 @@ static int map_frontend_pages(usbif_t *u
 	gnttab_set_map_op(&op, (unsigned long)usbif->urb_ring_area->addr,
 			  GNTMAP_host_map, urb_ring_ref, usbif->domid);
 
-	if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
-		BUG();
+	gnttab_check_GNTST_eagain_do_while(GNTTABOP_map_grant_ref, &op);
 
-	if (op.status) {
-		printk(KERN_ERR "grant table failure mapping urb_ring_ref\n");
+	if (op.status != GNTST_okay) {
+		printk(KERN_ERR "grant table failure mapping urb_ring_ref %d\n",
+							(int) op.status);
 		return op.status;
 	}
 

@@ -123,17 +123,17 @@ static int map_frontend_pages(usbif_t *u
 	gnttab_set_map_op(&op, (unsigned long)usbif->conn_ring_area->addr,
 			  GNTMAP_host_map, conn_ring_ref, usbif->domid);
 
-	if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
-		BUG();
+	gnttab_check_GNTST_eagain_do_while(GNTTABOP_map_grant_ref, &op);
 
-	if (op.status) {
+	if (op.status != GNTST_okay) {
 		struct gnttab_unmap_grant_ref unop;
 		gnttab_set_unmap_op(&unop,
 				(unsigned long) usbif->urb_ring_area->addr,
 				GNTMAP_host_map, usbif->urb_shmem_handle);
 		VOID(HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &unop,
 				1));
-		printk(KERN_ERR "grant table failure mapping conn_ring_ref\n");
+		printk(KERN_ERR "grant table failure mapping conn_ring_ref %d\n",
+							(int) op.status);
 		return op.status;
 	}
 

diff -r df9e25a0189b -r 1170bc32db41 drivers/xen/usbback/usbback.c

drivers/xen/usbback/usbback.c +3 -1

@@ -428,7 +428,9 @@ static int usbbk_gnttab_map(usbif_t *usb
 		BUG_ON(ret);
 
 		for (i = 0; i < nr_segs; i++) {
-			if (unlikely(map[i].status != 0)) {
+			if (unlikely(map[i].status == GNTST_eagain))
+				gnttab_check_GNTST_eagain_while(GNTTABOP_map_grant_ref, &map[i]);
+			if (unlikely(map[i].status != GNTST_okay)) {
 				printk(KERN_ERR "usbback: invalid buffer -- could not remap it\n");
 				map[i].handle = USBBACK_INVALID_HANDLE;
 				ret |= 1;

diff -r df9e25a0189b -r 1170bc32db41 drivers/xen/xenbus/xenbus_backend_client.c

drivers/xen/xenbus/xenbus_backend_client.c +5 -5

@@ -48,8 +48,7 @@ struct vm_struct *xenbus_map_ring_valloc
 	gnttab_set_map_op(&op, (unsigned long)area->addr, GNTMAP_host_map,
 			  gnt_ref, dev->otherend_id);
 
-	if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
-		BUG();
+	gnttab_check_GNTST_eagain_do_while(GNTTABOP_map_grant_ref, &op);
 
 	if (op.status != GNTST_okay) {
 		free_vm_area(area);

@@ -75,15 +74,16 @@ int xenbus_map_ring(struct xenbus_device
 
 	gnttab_set_map_op(&op, (unsigned long)vaddr, GNTMAP_host_map,
 			  gnt_ref, dev->otherend_id);
-	if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
-		BUG();
+	gnttab_check_GNTST_eagain_do_while(GNTTABOP_map_grant_ref, &op);
 
 	if (op.status != GNTST_okay) {
 		xenbus_dev_fatal(dev, op.status,
 				 "mapping in shared page %d from domain %d",
 				 gnt_ref, dev->otherend_id);
-	} else
+	} else {
 		*handle = op.handle;
+		return 0;
+	}
 
 	return op.status;
 }

diff -r df9e25a0189b -r 1170bc32db41 include/xen/gnttab.h

include/xen/gnttab.h +37 -0

@@ -187,4 +187,41 @@ gnttab_set_replace_op(struct gnttab_unma
 	unmap->handle = handle;
 }
 
+#define gnttab_check_GNTST_eagain_while(__HCop, __HCarg_p)					\
+do {																		\
+	u8 __hc_delay = 1;														\
+	int __ret;																\
+	while (unlikely((__HCarg_p)->status == GNTST_eagain && __hc_delay)) {	\
+		msleep(__hc_delay++);												\
+		__ret = HYPERVISOR_grant_table_op(__HCop, (__HCarg_p), 1);			\
+		BUG_ON(__ret);														\
+	}																		\
+	if (__hc_delay == 0) {													\
+		printk(KERN_ERR "%s: %s gnt busy\n", __func__, current->comm);		\
+		(__HCarg_p)->status = GNTST_bad_page;								\
+	}																		\
+	if ((__HCarg_p)->status != GNTST_okay)									\
+		printk(KERN_ERR "%s: %s gnt status %x\n", 							\
+			__func__, current->comm, (__HCarg_p)->status);					\
+} while(0)
+
+#define gnttab_check_GNTST_eagain_do_while(__HCop, __HCarg_p)			\
+do {																	\
+	u8 __hc_delay = 1;													\
+	int __ret;															\
+	do {																\
+		__ret = HYPERVISOR_grant_table_op(__HCop, (__HCarg_p), 1);		\
+		BUG_ON(__ret);													\
+		if ((__HCarg_p)->status == GNTST_eagain)						\
+			msleep(__hc_delay++);										\
+	} while ((__HCarg_p)->status == GNTST_eagain && __hc_delay);		\
+	if (__hc_delay == 0) {												\
+		printk(KERN_ERR "%s: %s gnt busy\n", __func__, current->comm);	\
+		(__HCarg_p)->status = GNTST_bad_page;							\
+	}																	\
+	if ((__HCarg_p)->status != GNTST_okay)								\
+		printk(KERN_ERR "%s: %s gnt status %x\n", 						\
+			__func__, current->comm, (__HCarg_p)->status);				\
+} while(0)
+
 #endif /* __ASM_GNTTAB_H__ */

_______________________________________________
Xen-devel mailing list
[email protected]
http://lists.xensource.com/xen-devel

Quoted 27 lines

 drivers/xen/blkback/blkback.c              |   6 ++-
 drivers/xen/blkback/interface.c            |   9 +++-
 drivers/xen/core/gnttab.c                  |   4 +-
 drivers/xen/gntdev/gntdev.c                |  49
+++++++++++++++++------------
 drivers/xen/netback/interface.c            |   5 +-
 drivers/xen/netback/netback.c              |  16 ++++++---
 drivers/xen/scsiback/interface.c           |  10 +++---
 drivers/xen/scsiback/scsiback.c            |   4 +-
 drivers/xen/tpmback/interface.c            |   7 +--
 drivers/xen/tpmback/tpmback.c              |  20 ++++-------
 drivers/xen/usbback/interface.c            |  16 ++++----
 drivers/xen/usbback/usbback.c              |   4 +-
 drivers/xen/xenbus/xenbus_backend_client.c |  10 +++---
 include/xen/gnttab.h                       |  37 ++++++++++++++++++++++
 14 files changed, 126 insertions(+), 71 deletions(-)

Handle GNTST_eagain status from GNTTABOP_map_grant_ref and GNTTABOP_copy operations properly to allow usage of xenpaging without causing crashes or data corruption.

Replace all relevant HYPERVISOR_grant_table_op() calls with a retry loop. This loop is implemented as a macro to allow different GNTTABOP_* args. It will sleep up to 33 seconds and wait for the page to be paged in again.

Quoted 3 lines

All ->status checks were updated to use the GNTST_* namespace. All return values are converted from GNTST_* namespace to 0/-EINVAL, since all callers did not use the actual return value.

Any plans to do this for the pvops tree?

Quoted 484 lines

Signed-off-by Olaf Hering <[email protected]>

Acked-by Patrick Colp <[email protected]>

This is a port from xenlinux 2.6.18 to the 2.6.32 xcp tree

Signed-off-by Andres Lagar-Cavilla <[email protected]>

diff -r df9e25a0189b -r 1170bc32db41 drivers/xen/blkback/blkback.c

drivers/xen/blkback/blkback.c +4 -2

@@ -701,11 +701,13 @@ static void dispatch_rw_block_io(blkif_t
 	BUG_ON(ret);
 
 	for (i = 0; i < nseg; i++) {
-		if (unlikely(map[i].status != 0)) {
+		if (unlikely(map[i].status == GNTST_eagain))
+			gnttab_check_GNTST_eagain_do_while(GNTTABOP_map_grant_ref, &map[i]);
+		if (unlikely(map[i].status != GNTST_okay)) {
 			DPRINTK("grant map of dom %u gref %u failed: status %d\n",
 				blkif->domid, req->seg[i].gref, map[i].status);
 			map[i].handle = BLKBACK_INVALID_HANDLE;
-			ret |= 1;
+			ret = 1;
 			continue;
 		}
 

diff -r df9e25a0189b -r 1170bc32db41 drivers/xen/blkback/interface.c

drivers/xen/blkback/interface.c +6 -3

@@ -95,7 +95,7 @@ static int map_frontend_pages(blkif_t *b
 	struct vm_struct *area = blkif->blk_ring_area;
 	struct gnttab_map_grant_ref op[BLKIF_MAX_RING_PAGES];
 	unsigned int i;
-	int status = 0;
+	int status = GNTST_okay;
 
 	for (i = 0; i < nr_shared_pages; i++) {
 		unsigned long addr = (unsigned long)area->addr +

@@ -110,7 +110,10 @@ static int map_frontend_pages(blkif_t *b
 		BUG();
 
 	for (i = 0; i < nr_shared_pages; i++) {
-		if ((status = op[i].status) != 0) {
+		if (op[i].status == GNTST_eagain)
+			gnttab_check_GNTST_eagain_do_while(GNTTABOP_map_grant_ref, &op[i]);
+		if (op[i].status != GNTST_okay) {
+			status = op[i].status;
 			blkif->shmem_handle[i] = INVALID_GRANT_HANDLE;
 			continue;
 		}

@@ -120,7 +123,7 @@ static int map_frontend_pages(blkif_t *b
 
 	blkif->nr_shared_pages = nr_shared_pages;
 
-	if (status != 0) {
+	if (status != GNTST_okay) {
 		DPRINTK(" Grant table operation failure !\n");
 		unmap_frontend_pages(blkif);
 	}

diff -r df9e25a0189b -r 1170bc32db41 drivers/xen/core/gnttab.c

drivers/xen/core/gnttab.c +2 -2

@@ -773,7 +773,7 @@ static int gnttab_map(unsigned int start
 		return -ENOSYS;
 	}
 
-	BUG_ON(rc || setup.status);
+	BUG_ON(rc || (setup.status != GNTST_okay));
 
 	if (shared.raw == NULL)
 		shared.raw = arch_gnttab_alloc_shared(gframes);

@@ -901,7 +901,7 @@ int gnttab_copy_grant_page(grant_ref_t r
 	err = HYPERVISOR_grant_table_op(GNTTABOP_unmap_and_replace,
 					&unmap, 1);
 	BUG_ON(err);
-	BUG_ON(unmap.status);
+	BUG_ON(unmap.status != GNTST_okay);
 
 	write_sequnlock_irq(&gnttab_dma_lock);
 

diff -r df9e25a0189b -r 1170bc32db41 drivers/xen/gntdev/gntdev.c

drivers/xen/gntdev/gntdev.c +27 -18

@@ -503,7 +503,7 @@ static int gntdev_mmap (struct file *fli
 	uint64_t ptep;
 	int ret;
 	int flags;
-	int i;
+	int i, exit_ret;
 	struct page *page;
 	gntdev_file_private_data_t *private_data = flip->private_data;
 

@@ -578,6 +578,7 @@ static int gntdev_mmap (struct file *fli
 	vma->vm_mm->context.has_foreign_mappings = 1;
 #endif
 
+	exit_ret = -ENOMEM;
 	for (i = 0; i < size; ++i) {
 
 		flags = GNTMAP_host_map;

@@ -598,14 +599,18 @@ static int gntdev_mmap (struct file *fli
 		ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref,
 						&op, 1);
 		BUG_ON(ret);
-		if (op.status) {
-			printk(KERN_ERR "Error mapping the grant reference "
-			       "into the kernel (%d). domid = %d; ref = %d\n",
-			       op.status,
-			       private_data->grants[slot_index+i]
-			       .u.valid.domid,
-			       private_data->grants[slot_index+i]
-			       .u.valid.ref);
+		if (op.status != GNTST_okay) {
+			if (op.status != GNTST_eagain)
+				printk(KERN_ERR "Error mapping the grant reference "
+					   "into the kernel (%d). domid = %d; ref = %d\n",
+					   op.status,
+					   private_data->grants[slot_index+i]
+					   .u.valid.domid,
+					   private_data->grants[slot_index+i]
+					   .u.valid.ref);
+			else
+				/* Propagate instead of trying to fix it up */
+				exit_ret = -EAGAIN;
 			goto undo_map_out;
 		}
 

@@ -674,14 +679,17 @@ static int gntdev_mmap (struct file *fli
 			ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref,
 							&op, 1);
 			BUG_ON(ret);
-			if (op.status) {
+			if (op.status != GNTST_okay) {
 				printk(KERN_ERR "Error mapping the grant "
-				       "reference into user space (%d). domid "
-				       "= %d; ref = %d\n", op.status,
-				       private_data->grants[slot_index+i].u
-				       .valid.domid,
-				       private_data->grants[slot_index+i].u
-				       .valid.ref);
+					   "reference into user space (%d). domid "
+					   "= %d; ref = %d\n", op.status,
+					   private_data->grants[slot_index+i].u
+					   .valid.domid,
+					   private_data->grants[slot_index+i].u
+					   .valid.ref);
+				/* GNTST_eagain (i.e. page paged out) sohuld never happen
+				 * once we've mapped into kernel space */
+				BUG_ON(op.status == GNTST_eagain);
 				goto undo_map_out;
 			}
 

@@ -705,9 +713,10 @@ static int gntdev_mmap (struct file *fli
 		}
 
 	}
+	exit_ret = 0;
 
 	up_write(&private_data->grants_sem);
-	return 0;
+	return exit_ret;
 
 undo_map_out:
 	/* If we have a mapping failure, the unmapping will be taken care of

@@ -725,7 +734,7 @@ undo_map_out:
 
 	up_write(&private_data->grants_sem);
 
-	return -ENOMEM;
+	return exit_ret;
 }
 
 static pte_t gntdev_clear_pte(struct vm_area_struct *vma, unsigned long

addr,

drivers/xen/gntdev/gntdev.c +2 -2

@@ -777,7 +786,7 @@ static pte_t gntdev_clear_pte(struct vm_
 			ret = HYPERVISOR_grant_table_op(
 				GNTTABOP_unmap_grant_ref, &op, 1);
 			BUG_ON(ret);
-			if (op.status)
+			if (op.status != GNTST_okay)
 				printk("User unmap grant status = %d\n",
 				       op.status);
 		} else {

@@ -794,7 +803,7 @@ static pte_t gntdev_clear_pte(struct vm_
 		ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref,
 						&op, 1);
 		BUG_ON(ret);
-		if (op.status)
+		if (op.status != GNTST_okay)
 			printk("Kernel unmap grant status = %d\n", op.status);
 
 

diff -r df9e25a0189b -r 1170bc32db41 drivers/xen/netback/interface.c

drivers/xen/netback/interface.c +2 -3

@@ -381,10 +381,9 @@ static int map_frontend_pages(struct xen
 	gnttab_set_map_op(&op, (unsigned long)comms->ring_area->addr,
 			  GNTMAP_host_map, ring_ref, domid);
 
-	if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
-		BUG();
+	gnttab_check_GNTST_eagain_do_while(GNTTABOP_map_grant_ref, &op);
 
-	if (op.status) {
+	if (op.status != GNTST_okay) {
 		DPRINTK(" Gnttab failure mapping ring_ref!\n");
 		free_vm_area(comms->ring_area);
 		return op.status;

diff -r df9e25a0189b -r 1170bc32db41 drivers/xen/netback/netback.c

drivers/xen/netback/netback.c +11 -5

@@ -419,11 +419,13 @@ static int netbk_check_gop(int nr_copy_s
 
 	for (i = 0; i < nr_copy_slots; i++) {
 		copy_op = npo->copy + npo->copy_cons++;
+		if (copy_op->status == GNTST_eagain)
+			gnttab_check_GNTST_eagain_while(GNTTABOP_copy, copy_op);
 		if (copy_op->status != GNTST_okay) {
-				DPRINTK("Bad status %d from copy to DOM%d.\n",
-					copy_op->status, domid);
-				status = NETIF_RSP_ERROR;
-			}
+			DPRINTK("Bad status %d from copy to DOM%d.\n",
+				copy_op->status, domid);
+			status = NETIF_RSP_ERROR;
+		}
 	}
 
 	return status;

@@ -1020,7 +1022,11 @@ static int netbk_tx_check_mop(struct xen
 
 	/* Check status of header. */
 	err = mop->status;
-	if (unlikely(err)) {
+	if (err == GNTST_eagain) {
+		gnttab_check_GNTST_eagain_do_while(GNTTABOP_map_grant_ref, mop);
+		err = mop->status;
+	}
+	if (unlikely(err != GNTST_okay)) {
 		pending_ring_idx_t index;
 		index = pending_index(netbk->pending_prod++);
 		txp = &pending_tx_info[pending_idx].req;

diff -r df9e25a0189b -r 1170bc32db41 drivers/xen/scsiback/interface.c

drivers/xen/scsiback/interface.c +5 -5

@@ -69,18 +69,18 @@ static int map_frontend_page( struct vsc
 				GNTMAP_host_map, ring_ref,
 				info->domid);
 
-	err = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1);
-	BUG_ON(err);
+	gnttab_check_GNTST_eagain_do_while(GNTTABOP_map_grant_ref, &op);
 
-	if (op.status) {
-		printk(KERN_ERR "scsiback: Grant table operation failure !\n");
+	if (op.status != GNTST_okay) {
+		printk(KERN_ERR "scsiback: Grant table operation failure %d!\n",
+							(int) op.status);
 		return op.status;
 	}
 
 	info->shmem_ref    = ring_ref;
 	info->shmem_handle = op.handle;
 
-	return (GNTST_okay);
+	return 0;
 }
 
 static void unmap_frontend_page(struct vscsibk_info *info)

diff -r df9e25a0189b -r 1170bc32db41 drivers/xen/scsiback/scsiback.c

drivers/xen/scsiback/scsiback.c +3 -1

@@ -287,7 +287,9 @@ static int scsiback_gnttab_data_map(vscs
 		for_each_sg (pending_req->sgl, sg, nr_segments, i) {
 			struct page *pg;
 
-			if (unlikely(map[i].status != 0)) {
+			if (unlikely(map[i].status == GNTST_eagain))
+				gnttab_check_GNTST_eagain_while(GNTTABOP_map_grant_ref, &map[i]);
+			if (unlikely(map[i].status != GNTST_okay)) {
 				printk(KERN_ERR "scsiback: invalid buffer -- could not remap
 it\n");
 				map[i].handle = SCSIBACK_INVALID_HANDLE;

err |= 1;
diff -r df9e25a0189b -r 1170bc32db41 drivers/xen/tpmback/interface.c

drivers/xen/tpmback/interface.c +3 -4

@@ -86,11 +86,10 @@ static int map_frontend_page(tpmif_t *tp
 	gnttab_set_map_op(&op, (unsigned long)tpmif->tx_area->addr,
 			  GNTMAP_host_map, shared_page, tpmif->domid);
 
-	if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
-		BUG();
+	gnttab_check_GNTST_eagain_do_while(GNTTABOP_map_grant_ref, &op);
 
-	if (op.status) {
-		DPRINTK(" Grant table operation failure !\n");
+	if (op.status != GNTST_okay) {
+		DPRINTK(" Grant table operation failure %d!\n", (int) op.status);
 		return op.status;
 	}
 

diff -r df9e25a0189b -r 1170bc32db41 drivers/xen/tpmback/tpmback.c

drivers/xen/tpmback/tpmback.c +8 -12

@@ -256,15 +256,13 @@ int _packet_write(struct packet *pak,
 		gnttab_set_map_op(&map_op, idx_to_kaddr(tpmif, i),
 				  GNTMAP_host_map, tx->ref, tpmif->domid);
 
-		if (unlikely(HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref,
-						       &map_op, 1))) {
-			BUG();
-		}
+		gnttab_check_GNTST_eagain_do_while(GNTTABOP_map_grant_ref, &map_op);
 
 		handle = map_op.handle;
 
-		if (map_op.status) {
-			DPRINTK(" Grant table operation failure !\n");
+		if (map_op.status != GNTST_okay) {
+			DPRINTK(" Grant table operation failure %d!\n",
+						(int) map_op.status);
 			return 0;
 		}
 

@@ -394,13 +392,11 @@ static int packet_read_shmem(struct pack
 		gnttab_set_map_op(&map_op, idx_to_kaddr(tpmif, i),
 				  GNTMAP_host_map, tx->ref, tpmif->domid);
 
-		if (unlikely(HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref,
-						       &map_op, 1))) {
-			BUG();
-		}
+		gnttab_check_GNTST_eagain_do_while(GNTTABOP_map_grant_ref, &map_op);
 
-		if (map_op.status) {
-			DPRINTK(" Grant table operation failure !\n");
+		if (map_op.status != GNTST_okay) {
+			DPRINTK(" Grant table operation failure %d!\n",
+						(int) map_op.status);
 			return -EFAULT;
 		}
 

diff -r df9e25a0189b -r 1170bc32db41 drivers/xen/usbback/interface.c

drivers/xen/usbback/interface.c +8 -8

@@ -109,11 +109,11 @@ static int map_frontend_pages(usbif_t *u
 	gnttab_set_map_op(&op, (unsigned long)usbif->urb_ring_area->addr,
 			  GNTMAP_host_map, urb_ring_ref, usbif->domid);
 
-	if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
-		BUG();
+	gnttab_check_GNTST_eagain_do_while(GNTTABOP_map_grant_ref, &op);
 
-	if (op.status) {
-		printk(KERN_ERR "grant table failure mapping urb_ring_ref\n");
+	if (op.status != GNTST_okay) {
+		printk(KERN_ERR "grant table failure mapping urb_ring_ref %d\n",
+							(int) op.status);
 		return op.status;
 	}
 

@@ -123,17 +123,17 @@ static int map_frontend_pages(usbif_t *u
 	gnttab_set_map_op(&op, (unsigned long)usbif->conn_ring_area->addr,
 			  GNTMAP_host_map, conn_ring_ref, usbif->domid);
 
-	if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
-		BUG();
+	gnttab_check_GNTST_eagain_do_while(GNTTABOP_map_grant_ref, &op);
 
-	if (op.status) {
+	if (op.status != GNTST_okay) {
 		struct gnttab_unmap_grant_ref unop;
 		gnttab_set_unmap_op(&unop,
 				(unsigned long) usbif->urb_ring_area->addr,
 				GNTMAP_host_map, usbif->urb_shmem_handle);
 		VOID(HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &unop,
 				1));
-		printk(KERN_ERR "grant table failure mapping conn_ring_ref\n");
+		printk(KERN_ERR "grant table failure mapping conn_ring_ref %d\n",
+							(int) op.status);
 		return op.status;
 	}
 

diff -r df9e25a0189b -r 1170bc32db41 drivers/xen/usbback/usbback.c

drivers/xen/usbback/usbback.c +3 -1

@@ -428,7 +428,9 @@ static int usbbk_gnttab_map(usbif_t *usb
 		BUG_ON(ret);
 
 		for (i = 0; i < nr_segs; i++) {
-			if (unlikely(map[i].status != 0)) {
+			if (unlikely(map[i].status == GNTST_eagain))
+				gnttab_check_GNTST_eagain_while(GNTTABOP_map_grant_ref, &map[i]);
+			if (unlikely(map[i].status != GNTST_okay)) {
 				printk(KERN_ERR "usbback: invalid buffer -- could not remap it\n");
 				map[i].handle = USBBACK_INVALID_HANDLE;
 				ret |= 1;

diff -r df9e25a0189b -r 1170bc32db41
drivers/xen/xenbus/xenbus_backend_client.c

drivers/xen/xenbus/xenbus_backend_client.c +5 -5

@@ -48,8 +48,7 @@ struct vm_struct *xenbus_map_ring_valloc
 	gnttab_set_map_op(&op, (unsigned long)area->addr, GNTMAP_host_map,
 			  gnt_ref, dev->otherend_id);
 
-	if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
-		BUG();
+	gnttab_check_GNTST_eagain_do_while(GNTTABOP_map_grant_ref, &op);
 
 	if (op.status != GNTST_okay) {
 		free_vm_area(area);

@@ -75,15 +74,16 @@ int xenbus_map_ring(struct xenbus_device
 
 	gnttab_set_map_op(&op, (unsigned long)vaddr, GNTMAP_host_map,
 			  gnt_ref, dev->otherend_id);
-	if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
-		BUG();
+	gnttab_check_GNTST_eagain_do_while(GNTTABOP_map_grant_ref, &op);
 
 	if (op.status != GNTST_okay) {
 		xenbus_dev_fatal(dev, op.status,
 				 "mapping in shared page %d from domain %d",
 				 gnt_ref, dev->otherend_id);
-	} else
+	} else {
 		*handle = op.handle;
+		return 0;
+	}
 
 	return op.status;
 }

diff -r df9e25a0189b -r 1170bc32db41 include/xen/gnttab.h

include/xen/gnttab.h +37 -0

@@ -187,4 +187,41 @@ gnttab_set_replace_op(struct gnttab_unma
 	unmap->handle = handle;
 }
 
+#define gnttab_check_GNTST_eagain_while(__HCop, __HCarg_p)					\
+do {																		\
+	u8 __hc_delay = 1;														\
+	int __ret;																\
+	while (unlikely((__HCarg_p)->status == GNTST_eagain && __hc_delay))
 {	\
+		msleep(__hc_delay++);												\
+		__ret = HYPERVISOR_grant_table_op(__HCop, (__HCarg_p), 1);			\
+		BUG_ON(__ret);														\
+	}																		\
+	if (__hc_delay == 0) {													\
+		printk(KERN_ERR "%s: %s gnt busy\n", __func__, current->comm);		\
+		(__HCarg_p)->status = GNTST_bad_page;								\
+	}																		\
+	if ((__HCarg_p)->status != GNTST_okay)									\
+		printk(KERN_ERR "%s: %s gnt status %x\n", 							\
+			__func__, current->comm, (__HCarg_p)->status);					\
+} while(0)
+
+#define gnttab_check_GNTST_eagain_do_while(__HCop, __HCarg_p)			\
+do {																	\
+	u8 __hc_delay = 1;													\
+	int __ret;															\
+	do {																\
+		__ret = HYPERVISOR_grant_table_op(__HCop, (__HCarg_p), 1);		\
+		BUG_ON(__ret);													\
+		if ((__HCarg_p)->status == GNTST_eagain)						\
+			msleep(__hc_delay++);										\
+	} while ((__HCarg_p)->status == GNTST_eagain && __hc_delay);		\
+	if (__hc_delay == 0) {												\
+		printk(KERN_ERR "%s: %s gnt busy\n", __func__, current->comm);	\
+		(__HCarg_p)->status = GNTST_bad_page;							\
+	}																	\
+	if ((__HCarg_p)->status != GNTST_okay)								\
+		printk(KERN_ERR "%s: %s gnt status %x\n", 						\
+			__func__, current->comm, (__HCarg_p)->status);				\
+} while(0)
+

#endif /* __ASM_GNTTAB_H__ */

_______________________________________________
Xen-devel mailing list
[email protected]
http://lists.xensource.com/xen-devel

Quoted 28 lines · Andres Lagar-Cavilla

Quoted 27 lines

 drivers/xen/blkback/blkback.c              |   6 ++-
 drivers/xen/blkback/interface.c            |   9 +++-
 drivers/xen/core/gnttab.c                  |   4 +-
 drivers/xen/gntdev/gntdev.c                |  49
+++++++++++++++++------------
 drivers/xen/netback/interface.c            |   5 +-
 drivers/xen/netback/netback.c              |  16 ++++++---
 drivers/xen/scsiback/interface.c           |  10 +++---
 drivers/xen/scsiback/scsiback.c            |   4 +-
 drivers/xen/tpmback/interface.c            |   7 +--
 drivers/xen/tpmback/tpmback.c              |  20 ++++-------
 drivers/xen/usbback/interface.c            |  16 ++++----
 drivers/xen/usbback/usbback.c              |   4 +-
 drivers/xen/xenbus/xenbus_backend_client.c |  10 +++---
 include/xen/gnttab.h                       |  37 ++++++++++++++++++++++
 14 files changed, 126 insertions(+), 71 deletions(-)

Handle GNTST_eagain status from GNTTABOP_map_grant_ref and GNTTABOP_copy operations properly to allow usage of xenpaging without causing crashes or data corruption.

Replace all relevant HYPERVISOR_grant_table_op() calls with a retry loop. This loop is implemented as a macro to allow different GNTTABOP_* args. It will sleep up to 33 seconds and wait for the page to be paged in again.

Quoted 5 lines

Quoted 3 lines

All ->status checks were updated to use the GNTST_* namespace. All return values are converted from GNTST_* namespace to 0/-EINVAL, since all callers did not use the actual return value.

Any plans to do this for the pvops tree?

Slowly but surely. Working with XCP presently, so pvops is not at the top of my stack. Do you want to get at a specific merge window?

Andres

Quoted 480 lines

Quoted 480 lines

Signed-off-by Olaf Hering <[email protected]>

Acked-by Patrick Colp <[email protected]>

This is a port from xenlinux 2.6.18 to the 2.6.32 xcp tree

Signed-off-by Andres Lagar-Cavilla <[email protected]>

diff -r df9e25a0189b -r 1170bc32db41 drivers/xen/blkback/blkback.c

drivers/xen/blkback/blkback.c +4 -2

@@ -701,11 +701,13 @@ static void dispatch_rw_block_io(blkif_t
 	BUG_ON(ret);
 
 	for (i = 0; i < nseg; i++) {
-		if (unlikely(map[i].status != 0)) {
+		if (unlikely(map[i].status == GNTST_eagain))
+			gnttab_check_GNTST_eagain_do_while(GNTTABOP_map_grant_ref, &map[i]);
+		if (unlikely(map[i].status != GNTST_okay)) {
 			DPRINTK("grant map of dom %u gref %u failed: status %d\n",
 				blkif->domid, req->seg[i].gref, map[i].status);
 			map[i].handle = BLKBACK_INVALID_HANDLE;
-			ret |= 1;
+			ret = 1;
 			continue;
 		}
 

diff -r df9e25a0189b -r 1170bc32db41 drivers/xen/blkback/interface.c

drivers/xen/blkback/interface.c +6 -3

@@ -95,7 +95,7 @@ static int map_frontend_pages(blkif_t *b
 	struct vm_struct *area = blkif->blk_ring_area;
 	struct gnttab_map_grant_ref op[BLKIF_MAX_RING_PAGES];
 	unsigned int i;
-	int status = 0;
+	int status = GNTST_okay;
 
 	for (i = 0; i < nr_shared_pages; i++) {
 		unsigned long addr = (unsigned long)area->addr +

@@ -110,7 +110,10 @@ static int map_frontend_pages(blkif_t *b
 		BUG();
 
 	for (i = 0; i < nr_shared_pages; i++) {
-		if ((status = op[i].status) != 0) {
+		if (op[i].status == GNTST_eagain)
+			gnttab_check_GNTST_eagain_do_while(GNTTABOP_map_grant_ref, &op[i]);
+		if (op[i].status != GNTST_okay) {
+			status = op[i].status;
 			blkif->shmem_handle[i] = INVALID_GRANT_HANDLE;
 			continue;
 		}

@@ -120,7 +123,7 @@ static int map_frontend_pages(blkif_t *b
 
 	blkif->nr_shared_pages = nr_shared_pages;
 
-	if (status != 0) {
+	if (status != GNTST_okay) {
 		DPRINTK(" Grant table operation failure !\n");
 		unmap_frontend_pages(blkif);
 	}

diff -r df9e25a0189b -r 1170bc32db41 drivers/xen/core/gnttab.c

drivers/xen/core/gnttab.c +2 -2

@@ -773,7 +773,7 @@ static int gnttab_map(unsigned int start
 		return -ENOSYS;
 	}
 
-	BUG_ON(rc || setup.status);
+	BUG_ON(rc || (setup.status != GNTST_okay));
 
 	if (shared.raw == NULL)
 		shared.raw = arch_gnttab_alloc_shared(gframes);

@@ -901,7 +901,7 @@ int gnttab_copy_grant_page(grant_ref_t r
 	err = HYPERVISOR_grant_table_op(GNTTABOP_unmap_and_replace,
 					&unmap, 1);
 	BUG_ON(err);
-	BUG_ON(unmap.status);
+	BUG_ON(unmap.status != GNTST_okay);
 
 	write_sequnlock_irq(&gnttab_dma_lock);
 

diff -r df9e25a0189b -r 1170bc32db41 drivers/xen/gntdev/gntdev.c

drivers/xen/gntdev/gntdev.c +27 -18

@@ -503,7 +503,7 @@ static int gntdev_mmap (struct file *fli
 	uint64_t ptep;
 	int ret;
 	int flags;
-	int i;
+	int i, exit_ret;
 	struct page *page;
 	gntdev_file_private_data_t *private_data = flip->private_data;
 

@@ -578,6 +578,7 @@ static int gntdev_mmap (struct file *fli
 	vma->vm_mm->context.has_foreign_mappings = 1;
 #endif
 
+	exit_ret = -ENOMEM;
 	for (i = 0; i < size; ++i) {
 
 		flags = GNTMAP_host_map;

@@ -598,14 +599,18 @@ static int gntdev_mmap (struct file *fli
 		ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref,
 						&op, 1);
 		BUG_ON(ret);
-		if (op.status) {
-			printk(KERN_ERR "Error mapping the grant reference "
-			       "into the kernel (%d). domid = %d; ref = %d\n",
-			       op.status,
-			       private_data->grants[slot_index+i]
-			       .u.valid.domid,
-			       private_data->grants[slot_index+i]
-			       .u.valid.ref);
+		if (op.status != GNTST_okay) {
+			if (op.status != GNTST_eagain)
+				printk(KERN_ERR "Error mapping the grant reference "
+					   "into the kernel (%d). domid = %d; ref = %d\n",
+					   op.status,
+					   private_data->grants[slot_index+i]
+					   .u.valid.domid,
+					   private_data->grants[slot_index+i]
+					   .u.valid.ref);
+			else
+				/* Propagate instead of trying to fix it up */
+				exit_ret = -EAGAIN;
 			goto undo_map_out;
 		}
 

@@ -674,14 +679,17 @@ static int gntdev_mmap (struct file *fli
 			ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref,
 							&op, 1);
 			BUG_ON(ret);
-			if (op.status) {
+			if (op.status != GNTST_okay) {
 				printk(KERN_ERR "Error mapping the grant "
-				       "reference into user space (%d). domid "
-				       "= %d; ref = %d\n", op.status,
-				       private_data->grants[slot_index+i].u
-				       .valid.domid,
-				       private_data->grants[slot_index+i].u
-				       .valid.ref);
+					   "reference into user space (%d). domid "
+					   "= %d; ref = %d\n", op.status,
+					   private_data->grants[slot_index+i].u
+					   .valid.domid,
+					   private_data->grants[slot_index+i].u
+					   .valid.ref);
+				/* GNTST_eagain (i.e. page paged out) sohuld never happen
+				 * once we've mapped into kernel space */
+				BUG_ON(op.status == GNTST_eagain);
 				goto undo_map_out;
 			}
 

@@ -705,9 +713,10 @@ static int gntdev_mmap (struct file *fli
 		}
 
 	}
+	exit_ret = 0;
 
 	up_write(&private_data->grants_sem);
-	return 0;
+	return exit_ret;
 
 undo_map_out:
 	/* If we have a mapping failure, the unmapping will be taken care of

@@ -725,7 +734,7 @@ undo_map_out:
 
 	up_write(&private_data->grants_sem);
 
-	return -ENOMEM;
+	return exit_ret;
 }
 
 static pte_t gntdev_clear_pte(struct vm_area_struct *vma, unsigned long

addr,

drivers/xen/gntdev/gntdev.c +2 -2

@@ -777,7 +786,7 @@ static pte_t gntdev_clear_pte(struct vm_
 			ret = HYPERVISOR_grant_table_op(
 				GNTTABOP_unmap_grant_ref, &op, 1);
 			BUG_ON(ret);
-			if (op.status)
+			if (op.status != GNTST_okay)
 				printk("User unmap grant status = %d\n",
 				       op.status);
 		} else {

@@ -794,7 +803,7 @@ static pte_t gntdev_clear_pte(struct vm_
 		ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref,
 						&op, 1);
 		BUG_ON(ret);
-		if (op.status)
+		if (op.status != GNTST_okay)
 			printk("Kernel unmap grant status = %d\n", op.status);
 
 

diff -r df9e25a0189b -r 1170bc32db41 drivers/xen/netback/interface.c

drivers/xen/netback/interface.c +2 -3

@@ -381,10 +381,9 @@ static int map_frontend_pages(struct xen
 	gnttab_set_map_op(&op, (unsigned long)comms->ring_area->addr,
 			  GNTMAP_host_map, ring_ref, domid);
 
-	if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
-		BUG();
+	gnttab_check_GNTST_eagain_do_while(GNTTABOP_map_grant_ref, &op);
 
-	if (op.status) {
+	if (op.status != GNTST_okay) {
 		DPRINTK(" Gnttab failure mapping ring_ref!\n");
 		free_vm_area(comms->ring_area);
 		return op.status;

diff -r df9e25a0189b -r 1170bc32db41 drivers/xen/netback/netback.c

drivers/xen/netback/netback.c +11 -5

@@ -419,11 +419,13 @@ static int netbk_check_gop(int nr_copy_s
 
 	for (i = 0; i < nr_copy_slots; i++) {
 		copy_op = npo->copy + npo->copy_cons++;
+		if (copy_op->status == GNTST_eagain)
+			gnttab_check_GNTST_eagain_while(GNTTABOP_copy, copy_op);
 		if (copy_op->status != GNTST_okay) {
-				DPRINTK("Bad status %d from copy to DOM%d.\n",
-					copy_op->status, domid);
-				status = NETIF_RSP_ERROR;
-			}
+			DPRINTK("Bad status %d from copy to DOM%d.\n",
+				copy_op->status, domid);
+			status = NETIF_RSP_ERROR;
+		}
 	}
 
 	return status;

@@ -1020,7 +1022,11 @@ static int netbk_tx_check_mop(struct xen
 
 	/* Check status of header. */
 	err = mop->status;
-	if (unlikely(err)) {
+	if (err == GNTST_eagain) {
+		gnttab_check_GNTST_eagain_do_while(GNTTABOP_map_grant_ref, mop);
+		err = mop->status;
+	}
+	if (unlikely(err != GNTST_okay)) {
 		pending_ring_idx_t index;
 		index = pending_index(netbk->pending_prod++);
 		txp = &pending_tx_info[pending_idx].req;

diff -r df9e25a0189b -r 1170bc32db41 drivers/xen/scsiback/interface.c

drivers/xen/scsiback/interface.c +5 -5

@@ -69,18 +69,18 @@ static int map_frontend_page( struct vsc
 				GNTMAP_host_map, ring_ref,
 				info->domid);
 
-	err = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1);
-	BUG_ON(err);
+	gnttab_check_GNTST_eagain_do_while(GNTTABOP_map_grant_ref, &op);
 
-	if (op.status) {
-		printk(KERN_ERR "scsiback: Grant table operation failure !\n");
+	if (op.status != GNTST_okay) {
+		printk(KERN_ERR "scsiback: Grant table operation failure %d!\n",
+							(int) op.status);
 		return op.status;
 	}
 
 	info->shmem_ref    = ring_ref;
 	info->shmem_handle = op.handle;
 
-	return (GNTST_okay);
+	return 0;
 }
 
 static void unmap_frontend_page(struct vscsibk_info *info)

diff -r df9e25a0189b -r 1170bc32db41 drivers/xen/scsiback/scsiback.c

drivers/xen/scsiback/scsiback.c +3 -1

@@ -287,7 +287,9 @@ static int scsiback_gnttab_data_map(vscs
 		for_each_sg (pending_req->sgl, sg, nr_segments, i) {
 			struct page *pg;
 
-			if (unlikely(map[i].status != 0)) {
+			if (unlikely(map[i].status == GNTST_eagain))
+				gnttab_check_GNTST_eagain_while(GNTTABOP_map_grant_ref, &map[i]);
+			if (unlikely(map[i].status != GNTST_okay)) {
 				printk(KERN_ERR "scsiback: invalid buffer -- could not remap
 it\n");
 				map[i].handle = SCSIBACK_INVALID_HANDLE;

err |= 1;
diff -r df9e25a0189b -r 1170bc32db41 drivers/xen/tpmback/interface.c

drivers/xen/tpmback/interface.c +3 -4

@@ -86,11 +86,10 @@ static int map_frontend_page(tpmif_t *tp
 	gnttab_set_map_op(&op, (unsigned long)tpmif->tx_area->addr,
 			  GNTMAP_host_map, shared_page, tpmif->domid);
 
-	if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
-		BUG();
+	gnttab_check_GNTST_eagain_do_while(GNTTABOP_map_grant_ref, &op);
 
-	if (op.status) {
-		DPRINTK(" Grant table operation failure !\n");
+	if (op.status != GNTST_okay) {
+		DPRINTK(" Grant table operation failure %d!\n", (int) op.status);
 		return op.status;
 	}
 

diff -r df9e25a0189b -r 1170bc32db41 drivers/xen/tpmback/tpmback.c

drivers/xen/tpmback/tpmback.c +8 -12

@@ -256,15 +256,13 @@ int _packet_write(struct packet *pak,
 		gnttab_set_map_op(&map_op, idx_to_kaddr(tpmif, i),
 				  GNTMAP_host_map, tx->ref, tpmif->domid);
 
-		if (unlikely(HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref,
-						       &map_op, 1))) {
-			BUG();
-		}
+		gnttab_check_GNTST_eagain_do_while(GNTTABOP_map_grant_ref, &map_op);
 
 		handle = map_op.handle;
 
-		if (map_op.status) {
-			DPRINTK(" Grant table operation failure !\n");
+		if (map_op.status != GNTST_okay) {
+			DPRINTK(" Grant table operation failure %d!\n",
+						(int) map_op.status);
 			return 0;
 		}
 

@@ -394,13 +392,11 @@ static int packet_read_shmem(struct pack
 		gnttab_set_map_op(&map_op, idx_to_kaddr(tpmif, i),
 				  GNTMAP_host_map, tx->ref, tpmif->domid);
 
-		if (unlikely(HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref,
-						       &map_op, 1))) {
-			BUG();
-		}
+		gnttab_check_GNTST_eagain_do_while(GNTTABOP_map_grant_ref, &map_op);
 
-		if (map_op.status) {
-			DPRINTK(" Grant table operation failure !\n");
+		if (map_op.status != GNTST_okay) {
+			DPRINTK(" Grant table operation failure %d!\n",
+						(int) map_op.status);
 			return -EFAULT;
 		}
 

diff -r df9e25a0189b -r 1170bc32db41 drivers/xen/usbback/interface.c

drivers/xen/usbback/interface.c +8 -8

@@ -109,11 +109,11 @@ static int map_frontend_pages(usbif_t *u
 	gnttab_set_map_op(&op, (unsigned long)usbif->urb_ring_area->addr,
 			  GNTMAP_host_map, urb_ring_ref, usbif->domid);
 
-	if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
-		BUG();
+	gnttab_check_GNTST_eagain_do_while(GNTTABOP_map_grant_ref, &op);
 
-	if (op.status) {
-		printk(KERN_ERR "grant table failure mapping urb_ring_ref\n");
+	if (op.status != GNTST_okay) {
+		printk(KERN_ERR "grant table failure mapping urb_ring_ref %d\n",
+							(int) op.status);
 		return op.status;
 	}
 

@@ -123,17 +123,17 @@ static int map_frontend_pages(usbif_t *u
 	gnttab_set_map_op(&op, (unsigned long)usbif->conn_ring_area->addr,
 			  GNTMAP_host_map, conn_ring_ref, usbif->domid);
 
-	if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
-		BUG();
+	gnttab_check_GNTST_eagain_do_while(GNTTABOP_map_grant_ref, &op);
 
-	if (op.status) {
+	if (op.status != GNTST_okay) {
 		struct gnttab_unmap_grant_ref unop;
 		gnttab_set_unmap_op(&unop,
 				(unsigned long) usbif->urb_ring_area->addr,
 				GNTMAP_host_map, usbif->urb_shmem_handle);
 		VOID(HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &unop,
 				1));
-		printk(KERN_ERR "grant table failure mapping conn_ring_ref\n");
+		printk(KERN_ERR "grant table failure mapping conn_ring_ref %d\n",
+							(int) op.status);
 		return op.status;
 	}
 

diff -r df9e25a0189b -r 1170bc32db41 drivers/xen/usbback/usbback.c

drivers/xen/usbback/usbback.c +3 -1

@@ -428,7 +428,9 @@ static int usbbk_gnttab_map(usbif_t *usb
 		BUG_ON(ret);
 
 		for (i = 0; i < nr_segs; i++) {
-			if (unlikely(map[i].status != 0)) {
+			if (unlikely(map[i].status == GNTST_eagain))
+				gnttab_check_GNTST_eagain_while(GNTTABOP_map_grant_ref, &map[i]);
+			if (unlikely(map[i].status != GNTST_okay)) {
 				printk(KERN_ERR "usbback: invalid buffer -- could not remap it\n");
 				map[i].handle = USBBACK_INVALID_HANDLE;
 				ret |= 1;

diff -r df9e25a0189b -r 1170bc32db41
drivers/xen/xenbus/xenbus_backend_client.c

drivers/xen/xenbus/xenbus_backend_client.c +5 -5

@@ -48,8 +48,7 @@ struct vm_struct *xenbus_map_ring_valloc
 	gnttab_set_map_op(&op, (unsigned long)area->addr, GNTMAP_host_map,
 			  gnt_ref, dev->otherend_id);
 
-	if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
-		BUG();
+	gnttab_check_GNTST_eagain_do_while(GNTTABOP_map_grant_ref, &op);
 
 	if (op.status != GNTST_okay) {
 		free_vm_area(area);

@@ -75,15 +74,16 @@ int xenbus_map_ring(struct xenbus_device
 
 	gnttab_set_map_op(&op, (unsigned long)vaddr, GNTMAP_host_map,
 			  gnt_ref, dev->otherend_id);
-	if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
-		BUG();
+	gnttab_check_GNTST_eagain_do_while(GNTTABOP_map_grant_ref, &op);
 
 	if (op.status != GNTST_okay) {
 		xenbus_dev_fatal(dev, op.status,
 				 "mapping in shared page %d from domain %d",
 				 gnt_ref, dev->otherend_id);
-	} else
+	} else {
 		*handle = op.handle;
+		return 0;
+	}
 
 	return op.status;
 }

diff -r df9e25a0189b -r 1170bc32db41 include/xen/gnttab.h

include/xen/gnttab.h +37 -0

@@ -187,4 +187,41 @@ gnttab_set_replace_op(struct gnttab_unma
 	unmap->handle = handle;
 }
 
+#define gnttab_check_GNTST_eagain_while(__HCop, __HCarg_p)					\
+do {																		\
+	u8 __hc_delay = 1;														\
+	int __ret;																\
+	while (unlikely((__HCarg_p)->status == GNTST_eagain && __hc_delay))
 {	\
+		msleep(__hc_delay++);												\
+		__ret = HYPERVISOR_grant_table_op(__HCop, (__HCarg_p), 1);			\
+		BUG_ON(__ret);														\
+	}																		\
+	if (__hc_delay == 0) {													\
+		printk(KERN_ERR "%s: %s gnt busy\n", __func__, current->comm);		\
+		(__HCarg_p)->status = GNTST_bad_page;								\
+	}																		\
+	if ((__HCarg_p)->status != GNTST_okay)									\
+		printk(KERN_ERR "%s: %s gnt status %x\n", 							\
+			__func__, current->comm, (__HCarg_p)->status);					\
+} while(0)
+
+#define gnttab_check_GNTST_eagain_do_while(__HCop, __HCarg_p)			\
+do {																	\
+	u8 __hc_delay = 1;													\
+	int __ret;															\
+	do {																\
+		__ret = HYPERVISOR_grant_table_op(__HCop, (__HCarg_p), 1);		\
+		BUG_ON(__ret);													\
+		if ((__HCarg_p)->status == GNTST_eagain)						\
+			msleep(__hc_delay++);										\
+	} while ((__HCarg_p)->status == GNTST_eagain && __hc_delay);		\
+	if (__hc_delay == 0) {												\
+		printk(KERN_ERR "%s: %s gnt busy\n", __func__, current->comm);	\
+		(__HCarg_p)->status = GNTST_bad_page;							\
+	}																	\
+	if ((__HCarg_p)->status != GNTST_okay)								\
+		printk(KERN_ERR "%s: %s gnt status %x\n", 						\
+			__func__, current->comm, (__HCarg_p)->status);				\
+} while(0)
+

#endif /* __ASM_GNTTAB_H__ */

Quoted 5 lines

Quoted 4 lines

_______________________________________________
Xen-devel mailing list
[email protected]
http://lists.xensource.com/xen-devel

_______________________________________________
Xen-devel mailing list
[email protected]
http://lists.xensource.com/xen-devel

Quoted 28 lines · Andres Lagar-Cavilla

Quoted 28 lines · Andres Lagar-Cavilla

Quoted 27 lines

 drivers/xen/blkback/blkback.c              |   6 ++- drivers/xen/blkback/interface.c            |   9 +++- drivers/xen/core/gnttab.c                  |   4 +- drivers/xen/gntdev/gntdev.c                |  49
+++++++++++++++++------------
 drivers/xen/netback/interface.c            |   5 +- drivers/xen/netback/netback.c              |  16 ++++++--- drivers/xen/scsiback/interface.c           |  10 +++--- drivers/xen/scsiback/scsiback.c            |   4 +- drivers/xen/tpmback/interface.c            |   7 +-- drivers/xen/tpmback/tpmback.c              |  20 ++++------- drivers/xen/usbback/interface.c            |  16 ++++---- drivers/xen/usbback/usbback.c              |   4 +- drivers/xen/xenbus/xenbus_backend_client.c |  10 +++--- include/xen/gnttab.h                       |  37 ++++++++++++++++++++++

 14 files changed, 126 insertions(+), 71 deletions(-)

Handle GNTST_eagain status from GNTTABOP_map_grant_ref and GNTTABOP_copy operations properly to allow usage of xenpaging without causing crashes or data corruption.

Replace all relevant HYPERVISOR_grant_table_op() calls with a retry loop. This loop is implemented as a macro to allow different GNTTABOP_* args. It will sleep up to 33 seconds and wait for the page to be paged in again.

Quoted 7 lines

Quoted 5 lines

Quoted 3 lines

All ->status checks were updated to use the GNTST_* namespace. All return values are converted from GNTST_* namespace to 0/-EINVAL, since all callers did not use the actual return value.

Any plans to do this for the pvops tree?

Slowly but surely. Working with XCP presently, so pvops is not at the top of my stack. Do you want to get at a specific merge window?

Its more of a review concern. Meaning that if you send for the upstream kernel lots of folks are going to be looking at it. So the patches will change - which means that the version upstream can be very different from the one that you have for XCP - so in the end you will have to deal with two different code-bases to maintain.

That can get a bit difficult to manage.

Granted not all of those drivers are in the upstream kernel so might not make any difference.

Quoted 490 lines

Andres

Quoted 480 lines

Quoted 480 lines

Signed-off-by Olaf Hering <[email protected]>

Acked-by Patrick Colp <[email protected]>

This is a port from xenlinux 2.6.18 to the 2.6.32 xcp tree

Signed-off-by Andres Lagar-Cavilla <[email protected]>

diff -r df9e25a0189b -r 1170bc32db41 drivers/xen/blkback/blkback.c

drivers/xen/blkback/blkback.c +4 -2

@@ -701,11 +701,13 @@ static void dispatch_rw_block_io(blkif_t
    BUG_ON(ret);
 
    for (i = 0; i < nseg; i++) {
-          if (unlikely(map[i].status != 0)) {
+          if (unlikely(map[i].status == GNTST_eagain))
+                  gnttab_check_GNTST_eagain_do_while(GNTTABOP_map_grant_ref, &map[i]);
+          if (unlikely(map[i].status != GNTST_okay)) {
                    DPRINTK("grant map of dom %u gref %u failed: status %d\n",
                            blkif->domid, req->seg[i].gref, map[i].status);
                    map[i].handle = BLKBACK_INVALID_HANDLE;
-                  ret |= 1;
+                  ret = 1;
                    continue;
            }
 

diff -r df9e25a0189b -r 1170bc32db41 drivers/xen/blkback/interface.c

drivers/xen/blkback/interface.c +1 -1

@@ -95,7 +95,7 @@ static int map_frontend_pages(blkif_t *b
    struct vm_struct *area = blkif->blk_ring_area;
    struct gnttab_map_grant_ref op[BLKIF_MAX_RING_PAGES];
    unsigned int i;
-  int status = 0;
+  int status = GNTST_okay;
 
    for (i = 0; i < nr_shared_pages; i++) {

           unsigned long addr = (unsigned long)area->addr +

drivers/xen/blkback/interface.c +5 -2

@@ -110,7 +110,10 @@ static int map_frontend_pages(blkif_t *b
            BUG();
 
    for (i = 0; i < nr_shared_pages; i++) {
-          if ((status = op[i].status) != 0) {
+          if (op[i].status == GNTST_eagain)
+                  gnttab_check_GNTST_eagain_do_while(GNTTABOP_map_grant_ref, &op[i]);
+          if (op[i].status != GNTST_okay) {
+                  status = op[i].status;
                    blkif->shmem_handle[i] = INVALID_GRANT_HANDLE;
                    continue;
            }

@@ -120,7 +123,7 @@ static int map_frontend_pages(blkif_t *b
 
    blkif->nr_shared_pages = nr_shared_pages;
 
-  if (status != 0) {
+  if (status != GNTST_okay) {
            DPRINTK(" Grant table operation failure !\n");
            unmap_frontend_pages(blkif);
    }

diff -r df9e25a0189b -r 1170bc32db41 drivers/xen/core/gnttab.c

drivers/xen/core/gnttab.c +2 -2

@@ -773,7 +773,7 @@ static int gnttab_map(unsigned int start
            return -ENOSYS;
    }
 
-  BUG_ON(rc || setup.status);
+  BUG_ON(rc || (setup.status != GNTST_okay));
 
    if (shared.raw == NULL)
            shared.raw = arch_gnttab_alloc_shared(gframes);

@@ -901,7 +901,7 @@ int gnttab_copy_grant_page(grant_ref_t r
    err = HYPERVISOR_grant_table_op(GNTTABOP_unmap_and_replace,
                                    &unmap, 1);
    BUG_ON(err);
-  BUG_ON(unmap.status);
+  BUG_ON(unmap.status != GNTST_okay);
 
    write_sequnlock_irq(&gnttab_dma_lock);
 

diff -r df9e25a0189b -r 1170bc32db41 drivers/xen/gntdev/gntdev.c

drivers/xen/gntdev/gntdev.c +15 -10

@@ -503,7 +503,7 @@ static int gntdev_mmap (struct file *fli
    uint64_t ptep;
    int ret;
    int flags;
-  int i;
+  int i, exit_ret;
    struct page *page;
    gntdev_file_private_data_t *private_data = flip->private_data;
 

@@ -578,6 +578,7 @@ static int gntdev_mmap (struct file *fli
    vma->vm_mm->context.has_foreign_mappings = 1;
  #endif
 
+  exit_ret = -ENOMEM;
    for (i = 0; i < size; ++i) {
 
            flags = GNTMAP_host_map;

@@ -598,14 +599,18 @@ static int gntdev_mmap (struct file *fli
            ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref,
                                            &op, 1);
            BUG_ON(ret);
-          if (op.status) {
-                  printk(KERN_ERR "Error mapping the grant reference "
-                         "into the kernel (%d). domid = %d; ref = %d\n",
-                         op.status,
-                         private_data->grants[slot_index+i]
-                         .u.valid.domid,
-                         private_data->grants[slot_index+i]
-                         .u.valid.ref);
+          if (op.status != GNTST_okay) {
+                  if (op.status != GNTST_eagain)
+                          printk(KERN_ERR "Error mapping the grant reference "
+                                     "into the kernel (%d). domid = %d; ref = %d\n",
+                                     op.status,
+                                     private_data->grants[slot_index+i]
+                                     .u.valid.domid,
+                                     private_data->grants[slot_index+i]
+                                     .u.valid.ref);
+                  else
+                          /* Propagate instead of trying to fix it up */
+                          exit_ret = -EAGAIN;
                    goto undo_map_out;
            }
 

@@ -674,14 +679,17 @@ static int gntdev_mmap (struct file *fli
                    ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref,
                                                    &op, 1);
                    BUG_ON(ret);
-                  if (op.status) {
+                  if (op.status != GNTST_okay) {

                           printk(KERN_ERR "Error mapping the grant "
-                                 "reference into user space (%d). domid "
-                                 "= %d; ref = %d\n", op.status,
-                                 private_data->grants[slot_index+i].u
-                                 .valid.domid,
-                                 private_data->grants[slot_index+i].u
-                                 .valid.ref);
+                                     "reference into user space (%d). domid "
+                                     "= %d; ref = %d\n", op.status,
+                                     private_data->grants[slot_index+i].u
+                                     .valid.domid,
+                                     private_data->grants[slot_index+i].u
+                                     .valid.ref);
+                          /* GNTST_eagain (i.e. page paged out) sohuld never happen
+                           * once we've mapped into kernel space */
+                          BUG_ON(op.status == GNTST_eagain);
                           goto undo_map_out;
                   }

drivers/xen/gntdev/gntdev.c +2 -1

@@ -705,9 +713,10 @@ static int gntdev_mmap (struct file *fli
            }
 
    }
+  exit_ret = 0;
 
    up_write(&private_data->grants_sem);
-  return 0;
+  return exit_ret;
 

 undo_map_out:
   /* If we have a mapping failure, the unmapping will be taken care of

drivers/xen/gntdev/gntdev.c +1 -1

@@ -725,7 +734,7 @@ undo_map_out:
 
    up_write(&private_data->grants_sem);
 
-  return -ENOMEM;
+  return exit_ret;
  }
 

 static pte_t gntdev_clear_pte(struct vm_area_struct *vma, unsigned long addr,

drivers/xen/gntdev/gntdev.c +0 -0

@@ -777,7 +786,7 @@ static pte_t gntdev_clear_pte(struct vm_

                   ret = HYPERVISOR_grant_table_op( GNTTABOP_unmap_grant_ref, &op, 1); BUG_ON(ret);
-                  if (op.status)
+                  if (op.status != GNTST_okay) printk("User unmap grant status = %d\n", op.status);
           } else {

drivers/xen/gntdev/gntdev.c +1 -1

@@ -794,7 +803,7 @@ static pte_t gntdev_clear_pte(struct vm_
            ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref,
                                            &op, 1);
            BUG_ON(ret);
-          if (op.status)
+          if (op.status != GNTST_okay)
                    printk("Kernel unmap grant status = %d\n", op.status);
 
 

diff -r df9e25a0189b -r 1170bc32db41 drivers/xen/netback/interface.c

drivers/xen/netback/interface.c +2 -3

@@ -381,10 +381,9 @@ static int map_frontend_pages(struct xen
    gnttab_set_map_op(&op, (unsigned long)comms->ring_area->addr,
                      GNTMAP_host_map, ring_ref, domid);
 
-  if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
-          BUG();
+  gnttab_check_GNTST_eagain_do_while(GNTTABOP_map_grant_ref, &op);
 
-  if (op.status) {
+  if (op.status != GNTST_okay) {
            DPRINTK(" Gnttab failure mapping ring_ref!\n");
            free_vm_area(comms->ring_area);
            return op.status;

diff -r df9e25a0189b -r 1170bc32db41 drivers/xen/netback/netback.c

drivers/xen/netback/netback.c +11 -5

@@ -419,11 +419,13 @@ static int netbk_check_gop(int nr_copy_s
 
    for (i = 0; i < nr_copy_slots; i++) {
            copy_op = npo->copy + npo->copy_cons++;
+          if (copy_op->status == GNTST_eagain)
+                  gnttab_check_GNTST_eagain_while(GNTTABOP_copy, copy_op);
            if (copy_op->status != GNTST_okay) {
-                          DPRINTK("Bad status %d from copy to DOM%d.\n",
-                                  copy_op->status, domid);
-                          status = NETIF_RSP_ERROR;
-                  }
+                  DPRINTK("Bad status %d from copy to DOM%d.\n",
+                          copy_op->status, domid);
+                  status = NETIF_RSP_ERROR;
+          }
    }
 
    return status;

@@ -1020,7 +1022,11 @@ static int netbk_tx_check_mop(struct xen
 
    /* Check status of header. */
    err = mop->status;
-  if (unlikely(err)) {
+  if (err == GNTST_eagain) {
+          gnttab_check_GNTST_eagain_do_while(GNTTABOP_map_grant_ref, mop);
+          err = mop->status;
+  }
+  if (unlikely(err != GNTST_okay)) {
            pending_ring_idx_t index;
            index = pending_index(netbk->pending_prod++);
            txp = &pending_tx_info[pending_idx].req;

diff -r df9e25a0189b -r 1170bc32db41 drivers/xen/scsiback/interface.c

drivers/xen/scsiback/interface.c +5 -5

@@ -69,18 +69,18 @@ static int map_frontend_page( struct vsc
                            GNTMAP_host_map, ring_ref,
                            info->domid);
 
-  err = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1);
-  BUG_ON(err);
+  gnttab_check_GNTST_eagain_do_while(GNTTABOP_map_grant_ref, &op);
 
-  if (op.status) {
-          printk(KERN_ERR "scsiback: Grant table operation failure !\n");
+  if (op.status != GNTST_okay) {
+          printk(KERN_ERR "scsiback: Grant table operation failure %d!\n",
+                                                  (int) op.status);
            return op.status;
    }
 
    info->shmem_ref    = ring_ref;
    info->shmem_handle = op.handle;
 
-  return (GNTST_okay);
+  return 0;
  }
 
  static void unmap_frontend_page(struct vscsibk_info *info)

diff -r df9e25a0189b -r 1170bc32db41 drivers/xen/scsiback/scsiback.c

drivers/xen/scsiback/scsiback.c +3 -1

@@ -287,7 +287,9 @@ static int scsiback_gnttab_data_map(vscs
            for_each_sg (pending_req->sgl, sg, nr_segments, i) {
                    struct page *pg;
 
-                  if (unlikely(map[i].status != 0)) {
+                  if (unlikely(map[i].status == GNTST_eagain))
+                          gnttab_check_GNTST_eagain_while(GNTTABOP_map_grant_ref, &map[i]);
+                  if (unlikely(map[i].status != GNTST_okay)) {

                           printk(KERN_ERR "scsiback: invalid buffer -- could not remap it\n");
                           map[i].handle = SCSIBACK_INVALID_HANDLE;
                           err |= 1;
diff -r df9e25a0189b -r 1170bc32db41 drivers/xen/tpmback/interface.c

drivers/xen/tpmback/interface.c +3 -4

@@ -86,11 +86,10 @@ static int map_frontend_page(tpmif_t *tp
    gnttab_set_map_op(&op, (unsigned long)tpmif->tx_area->addr,
                      GNTMAP_host_map, shared_page, tpmif->domid);
 
-  if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
-          BUG();
+  gnttab_check_GNTST_eagain_do_while(GNTTABOP_map_grant_ref, &op);
 
-  if (op.status) {
-          DPRINTK(" Grant table operation failure !\n");
+  if (op.status != GNTST_okay) {
+          DPRINTK(" Grant table operation failure %d!\n", (int) op.status);
            return op.status;
    }
 

diff -r df9e25a0189b -r 1170bc32db41 drivers/xen/tpmback/tpmback.c

drivers/xen/tpmback/tpmback.c +8 -12

@@ -256,15 +256,13 @@ int _packet_write(struct packet *pak,
            gnttab_set_map_op(&map_op, idx_to_kaddr(tpmif, i),
                              GNTMAP_host_map, tx->ref, tpmif->domid);
 
-          if (unlikely(HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref,
-                                                 &map_op, 1))) {
-                  BUG();
-          }
+          gnttab_check_GNTST_eagain_do_while(GNTTABOP_map_grant_ref, &map_op);
 
            handle = map_op.handle;
 
-          if (map_op.status) {
-                  DPRINTK(" Grant table operation failure !\n");
+          if (map_op.status != GNTST_okay) {
+                  DPRINTK(" Grant table operation failure %d!\n",
+                                          (int) map_op.status);
                    return 0;
            }
 

@@ -394,13 +392,11 @@ static int packet_read_shmem(struct pack
            gnttab_set_map_op(&map_op, idx_to_kaddr(tpmif, i),
                              GNTMAP_host_map, tx->ref, tpmif->domid);
 
-          if (unlikely(HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref,
-                                                 &map_op, 1))) {
-                  BUG();
-          }
+          gnttab_check_GNTST_eagain_do_while(GNTTABOP_map_grant_ref, &map_op);
 
-          if (map_op.status) {
-                  DPRINTK(" Grant table operation failure !\n");
+          if (map_op.status != GNTST_okay) {
+                  DPRINTK(" Grant table operation failure %d!\n",
+                                          (int) map_op.status);
                    return -EFAULT;
            }
 

diff -r df9e25a0189b -r 1170bc32db41 drivers/xen/usbback/interface.c

drivers/xen/usbback/interface.c +8 -8

@@ -109,11 +109,11 @@ static int map_frontend_pages(usbif_t *u
    gnttab_set_map_op(&op, (unsigned long)usbif->urb_ring_area->addr,
                      GNTMAP_host_map, urb_ring_ref, usbif->domid);
 
-  if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
-          BUG();
+  gnttab_check_GNTST_eagain_do_while(GNTTABOP_map_grant_ref, &op);
 
-  if (op.status) {
-          printk(KERN_ERR "grant table failure mapping urb_ring_ref\n");
+  if (op.status != GNTST_okay) {
+          printk(KERN_ERR "grant table failure mapping urb_ring_ref %d\n",
+                                                  (int) op.status);
            return op.status;
    }
 

@@ -123,17 +123,17 @@ static int map_frontend_pages(usbif_t *u
    gnttab_set_map_op(&op, (unsigned long)usbif->conn_ring_area->addr,
                      GNTMAP_host_map, conn_ring_ref, usbif->domid);
 
-  if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
-          BUG();
+  gnttab_check_GNTST_eagain_do_while(GNTTABOP_map_grant_ref, &op);
 
-  if (op.status) {
+  if (op.status != GNTST_okay) {
            struct gnttab_unmap_grant_ref unop;
            gnttab_set_unmap_op(&unop,
                            (unsigned long) usbif->urb_ring_area->addr,
                            GNTMAP_host_map, usbif->urb_shmem_handle);
            VOID(HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &unop,
                            1));
-          printk(KERN_ERR "grant table failure mapping conn_ring_ref\n");
+          printk(KERN_ERR "grant table failure mapping conn_ring_ref %d\n",
+                                                  (int) op.status);
            return op.status;
    }
 

diff -r df9e25a0189b -r 1170bc32db41 drivers/xen/usbback/usbback.c

drivers/xen/usbback/usbback.c +3 -1

@@ -428,7 +428,9 @@ static int usbbk_gnttab_map(usbif_t *usb
            BUG_ON(ret);
 
            for (i = 0; i < nr_segs; i++) {
-                  if (unlikely(map[i].status != 0)) {
+                  if (unlikely(map[i].status == GNTST_eagain))
+                          gnttab_check_GNTST_eagain_while(GNTTABOP_map_grant_ref, &map[i]);
+                  if (unlikely(map[i].status != GNTST_okay)) {
                            printk(KERN_ERR "usbback: invalid buffer -- could not remap it\n");
                            map[i].handle = USBBACK_INVALID_HANDLE;
                            ret |= 1;

diff -r df9e25a0189b -r 1170bc32db41
drivers/xen/xenbus/xenbus_backend_client.c

drivers/xen/xenbus/xenbus_backend_client.c +5 -5

@@ -48,8 +48,7 @@ struct vm_struct *xenbus_map_ring_valloc
    gnttab_set_map_op(&op, (unsigned long)area->addr, GNTMAP_host_map,
                      gnt_ref, dev->otherend_id);
 
-  if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
-          BUG();
+  gnttab_check_GNTST_eagain_do_while(GNTTABOP_map_grant_ref, &op);
 
    if (op.status != GNTST_okay) {
            free_vm_area(area);

@@ -75,15 +74,16 @@ int xenbus_map_ring(struct xenbus_device
 
    gnttab_set_map_op(&op, (unsigned long)vaddr, GNTMAP_host_map,
                      gnt_ref, dev->otherend_id);
-  if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
-          BUG();
+  gnttab_check_GNTST_eagain_do_while(GNTTABOP_map_grant_ref, &op);
 
    if (op.status != GNTST_okay) {
            xenbus_dev_fatal(dev, op.status,
                             "mapping in shared page %d from domain %d",
                             gnt_ref, dev->otherend_id);
-  } else
+  } else {
            *handle = op.handle;
+          return 0;
+  }
 
    return op.status;
  }

diff -r df9e25a0189b -r 1170bc32db41 include/xen/gnttab.h

include/xen/gnttab.h +37 -0

@@ -187,4 +187,41 @@ gnttab_set_replace_op(struct gnttab_unma
    unmap->handle = handle;
  }
 
+#define gnttab_check_GNTST_eagain_while(__HCop, __HCarg_p)                                        \
+do {                                                                                                                                              \
+  u8 __hc_delay = 1;                                                                                                              \
+  int __ret;                                                                                                                              \
+  while (unlikely((__HCarg_p)->status == GNTST_eagain && __hc_delay))
 {  \
+          msleep(__hc_delay++);                                                                                           \
+          __ret = HYPERVISOR_grant_table_op(__HCop, (__HCarg_p), 1);                      \
+          BUG_ON(__ret);                                                                                                          \
+  }                                                                                                                                               \
+  if (__hc_delay == 0) {                                                                                                  \
+          printk(KERN_ERR "%s: %s gnt busy\n", __func__, current->comm);          \
+          (__HCarg_p)->status = GNTST_bad_page;                                                           \
+  }                                                                                                                                               \
+  if ((__HCarg_p)->status != GNTST_okay)                                                                  \
+          printk(KERN_ERR "%s: %s gnt status %x\n",                                                       \
+                  __func__, current->comm, (__HCarg_p)->status);                                  \
+} while(0)
+
+#define gnttab_check_GNTST_eagain_do_while(__HCop, __HCarg_p)                     \
+do {                                                                                                                                      \
+  u8 __hc_delay = 1;                                                                                                      \
+  int __ret;                                                                                                                      \
+  do {                                                                                                                            \
+          __ret = HYPERVISOR_grant_table_op(__HCop, (__HCarg_p), 1);              \
+          BUG_ON(__ret);                                                                                                  \
+          if ((__HCarg_p)->status == GNTST_eagain)                                                \
+                  msleep(__hc_delay++);                                                                           \
+  } while ((__HCarg_p)->status == GNTST_eagain && __hc_delay);            \
+  if (__hc_delay == 0) {                                                                                          \
+          printk(KERN_ERR "%s: %s gnt busy\n", __func__, current->comm);  \
+          (__HCarg_p)->status = GNTST_bad_page;                                                   \
+  }                                                                                                                                       \
+  if ((__HCarg_p)->status != GNTST_okay)                                                          \
+          printk(KERN_ERR "%s: %s gnt status %x\n",                                               \
+                  __func__, current->comm, (__HCarg_p)->status);                          \
+} while(0)
+

 #endif /* __ASM_GNTTAB_H__ */

Quoted 5 lines

Quoted 4 lines

_______________________________________________
Xen-devel mailing list
[email protected]
http://lists.xensource.com/xen-devel

Quoted 4 lines

_______________________________________________
Xen-devel mailing list
[email protected]
http://lists.xensource.com/xen-devel

_______________________________________________
Xen-devel mailing list
[email protected]
http://lists.xensource.com/xen-devel

Quoted 1 line

Quoted 1 line · Andres Lagar-Cavilla

This is a cherry pick of two patches that add support for guest paged out frames in the XCP 2.6.32 dom0 patch queue.

First patch propagates the ENOENT returned by the hypervisor in the case of a paged out page, all the way up the call chain to the MMAPBATCH_V2 ioctl. The ioctl is mainly used to harvest those return values and retry.

The second patch adds retry loops to all backend grant operations (map and netback copy), in the case of a paged out frame.

Signed-off-by Olaf Hering <[email protected]>

Signed-off-by Jan Beulich <[email protected]>

Acked-by Patrick Colp <[email protected]>

Acked-by Andres Lagar-Cavilla <andres@lagarcavilla>

Ported and submitted by Andres Lagar-Cavilla

 arch/x86/mm/ioremap-xen.c                  |  12 ++----
 drivers/xen/blkback/blkback.c              |   6 ++-
 drivers/xen/blkback/interface.c            |   9 +++-
 drivers/xen/core/gnttab.c                  |   4 +-
 drivers/xen/gntdev/gntdev.c                |  49 +++++++++++++++++------------
 drivers/xen/netback/interface.c            |   5 +-
 drivers/xen/netback/netback.c              |  16 ++++++---
 drivers/xen/scsiback/interface.c           |  10 +++---
 drivers/xen/scsiback/scsiback.c            |   4 +-
 drivers/xen/tpmback/interface.c            |   7 +--
 drivers/xen/tpmback/tpmback.c              |  20 ++++-------
 drivers/xen/usbback/interface.c            |  16 ++++----
 drivers/xen/usbback/usbback.c              |   4 +-
 drivers/xen/xenbus/xenbus_backend_client.c |  10 +++---
 include/xen/gnttab.h                       |  37 ++++++++++++++++++++++
 15 files changed, 130 insertions(+), 79 deletions(-)